title: A disulfide bond in the TIM23 complex is crucial for voltage gating and mitochondrial protein import.
abstract: Tim17 is a central, membrane-embedded subunit of the mitochondrial protein import machinery. In this study, we show that Tim17 contains a pair of highly conserved cysteine residues that form a structural disulfide bond exposed to the intermembrane space (IMS). This disulfide bond is critical for efficient protein translocation through the TIM23 complex and for dynamic gating of its preprotein-conducting channel. The disulfide bond in Tim17 is formed during insertion of the protein into the inner membrane. Whereas the import of Tim17 depends on the binding to the IMS protein Mia40, the oxidoreductase activity of Mia40 is surprisingly dispensable for Tim17 oxidation. Our observations suggest that Tim17 can be directly oxidized by the sulfhydryl oxidase Erv1. Thus, import and oxidation of Tim17 are mediated by the mitochondrial disulfide relay, though the mechanism by which the disulfide bond in Tim17 is formed differs considerably from that of soluble IMS proteins.
authors: Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Ajay
authors: 0000-0001-5437-8875
authors: A
authors: Ramesh
authors: Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Valentina
authors: V
authors: Peleh
authors: Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, 10003 Cáceres, Spain.
authors: Sonia
authors: S
authors: Martinez-Caballero
authors: Biochemistry, Saarland University, 66421 Homburg, Germany Faculty of Medicine, Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research, University of Freiburg, 79104 Freiburg, Germany.
authors: Florian
authors: 0000-0003-4191-5226
authors: F
authors: Wollweber
authors: Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Frederik
authors: F
authors: Sommer
authors: Biochemistry, Saarland University, 66421 Homburg, Germany.
authors: Martin
authors: M
authors: van der Laan
authors: Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Michael
authors: M
authors: Schroda
authors: Department of Pediatrics, University of Alberta, Edmonton, Alberta T6G 1C9, Canada.
authors: R Todd
authors: 0000-0001-7396-7894
authors: RT
authors: Alexander
authors: Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, 10003 Cáceres, Spain.
authors: María Luisa
authors: 0000-0001-7953-9452
authors: ML
authors: Campo
authors: Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany hannes.herrmann@biologie.uni-kl.de.
authors: Johannes M
authors: 0000-0003-2081-4506
authors: JM
authors: Herrmann
mesh_terms: D017124:Conserved Sequence; D004220:Disulfides / Q000378:metabolism*; D015640:Ion Channel Gating; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D004220:Disulfides; D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; D050505:Mutant Proteins; D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae