The mitochondrial import protein Mim1 promotes biogenesis of multispanning outer membrane proteins

Thomas Becker, Lena-Sophie Wenz, Vivien Kruger, Waltraut Lehmann, Judith Muller, Luise Goroncy, Nicole Zufall, Trevor Lithgow, Bernard Guiard, Agnieszka Chacinska, Richard Wagner, Chris Meisinger, Nikolaus Pfanner

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84 Citations (Scopus)


The mitochondrial outer membrane contains translocase complexes for the import of precursor proteins. The translocase of the outer membrane complex functions as a general preprotein entry gate, whereas the sorting and assembly machinery complex mediates membrane insertion of beta-barrel proteins of the outer membrane. Several alpha-helical outer membrane proteins are known to carry multiple transmembrane segments; however, only limited information is available on the biogenesis of these proteins. We report that mitochondria lacking the mitochondrial import protein 1 (Mim1) are impaired in the biogenesis of multispanning outer membrane proteins, whereas overexpression of Mim1 stimulates their import. The Mim1 complex cooperates with the receptor Tom70 in binding of precursor proteins and promotes their insertion and assembly into the outer membrane. We conclude that the Mim1 complex plays a central role in the import of alpha-helical outer membrane proteins with multiple transmembrane segments.
Original languageEnglish
Pages (from-to)387 - 395
Number of pages9
JournalJournal of Cell Biology
Issue number3
Publication statusPublished - 2011

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