title: A crucial role for Mim2 in the biogenesis of mitochondrial outer membrane proteins.
abstract: Most of the mitochondrial outer membrane (MOM) proteins contain helical transmembrane domains. Some of the single-span proteins and all known multiple-span proteins are inserted into the membrane in a pathway that depends on the MOM protein Mitochondrial Import 1 (Mim1). So far it has been unknown whether additional proteins are required for this process. Here, we describe the identification and characterization of Mim2, a novel protein of the MOM that has a crucial role in the biogenesis of MOM helical proteins. Mim2 physically and genetically interacts with Mim1, and both proteins form the MIM complex. Cells lacking Mim2 exhibit a severely reduced growth rate and lower steady-state levels of helical MOM proteins. In addition, absence of Mim2 leads to compromised assembly of the translocase of the outer mitochondrial membrane (TOM complex), hampered mitochondrial protein import, and defects in mitochondrial morphology. In summary, the current study demonstrates that Mim2 is a novel central player in the biogenesis of MOM proteins.
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen,  Germany.
authors.forename: Kai S
authors.initials: KS
authors.lastname: Dimmer
authors.forename: Drazen
authors.initials: D
authors.lastname: Papić
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schumann
authors.forename: Desirée
authors.initials: D
authors.lastname: Sperl
authors.forename: Katrin
authors.initials: K
authors.lastname: Krumpe
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Walther
authors.forename: Doron
authors.initials: D
authors.lastname: Rapaport
mesh_terms: D000595:Amino Acid Sequence; D008565:Membrane Proteins / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism*; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C492709:MIM1 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins