title: The mitochondrial import protein Mim1 promotes biogenesis of multispanning outer membrane proteins.
abstract: 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 β-barrel proteins of the outer membrane. Several α-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 α-helical outer membrane proteins with multiple transmembrane segments.
authors.affiliation: Institute for Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.forename: Lena-Sophie
authors.initials: LS
authors.lastname: Wenz
authors.forename: Vivien
authors.initials: V
authors.lastname: Krüger
authors.forename: Waltraut
authors.initials: W
authors.lastname: Lehmann
authors.forename: Judith M
authors.initials: JM
authors.lastname: Müller
authors.forename: Luise
authors.initials: L
authors.lastname: Goroncy
authors.forename: Nicole
authors.initials: N
authors.lastname: Zufall
authors.forename: Trevor
authors.initials: T
authors.lastname: Lithgow
authors.forename: Bernard
authors.initials: B
authors.lastname: Guiard
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Chacinska
authors.forename: Richard
authors.initials: R
authors.lastname: Wagner
authors.forename: Chris
authors.initials: C
authors.lastname: Meisinger
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pfanner
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C492709:MIM1 protein, S cerevisiae; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C078718:SCM4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C489039:TOM70 protein, S cerevisiae; D014157:Transcription Factors