Abstract 234: Mitofilin Directly Interacts With Cyclophilin D in the Inner Membrane of Heart Mitochondria
Introduction: We recently found that acute estrogen treatment delays the mitochondrial permeability transition pore (mPTP) opening and reduces ROS production after ischemia/reperfusion, suggesting that estrogen promotes mitochondrial integrity. As mitochondrial inner membrane protein (mitofilin) has been found to control mitochondrial cristae morphology and function, and cyclophylin-D is a mitochondrial peptidyl-prolyl isomerase known to modulate the opening of the mPTP, we investigated whether a direct interaction between these two proteins exist in the inner membrane of mitochondria.
Methods: Western blot analysis and immunoprecipitation were performed in isolated heart mitochondrial fractions from male WT (C57BL/6NCrL) mice using mitofilin and cyclophilin-D monoclonal antibodies of. Mitofilin and cyclophylin-D distribution in isolated cardiomyocytes as well as in single mitochondria was also visualized using high resolution microscopy.
Results: Western blot analysis shows that both mitofilin and cyclophilin-D proteins were abundantly expressed in the heart mitochondria. Immunoprecipitation with mitofilin antibody pulled down cyclophilin-D, which was detected by Western blot analysis. Co-immunoprecipitation with cyclophylin-D antibody confirms its direct association with mitofilin as mitofilin was detected by Western analysis in the immunoprecipitated product. High resolution microscopy revealed a higher degree of colocalization between mitofilin and cyclophylin-D in both cardiomyocytes and mitochondrial fractions.
Conclusion: Together, these data indicate that mitofilin directly interacts with cyclophylin-D in the inner membrane of heart mitochondria. As mitofilin plays an important role in controlling mitochondrial cristae morphology and cyclophylin-D, known to modulate the opening of the mPTP, this interaction between mitofilin-cyclophilin-D may have an impact in the opening of the mPT pore.
Author Disclosures: J. Bopassa: None.
- © 2015 by American Heart Association, Inc.