Reviews

Molecular Mechanisms of Autophagy in the Cardiovascular System

Damián Gatica, Mario Chiong, Sergio Lavandero, Daniel J. Klionsky
https://doi.org/10.1161/CIRCRESAHA.114.303788
Circulation Research. 2015;116:456-467
Originally published January 29, 2015

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Abstract

Autophagy is a catabolic recycling pathway triggered by various intra- or extracellular stimuli that is conserved from yeast to mammals. During autophagy, diverse cytosolic constituents are enveloped by double-membrane vesicles, autophagosomes, which later fuse with lysosomes or the vacuole to degrade their cargo. Dysregulation in autophagy is associated with a diverse range of pathologies including cardiovascular disease, the leading cause of death in the world. Accordingly, there is tremendous interest in modulating autophagy for therapeutic purposes. One complexity with regard to cardiovascular homeostasis, however, is that the timing of autophagic activity appears to be critical; for example, cardiomyocyte autophagy during ischemia/reperfusion can be either beneficial or harmful. Here, we review the molecular mechanisms that govern autophagosome formation and analyze the link between autophagy and cardiovascular disease.

Autophagy is a key catabolic process for cell survival against different types of stress. During macroautophagy the cell carries out the sequestration of different substrates such as invading pathogens, proteins, lipids, or even damaged or superfluous organelles inside double-membrane vesicles termed autophagosomes. To degrade their cargo, autophagosomes fuse with the lysosome/vacuole, which contains various hydrolases able to break down the sequestered substrates. After this event, the basic components obtained from cargo degradation are released into the cytoplasm for recycling.1 Autophagy is triggered by different stimuli such as hypoxia,2 oxidative stress,3 pathogen infection,4 endoplasmic reticulum (ER) stress,5 and most notably nutrient starvation.

Autophagy can be divided into 3 main types: macroautophagy, microautophagy, and chaperone-mediated autophagy. Whereas microautophagy and macroautophagy can be selective or nonselective processes found in yeast and higher eukaryotes, chaperone-mediated autophagy is a selective process that has only been described in mammalian cells. During chaperone-mediated autophagy, specific protein substrates containing the amino acid sequence KFERQ are recognized by chaperones, unfolded and translocated into the lysosome through the lysosomal membrane protein LAMP2A (Figure 1A). In microautophagy uptake also occurs directly at the limiting membrane of the lysosome/vacuole. In this case, however, the process operates by directly sequestering the substrates through invagination of the vacuole/lysosome membrane.6 Of the 3 types mentioned, macroautophagy is clearly the most well-studied process (Figure 1B). Multiple autophagy-related (ATG) genes and proteins have been described as being involved in the different stages of auto phagy, comprising what is now known as the core autophagy machinery that is required for autophagosome formation, and additional proteins that act in making the process selective, or in stages other than autophagosome biogenesis. Accordingly, macroautophagy (hereafter referred to as autophagy) can be dissected into different steps based on the proteins involved, including induction, nucleation of the autophagosome precursor (termed the phagophore), membrane expansion and maturation of the autophagosome, fusion with the lysosome/vacuole, and recycling of the degraded cargo.

Figure 1.
Figure 1.

The 3 main types of autophagy. A, Yeast cells carry out both macroautophagy and microautophagy. Although macroautophagy consists of the bulk degradation of cytoplasmic material that is sequestered inside double-membrane autophagosomes that then fuse with the vacuole, microautophagy works by directly taking up the substrates through invagination of the vacuole. B, In mammals along with microautophagy and macroautophagy, chaperone-mediated autophagy enables the degradation of specific protein substrates that contain a KFERQ motif that is recognized by chaperones that mediate the translocation of the unfolded protein into the lysosome through LAMP2A.

Autophagy Induction in Yeast

During growth in nutrient-rich conditions autophagy activity is kept to a minimum by different nutrient sensing pathways including those regulated by the target of rapamycin (TOR) kinase and cAMP-dependent protein kinase A. The ability of TOR to sense nutrient levels, in particular amino acids, makes it a critical negative regulator of autophagy. The rapamycin-sensitive TOR complex 1 (TORC1) inhibits autophagy in part by preventing the activation of the Atg1 kinase complex.7 In yeast, the Atg1 kinase complex is formed by the Ser/Thr kinase Atg1, the regulatory subunit protein Atg13, and the Atg17–Atg31–Atg29 complex, which is thought to function as a scaffold.7,8 Although specific substrates of Atg1 may remain to be discovered, the Atg1 kinase complex plays an essential role in autophagy induction by recruiting other Atg proteins to what is known as the phagophore assembly site (PAS), a perivacuolar location found in yeast that is proposed to be the organizing center for phagophore formation.9–12 Upon nutrient starvation or rapamycin treatment TORC1 activity is inhibited and Atg13 is rapidly but partially dephosphorylated leading to the activation of Atg1.13 Autophosphorylation of Atg1 within its activation loop is also important for activating its kinase activity and inducing autophagy (Figure 2A).14 Atg13 dephosphorylation was linked to an increased interaction with Atg1 leading to a model in which starvation increased affinity between the 2 proteins; however, recent data as well as interaction studies in other model organisms support the idea that Atg1 and Atg13 interact independently of nutrient conditions.15 In addition to Atg13, TORC1 may also inhibit autophagy by directly phosphorylating Atg1.16

Figure 2.
Figure 2.

Autophagy induction. A, In yeast in nutrient-rich conditions target of rapamycin complex 1 (TORC1) and protein kinase A (PKA) inhibit autophagy by phosphorylating autophagy related (Atg) 1 and Atg13. During starvation the Atg1 kinase complex is no longer repressed, Atg13 is partially dephosphorylated, and Atg1 is activated. Atg1 then phosphorylates itself and other targets to induce autophagy. B, In mammals in nutrient-rich conditions mechanistic TORC1 (MTORC1) directly binds unc-51 like autophagy activating kinase (ULK) 1 through regulatory associated protein of MTOR, complex 1 (RPTOR) and inhibits ULK1/2 and ATG13 by phosphorylation. Upon starvation MTORC1 dissociates from the ULK1 kinase complex, allowing ATG13 dephosphorylation and activating ULK1/2 that then phosphorylates members of the complex and other targets to induce autophagy.

Protein kinase A is also a negative regulator of autophagy. Protein kinase A suppresses autophagy by phosphorylating both Atg1 and Atg13.17–19 Although the 2 pathways target similar proteins, TOR and protein kinase A seem to work largely independent of one another by targeting different phosphorylation sites.19 Other nutrient-sensing kinases involved in autophagy induction are Snf1 and Gcn2. Although the former corresponds to the yeast homolog of 5′-AMP–activated protein kinase (AMPK), which will be discussed below, Gcn2 promotes autophagy during amino acid starvation by phosphorylating Sui2/eIF2α (suppressor of initiator codon 2). Phosphorylation of Sui2 blocks general protein synthesis and specifically activates the translation of the transcription factor Gcn4, which in turn induces the transcription of various ATG genes.20,21

Autophagy Induction in Mammals

In contrast to yeast, mammalian cells have multiple Atg1 homologs, and the ones most relevant to autophagy are unc-51 like autophagy activating kinase 1 (ULK1) and ULK2.22,23 Thus, in mammals the Atg1 kinase complex is known as the ULK kinase complex and is formed by ULK1/2, the mammalian homolog of Atg13 (ATG13), the functional homolog of Atg17 (RB1CC1), and the ATG13-stabilizing protein ATG101, which has no yeast counterpart. All members of the ULK kinase complex are required for autophagy induction in mammalian cells.24–26 As mentioned above, in mammalian cells the interaction between the members of the ULK kinase complex does not depend on nutrient conditions.27 Although some studies indicate that ATG13 mediates the interaction between RB1CC1 and ULK,25 others have reported that all members of the complex can interact independently.27 Similar to the yeast Atg1 complex, regulation of the ULK kinase complex depends on the mechanistic target of rapamycin complex 1 (MTORC1). During nutrient-rich conditions, MTORC1 interacts directly with ULK1 through the scaffold protein regulatory associated protein of MTOR, complex 1 (RPTOR) and inhibits its kinase activity by phosphorylating both ATG13 and ULK1/2.25,28 Upon nutrient starvation or rapamycin treatment, MTORC1 is released from the ULK kinase complex leading to the dephosphorylation of both proteins and the activation of ULK kinase activity.25,27,28 Once activated, ULK1 phosphorylates ATG13, RB1CC1, and itself, stabilizing its enzymatic activity and inducing the autophagic process (Figure 2B).25,28,29

Another protein capable of sensing energy levels that is involved in autophagy regulation is AMPK. Through the upstream kinase serine/threonine kinase 11 (STK11/LKB1), AMPK is able to sense decreases in the cellular ATP/AMP ratio leading to its activation and autophagy induction.30 During glucose deprivation AMPK phosphorylates and activates the tuberous sclerosis complex, tuberous sclerosis (TSC) 1-TSC2, which in turn inactivates the GTPase-activating protein Ras homolog enriched in brain (RHEB), leading to MTORC1 inhibition and the release of the ULK kinase complex (Figure 3).31,32 Once MTORC1 leaves the ULK complex, AMPK directly phosphorylates ULK1, stimulating its catalytic activity and inducing autophagy.30 Interestingly, the ULK kinase complex also phosphorylates and inactivates AMPK, through a mechanism that has been described as an inhibitory feedback loop.33

Figure 3.
Figure 3.

Autophagy regulation. Through serine/threonine kinase 11 (STK11/LKB1), AMP-activated protein kinase (AMPK) senses decreases in the ATP/AMP ratio and phosphorylates tuberous sclerosis (TSC) 1-TSC2, which then targets Ras homolog enriched in brain (RHEB), leading to mechanistic target of rapamycin complex 1 (MTORC1) inhibition and autophagy activation. insulin receptor/insulin-like growth factor 1 receptor (INSR/IGF1R) triggers the activation of the class I phosphoinositide 3-kinase (PI3K), inducing the formation of phosphatidylinositol(3,4,5)trisphosphate (PIP3) and AKT/PKB activation; AKT can inhibit TSC1-TSC2, blocking autophagy. Phosphatase and tensin homolog (PTEN) works as a PIP3 phosphatase generating phosphatidylinositol(4,5)bisphosphate (PIP2) and inducing autophagy.

Although functioning in part in a hormone-sensing pathway, AKT/PKB can also regulate autophagy by controlling MTORC1 activation. On ligand binding, dimerization, autophosphorylation, and activation of insulin receptor or insulin-like growth factor 1 receptor, the class I phosphoinositide 3-kinase is recruited to the plasma membrane and activated.34 Phosphoinositide 3-kinase catalyzes the phosphorylation of phosphatidylinositol(4,5)bisphosphate generating the lipid second messenger phosphatidylinositol(3,4,5)trisphosphate (PIP3), which in turn recruits AKT to the plasma membrane where it is activated via phosphorylation by PDPK1 and MTORC2.34,35 AKT-dependent phosphorylation of TSC2 prevents RHEB inhibition, leading to MTORC1 activation and autophagy inhibition.36,37 As a consequence, the tumor suppressor and lipid phosphatase and tensin homolog (PTEN) can induce autophagy by dephosphorylating PIP3 and downregulating the AKT-phosphoinositide 3-kinase pathway (Figure 3).38

Membrane Nucleation and Source

Once autophagy is induced, assembly of the phagophore is initiated by membrane nucleation. As mentioned above, in yeast the PAS corresponds to the location at which several Atg proteins are recruited to assemble the phagophore. In contrast, mammalian cells lack a single defined PAS, and autophagosome formation seems to be initiated at different locations inside the cell. In both yeast and mammals the class III phosphatidylinositol 3-kinase (PtdIns3K) catalyzes the nucleation of the phagophore by generating phosphatydilin ositol 3-phosphate (PtdIns3P) and inducing the recruitment of PtdIns3P-binding proteins.37 In yeast the PtdIns3K is formed by the regulatory subunit vacuolar protein sorting 15 (Vps15), the catalytic subunit Vps34, Vps30/Atg6, Atg14 and Atg38, all of which are essential for autophagy.39–41 Similarly, the core mammalian PtdIns3K is composed of the Vps15 homolog phosphoinositide-3-kinase, regulatory subunit 4 (PIK3R4), the Vps34 homolog phosphatidylinositol 3-kinase, catalytic subunit type 3 (PIK3C3), and the Vps30/Atg6 homolog beclin 1, autophagy related (BECN1).37,42 Although these 3 proteins constitute the core machinery of the mammalian PtdIns3K, distinct interactions with specific proteins lead to the formation of ≥3 different PtdIns3K complexes that play different roles in autophagy.43–45 One of these complexes is formed by the interaction of the PtdIns3K core complex with the mammalian Atg14 homolog (ATG14) and autophagy/beclin-1 regulator 1 (AMBRA1).46,47 The ATG14-containing PtdIns3K complex is thought to positively regulate autophagy by promoting translocation of the complex to the phagophore and inducing the generation of PtdIns3P.44,47,48 The other 2 PtdIns3K complexes contain the BECN1-interacting protein UV radiation resistance associated (UVRAG) as a common component. Whereas the PtdIns3K complex formed by UVRAG and SH3-domain GRB2-like endophilin B1 (SH3GLB1/Bif-1) promotes autophagosome formation,48,49 the complex formed by UVRAG and KIAA0226/RUBICON downregulates autophagy by impairing autophagosome maturation (Figure 4).44,45 Other BECN1-interacting proteins include the antiapoptotic protein B-cell CLL/lymphoma 2 (BCL2), which inhibits the PtdIns3K complex by sequestering BECN1 under nutrient-rich conditions.50 Besides alterations in protein interactions, BECN1 post-translational modifications also regulate PtdIns3K activity. For example, BECN1 phosphorylation by DAPK promotes dissociation of BCL2 and autophagy induction.51 ULK1-dependent phosphorylation of BECN1 activates the ATG14- and UVRAG-containing PtdIns3K complexes inducing autophagy during amino acid starvation.52 Activation of both these PtdIns3K complexes by ULK1-mediated BECN1 phosphorylation would argue for the importance of this post-translational modification for autophagosome induction and later maturation and provides a link between the ULK kinase initiation complex and the membrane nucleation complex. Most recently, AMPK was described as regulating the activity of different PtdIns3K complexes by phosphorylating BECN1 and PIK3C3.53

Figure 4.
Figure 4.

