Published online before print April 25, 2002, doi: 10.1161/01.RES.0000019580.64013.31
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on November 26, 2001
Revised on April 12, 2002
Accepted on April 12, 2002
Connexin43 and Connexinx45 Form Heteromeric Gap Junction Channels in Which Individual Components Determine Permeability and Regulation
Agustin D. Martinez ;
From the Department of Pediatrics (A.D.M., E.C.B.), University of Chicago, Chicago, Ill, and the Krannert Institute of Cardiology (A.P.M.), Indiana University, Indianapolis.
* To whom correspondence should be addressed. E-mail: ebeyer{at}peds.bsd.uchicago.edu.
Two gap junction proteins, connexin43 (Cx43) and connexin45 (Cx45), are coexpressed in many cardiac and other cells. Homomeric channels formed by these proteins differ in unitary conductance, permeability, and regulation. We sought to determine the ability of Cx43 and Cx45 to oligomerize with each other to form heteromeric gap junction channels and to determine the functional and regulatory properties of these heteromeric channels. HeLa cells were transfected with Cx45 or (His)6-tagged Cx43 or sequentially transfected with both connexins. Immunoblots verified production of the transfected connexins, and immunofluorescence demonstrated that they were colocalized in the HeLa-Cx43(His)6/Cx45 cells. Connexons were solubilized from HeLa-Cx43(His)6/Cx45 cells by using Triton X-100 and were applied to a Ni2+-NTA column, which binds the His6 sequence. Cx45 was coeluted from the column with Cx43(His)6, demonstrating that some hemichannels contain both connexins. Single-channel recordings showed that the HeLa-Cx43(His)6/Cx45 cells exhibited single-channel conductances that were not observed in cells expressing either connexin alone. Dye-coupling experiments showed that HeLa-Cx43(His)6 cells readily passed Lucifer yellow and N-(2-aminoethyl)biotinamide hydrochloride (neurobiotin); in contrast, HeLa-Cx45 and HeLa-Cx43(His)6/Cx45 cells showed extensive intercellular passage of neurobiotin but little coupling with Lucifer yellow. Treatment with the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate reduced junctional conductance in cells expressing Cx43, Cx45, or both connexins, but it reduced the extent of neurobiotin transfer only in HeLa-Cx43(His)6 and HeLa-Cx43(His)6/Cx45 cells but not in the HeLa-Cx45 cells. Thus, biochemical and electrophysiological evidence suggests that Cx43 and Cx45 extensively mix to form heteromeric channels; however, individual connexin components dominate aspects of the physiological behavior of these channels.
Key words: intercellular communication • heteromeric channels • gap junctions • permeability • protein kinase C
This article has been cited by other articles:
 |
|
 |
|
  F. Lima, C. Niger, C. Hebert, and J. P. Stains Connexin43 Potentiates Osteoblast Responsiveness to Fibroblast Growth Factor 2 via a Protein Kinase C-Delta/Runx2-dependent Mechanism Mol. Biol. Cell, June 1, 2009; 20(11): 2697 - 2708. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. J. Severs, A. F. Bruce, E. Dupont, and S. Rothery Remodelling of gap junctions and connexin expression in diseased myocardium Cardiovasc Res, October 1, 2008; 80(1): 9 - 19. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X.-H. Weng, P. M. Piermarini, A. Yamahiro, M.-J. Yu, D. J. Aneshansley, and K. W. Beyenbach Gap junctions in Malpighian tubules of Aedes aegypti J. Exp. Biol., February 1, 2008; 211(3): 409 - 422. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Wang, V. M. Berthoud, and E. C. Beyer Connexin43 increases the sensitivity of prostate cancer cells to TNF{alpha}-induced apoptosis J. Cell Sci., January 15, 2007; 120(2): 320 - 329. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. D. Lampe, C. D. Cooper, T. J. King, and J. M. Burt Analysis of Connexin43 phosphorylated at S325, S328 and S330 in normoxic and ischemic heart J. Cell Sci., August 15, 2006; 119(16): 3435 - 3442. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. A. Ayad, D. Locke, I. V. Koreen, and A. L. Harris Heteromeric, but Not Homomeric, Connexin Channels Are Selectively Permeable to Inositol Phosphates J. Biol. Chem., June 16, 2006; 281(24): 16727 - 16739. