生物化学セミナー

生物化学セミナー
総合生命科学部生命科学セミナー
演者： Prof. Agnieszka Chacinska
（ポーランド・ワルシャワ国際細胞生物学研究所）
日時： 2016年8月31日（水）16：00～17：00
場所：京都産業大学総合生命科学部15号館1階 15102セミナー室
http://www.kyoto-su.ac.jp/access.html
演題：Oxidation of mitochondrial membrane proteins
Mitochondrial proteins require essential and sophisticated machineries to reach their intramitochondrial 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.
Agnieszka Chacinska
International Institute of
Molecular and Cell
Biology in Warsaw,
Poland
世話人：京都産業大学総合生命科学部
遠藤斗志也
共催：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」

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