Class III phosphatidylinositol 3-kinase (PtdIns3K) complexes. Three class III PtdIns3K complexes can be observed in mammals. All of them require phosphatidylinositol 3-kinase, catalytic subunit type 3 (PIK3C3/VPS34), phosphoinositide-3-kinase, regulatory subunit 4 (PIK3R4/VPS15) and beclin 1, autophagy related (BECN1). Specific subunits regulate the function of the different complexes. Binding of ATG14 and autophagy/beclin-1 regulator 1 (AMBRA1) leads to autophagy induction. UV radiation resistance associated (UVRAG) and SH3-domain GRB2-like endophilin B1 (SH3GLB1) binding also activates autophagy, whereas binding to KIAA0226/RUBICON inhibits autophagosome maturation.

Although membrane nucleation has been established as a key step in the autophagic process, the origin of the membrane that gives rise to the phagophore, and subsequently the autophagosome, remains an open question. Different studies have described the ER, mitochondria, plasma membrane, and trans-Golgi network as possible membrane donors (Figure 5).54–56 Evidence supporting the ER as a possible membrane source include 3-dimensional tomography studies showing a connection between the phagophore and ER, as well as ATG14-containing PtdIns3K complex localization to the ER to initiate autophagosome formation.48,57 Generation of PtdIns3P at the ER triggers the recruitment of the PtdIns3P-binding protein ZFYVE1/DFCP1 (zinc finger, FYVE domain containing 1) and one of the mammalian homologs of Atg18, WD repeat domain, phosphoinositide interacting 2 (WIPI2). Both of these proteins have been linked to autophagosome formation from a PtdIns3P-enriched ER-associated structure termed the omegasome for its Ω-like shape.58,59 Omegasomes have been described as platforms for autophagome formation, which seem to depend on PtdIns3P, because ATG14 depletion leads to omegasome disappearance.48 Although the role of ZFYVE1 in autophagy is not well defined, WIPI2 silencing results in accumulation of omegasome structures and failure to mature into autophagosomes, suggesting that WIPI2 is involved in the transition between omegasomes and autophagosomes.59 Other ATG proteins that have been associated with omegasomes include the ULK kinase complex, which localizes transiently to omegasomes in a PtdIns3P-dependent manner.58,60 The precise mechanism by which the ER gives rise to autophagosomes via an omegasome intermediate is unknown, and several questions remain to be answered about the conditions, specific proteins involved, and the selectivity of the process (Figure 5).61

Figure 5.
Figure 5.

Autophagosomes have a diverse range of potential membrane sources. The trans-Golgi network, mitochondria, mitochondrial-associated membrane, and endoplasmic reticulum (ER) have been postulated as membrane donors. Omegasomes have been described as the ER structures that work as a platform for autophagosome formation. The phagophore (shown in red) elongates and engulfs part of a cisternae before it buds off the ER and becomes an autophagosome. MAM indicates mitochondria-associated ER membrane.

As mentioned above, mitochondria are another organelle that have been proposed as a membrane source for the phagophore. During starvation conditions an outer mitochondria membrane fluorescent marker colocalizes with autophagosomes; mitochondrial lipids also seem to transit to autophagosomes.54 The same study showed that autophagosome formation during nutrient starvation is impaired in cells lacking the ER-mitochondria tethering protein mitofusin 2. Mitochondria-associated ER membrane, which are sites where the mitochondria and ER are in close proximity to each other, have been implicated in autophagosome formation. ATG14 and other autophagy markers localize to the mitochondria-associated ER membrane during starvation conditions. In mitofusin 2–depleted cells, which are unable to tether the ER to the mitochondria, ATG14 localization to the mitochondria-associated ER membrane is impaired. In addition, the omegasome protein marker ZFYVE1 localizes to the mitochondria-associated ER membrane upon starvation.62 This remarkable finding opens the possibility that the functions of omegasomes and mitochondria in autophagosome formation are essentially one and the same, unified by the association between the 2.

Other studies on the transmembrane protein Atg9 have advanced our understanding of the membrane source from which phagophores are assembled. Atg9 has been characterized as a self-interacting protein containing 6 putative transmembrane domains, with both its carboxyl and amino termini facing the cytosol.63,64 In yeast, Atg9 cycles from the PAS to peripheral membranes; Atg9-containing vesicles are thought to be part of the initial membranes that will generate the pha gophore.65,66 The Atg9-containing membrane reservoir seems to be composed of tubules and vesicle clusters formed through the ER-Golgi trafficking pathway65; however, Atg9 also cycles between perimitochondrial sites and the PAS.67 Although the precise mechanisms by which Atg9 cycling is controlled remains unknown, several Atg proteins are involved in the regulation of Atg9 movement. Atg9 anterograde transport, which is defined as movement from the peripheral sites to the PAS, depends on Atg11, Atg23, and Atg27,11,68,69 whereas retrograde transport, that is from the PAS to the peripheral sites, is directed by the Atg1–Atg13 complex, Atg2, Atg18, and the PtdIns3K complex.11 In mammalian cells, nutrient starvation induces ATG9 redistribution from the trans-Golgi network to phagophores. Both ULK1 silencing and PtdIns3K inhibition block ATG9 trafficking to phagophores, suggesting both complexes are involved in mammalian ATG9 cycling.56,70 The MAPK pathway is also implicated in mammalian ATG9 traffic, SUPT20H/FAM48A/p38IP (suppressor of Ty 20 homolog [Saccharomyces cerevisiae]) interacts with ATG9 and induces its redistribution leading to autophagy activation. Conversely, binding between SUPT20H and MAPK14/p38α inhibits ATG9 interaction with SUPT20H and autophagy.71

Phagophore Expansion

Elongation and expansion of the phagophore membrane are key steps in the autophagic process. The Atg12–Atg5-Atg16 and Atg8 conjugation systems, 2 inter-related ubiquitin-like conjugation pathways, regulate this stage in both yeast and mammals. Before being covalently linked to their final substrates, both Atg12 and Atg8 go through an activation and conjugation reaction, triggered by an E1-like and an E2-like enzyme, respectively. In the Atg12–Atg5-Atg16 system, Atg12 is first activated in an ATP-dependent manner by the E1-like activating enzyme Atg7, forming a thioester bond between the 2 proteins.72,73 After this event, Atg12 is transferred to the E2-like conjugating enzyme Atg10, generating the Atg12–Atg10 intermediate through the formation of another thioester bond.74 Finally, Atg12 is covalently attached to a specific lysine residue on Atg5 in a process that, unlike ubiquitination, seems to be constitutive, irreversible and does not require an E3-like ligase enzyme.75,76 Further interaction between Atg12–Atg5 and Atg16 leads to the formation of the Atg12–Atg5-Atg16 complex. Unlike Atg12, Atg16 is not covalently bound to Atg5 and is able to self-interact when bound to Atg12–Atg5 forming a large multimeric protein complex.77–79 The Atg12–Atg5-Atg16 complex is essential for autophagy and localizes to the phagophore.78,80,81 In yeast the second ubiquitin-like conjugation system catalyzes the lipidation of Atg8 by covalently linking it to phosphatidylethanolamine. The first event in this process corresponds to the cleavage of the carboxyl terminus of Atg8 by the cysteine protease Atg4, exposing a glycine residue.82,83 In the next step, Atg7, again working as an E1-like enzyme, activates Atg8.84 The activated protein is then conjugated to the E2-like enzyme Atg3, before finally being linked to phosphatidylethanolamine through an amide bond.84 Different studies have proposed that the E3-like enzyme that facilitates the Atg8–phosphatidylethanolamine linkage is the Atg12–Atg5-Atg16 complex.85–88 In its conjugated form Atg8 is bound to both sides of the autophagosome membrane and thus its N terminus GFP-tagged form is widely used as an autophagosome marker.89,90 However, Atg8 lipidation is a reversible process because Atg8–phosphatidylethanolamine bound to the external autophagosome membrane can be cleaved by Atg4, releasing it from the autophagosome (Figure 6).82

Figure 6.
Figure 6.

Two ubiquitin-like conjugation systems. Autophagy related (Atg) 8 and Atg12 go through subsequent activation, mediated by Atg7 and conjugation mediated by Atg3 and Atg10, respectively, before covalently binding to phosphatidylethanolamine (PE) in the case of Atg8, and Atg5 in the case of Atg12. Atg8–PE binds both the inner and outer membrane of the autophagosome, but can be deconjugated by Atg4, the same protein that removes the C-terminal arginine initially present at the Atg8 C terminus. Atg12–Atg5 bind Atg16 creating a large multimeric complex that locates to the phagophore and enhances Atg8 lipidation and membrane expansion. GR indicates glycine-arginine.

Both ubiquitin-like conjugation pathways are conserved and work similarly between mammals and yeast with the specific difference being that mammalian cells have several Atg8 homologs further divided into the microtubule-associated protein 1 light chain 3 (MAP1LC3/LC3) and GABA(A) receptor-associated protein (GABARAP) subfamilies. Although all of the homologs go through a similar conjugation process, each subfamily works at different stages of autophagy91–93; the LC3 subfamily is involved in expansion of the phagophore and the GABARAP subfamily participates at a later stage in autophagosome maturation.94

Lysosome/Vacuole Fusion and Recycling of the Degraded Cargo

The fusion of autophagosomes with lysosomes/vacuoles results in the generation of autolysosomes in higher eukaryotes and autophagic bodies in yeast. In either case, the fusion process seems to involve similar machinery that plays a role in other transport processes that terminate at these degradative organelles.95 In yeast, this machinery includes the class C Vps/HOPS complex, the SNARE family proteins Ykt6, Vti1, Vam3, and Vam7, the small GTPase Ypt7, and the proteins Mon1 and Ccz1.95–101 Fewer details are known in mammalian cells; however, the Ypt7 homolog RAB7 is required.102 One difference between yeast and mammals is that there is a clear convergence between autophagy and the endocytic pathway in the latter; autophagosomes can fuse with endosomes to form amphisomes that subsequently fuse with the lysosome.103 Once fusion occurs, the inner autophagosomal membrane and its cargo are degraded inside the lysosome/vacuole by various hydrolases. The resulting macromolecules such as amino acids that are obtained after cargo degradation are transported back into the cytoplasm for recycling. In yeast this process is regulated by protein permeases such as Atg22.104

Autophagy in the Cardiovascular System

According to the World Health Organization, cardiovascular disease is the leading cause of mortality in the globalized world, accounting for 30% of all deaths.105 As expected, considerable resources have gone toward understanding the nature of cardiovascular disease and to search for possible therapeutic targets. Autophagy has been described widely in the cardiovascular system,106–111 and our understanding of the molecular machinery as described above provides the possibility for specific therapeutic intervention in treating cardiovascular disease. Autophagic activity is linked to cardiovascular development, preserving heart and vascular homeostasis, as well as in the onset and progression of several cardiovascular diseases. Interestingly, whether autophagy plays a survival role or has a deleterious effect during heart disease it is still a matter of discussion.