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Gemel, X. Lin, R. D. Veenstra, and E. C. Beyer N-terminal residues in Cx43 and Cx40 determine physiological properties of gap junction channels, but do not influence heteromeric assembly with each other or with Cx26 J. Cell Sci., June 1, 2006; 119(11): 2258 - 2268. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Betsuyaku, N. S. Nnebe, R. Sundset, S. Patibandla, C. M. Krueger, and K. A. Yamada Overexpression of cardiac connexin45 increases susceptibility to ventricular tachyarrhythmias in vivo Am J Physiol Heart Circ Physiol, January 1, 2006; 290(1): H163 - H171. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Vogalis, C. C. Hegg, and M. T. Lucero Electrical Coupling in Sustentacular Cells of the Mouse Olfactory Epithelium J Neurophysiol, August 1, 2005; 94(2): 1001 - 1012. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. P. Moreno, V. M. Berthoud, G. Perez-Palacios, and E. M. Perez-Armendariz Biophysical evidence that connexin-36 forms functional gap junction channels between pancreatic mouse {beta}-cells Am J Physiol Endocrinol Metab, May 1, 2005; 288(5): E948 - E956. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Stains and R. Civitelli Gap Junctions Regulate Extracellular Signal-regulated Kinase Signaling to Affect Gene Transcription Mol. Biol. Cell, January 1, 2005; 16(1): 64 - 72. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. G. Akar, D. D. Spragg, R. S. Tunin, D. A. Kass, and G. F. Tomaselli Mechanisms Underlying Conduction Slowing and Arrhythmogenesis in Nonischemic Dilated Cardiomyopathy Circ. Res., October 1, 2004; 95(7): 717 - 725. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Gemel, V. Valiunas, P. R. Brink, and E. C. Beyer Connexin43 and connexin26 form gap junctions, but not heteromeric channels in co-expressing cells J. Cell Sci., May 15, 2004; 117(12): 2469 - 2480. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Poelzing, F. G. Akar, E. Baron, and D. S. Rosenbaum Heterogeneous connexin43 expression produces electrophysiological heterogeneities across ventricular wall Am J Physiol Heart Circ Physiol, May 1, 2004; 286(5): H2001 - H2009. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. P Moreno Biophysical properties of homomeric and heteromultimeric channels formed by cardiac connexins Cardiovasc Res, May 1, 2004; 62(2): 276 - 286. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-A. Haefliger, P. Nicod, and P. Meda Contribution of connexins to the function of the vascular wall Cardiovasc Res, May 1, 2004; 62(2): 345 - 356. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Camelliti, G. P Devlin, K. G Matthews, P. Kohl, and C. R Green Spatially and temporally distinct expression of fibroblast connexins after sheep ventricular infarction Cardiovasc Res, May 1, 2004; 62(2): 415 - 425. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Camelliti, C. R. Green, I. LeGrice, and P. Kohl Fibroblast Network in Rabbit Sinoatrial Node: Structural and Functional Identification of Homogeneous and Heterogeneous Cell Coupling Circ. Res., April 2, 2004; 94(6): 828 - 835. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Saffitz and A. G. Kleber Effects of Mechanical Forces and Mediators of Hypertrophy on Remodeling of Gap Junctions in the Heart Circ. Res., March 19, 2004; 94(5): 585 - 591. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. SAEZ, V. M. BERTHOUD, M. C. BRANES, A. D. MARTINEZ, and E. C. BEYER Plasma Membrane Channels Formed by Connexins: Their Regulation and Functions Physiol Rev, October 1, 2003; 83(4): 1359 - 1400. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Stains, F. Lecanda, J. Screen, D. A. Towler, and R. Civitelli Gap Junctional Communication Modulates Gene Transcription by Altering the Recruitment of Sp1 and Sp3 to Connexin-response Elements in Osteoblast Promoters J. Biol. Chem., June 27, 2003; 278(27): 24377 - 24387. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Thomas, N. Zosso, I. Scerri, N. Demaurex, M. Chanson, and O. Staub A tyrosine-based sorting signal is involved in connexin43 stability and gap junction turnover J. Cell Sci., June 1, 2003; 116(11): 2213 - 2222. [Abstract] [Full Text] [PDF]
|
|