title: Sam35 of the mitochondrial protein sorting and assembly machinery is a peripheral outer membrane protein essential for cell viability.
abstract: The mitochondrial outer membrane contains two integral proteins essential for cell viability, Tom40 of the translocase of the outer membrane (TOM complex) and Sam50 of the sorting and assembly machinery (SAM complex). Here we report the identification of Sam35, the first peripheral mitochondrial outer membrane protein that is essential for cell viability. Sam35 (encoded by the Saccharomyces cerevisiae ORF YHR083w) is a novel subunit of the SAM complex and is crucial for the assembly pathway of outer membrane beta-barrel proteins, such as the precursors of Tom40 and porin. Sam35 is not required for the import of inner membrane or matrix targeted proteins. The presence of two essential proteins in the SAM complex, Sam35 and Sam50, indicates that it plays a central role in mitochondrial biogenesis.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universität Freiburg, D-79104 Freiburg, Germany.
authors.forename: Dusanka
authors.initials: D
authors.lastname: Milenkovic
authors.forename: Vera
authors.initials: V
authors.lastname: Kozjak
authors.forename: Nils
authors.initials: N
authors.lastname: Wiedemann
authors.forename: Christiane
authors.initials: C
authors.lastname: Lohaus
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Meyer
authors.forename: Bernard
authors.initials: B
authors.lastname: Guiard
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pfanner
authors.forename: Chris
authors.initials: C
authors.lastname: Meisinger
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D008565:Membrane Proteins / Q000737:chemistry*; D026901:Membrane Transport Proteins / Q000737:chemistry; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000502:physiology*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000502:physiology*; D013696:Temperature
chemical_list: D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C487332:Sam35 protein, S cerevisiae; C487333:Sam50 protein, S cerevisiae; C066555:Tom40 protein, S cerevisiae