Autophagy and Cardiovascular Development

Autophagy plays a role in the regulation of mammalian cardiac development starting at an early stage. Morpholino knockdown of atg5, atg7, and becn1 result in abnormal heart structure, including defects in cardiac looping, abnormal chamber morphology, and aberrant valve development in zebrafish.112 Similarly, Atg5 knockout mice display defects in heart valve development and chamber septation indicating that autophagy regulates cardiac progenitor cell differentiation and is involved in heart development.

Autophagy in the Genesis of Cardiovascular Diseases

Several risk factors underlie the genesis and progression of cardiovascular diseases. These factors include age, tobacco, unhealthy diet, insufficient physical activity, excessive weight/obesity, hypertension, diabetes mellitus, and hyperlipidemia/hypercholesterolemia.105 Hypertension is one of the largest contributors to the worldwide burden of cardiovascular diseases, and its prevalence is close to 30% in the world population.113 The main mechanisms involved in the regulation of blood pressure are the sympathetic, parasympathetic, renin–angiotensin–aldosterone and antidiuretic hormone systems. Dysregulation of these systems, as well as obesity and diabetes mellitus, is associated with the genesis and development of hypertension.114 Because most of the peptides and hormones belonging to these systems are capable of regulating autophagy, it is possible to speculate that dysregulation of autophagy could be associated with hypertension, obesity, diabetes mellitus, and end organ damage (Figure 7).

Figure 7.
Figure 7.

Autophagy regulators in cardiomyocytes. A wide variety of stimuli can regulate autophagy in cardiomyocytes. Some of them are autophagy activators and are associated with cardiovascular diseases. However, acetylcholine, catecholamines, aging, insulin-like growth factor 1 (IGF1), and insulin (INS) are capable of inhibiting autophagy. INS and IGF1 are well-known cardioprotective agents. AchR indicates acetylcholine receptor; AGT II, angiotensin II; AGTR, angiotensin II receptor, type 1; IGF1R, IGF1 receptor; INSR1, INS receptor 1; and PKA, protein kinase A.

Sympathetic and Renin–Angiotensin–Aldosterone Systems

Although there is not a lot of information on the parasympathetic system and autophagy, studies involving the sympathetic system have shown that autophagy protects cells against excessive β-adrenergic stimulation.115 Regarding the renin–angiotensin–aldosterone system, autophagy is stimulated by angiotensin II via the angiotensin II receptor, type 1 (AGTR1) but diminished via AGTR2 in neonatal rat cardiomyocytes overexpressing AGTR1, AGTR2, or both receptors after adenoviral transduction.116,117 Cardiomyocytes derived from a genetic rat model of heart hypertrophy are more susceptible to AGTR1-induced autophagy, but also show a strong reduction of autophagy via AGTR2.116 Therefore, besides their well-known favorable hemodynamic and neurohumoral effects in the treatment of heart failure (HF), AGTR1 antagonists may also downregulate excessive autophagic cell death and consequently preserve cardiomyocytes.

Obesity

Autophagy is upregulated in adipose tissue of obese patients, correlating with the degree of obesity, visceral fat distribution, and adipocyte hypertrophy.118 Xu et al119 showed that the autophagosome maturation process is involved in high-fat diet (HFD)–induced and AKT2 knockout–induced cardiac hypertrophy and contractile dysfunction. In the heart, HFD promotes the initiation and accumulation of autophagy, although it disrupts autophagosome maturation probably at the step of autophagosome–lysosome fusion. However, although AKT2 knockout does not affect the initiation of autophagy by HFD, it rescues HFD-induced disruption of the autophagosome maturation process and facilitates the transition from autophagosomes to autolysosomes, indicating a cardioprotective effect of cardiac autophagy in the presence of a HFD.119

Diabetes Mellitus

On insulin resistance, pancreatic β cells enhance their insulin secretion to compensate for hyperglycemia. However, the progressive diminution of the number of pancreatic β cells, mainly because of apoptosis, and the decrease of their function lead to the development of type 2 diabetes mellitus (T2DM). In this model autophagy plays a protective role by limiting death of β cells. On exposure to a HFD, β-cell–specific Atg7-deficient mice display a decrease in the β cell number and an impairment of glucose tolerance because of a reduction in insulin secretion.120–123 In these mice, the lack of autophagy results in a range of defects including impairment in INS secretion and a reduction in glucose tolerance.120,124 The connection between autophagy and diabetes is observed not only in situations where the genetic defect is specifically induced as with the atg7 model, because cardiomyocytes from db/db mice that exhibit T2DM have a reduction in autophagy.125,126 There is some controversy, however, as to whether autophagy in the diabetic model is beneficial. For example, an increase in autophagy in T2DM mice resulting from a high-fructose diet may cause systemic INS resistance and decreased survival due to pathological myocardial remodeling.127 Along these lines, cells from human patients with T2DM may display elevated levels of autophagy and increased cell death128; however, it is not possible to verify in these cells that autophagy is the cause of cell death.

Autophagy in Cardiovascular Diseases

In the heart, isolated cardiomyocytes, vascular epithelial cells, and vascular smooth muscle cells, autophagy is strongly induced by physiological conditions, such as nutrient starvation.129–134 In those conditions, autophagy is important for the turnover of organelles and protein aggregate degradation at low basal levels under normal conditions.106,129 During conditions of cardiovascular stress, including ischemia/reperfusion (I/R) and HF, among others, autophagy is also activated.106,109,111,135–138 However, whether autophagy in these contexts is beneficial or detrimental is not well defined.

Ischemia/Reperfusion

During ischemia, autophagy is triggered as an adaptive mechanism providing nutrients and eliminating damaged mitochondria.139 The selective autophagic removal of dysfunctional organelles can be a critical aspect of maintaining cellular homeostasis. For example, damaged mitochondria can result in the production of excess reactive oxygen species that can further harm organelles or cause DNA damage, leading to apoptosis. During mild ischemic stress, autophagy activation depends on AMPK-mediated inhibition of MTOR.140,141 Pharmacological inhibition of autophagy increases cardiomyocyte death, indicating that autophagy functions as a prosurvival mechanism.142 During chronic ischemia, autophagy can inhibit apoptosis and diminish tissue damage.143 During reperfusion, cardiomyocyte autophagy is upregulated dramatically in rat,144 rabbit,145 and swine143 hearts, and primary neonatal cardiomyocytes.140,142 Cardiac autophagy triggered by reperfusion can be either adaptive or detrimental and involves BECN1 activation.140 In cultured neonatal cardiomyocytes exposed to simulated I/R, inhibition of autophagy with 3-methyladenine enhances cell viability.142 In contrast, other studies describe protective actions of autophagy in simulated I/R.146,147 One possible explanation to these discrepancies is the dual role of BECN1 during I/R. While BECN1 is critical in the initial stage of autophagy induction, excessive amounts of this protein during reperfusion may result in an autophagic imbalance that leads to cell death,148 providing another example of the dual relationship between autophagy and cardiovascular physiology.149

Heart Failure

The initial response of the heart to several stresses is hypertrophy.110 If the stresses persist, a pathological hypertrophy is developed followed by heart failure,150 and there is some indication that autophagy plays a role in the progression of structural remodeling that leads to HF in the pressure-overloaded human heart.151 Cardiomyocyte-specific overexpression of BECN1 amplifies the pathological remodeling response.151,152 Conversely, BECN1 haploinsufficiency partially rescues HF.151 Collectively, these data provide yet another example of autophagy having a maladaptive role in cardiovascular disease. Analysis of human samples has supported additional evidence that autophagic cell death contributes to HF pathogenesis153,154; however, it is important to keep in mind that autophagy is fundamentally a cytoprotective response, and a complete block in this process generally has severe negative consequences. For example, in adult mice acute cardiac-specific ATG5 deficiency leads to cardiomyopathy,115 consistent with the notion that basal levels of cardiomyocyte autophagy are required for cellular proteostasis. Thus, whether elevated autophagy observed in human failing heart promotes cell death and contributes to the progression of HF, or if it represents an adaptive response of the heart to promote survival remains to be elucidated. Accordingly, with regard to therapeutic intervention, we propose that there is an optimal zone of cardiomyocyte autophagy that may be beneficial, and that treatments resulting in either decreased or elevated levels of autophagy are likely to be deleterious (Figure 8).108

Figure 8.
Figure 8.

Autophagy in cardiovascular diseases. The relationship between autophagy and cardiovascular diseases is complex. Although basal autophagy is critical to maintain cell homeostasis, both increases and decreases in autophagy to an excessive degree can induce alterations in normal heart and blood vessel functions. In ischemia/reperfusion, heart failure, hypertrophy, diabetes mellitus, atherosclerosis, plaque destabilization, lesional thrombosis, and vascular smooth muscle cell (VSMC) proliferation, autophagic flux is abnormally elevated, contributing to cardiac and vessel dysfunction. In Atg5 and Becn1 knockout animals and during aging, autophagic activity is decreased, perturbing cellular homeostasis and contributing to cardiovascular diseases, such as postoperative atrial fibrillation (POAF), ischemia-induced damage, hypertrophy, heart failure, and vascular endothelial cell dysfunction.

Conclusions and Perspectives

As one of the major catabolic pathways in the cell, auto phagy has become an important focus of research in a diverse range of biological fields. Autophagy is essential in normal cardiovascular homeostasis. However, alterations in autophagic flux are seen in all forms of cardiovascular diseases. The relationship of autophagy to cardiovascular physiology is complex and can be either beneficial or harmful, depending on the timing and magnitude. Despite all knowledge accumulated to date, a substantial amount of work must be done to clarify the real contribution of autophagy in cardiovascular systems. This knowledge will not only help develop our basic understanding on how and to what end autophagy is activated but may also give rise to potential drug treatment for several diseases. To this end, we must advance our current comprehension of the autophagic pathway and its various modulators. We are optimistic that in the near future pharmacological targeting of autophagy will emerge as a therapeutic alternative to treat cardiovascular diseases.

Acknowledgments

We would like to thank Roberto Bravo at the Advanced Center for Chronic Diseases at the University of Chile for kindly providing figure templates.

Sources of Funding

This work was supported by National Institutes of Health grant GM053396 (D.J. Klionsky), and by grants from the Comision Nacional de Investigacion Cientifica y Tecnologica Chile (FONDAP 15130011 to S. Lavandero and M. Chiong; and FONDECYT 1140329 to M. Chiong).

Disclosures

None.

Footnotes

  • In November, 2014, the average time from submission to first decision for all original research papers submitted to Circulation Research was 13.96 days.

  • This Review is the first a thematic series on Autophagy in Health and Disease, which includes the following articles:

    Molecular Mechanisms of Autophagy in the Cardiovascular System

    Autophagy in Vascular Disease

    The Role of Autophagy in Vascular Biology

    Therapeutic Targeting of Autophagy: Potential and Concerns in Treating Cardiovascular Disease

    Untangling Autophagy Measurements: All Fluxed Up

    Mitochondria and Autophagy

    Daniel Klionsky, Guest Editor

  • Nonstandard Abbreviations and Acronyms
    AMPK
    5′-AMP–activated protein kinase
    Atg
    autophagy related
    ER
    endoplasmic reticulum
    HF
    heart failure
    HFD
    high-fat diet
    I/R
    ischemia/reperfusion
    PAS
    phagophore assembly site
    PtdIns3K
    phosphatidylinositol 3-kinase
    PtdIns3P
    phosphatydilinositol 3-phosphate
    T2DM
    type 2 diabetes mellitus
    TOR
    target of rapamycin
    TORC1
    TOR complex 1
    ULK
    unc-51 like autophagy activating kinase

  • Received September 23, 2014.
  • Revision received December 12, 2014.
  • Accepted December 15, 2014.

