Interaction of mitofilin with respiratory complexes in mitochondrial subpopulations

Abstract

Mitofilin, a mitochondrial inner membrane structural protein is central to mitochondrial inner membrane organizing system (MINOS) and mitochondrial organizing structure (MitOS). Interactions of mitofilin with outer and inner membrane proteins have been reported to be crucial for mitochondrial membrane organization and morphology. Moreover, MitOS has been shown to function in concert with ATP synthase dimers. However, interaction of mitofilin with the respiratory complex is not known. The goal of this study was to investigate potential interactions of mitofilin with the respiratory complex in cardiac mitochondrial subpopulations. Cardiac mitochondria are comprised of two spatially located mitochondria, subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM). Using a gel based technique, mitochondrial proteins immunoprecipitated with mitofilin were subjected to LC‐ESI‐MS analysis. Thirty‐six respiratory chain proteins from complexes I, II, III, IV, and V were identified in an immunoprecipitated complex. Furthermore, interaction of mitofilin with F0‐ATP synthase subunits b and d in the immunoprecipitated complex was observed to a greater extent in the IFM as compared to the SSM. Together these results suggest that interaction of mitofilin with the respiratory chain may differ in mitochondrial subpopulations. (Support: NIH DP2DK083095, NIH T32HL090610, AHA 10PRE3420006)