Ups1p and Ups2p antagonistically regulate cardiolipin metabolism in mitochondria

Yasushi Tamura, Toshiya Endo, Miho Iijima, Hiromi Sesaki

Research output: Contribution to journalArticlepeer-review

Abstract

Cardiolipin, a unique phospholipid composed of four fatty acid chains, is located mainly in the mitochondrial inner membrane (IM). Cardiolipin is required for the integrity of several protein complexes in the IM, including the TIM23 translocase, a dynamic complex which mediates protein import into the mitochondria through interactions with the import motor presequence translocase-associated motor (PAM). In this study, we report that two homologous intermembrane space proteins, Ups1p and Ups2p, control cardiolipin metabolism and affect the assembly state of TIM23 and its association with PAM in an opposing manner. In ups1. mitochondria, cardiolipin levels were decreased, and the TIM23 translocase showed altered conformation and decreased association with PAM, leading to defects in mitochondrial protein import. Strikingly, loss of Ups2p restored normal cardiolipin levels and rescued TIM23 defects in ups1. mitochondria. Furthermore, we observed synthetic growth defects in ups mutants in combination with loss of Pam17p, which controls the integrity of PAM. Our findings provide a novel molecular mechanism for the regulation of cardiolipin metabolism.

Original languageEnglish (US)
Pages (from-to)1029-1045
Number of pages17
JournalJournal of Cell Biology
Volume185
Issue number6
DOIs
StatePublished - Jun 15 2009

ASJC Scopus subject areas

  • Cell Biology

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