References

  1. 1.↵
    1. Klionsky DJ,
    2. Baehrecke EH,
    3. Brumell JH,
    4. et al
    . A comprehensive glossary of autophagy-related molecules and processes (2nd edition). Autophagy. 2011;7:1273–1294. doi:10.4161/auto.7.11.17661.
    OpenUrlCrossRefPubMed
  2. 2.↵
    1. Azad MB,
    2. Chen Y,
    3. Henson ES,
    4. Cizeau J,
    5. McMillan-Ward E,
    6. Israels SJ,
    7. Gibson SB
    . Hypoxia induces autophagic cell death in apoptosis-competent cells through a mechanism involving BNIP3. Autophagy. 2008;4:195–204.
    OpenUrlCrossRefPubMed
  3. 3.↵
    1. Chen Y,
    2. McMillan-Ward E,
    3. Kong J,
    4. Israels SJ,
    5. Gibson SB
    . Oxidative stress induces autophagic cell death independent of apoptosis in transformed and cancer cells. Cell Death Differ. 2008;15:171–182. doi:10.1038/sj.cdd.4402233.
    OpenUrlCrossRefPubMed
  4. 4.↵
    1. Gutierrez MG,
    2. Master SS,
    3. Singh SB,
    4. Taylor GA,
    5. Colombo MI,
    6. Deretic V
    . Autophagy is a defense mechanism inhibiting BCG and Mycobacterium tuberculosis survival in infected macrophages. Cell. 2004;119:753–766. doi:10.1016/j.cell.2004.11.038.
    OpenUrlCrossRefPubMed
  5. 5.↵
    1. Yorimitsu T,
    2. Nair U,
    3. Yang Z,
    4. Klionsky DJ
    . Endoplasmic reticulum stress triggers autophagy. J Biol Chem. 2006;281:30299–30304. doi:10.1074/jbc.M607007200.
    OpenUrlAbstract/FREE Full Text
  6. 6.↵
    1. Mijaljica D,
    2. Prescott M,
    3. Devenish RJ
    . Microautophagy in mammalian cells: revisiting a 40-year-old conundrum. Autophagy. 2011;7:673–682.
    OpenUrlCrossRefPubMed
  7. 7.↵
    1. Kamada Y,
    2. Yoshino K,
    3. Kondo C,
    4. Kawamata T,
    5. Oshiro N,
    6. Yonezawa K,
    7. Ohsumi Y
    . Tor directly controls the Atg1 kinase complex to regulate autophagy. Mol Cell Biol. 2010;30:1049–1058. doi:10.1128/MCB.01344-09.
    OpenUrlAbstract/FREE Full Text
  8. 8.↵
    1. Kabeya Y,
    2. Noda NN,
    3. Fujioka Y,
    4. Suzuki K,
    5. Inagaki F,
    6. Ohsumi Y
    . Characterization of the Atg17-Atg29-Atg31 complex specifically required for starvation-induced autophagy in Saccharomyces cerevisiae. Biochem Biophys Res Commun. 2009;389:612–615. doi:10.1016/j.bbrc.2009.09.034.
    OpenUrlCrossRefPubMed
  9. 9.↵
    1. Cheong H,
    2. Nair U,
    3. Geng J,
    4. Klionsky DJ
    . The Atg1 kinase complex is involved in the regulation of protein recruitment to initiate sequestering vesicle formation for nonspecific autophagy in Saccharomyces cerevisiae. Mol Biol Cell. 2008;19:668–681. doi:10.1091/mbc.E07-08-0826.
    OpenUrlAbstract/FREE Full Text
  10. 10.↵
    1. Kim J,
    2. Huang W-P,
    3. Stromhaug PE,
    4. Klionsky DJ
    . Convergence of multiple autophagy and cytoplasm to vacuole targeting components to a perivacuolar membrane compartment prior to de novo vesicle formation. J Biol Chem. 2002;277:763–773. doi:10.1074/jbc.M109134200.
    OpenUrlAbstract/FREE Full Text
  11. 11.↵
    1. Reggiori F,
    2. Tucker KA,
    3. Stromhaug PE,
    4. Klionsky DJ
    . The Atg1-Atg13 complex regulates Atg9 and Atg23 retrieval transport from the pre-autophagosomal structure. Dev Cell. 2004;6:79–90.
    OpenUrlCrossRefPubMed
  12. 12.↵
    1. Suzuki K,
    2. Kirisako T,
    3. Kamada Y,
    4. Mizushima N,
    5. Noda T,
    6. Ohsumi Y
    . The pre-autophagosomal structure organized by concerted functions of APGgenes is essential for autophagosome formation. EMBO J. 2001;20:5971–5981. doi:10.1093/emboj/20.21.5971.
    OpenUrlAbstract/FREE Full Text
  13. 13.↵
    1. Kamada Y,
    2. Funakoshi T,
    3. Shintani T,
    4. Nagano K,
    5. Ohsumi M,
    6. Ohsumi Y
    . Tor-mediated induction of autophagy via an Apg1 protein kinase complex. J Cell Biol. 2000;150:1507–1513.
    OpenUrlAbstract/FREE Full Text
  14. 14.↵
    1. Yeh YY,
    2. Wrasman K,
    3. Herman PK
    . Autophosphorylation within the Atg1 activation loop is required for both kinase activity and the induction of autophagy in Saccharomyces cerevisiae. Genetics. 2010;185:871–882. doi:10.1534/genetics.110.116566.
    OpenUrlAbstract/FREE Full Text
  15. 15.↵
    1. Kraft C,
    2. Kijanska M,
    3. Kalie E,
    4. Siergiejuk E,
    5. Lee SS,
    6. Semplicio G,
    7. Stoffel I,
    8. Brezovich A,
    9. Verma M,
    10. Hansmann I,
    11. Ammerer G,
    12. Hofmann K,
    13. Tooze S,
    14. Peter M
    . Binding of the Atg1/ULK1 kinase to the ubiquitin-like protein Atg8 regulates autophagy. EMBO J. 2012;31:3691–3703. doi:10.1038/emboj.2012.225.
    OpenUrlAbstract/FREE Full Text
  16. 16.↵
    1. Kijanska M,
    2. Dohnal I,
    3. Reiter W,
    4. Kaspar S,
    5. Stoffel I,
    6. Ammerer G,
    7. Kraft C,
    8. Peter M
    . Activation of Atg1 kinase in autophagy by regulated phosphorylation. Autophagy. 2010;6:1168–1178.
    OpenUrlCrossRefPubMed
  17. 17.↵
    1. Budovskaya YV,
    2. Stephan JS,
    3. Deminoff SJ,
    4. Herman PK
    . An evolutionary proteomics approach identifies substrates of the cAMP-dependent protein kinase. Proc Natl Acad Sci USA. 2005;102:13933–13938. doi:10.1073/pnas.0501046102.
    OpenUrlAbstract/FREE Full Text
  18. 18.↵
    1. Budovskaya YV,
    2. Stephan JS,
    3. Reggiori F,
    4. Klionsky DJ,
    5. Herman PK
    . The Ras/cAMP-dependent protein kinase signaling pathway regulates an early step of the autophagy process in Saccharomyces cerevisiae. J Biol Chem. 2004;279:20663–20671. doi:10.1074/jbc.M400272200.
    OpenUrlAbstract/FREE Full Text
  19. 19.↵
    1. Stephan JS,
    2. Yeh YY,
    3. Ramachandran V,
    4. Deminoff SJ,
    5. Herman PK
    . The Tor and PKA signaling pathways independently target the Atg1/Atg13 protein kinase complex to control autophagy. Proc Natl Acad Sci USA. 2009;106:17049–17054. doi:10.1073/pnas.0903316106.
    OpenUrlAbstract/FREE Full Text
  20. 20.↵
    1. Natarajan K,
    2. Meyer MR,
    3. Jackson BM,
    4. Slade D,
    5. Roberts C,
    6. Hinnebusch AG,
    7. Marton MJ
    . Transcriptional profiling shows that Gcn4p is a master regulator of gene expression during amino acid starvation in yeast. Mol Cell Biol. 2001;21:4347–4368. doi:10.1128/MCB.21.13.4347-4368.2001.
    OpenUrlAbstract/FREE Full Text
  21. 21.↵
    1. Tallóczy Z,
    2. Jiang W,
    3. Virgin HW IV.,
    4. Leib DA,
    5. Scheuner D,
    6. Kaufman RJ,
    7. Eskelinen E-L,
    8. Levine B
    . Regulation of starvation- and virus-induced autophagy by the eIF2alpha kinase signaling pathway. Proc Natl Acad Sci USA. 2002;99:190–195. doi:10.1073/pnas.012485299.
    OpenUrlAbstract/FREE Full Text
  22. 22.↵
    1. Yan J,
    2. Kuroyanagi H,
    3. Kuroiwa A,
    4. Matsuda Y,
    5. Tokumitsu H,
    6. Tomoda T,
    7. Shirasawa T,
    8. Muramatsu M
    . Identification of mouse ULK1, a novel protein kinase structurally related to C. elegans UNC-51. Biochem Biophys Res Commun. 1998;246:222–227.
    OpenUrlCrossRefPubMed
  23. 23.↵
    1. Yan J,
    2. Kuroyanagi H,
    3. Tomemori T,
    4. Okazaki N,
    5. Asato K,
    6. Matsuda Y,
    7. Suzuki Y,
    8. Ohshima Y,
    9. Mitani S,
    10. Masuho Y,
    11. Shirasawa T,
    12. Muramatsu M
    . Mouse ULK2, a novel member of the UNC-51-like protein kinases: unique features of functional domains. Oncogene. 1999;18:5850–5859. doi:10.1038/sj.onc.1202988.
    OpenUrlCrossRefPubMed
  24. 24.↵
    1. Hara T,
    2. Takamura A,
    3. Kishi C,
    4. Iemura S,
    5. Natsume T,
    6. Guan JL,
    7. Mizushima N
    . FIP200, a ULK-interacting protein, is required for autophagosome formation in mammalian cells. J Cell Biol. 2008;181:497–510. doi:10.1083/jcb.200712064.
    OpenUrlAbstract/FREE Full Text
  25. 25.↵
    1. Jung CH,
    2. Jun CB,
    3. Ro SH,
    4. Kim YM,
    5. Otto NM,
    6. Cao J,
    7. Kundu M,
    8. Kim DH
    . ULK-Atg13-FIP200 complexes mediate mTOR signaling to the autophagy machinery. Mol Biol Cell. 2009;20:1992–2003. doi:10.1091/mbc.E08-12-1249.
    OpenUrlAbstract/FREE Full Text
  26. 26.↵
    1. Mercer CA,
    2. Kaliappan A,
    3. Dennis PB
    . A novel, human Atg13 binding protein, Atg101, interacts with ULK1 and is essential for macroautophagy. Autophagy. 2009;5:649–662.
    OpenUrlCrossRefPubMed
  27. 27.↵
    1. Ganley IG,
    2. Lam du H,
    3. Wang J,
    4. Ding X,
    5. Chen S,
    6. Jiang X
    . ULK1.ATG13.FIP200 complex mediates mTOR signaling and is essential for autophagy. J Biol Chem. 2009;284:12297–12305. doi:10.1074/jbc.M900573200.
    OpenUrlAbstract/FREE Full Text
  28. 28.↵
    1. Hosokawa N,
    2. Hara T,
    3. Kaizuka T,
    4. Kishi C,
    5. Takamura A,
    6. Miura Y,
    7. Iemura S,
    8. Natsume T,
    9. Takehana K,
    10. Yamada N,
    11. Guan JL,
    12. Oshiro N,
    13. Mizushima N
    . Nutrient-dependent mTORC1 association with the ULK1-Atg13-FIP200 complex required for autophagy. Mol Biol Cell. 2009;20:1981–1991. doi:10.1091/mbc.E08-12-1248.
    OpenUrlAbstract/FREE Full Text
  29. 29.↵
    1. Chan EY,
    2. Longatti A,
    3. McKnight NC,
    4. Tooze SA
    . Kinase-inactivated ULK proteins inhibit autophagy via their conserved C-terminal domains using an Atg13-independent mechanism. Mol Cell Biol. 2009;29:157–171. doi:10.1128/MCB.01082-08.
    OpenUrlAbstract/FREE Full Text
  30. 30.↵
    1. Kim J,
    2. Kundu M,
    3. Viollet B,
    4. Guan K-L
    . AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1. Nat Cell Biol. 2011;13:132–141. doi:10.1038/ncb2152.
    OpenUrlCrossRefPubMed
  31. 31.↵
    1. Inoki K,
    2. Li Y,
    3. Xu T,
    4. Guan K-L
    . Rheb GTPase is a direct target of TSC2 GAP activity and regulates mTOR signaling. Genes Dev. 2003;17:1829–1834. doi:10.1101/gad.1110003.
    OpenUrlAbstract/FREE Full Text
