title: Sam37 is crucial for formation of the mitochondrial TOM-SAM supercomplex, thereby promoting β-barrel biogenesis.
abstract: Biogenesis of mitochondrial β-barrel proteins requires two preprotein translocases, the general translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). TOM and SAM form a supercomplex that promotes transfer of β-barrel precursors. The SAM core complex contains the channel protein Sam50, which cooperates with Sam35 in precursor recognition, and the peripheral membrane protein Sam37. The molecular function of Sam37 has been unknown. We report that Sam37 is crucial for formation of the TOM-SAM supercomplex. Sam37 interacts with the receptor domain of Tom22 on the cytosolic side of the mitochondrial outer membrane and links TOM and SAM complexes. Sam37 thus promotes efficient transfer of β-barrel precursors to the SAM complex. We conclude that Sam37 functions as a coupling factor of the translocase supercomplex of the mitochondrial outer membrane.
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Lena-Sophie
authors.initials: LS
authors.lastname: Wenz
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Ellenrieder
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Jian
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Bohnert
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Zufall
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: van der Laan
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany nikolaus.pfanner@biochemie.uni-freiburg.de nils.wiedemann@biochemie.uni-freiburg.de.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pfanner
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany nikolaus.pfanner@biochemie.uni-freiburg.de nils.wiedemann@biochemie.uni-freiburg.de.
authors.forename: Nils
authors.initials: N
authors.lastname: Wiedemann
authors.affiliation: Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
mesh_terms: D003600:Cytosol / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; C092812:SAM37 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C487333:Sam50 protein, S cerevisiae; C090857:TOM22 protein, S cerevisiae