Author: Schuler, M.-H., Di Bartolomeo, F., Böttinger, L., Horvath, S. E., Wenz, L.-S., Daum, G., & Becker, T.
Description: Two protein translocases drive the import of B-barrel precursor proteins into the mitochondrial outer membrane: The translocase of the outer membrane (TOM complex) promotes transport of the precursor to the intermembrane space, whereas the sorting and assembly machinery (SAM complex) mediates subsequent folding of the B-barrel and its integration into the target membrane. The non-bilayer-forming phospholipids phosphatidylethanolamine (PE) and cardiolipin (CL) are required for the biogenesis of B-barrel proteins. Whether bilayer-forming phospholipids such as phosphatidylcholine (PC), the most abundant phospholipid of the mitochondrial outer membrane, play a role in the import of B-barrel precursors is unclear. In this study, we show that PC is required for stability and function of the SAM complex during the biogenesis of B-barrel proteins. PC further promotes the SAM-dependent assembly of the TOM complex, indicating a general role of PC for the function of the SAM complex. In contrast to PE-deficient mitochondria precursor accumulation at the TOM complex is not affected by depletion of PC. We conclude that PC and PE affect the function of distinct protein translocases in mitochondrial B-barrel biogenesis.
Subject headings: Mitochondria; Phosphatidylcholine; Phosphatidylethanolamine; Protein complex; Protein sorting; Protein translocation; SAM complex; TOM complex
Publication year: 2015
Journal or book title: Journal of Biological Chemistry
Volume: 290
Issue: 44
Pages: 26523–26532
Find the full text: https://www.strategian.com/fulltext/Schuler2015.pdf
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Type: Journal article
Serial number: 3145