  32. 32.↵
    1. Inoki K,
    2. Zhu T,
    3. Guan K-L
    . TSC2 mediates cellular energy response to control cell growth and survival. Cell. 2003;115:577–590.
    OpenUrlCrossRefPubMed
  33. 33.↵
    1. Löffler AS,
    2. Alers S,
    3. Dieterle AM,
    4. Keppeler H,
    5. Franz-Wachtel M,
    6. Kundu M,
    7. Campbell DG,
    8. Wesselborg S,
    9. Alessi DR,
    10. Stork B
    . Ulk1-mediated phosphorylation of AMPK constitutes a negative regulatory feedback loop. Autophagy. 2011;7:696–706.
    OpenUrlCrossRefPubMed
  34. 34.↵
    1. Alessi DR,
    2. James SR,
    3. Downes CP,
    4. Holmes AB,
    5. Gaffney PR,
    6. Reese CB,
    7. Cohen P
    . Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Balpha. Curr Biol. 1997;7:261–269.
    OpenUrlCrossRefPubMed
  35. 35.↵
    1. Sarbassov DD,
    2. Guertin DA,
    3. Ali SM,
    4. Sabatini DM
    . Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex. Science. 2005;307:1098–1101. doi:10.1126/science.1106148.
    OpenUrlAbstract/FREE Full Text
  36. 36.↵
    1. Manning BD,
    2. Tee AR,
    3. Logsdon MN,
    4. Blenis J,
    5. Cantley LC
    . Identification of the tuberous sclerosis complex-2 tumor suppressor gene product tuberin as a target of the phosphoinositide 3-kinase/akt pathway. Mol Cell. 2002;10:151–162.
    OpenUrlCrossRefPubMed
  37. 37.↵
    1. Petiot A,
    2. Ogier-Denis E,
    3. Blommaart EF,
    4. Meijer AJ,
    5. Codogno P
    . Distinct classes of phosphatidylinositol 3’-kinases are involved in signaling pathways that control macroautophagy in HT-29 cells. J Biol Chem. 2000;275:992–998.
    OpenUrlAbstract/FREE Full Text
  38. 38.↵
    1. Arico S,
    2. Petiot A,
    3. Bauvy C,
    4. Dubbelhuis PF,
    5. Meijer AJ,
    6. Codogno P,
    7. Ogier-Denis E
    . The tumor suppressor PTEN positively regulates macroautophagy by inhibiting the phosphatidylinositol 3-kinase/protein kinase B pathway. J Biol Chem. 2001;276:35243–35246. doi:10.1074/jbc.C100319200.
    OpenUrlAbstract/FREE Full Text
  39. 39.↵
    1. Kametaka S,
    2. Okano T,
    3. Ohsumi M,
    4. Ohsumi Y
    . Apg14p and Apg6/Vps30p form a protein complex essential for autophagy in the yeast, Saccharomyces cerevisiae. J Biol Chem. 1998;273:22284–22291.
    OpenUrlAbstract/FREE Full Text
  40. 40.↵
    1. Kihara A,
    2. Noda T,
    3. Ishihara N,
    4. Ohsumi Y
    . Two distinct Vps34 phosphatidylinositol 3-kinase complexes function in autophagy and carboxypeptidase Y sorting in Saccharomyces cerevisiae. J Cell Biol. 2001;152:519–530.
    OpenUrlAbstract/FREE Full Text
  41. 41.↵
    1. Obara K,
    2. Sekito T,
    3. Ohsumi Y
    . Assortment of phosphatidylinositol 3-kinase complexes–Atg14p directs association of complex I to the pre-autophagosomal structure in Saccharomyces cerevisiae. Mol Biol Cell. 2006;17:1527–1539. doi:10.1091/mbc.E05-09-0841.
    OpenUrlAbstract/FREE Full Text
  42. 42.↵
    1. Furuya N,
    2. Yu J,
    3. Byfield M,
    4. Pattingre S,
    5. Levine B
    . The evolutionarily conserved domain of Beclin 1 is required for Vps34 binding, autophagy and tumor suppressor function. Autophagy. 2005;1:46–52.
    OpenUrlCrossRefPubMed
  43. 43.↵
    1. Itakura E,
    2. Kishi C,
    3. Inoue K,
    4. Mizushima N
    . Beclin 1 forms two distinct phosphatidylinositol 3-kinase complexes with mammalian Atg14 and UVRAG. Mol Biol Cell. 2008;19:5360–5372. doi:10.1091/mbc.E08-01-0080.
    OpenUrlAbstract/FREE Full Text
  44. 44.↵
    1. Matsunaga K,
    2. Saitoh T,
    3. Tabata K,
    4. Omori H,
    5. Satoh T,
    6. Kurotori N,
    7. Maejima I,
    8. Shirahama-Noda K,
    9. Ichimura T,
    10. Isobe T,
    11. Akira S,
    12. Noda T,
    13. Yoshimori T
    . Two Beclin 1-binding proteins, Atg14L and Rubicon, reciprocally regulate autophagy at different stages. Nat Cell Biol. 2009;11:385–396. doi:10.1038/ncb1846.
    OpenUrlCrossRefPubMed
  45. 45.↵
    1. Zhong Y,
    2. Wang QJ,
    3. Li X,
    4. Yan Y,
    5. Backer JM,
    6. Chait BT,
    7. Heintz N,
    8. Yue Z
    . Distinct regulation of autophagic activity by Atg14L and Rubicon associated with Beclin 1-phosphatidylinositol-3-kinase complex. Nat Cell Biol. 2009;11:468–476. doi:10.1038/ncb1854.
    OpenUrlCrossRefPubMed
  46. 46.↵
    1. Fimia GM,
    2. Stoykova A,
    3. Romagnoli A,
    4. Giunta L,
    5. Di Bartolomeo S,
    6. Nardacci R,
    7. Corazzari M,
    8. Fuoco C,
    9. Ucar A,
    10. Schwartz P,
    11. Gruss P,
    12. Piacentini M,
    13. Chowdhury K,
    14. Cecconi F
    . Ambra1 regulates autophagy and development of the nervous system. Nature. 2007;447:1121–1125. doi:10.1038/nature05925.
    OpenUrlCrossRefPubMed
  47. 47.↵
    1. Sun Q,
    2. Fan W,
    3. Chen K,
    4. Ding X,
    5. Chen S,
    6. Zhong Q
    . Identification of Barkor as a mammalian autophagy-specific factor for Beclin 1 and class III phosphatidylinositol 3-kinase. Proc Natl Acad Sci USA. 2008;105:19211–19216. doi:10.1073/pnas.0810452105.
    OpenUrlAbstract/FREE Full Text
  48. 48.↵
    1. Matsunaga K,
    2. Morita E,
    3. Saitoh T,
    4. Akira S,
    5. Ktistakis NT,
    6. Izumi T,
    7. Noda T,
    8. Yoshimori T
    . Autophagy requires endoplasmic reticulum targeting of the PI3-kinase complex via Atg14L. J Cell Biol. 2010;190:511–521. doi:10.1083/jcb.200911141.
    OpenUrlAbstract/FREE Full Text
  49. 49.↵
    1. Takahashi Y,
    2. Coppola D,
    3. Matsushita N,
    4. Cualing HD,
    5. Sun M,
    6. Sato Y,
    7. Liang C,
    8. Jung JU,
    9. Cheng JQ,
    10. Mulé JJ,
    11. Pledger WJ,
    12. Wang HG
    . Bif-1 interacts with Beclin 1 through UVRAG and regulates autophagy and tumorigenesis. Nat Cell Biol. 2007;9:1142–1151. doi:10.1038/ncb1634.
    OpenUrlCrossRefPubMed
  50. 50.↵
    1. Pattingre S,
    2. Tassa A,
    3. Qu X,
    4. Garuti R,
    5. Liang XH,
    6. Mizushima N,
    7. Packer M,
    8. Schneider MD,
    9. Levine B
    . Bcl-2 antiapoptotic proteins inhibit Beclin 1-dependent autophagy. Cell. 2005;122:927–939. doi:10.1016/j.cell.2005.07.002.
    OpenUrlCrossRefPubMed
  51. 51.↵
    1. Zalckvar E,
    2. Berissi H,
    3. Mizrachy L,
    4. Idelchuk Y,
    5. Koren I,
    6. Eisenstein M,
    7. Sabanay H,
    8. Pinkas-Kramarski R,
    9. Kimchi A
    . DAP-kinase-mediated phosphorylation on the BH3 domain of beclin 1 promotes dissociation of beclin 1 from Bcl-XL and induction of autophagy. EMBO Rep. 2009;10:285–292. doi:10.1038/embor.2008.246.
    OpenUrlAbstract/FREE Full Text
  52. 52.↵
    1. Russell RC,
    2. Tian Y,
    3. Yuan H,
    4. Park HW,
    5. Chang YY,
    6. Kim J,
    7. Kim H,
    8. Neufeld TP,
    9. Dillin A,
    10. Guan K-L
    . ULK1 induces autophagy by phosphorylating Beclin-1 and activating VPS34 lipid kinase. Nat Cell Biol. 2013;15:741–750. doi:10.1038/ncb2757.
    OpenUrlCrossRefPubMed
  53. 53.↵
    1. Kim J,
    2. Kim YC,
    3. Fang C,
    4. Russell RC,
    5. Kim JH,
    6. Fan W,
    7. Liu R,
    8. Zhong Q,
    9. Guan K-L
    . Differential regulation of distinct Vps34 complexes by AMPK in nutrient stress and autophagy. Cell. 2013;152:290–303. doi:10.1016/j.cell.2012.12.016.
    OpenUrlCrossRefPubMed
  54. 54.↵
    1. Hailey DW,
    2. Rambold AS,
    3. Satpute-Krishnan P,
    4. Mitra K,
    5. Sougrat R,
    6. Kim PK,
    7. Lippincott-Schwartz J
    . Mitochondria supply membranes for autophagosome biogenesis during starvation. Cell. 2010;141:656–667. doi:10.1016/j.cell.2010.04.009.
    OpenUrlCrossRefPubMed
  55. 55.↵
    1. Hayashi-Nishino M,
    2. Fujita N,
    3. Noda T,
    4. Yamaguchi A,
    5. Yoshimori T,
    6. Yamamoto A
    . A subdomain of the endoplasmic reticulum forms a cradle for autophagosome formation. Nat Cell Biol. 2009;11:1433–1437. doi:10.1038/ncb1991.
    OpenUrlCrossRefPubMed
  56. 56.↵
    1. Young ARJ,
    2. Chan EYW,
    3. Hu XW,
    4. Köchl R,
    5. Crawshaw SG,
    6. High S,
    7. Hailey DW,
    8. Lippincott-Schwartz J,
    9. Tooze SA
    . Starvation and ULK1-dependent cycling of mammalian Atg9 between the TGN and endosomes. J Cell Sci. 2006;119:3888–3900. doi:10.1242/jcs.03172.
    OpenUrlAbstract/FREE Full Text
  57. 57.↵
    1. Ylä-Anttila P,
    2. Vihinen H,
    3. Jokitalo E,
    4. Eskelinen E-L
    . 3D tomography reveals connections between the phagophore and endoplasmic reticulum. Autophagy. 2009;5:1180–1185. doi: 10.4161/auto.5.8.10274.
    OpenUrlCrossRefPubMed
  58. 58.↵
    1. Axe EL,
    2. Walker SA,
    3. Manifava M,
    4. Chandra P,
    5. Roderick HL,
    6. Habermann A,
    7. Griffiths G,
    8. Ktistakis NT
    . Autophagosome formation from membrane compartments enriched in phosphatidylinositol 3-phosphate and dynamically connected to the endoplasmic reticulum. J Cell Biol. 2008;182:685–701. doi:10.1083/jcb.200803137.
    OpenUrlAbstract/FREE Full Text
  59. 59.↵
    1. Polson HE,
    2. de Lartigue J,
    3. Rigden DJ,
    4. Reedijk M,
    5. Urbé S,
    6. Clague MJ,
    7. Tooze SA
    . Mammalian Atg18 (WIPI2) localizes to omegasome-anchored phagophores and positively regulates LC3 lipidation. Autophagy. 2010;6:506–522. doi:10.4161/auto.6.4.11863.
    OpenUrlCrossRefPubMed
  60. 60.↵
    1. Karanasios E,
    2. Stapleton E,
    3. Manifava M,
    4. Kaizuka T,
    5. Mizushima N,
    6. Walker SA,
    7. Ktistakis NT
    . Dynamic association of the ULK1 complex with omegasomes during autophagy induction. J Cell Sci. 2013;126:5224–5238. doi:10.1242/jcs.132415.
    OpenUrlAbstract/FREE Full Text
  61. 61.↵
    1. Tooze SA,
    2. Yoshimori T
    . The origin of the autophagosomal membrane. Nat Cell Biol. 2010;12:831–835. doi:10.1038/ncb0910-831.
    OpenUrlCrossRefPubMed
  62. 62.↵
    1. Hamasaki M,
    2. Furuta N,
