Mitochondrial proteins require essential and sophisticated machineries to reach their intra-mitochondrial location. The mitochondrial intermembrane space assembly (MIA) pathway is dedicated to the redox-dependent import and biogenesis of proteins localized to the intermembrane space of mitochondria. The oxidoreductase Mia40 is a central component of the pathway responsible for the transfer of disulfide bonds to intermembrane space precursor proteins causing their oxidative folding. We identified Tim22, a multispanning membrane protein and core component of the TIM22 translocase, as a protein with cysteine residues undergoing oxidation during Tim22 biogenesis. Tim22 forms a disulfide-bonded intermediate with Mia40 upon import into mitochondria. Interestingly, Mia40 binds the Tim22 precursor also via non-covalent interactions. Tim22 belongs to the Tim17/Tim22/Tim23 family of protein translocases. Disulfide bond formation in Tim17 and Tim22 are conserved among fungi and metazoan. Yeast and human Tim22 variants that are not oxidized do not properly integrate into the membrane complex. Consistently, the lack of Tim17 oxidation disrupts the TIM23 translocase complex. The findings underline the importance of disulfide bond formation for mature translocase assembly through membrane stabilization of weak transmembrane domains.

日　時	2016年8月31日（水） 16:00～17:00（15:45開場）
場　所	京都産業大学 15号館1階15102セミナー室
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備　考	事前申込不要・入場無料

なお、本セミナーは、JSPS 科研費 15H05705 「ミトコンドリア生合成を司る細胞内統合的ネットワークの解明」の助成を受けています。