title: Tim50 is a subunit of the TIM23 complex that links protein translocation across the outer and inner mitochondrial membranes.
abstract: Based on the results of site-specific photocrosslinking of translocation intermediates, we have identified Tim50, a component of the yeast TIM23 import machinery, which mediates translocation of presequence-containing proteins across the mitochondrial inner membrane. Tim50 is anchored to the inner mitochondrial membrane, exposing the C-terminal domain to the intermembrane space. Tim50 interacts with the N-terminal intermembrane space domain of Tim23. Functional defects of Tim50 either by depletion of the protein or addition of anti-Tim50 antibodies block the protein translocation across the inner membrane. A translocation intermediate accumulated at the TOM complex is crosslinked to Tim50. We suggest that Tim50, in cooperation with Tim23, facilitates transfer of the translocating protein from the TOM complex to the TIM23 complex
authors.affiliation: Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Nagoya, Japan.
authors.forename: Hayashi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Esaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanamori
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tamura
authors.forename: Shuh ichi
authors.initials: Si
authors.lastname: Nishikawa
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D003432:Cross-Linking Reagents; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors / Q000378:metabolism; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae; C469615:TIM50 protein, S cerevisiae