    3. Matsuda A,
    4. Nezu A,
    5. Yamamoto A,
    6. Fujita N,
    7. Oomori H,
    8. Noda T,
    9. Haraguchi T,
    10. Hiraoka Y,
    11. Amano A,
    12. Yoshimori T
    . Autophagosomes form at ER-mitochondria contact sites. Nature. 2013;495:389–393. doi:10.1038/nature11910.
    OpenUrlCrossRefPubMed
  63. 63.↵
    1. He C,
    2. Baba M,
    3. Cao Y,
    4. Klionsky DJ
    . Self-interaction is critical for Atg9 transport and function at the phagophore assembly site during autophagy. Mol Biol Cell. 2008;19:5506–5516. doi:10.1091/mbc.E08-05-0544.
    OpenUrlAbstract/FREE Full Text
  64. 64.↵
    1. Noda T,
    2. Kim J,
    3. Huang W-P,
    4. Baba M,
    5. Tokunaga C,
    6. Ohsumi Y,
    7. Klionsky DJ
    . Apg9p/Cvt7p is an integral membrane protein required for transport vesicle formation in the Cvt and autophagy pathways. J Cell Biol. 2000;148:465–480. doi: 10.1083/jcb.148.3.465.
    OpenUrlAbstract/FREE Full Text
  65. 65.↵
    1. Mari M,
    2. Griffith J,
    3. Rieter E,
    4. Krishnappa L,
    5. Klionsky DJ,
    6. Reggiori F
    . An Atg9-containing compartment that functions in the early steps of autophagosome biogenesis. J Cell Biol. 2010;190:1005–1022. doi:10.1083/jcb.200912089.
    OpenUrlAbstract/FREE Full Text
  66. 66.↵
    1. Yamamoto H,
    2. Kakuta S,
    3. Watanabe TM,
    4. Kitamura A,
    5. Sekito T,
    6. Kondo-Kakuta C,
    7. Ichikawa R,
    8. Kinjo M,
    9. Ohsumi Y
    . Atg9 vesicles are an important membrane source during early steps of autophagosome formation. J Cell Biol. 2012;198:219–233. doi:10.1083/jcb.201202061.
    OpenUrlAbstract/FREE Full Text
  67. 67.↵
    1. Reggiori F,
    2. Shintani T,
    3. Nair U,
    4. Klionsky DJ
    . Atg9 cycles between mitochondria and the pre-autophagosomal structure in yeasts. Autophagy. 2005;1:101–109.
    OpenUrlCrossRefPubMed
  68. 68.↵
    1. He C,
    2. Song H,
    3. Yorimitsu T,
    4. Monastyrska I,
    5. Yen W-L,
    6. Legakis JE,
    7. Klionsky DJ
    . Recruitment of Atg9 to the preautophagosomal structure by Atg11 is essential for selective autophagy in budding yeast. J Cell Biol. 2006;175:925–935. doi:10.1083/jcb.200606084.
    OpenUrlAbstract/FREE Full Text
  69. 69.↵
    1. Yen W-L,
    2. Legakis JE,
    3. Nair U,
    4. Klionsky DJ
    . Atg27 is required for autophagy-dependent cycling of Atg9. Mol Biol Cell. 2007;18:581–593. doi:10.1091/mbc.E06-07-0612.
    OpenUrlAbstract/FREE Full Text
  70. 70.↵
    1. Orsi A,
    2. Razi M,
    3. Dooley HC,
    4. Robinson D,
    5. Weston AE,
    6. Collinson LM,
    7. Tooze SA
    . Dynamic and transient interactions of Atg9 with autophagosomes, but not membrane integration, are required for autophagy. Mol Biol Cell. 2012;23:1860–1873. doi:10.1091/mbc.E11-09-0746.
    OpenUrlAbstract/FREE Full Text
  71. 71.↵
    1. Webber JL,
    2. Tooze SA
    . Coordinated regulation of autophagy by p38alpha MAPK through mAtg9 and p38IP. EMBO J. 2010;29:27–40. doi:10.1038/emboj.2009.321.
    OpenUrlAbstract/FREE Full Text
  72. 72.↵
    1. Kim J,
    2. Dalton VM,
    3. Eggerton KP,
    4. Scott SV,
    5. Klionsky DJ
    . Apg7p/Cvt2p is required for the cytoplasm-to-vacuole targeting, macroautophagy, and peroxisome degradation pathways. Mol Biol Cell. 1999;10:1337–1351.
    OpenUrlAbstract/FREE Full Text
  73. 73.↵
    1. Tanida I,
    2. Mizushima N,
    3. Kiyooka M,
    4. Ohsumi M,
    5. Ueno T,
    6. Ohsumi Y,
    7. Kominami E
    . Apg7p/Cvt2p: A novel protein-activating enzyme essential for autophagy. Mol Biol Cell. 1999;10:1367–1379.
    OpenUrlAbstract/FREE Full Text
  74. 74.↵
    1. Shintani T,
    2. Mizushima N,
    3. Ogawa Y,
    4. Matsuura A,
    5. Noda T,
    6. Ohsumi Y
    . Apg10p, a novel protein-conjugating enzyme essential for autophagy in yeast. EMBO J. 1999;18:5234–5241. doi:10.1093/emboj/18.19.5234.
    OpenUrlAbstract/FREE Full Text
  75. 75.↵
    1. Mizushima N,
    2. Noda T,
    3. Yoshimori T,
    4. Tanaka Y,
    5. Ishii T,
    6. George MD,
    7. Klionsky DJ,
    8. Ohsumi M,
    9. Ohsumi Y
    . A protein conjugation system essential for autophagy. Nature. 1998;395:395–398. doi:10.1038/26506.
    OpenUrlCrossRefPubMed
  76. 76.↵
    1. Mizushima N,
    2. Sugita H,
    3. Yoshimori T,
    4. Ohsumi Y
    . A new protein conjugation system in human. The counterpart of the yeast Apg12p conjugation system essential for autophagy. J Biol Chem. 1998;273:33889–33892.
    OpenUrlAbstract/FREE Full Text
  77. 77.↵
    1. Kuma A,
    2. Mizushima N,
    3. Ishihara N,
    4. Ohsumi Y
    . Formation of the approximately 350-kDa Apg12-Apg5.Apg16 multimeric complex, mediated by Apg16 oligomerization, is essential for autophagy in yeast. J Biol Chem. 2002;277:18619–18625. doi:10.1074/jbc.M111889200.
    OpenUrlAbstract/FREE Full Text
  78. 78.↵
    1. Mizushima N,
    2. Kuma A,
    3. Kobayashi Y,
    4. Yamamoto A,
    5. Matsubae M,
    6. Takao T,
    7. Natsume T,
    8. Ohsumi Y,
    9. Yoshimori T
    . Mouse Apg16L, a novel WD-repeat protein, targets to the autophagic isolation membrane with the Apg12-Apg5 conjugate. J Cell Sci. 2003;116:1679–1688.
    OpenUrlAbstract/FREE Full Text
  79. 79.↵
    1. Mizushima N,
    2. Noda T,
    3. Ohsumi Y
    . Apg16p is required for the function of the Apg12p-Apg5p conjugate in the yeast autophagy pathway. EMBO J. 1999;18:3888–3896. doi:10.1093/emboj/18.14.3888.
    OpenUrlAbstract/FREE Full Text
  80. 80.↵
    1. Geng J,
    2. Klionsky DJ
    . The Atg8 and Atg12 ubiquitin-like conjugation systems in macroautophagy. EMBO Rep. 2008;9:859–864. doi:10.1038/embor.2008.163.
    OpenUrlAbstract/FREE Full Text
  81. 81.↵
    1. Ohsumi Y
    . Molecular dissection of autophagy: two ubiquitin-like systems. Nat Rev Mol Cell Biol. 2001;2:211–216. doi:10.1038/35056522.
    OpenUrlCrossRefPubMed
  82. 82.↵
    1. Kirisako T,
    2. Ichimura Y,
    3. Okada H,
    4. Kabeya Y,
    5. Mizushima N,
    6. Yoshimori T,
    7. Ohsumi M,
    8. Takao T,
    9. Noda T,
    10. Ohsumi Y
    . The reversible modification regulates the membrane-binding state of Apg8/Aut7 essential for autophagy and the cytoplasm to vacuole targeting pathway. J Cell Biol. 2000;151:263–276.
    OpenUrlAbstract/FREE Full Text
  83. 83.↵
    1. Tanida I,
    2. Ueno T,
    3. Kominami E
    . Human light chain 3/MAP1LC3B is cleaved at its carboxyl-terminal Met121 to expose Gly120 for lipidation and targeting to autophagosomal membranes. J Biol Chem. 2004;279:47704–47710. doi:10.1074/jbc.M407016200.
    OpenUrlAbstract/FREE Full Text
  84. 84.↵
    1. Ichimura Y,
    2. Kirisako T,
    3. Takao T,
    4. Satomi Y,
    5. Shimonishi Y,
    6. Ishihara N,
    7. Mizushima N,
    8. Tanida I,
    9. Kominami E,
    10. Ohsumi M,
    11. Noda T,
    12. Ohsumi Y
    . A ubiquitin-like system mediates protein lipidation. Nature. 2000;408:488–492. doi:10.1038/35044114.
    OpenUrlCrossRefPubMed
  85. 85.↵
    1. Fujita N,
    2. Itoh T,
    3. Omori H,
    4. Fukuda M,
    5. Noda T,
    6. Yoshimori T
    . The Atg16L complex specifies the site of LC3 lipidation for membrane biogenesis in autophagy. Mol Biol Cell. 2008;19:2092–2100. doi:10.1091/mbc.E07-12-1257.
    OpenUrlAbstract/FREE Full Text
  86. 86.↵
    1. Hanada T,
    2. Noda NN,
    3. Satomi Y,
    4. Ichimura Y,
    5. Fujioka Y,
    6. Takao T,
    7. Inagaki F,
    8. Ohsumi Y
    . The Atg12-Atg5 conjugate has a novel E3-like activity for protein lipidation in autophagy. J Biol Chem. 2007;282:37298–37302. doi:10.1074/jbc.C700195200.
    OpenUrlAbstract/FREE Full Text
  87. 87.↵
    1. Romanov J,
    2. Walczak M,
    3. Ibiricu I,
    4. Schüchner S,
    5. Ogris E,
    6. Kraft C,
    7. Martens S
    . Mechanism and functions of membrane binding by the Atg5-Atg12/Atg16 complex during autophagosome formation. EMBO J. 2012;31:4304–4317. doi:10.1038/emboj.2012.278.
    OpenUrlAbstract/FREE Full Text
  88. 88.↵
    1. Noda NN,
    2. Fujioka Y,
    3. Hanada T,
    4. Ohsumi Y,
    5. Inagaki F
    . Structure of the Atg12-Atg5 conjugate reveals a platform for stimulating Atg8-PE conjugation. EMBO Rep. 2013;14:206–211. doi:10.1038/embor.2012.208.
    OpenUrlAbstract/FREE Full Text
  89. 89.↵
    1. Kabeya Y,
    2. Mizushima N,
    3. Ueno T,
    4. Yamamoto A,
    5. Kirisako T,
    6. Noda T,
    7. Kominami E,
    8. Ohsumi Y,
    9. Yoshimori T
    . LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing. EMBO J. 2000;19:5720–5728. doi:10.1093/emboj/19.21.5720.
    OpenUrlAbstract/FREE Full Text
  90. 90.↵
    1. Klionsky DJ,
    2. Abdalla FC,
    3. Abeliovich H,
    4. et al
    . Guidelines for the use and interpretation of assays for monitoring autophagy. Autophagy. 2012;8:445–544.
    OpenUrlCrossRefPubMed
  91. 91.↵
    1. Kabeya Y,
    2. Mizushima N,
    3. Yamamoto A,
    4. Oshitani-Okamoto S,
    5. Ohsumi Y,
    6. Yoshimori T
    . LC3, GABARAP and GATE16 localize to autophagosomal membrane depending on form-II formation. J Cell Sci. 2004;117:2805–2812. doi:10.1242/jcs.01131.
    OpenUrlAbstract/FREE Full Text
  92. 92.↵
    1. Tanida I,
    2. Komatsu M,
    3. Ueno T,
    4. Kominami E
    . GATE-16 and GABARAP are authentic modifiers mediated by Apg7 and Apg3. Biochem Biophys Res Commun. 2003;300:637–644.
    OpenUrlCrossRefPubMed
  93. 93.↵
    1. Tanida I,
    2. Tanida-Miyake E,
    3. Komatsu M,
    4. Ueno T,
    5. Kominami E
    . Human Apg3p/Aut1p homologue is an authentic E2 enzyme for multiple substrates, GATE-16, GABARAP, and MAP-LC3, and facilitates the conjugation of hApg12p to hApg5p. J Biol Chem. 2002;277:13739–13744. doi:10.1074/jbc.M200385200.
    OpenUrlAbstract/FREE Full Text
  94. 94.↵
    1. Weidberg H,
    2. Shvets E,
    3. Shpilka T,
    4. Shimron F,
    5. Shinder V,
    6. Elazar Z
    . LC3 and GATE-16/GABARAP subfamilies are both essential yet act differently in autophagosome biogenesis. EMBO J. 2010;29:1792–1802. doi:10.1038/emboj.2010.74.
    OpenUrlAbstract/FREE Full Text
  95. 95.↵
    1. Klionsky DJ
    . The molecular machinery of autophagy: unanswered questions. J Cell Sci. 2005;118:7–18. doi:10.1242/jcs.01620.
    OpenUrlAbstract/FREE Full Text
  96. 96.↵
    1. Harding TM,
    2. Morano KA,
    3. Scott SV,
    4. Klionsky DJ
    . Isolation and characterization of yeast mutants in the cytoplasm to vacuole protein targeting pathway. J Cell Biol. 1995;131:591–602.
    OpenUrlAbstract/FREE Full Text
  97. 97.↵
    1. Darsow T,
    2. Rieder SE,
    3. Emr SD
    . A multispecificity syntaxin homologue, Vam3p, essential for autophagic and biosynthetic protein transport to the vacuole. J Cell Biol. 1997;138:517–529.
    OpenUrlAbstract/FREE Full Text
  98. 98.↵
    1. Sato TK,
    2. Darsow T,
    3. Emr SD
    . Vam7p, a SNAP-25-like molecule, and Vam3p, a syntaxin homolog, function together in yeast vacuolar protein trafficking. Mol Cell Biol. 1998;18:5308–5319.
    OpenUrlAbstract/FREE Full Text
  99. 99.↵
    1. Mollard G. F.,
    2. Von, Stevens T. H.
    The Saccharomyces cerevisiae v-SNARE Vti1p is required for multiple membrane transport pathways to the vacuole. Mol. Biol. Cell 1999;10, 1719–1732
    OpenUrlAbstract/FREE Full Text
  100. 100.↵
    1. Wang C-W,
    2. Stromhaug PE,
    3. Kauffman EJ,
    4. Weisman LS,
    5. Klionsky DJ
    . Yeast homotypic vacuole fusion requires the Ccz1-Mon1 complex during the tethering/docking stage. J Cell Biol. 2003;163:973–985. doi:10.1083/jcb.200308071.
    OpenUrlAbstract/FREE Full Text
  101. 101.↵
    1. Wang C-W,
    2. Stromhaug PE,
    3. Shima J,
    4. Klionsky DJ
    . The Ccz1-Mon1 protein complex is required for the late step of multiple vacuole delivery pathways. J Biol Chem. 2002;277:47917–47927. doi:10.1074/jbc.M208191200.
    OpenUrlAbstract/FREE Full Text
  102. 102.↵
    1. Jäger S,
    2. Bucci C,
    3. Tanida I,
    4. Ueno T,
    5. Kominami E,
    6. Saftig P,
    7. Eskelinen E-L
    . Role for Rab7 in maturation of late autophagic vacuoles. J Cell Sci. 2004;117:4837–4848. doi:10.1242/jcs.01370.
    OpenUrlAbstract/FREE Full Text
  103. 103.↵
    1. Sanchez-Wandelmer J,
    2. Reggiori F
    . Amphisomes: out of the autophagosome shadow? EMBO J. 2013;32:3116–3118. doi:10.1038/emboj.2013.246.
    OpenUrlFREE Full Text
  104. 104.↵
    1. Yang Z,
    2. Huang J,
    3. Geng J,
    4. Nair U,
    5. Klionsky DJ
    . Atg22 recycles amino acids to link the degradative and recycling functions of autophagy. Mol Biol Cell. 2006;17:5094–5104. doi:10.1091/mbc.E06-06-0479.
    OpenUrlAbstract/FREE Full Text
  105. 105.↵
    World Health Organization. Global Health Risks: Mortality and Burden of Disease Attributable to Selected Major Risks. Geneva, Switzerland: WHO Press; 2009.
  106. 106.↵
    1. Nemchenko A,
    2. Chiong M,
    3. Turer A,
    4. Lavandero S,
    5. Hill JA
    . Autophagy as a therapeutic target in cardiovascular disease. J Mol Cell Cardiol. 2011;51:584–593. doi:10.1016/j.yjmcc.2011.06.010.
    OpenUrlCrossRefPubMed
  107. 107.↵
    1. Wang ZV,
    2. Rothermel BA,
    3. Hill JA
    . Autophagy in hypertensive heart disease. J Biol Chem. 2010;285:8509–8514. doi:10.1074/jbc.R109.025023.
    OpenUrlAbstract/FREE Full Text
  108. 108.↵
    1. Rothermel BA,
    2. Hill JA
    . Autophagy in load-induced heart disease. Circ Res. 2008;103:1363–1369. doi:10.1161/CIRCRESAHA.108.186551.
    OpenUrlAbstract/FREE Full Text
  109. 109.↵
    1. Rifki OF,
    2. Hill JA
    . Cardiac autophagy: good with the bad. J Cardiovasc Pharmacol. 2012;60:248–252. doi:10.1097/FJC.0b013e3182646cb1.
    OpenUrlCrossRefPubMed
  110. 110.↵
    1. Hill JA,
    2. Olson EN
    . Cardiac plasticity. N Engl J Med. 2008;358:1370–1380. doi:10.1056/NEJMra072139.
    OpenUrlCrossRefPubMed
  111. 111.↵
    1. Chiong M,
    2. Wang ZV,
    3. Pedrozo Z,
    4. Cao DJ,
    5. Troncoso R,
    6. Ibacache M,
    7. Criollo A,
    8. Nemchenko A,
    9. Hill JA,
    10. Lavandero S
    . Cardiomyocyte death: mechanisms and translational implications. Cell Death Dis. 2011;2:e244. doi:10.1038/cddis.2011.130.
    OpenUrlCrossRefPubMed
  112. 112.↵
    1. Lee E,
    2. Koo Y,
    3. Ng A,
    4. Wei Y,
    5. Luby-Phelps K,
    6. Juraszek A,
    7. Xavier RJ,
    8. Cleaver O,
    9. Levine B,
    10. Amatruda JF
    . Autophagy is essential for cardiac morphogenesis during vertebrate development. Autophagy. 2014;10:572–587. doi:10.4161/auto.27649.
    OpenUrlCrossRefPubMed
  113. 113.↵
    1. Chobanian AV,
    2. Bakris GL,
    3. Black HR,
    4. Cushman WC,
    5. Green LA,
    6. Izzo JL Jr.,
    7. Jones DW,
    8. Materson BJ,
    9. Oparil S,
    10. Wright JT Jr.,
    11. Roccella EJ
    ; Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. National Heart, Lung, and Blood Institute; National High Blood Pressure Education Program Coordinating Committee. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension. 2003;42:1206–1252. doi:10.1161/01.HYP.0000107251.49515.c2.
    OpenUrlCrossRefPubMed
  114. 114.↵
    1. Ocaranza MP,
    2. Michea L,
    3. Chiong M,
    4. Lagos CF,
    5. Lavandero S,
    6. Jalil JE
    . Recent insights and therapeutic perspectives of angiotensin-(1-9) in the cardiovascular system. Clin Sci (Lond). 2014;127:549–557. doi:10.1042/CS20130449.
    OpenUrlCrossRefPubMed
  115. 115.↵
    1. Nakai A,
    2. Yamaguchi O,
    3. Takeda T,
    4. Higuchi Y,
    5. Hikoso S,
    6. Taniike M,
    7. Omiya S,
    8. Mizote I,
    9. Matsumura Y,
    10. Asahi M,
    11. Nishida K,
    12. Hori M,
    13. Mizushima N,
    14. Otsu K
    . The role of autophagy in cardiomyocytes in the basal state and in response to hemodynamic stress. Nat Med. 2007;13:619–624. doi:10.1038/nm1574.
    OpenUrlCrossRefPubMed
  116. 116.↵
    1. Porrello ER,
    2. D’Amore A,
    3. Curl CL,
    4. Allen AM,
    5. Harrap SB,
    6. Thomas WG,
    7. Delbridge LM
    . Angiotensin II type 2 receptor antagonizes angiotensin II type 1 receptor-mediated cardiomyocyte autophagy. Hypertension. 2009;53:1032–1040. doi:10.1161/HYPERTENSIONAHA.108.128488.
    OpenUrlCrossRef
  117. 117.↵
    1. Steckelings UM,
    2. Unger T
    . Angiotensin receptors and autophagy: live and let die. Hypertension. 2009;53:898–899. doi:10.1161/HYPERTENSIONAHA.109.131425.
    OpenUrlCrossRef
  118. 118.↵
    1. Kovsan J,
    2. Blüher M,
    3. Tarnovscki T,
    4. Klöting N,
    5. Kirshtein B,
    6. Madar L,
    7. Shai I,
    8. Golan R,
    9. Harman-Boehm I,
    10. Schön MR,
    11. Greenberg AS,
    12. Elazar Z,
    13. Bashan N,
    14. Rudich A
    . Altered autophagy in human adipose tissues in obesity. J Clin Endocrinol Metab. 2011;96:E268–E277. doi:10.1210/jc.2010-1681.
    OpenUrlCrossRefPubMed
  119. 119.↵
    1. Xu X,
    2. Hua Y,
    3. Nair S,
    4. Sreejayan N,
    5. Zhang Y,
    6. Ren J
    . Akt2 knockout preserves cardiac function in high-fat diet-induced obesity by rescuing cardiac autophagosome maturation. J Mol Cell Biol. 2013;5:61–63. doi:10.1093/jmcb/mjs055.
    OpenUrlFREE Full Text
  120. 120.↵
    1. Ebato C,
    2. Uchida T,
    3. Arakawa M,
    4. Komatsu M,
    5. Ueno T,
    6. Komiya K,
    7. Azuma K,
    8. Hirose T,
    9. Tanaka K,
    10. Kominami E,
    11. Kawamori R,
    12. Fujitani Y,
    13. Watada H
    . Autophagy is important in islet homeostasis and compensatory increase of beta cell mass in response to high-fat diet. Cell Metab. 2008;8:325–332. doi:10.1016/j.cmet.2008.08.009.
    OpenUrlCrossRefPubMed
  121. 121.↵
    1. Jung HS,
    2. Chung KW,
    3. Won Kim J,
    4. et al
    . Loss of autophagy diminishes pancreatic beta cell mass and function with resultant hyperglycemia. Cell Metab. 2008;8:318–324. doi:10.1016/j.cmet.2008.08.013.
    OpenUrlCrossRefPubMed
  122. 122.↵
    1. Lim YM,
    2. Lim H,
    3. Hur KY,
    4. Quan W,
    5. Lee HY,
    6. Cheon H,
    7. Ryu D,
    8. Koo SH,
    9. Kim HL,
    10. Kim J,
    11. Komatsu M,
    12. Lee MS
    . Systemic autophagy insufficiency compromises adaptation to metabolic stress and facilitates progression from obesity to diabetes. Nat Commun. 2014;5:4934. doi:10.1038/ncomms5934.
    OpenUrlCrossRefPubMed
  123. 123.↵
    1. Quan W,
    2. Hur KY,
    3. Lim Y,
    4. Oh SH,
    5. Lee JC,
    6. Kim KH,
    7. Kim GH,
    8. Kim SW,
    9. Kim HL,
    10. Lee MK,
    11. Kim KW,
    12. Kim J,
    13. Komatsu M,
    14. Lee MS
    . Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice. Diabetologia. 2012;55:392–403. doi:10.1007/s00125-011-2350-y.
    OpenUrlCrossRefPubMed
  124. 124.
    1. Fujitani Y,
    2. Ebato C,
    3. Uchida T,
    4. Kawamori R,
    5. Watada H
    . β-cell autophagy: A novel mechanism regulating β-cell function and mass: Lessons from β-cell-specific Atg7-deficient mice. Islets. 2009;1:151–153. doi:10.4161/isl.1.2.9057.
    OpenUrlCrossRefPubMed
  125. 125.
    1. Marsh BJ,
    2. Soden C,
    3. Alarcón C,
    4. Wicksteed BL,
    5. Yaekura K,
    6. Costin AJ,
    7. Morgan GP,
    8. Rhodes CJ
    . Regulated autophagy controls hormone content in secretory-deficient pancreatic endocrine beta-cells. Mol Endocrinol. 2007;21:2255–2269. doi:10.1210/me.2007-0077.
    OpenUrlCrossRefPubMed
  126. 126.
    1. Sciarretta S,
    2. Zhai P,
    3. Shao D,
    4. Maejima Y,
    5. Robbins J,
    6. Volpe M,
    7. Condorelli G,
    8. Sadoshima J
    . Rheb is a critical regulator of autophagy during myocardial ischemia: pathophysiological implications in obesity and metabolic syndrome. Circulation. 2012;125:1134–1146. doi:10.1161/CIRCULATIONAHA.111.078212.
    OpenUrlAbstract/FREE Full Text
  127. 127.
    1. Mellor KM,
    2. Bell JR,
    3. Young MJ,
    4. Ritchie RH,
    5. Delbridge LM
    . Myocardial autophagy activation and suppressed survival signaling is associated with insulin resistance in fructose-fed mice. J Mol Cell Cardiol. 2011;50:1035–1043. doi:10.1016/j.yjmcc.2011.03.002.
    OpenUrlCrossRefPubMed
  128. 128.↵
    1. Masini M,
    2. Bugliani M,
    3. Lupi R,
    4. del Guerra S,
    5. Boggi U,
    6. Filipponi F,
    7. Marselli L,
    8. Masiello P,
    9. Marchetti P
    . Autophagy in human type 2 diabetes pancreatic beta cells. Diabetologia. 2009;52:1083–1086. doi:10.1007/s00125-009-1347-2.
    OpenUrlCrossRefPubMed
  129. 129.↵
    1. Marambio P,
    2. Toro B,
    3. Sanhueza C,
    4. et al
    . Glucose deprivation causes oxidative stress and stimulates aggresome formation and autophagy in cultured cardiac myocytes. Biochim Biophys Acta. 2010;1802:509–518. doi:10.1016/j.bbadis.2010.02.002.
    OpenUrlCrossRefPubMed
  130. 130.↵
    1. Maruyama R,
    2. Goto K,
    3. Takemura G,
    4. Ono K,
    5. Nagao K,
    6. Horie T,
    7. Tsujimoto A,
    8. Kanamori H,
    9. Miyata S,
    10. Ushikoshi H,
    11. Nagashima K,
    12. Minatoguchi S,
    13. Fujiwara T,
    14. Fujiwara H
    . Morphological and biochemical characterization of basal and starvation-induced autophagy in isolated adult rat cardiomyocytes. Am J Physiol Heart Circ Physiol. 2008;295:H1599–H1607. doi:10.1152/ajpheart.91449.2007.
    OpenUrlAbstract/FREE Full Text
  131. 131.↵
    1. Kanamori H,
    2. Takemura G,
    3. Maruyama R,
    4. Goto K,
    5. Tsujimoto A,
    6. Ogino A,
    7. Li L,
    8. Kawamura I,
    9. Takeyama T,
    10. Kawaguchi T,
    11. Nagashima K,
    12. Fujiwara T,
    13. Fujiwara H,
    14. Seishima M,
    15. Minatoguchi S
    . Functional significance and morphological characterization of starvation-induced autophagy in the adult heart. Am J Pathol. 2009;174:1705–1714. doi:10.2353/ajpath.2009.080875.
    OpenUrlCrossRefPubMed
  132. 132.↵
    1. Mizushima N,
    2. Yamamoto A,
    3. Matsui M,
    4. Yoshimori T,
    5. Ohsumi Y
    . In vivo analysis of autophagy in response to nutrient starvation using transgenic mice expressing a fluorescent autophagosome marker. Mol Biol Cell. 2004;15:1101–1111. doi:10.1091/mbc.E03-09-0704.
    OpenUrlAbstract/FREE Full Text
  133. 133.↵
    1. Salabei JK,
    2. Hill BG
    . Implications of autophagy for vascular smooth muscle cell function and plasticity. Free Radic Biol Med. 2013;65:693–703. doi:10.1016/j.freeradbiomed.2013.08.003.
    OpenUrlCrossRefPubMed
  134. 134.↵
    1. De Meyer GR,
    2. Martinet W
    . Autophagy in the cardiovascular system. Biochim Biophys Acta. 2009;1793:1485–1495. doi:10.1016/j.bbamcr.2008.12.011.
    OpenUrlPubMed
  135. 135.↵
    1. Cao DJ,
    2. Hill JA
    . Titrating autophagy in cardiac plasticity. Autophagy. 2011;7:1078–1079.
    OpenUrlCrossRefPubMed
  136. 136.↵
    1. Lavandero S,
    2. Troncoso R,
    3. Rothermel BA,
    4. Martinet W,
    5. Sadoshima J,
    6. Hill JA
    . Cardiovascular autophagy: concepts, controversies, and perspectives. Autophagy. 2013;9:1455–1466. doi:10.4161/auto.25969.
    OpenUrlCrossRefPubMed
  137. 137.↵
    1. Wang ZV,
    2. Ferdous A,
    3. Hill JA
    . Cardiomyocyte autophagy: metabolic profit and loss. Heart Fail Rev. 2013;18:585–594. doi:10.1007/s10741-012-9350-y.
    OpenUrlCrossRefPubMed
  138. 138.↵
    1. Ryter SW,
    2. Lee SJ,
    3. Smith A,
    4. Choi AM
    . Autophagy in vascular disease. Proc Am Thorac Soc. 2010;7:40–47. doi:10.1513/pats.200909-100JS.
    OpenUrlCrossRefPubMed
  139. 139.↵
    1. Zhang H,
    2. Bosch-Marce M,
    3. Shimoda LA,
    4. Tan YS,
    5. Baek JH,
    6. Wesley JB,
    7. Gonzalez FJ,
    8. Semenza GL
    . Mitochondrial autophagy is an HIF-1-dependent adaptive metabolic response to hypoxia. J Biol Chem. 2008;283:10892–10903. doi:10.1074/jbc.M800102200.
    OpenUrlAbstract/FREE Full Text
  140. 140.↵
    1. Matsui Y,
    2. Takagi H,
    3. Qu X,
    4. Abdellatif M,
    5. Sakoda H,
    6. Asano T,
    7. Levine B,
    8. Sadoshima J
    . Distinct roles of autophagy in the heart during ischemia and reperfusion: roles of AMP-activated protein kinase and Beclin 1 in mediating autophagy. Circ Res. 2007;100:914–922. doi:10.1161/01.RES.0000261924.76669.36.
    OpenUrlAbstract/FREE Full Text
  141. 141.↵
    1. Troncoso R,
    2. Vicencio JM,
    3. Parra V,
    4. et al
    . Energy-preserving effects of IGF-1 antagonize starvation-induced cardiac autophagy. Cardiovasc Res. 2012;93:320–329. doi:10.1093/cvr/cvr321.
    OpenUrlAbstract/FREE Full Text
  142. 142.↵
    1. Valentim L,
    2. Laurence KM,
    3. Townsend PA,
    4. Carroll CJ,
    5. Soond S,
    6. Scarabelli TM,
    7. Knight RA,
    8. Latchman DS,
    9. Stephanou A
    . Urocortin inhibits Beclin1-mediated autophagic cell death in cardiac myocytes exposed to ischaemia/reperfusion injury. J Mol Cell Cardiol. 2006;40:846–852. doi:10.1016/j.yjmcc.2006.03.428.
    OpenUrlCrossRefPubMed
  143. 143.↵
    1. Yan L,
    2. Vatner DE,
    3. Kim SJ,
    4. Ge H,
    5. Masurekar M,
    6. Massover WH,
    7. Yang G,
    8. Matsui Y,
    9. Sadoshima J,
    10. Vatner SF
    . Autophagy in chronically ischemic myocardium. Proc Natl Acad Sci USA. 2005;102:13807–13812. doi:10.1073/pnas.0506843102.
    OpenUrlAbstract/FREE Full Text
  144. 144.↵
    1. Huang C,
    2. Liu W,
    3. Perry CN,
    4. Yitzhaki S,
    5. Lee Y,
    6. Yuan H,
    7. Tsukada YT,
    8. Hamacher-Brady A,
    9. Mentzer RM Jr.,
    10. Gottlieb RA
    . Autophagy and protein kinase C are required for cardioprotection by sulfaphenazole. Am J Physiol Heart Circ Physiol. 2010;298:H570–H579. doi:10.1152/ajpheart.00716.2009.
    OpenUrlAbstract/FREE Full Text
  145. 145.↵
    1. Decker RS,
    2. Wildenthal K
    . Lysosomal alterations in hypoxic and reoxygenated hearts. I. Ultrastructural and cytochemical changes. Am J Pathol. 1980;98:425–444.
    OpenUrlPubMed
  146. 146.↵
    1. Gurusamy N,
    2. Lekli I,
    3. Gorbunov NV,
    4. Gherghiceanu M,
    5. Popescu LM,
    6. Das DK
    . Cardioprotection by adaptation to ischaemia augments autophagy in association with BAG-1 protein. J Cell Mol Med. 2009;13:373–387. doi:10.1111/j.1582-4934.2008.00495.x.
    OpenUrlCrossRefPubMed
  147. 147.↵
    1. Huang C,
    2. Yitzhaki S,
    3. Perry CN,
    4. Liu W,
    5. Giricz Z,
    6. Mentzer RM Jr.,
    7. Gottlieb RA
    . Autophagy induced by ischemic preconditioning is essential for cardioprotection. J Cardiovasc Transl Res. 2010;3:365–373. doi:10.1007/s12265-010-9189-3.
    OpenUrlCrossRefPubMed
  148. 148.
    1. Ma X,
    2. Liu H,
    3. Foyil SR,
    4. Godar RJ,
    5. Weinheimer CJ,
    6. Hill JA,
    7. Diwan A
    . Impaired autophagosome clearance contributes to cardiomyocyte death in ischemia/reperfusion injury. Circulation. 2012;125:3170–3181. doi:10.1161/CIRCULATIONAHA.111.041814.
    OpenUrlAbstract/FREE Full Text
  149. 149.↵
    1. Ma X,
    2. Liu H,
    3. Foyil SR,
    4. Godar RJ,
    5. Weinheimer CJ,
    6. Diwan A
    . Autophagy is impaired in cardiac ischemia-reperfusion injury. Autophagy. 2012;8:1394–1396. doi:10.4161/auto.21036.
    OpenUrlCrossRefPubMed
  150. 150.
    1. Hein S,
    2. Arnon E,
    3. Kostin S,
    4. Schönburg M,
    5. Elsässer A,
    6. Polyakova V,
    7. Bauer EP,
    8. Klövekorn WP,
    9. Schaper J
    . Progression from compensated hypertrophy to failure in the pressure-overloaded human heart: structural deterioration and compensatory mechanisms. Circulation. 2003;107:984–991.
    OpenUrlAbstract/FREE Full Text
  151. 151.↵
    1. Zhu H,
    2. Tannous P,
    3. Johnstone JL,
    4. Kong Y,
    5. Shelton JM,
    6. Richardson JA,
    7. Le V,
    8. Levine B,
    9. Rothermel BA,
    10. Hill JA
    . Cardiac autophagy is a maladaptive response to hemodynamic stress. J Clin Invest. 2007;117:1782–1793. doi:10.1172/JCI27523.
    OpenUrlCrossRefPubMed
  152. 152.↵
    1. Cao DJ,
    2. Wang ZV,
    3. Battiprolu PK,
    4. Jiang N,
    5. Morales CR,
    6. Kong Y,
    7. Rothermel BA,
    8. Gillette TG,
    9. Hill JA
    . Histone deacetylase (HDAC) inhibitors attenuate cardiac hypertrophy by suppressing autophagy. Proc Natl Acad Sci USA. 2011;108:4123–4128. doi:10.1073/pnas.1015081108.
    OpenUrlAbstract/FREE Full Text
  153. 153.↵
    1. Kostin S,
    2. Pool L,
    3. Elsässer A,
    4. Hein S,
    5. Drexler HC,
    6. Arnon E,
    7. Hayakawa Y,
    8. Zimmermann R,
    9. Bauer E,
    10. Klövekorn WP,
    11. Schaper J
    . Myocytes die by multiple mechanisms in failing human hearts. Circ Res. 2003;92:715–724. doi:10.1161/01.RES.0000067471.95890.5C.
    OpenUrlAbstract/FREE Full Text
  154. 154.↵
    1. Saijo M,
    2. Takemura G,
    3. Koda M,
    4. Okada H,
    5. Miyata S,
    6. Ohno Y,
    7. Kawasaki M,
    8. Tsuchiya K,
    9. Nishigaki K,
    10. Minatoguchi S,
    11. Goto K,
    12. Fujiwara H
    . Cardiomyopathy with prominent autophagic degeneration, accompanied by an elevated plasma brain natriuretic peptide level despite the lack of overt heart failure. Intern Med. 2004;43:700–703.
    OpenUrlCrossRefPubMed
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  • Molecular Mechanisms of Autophagy in the Cardiovascular System
    Damián Gatica, Mario Chiong, Sergio Lavandero and Daniel J. Klionsky
    Circulation Research. 2015;116:456-467, originally published January 29, 2015
    https://doi.org/10.1161/CIRCRESAHA.114.303788
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