title: Mitochondrial Hsp70/MIM44 complex facilitates protein import.
abstract: Protein translocation into mitochondria requires the mitochondrial protein Hsp70. This molecular chaperone of the mitochondrial matrix is recruited to the protein import machinery by MIM44, a component associated with the inner membrane of the mitochondria. Formation of the mt-Hsp70/MIM44 complex is regulated by ATP. MIM44 and mt-Hsp 70 interact in a sequential manner with incoming segments of unfolded preproteins and thereby facilitate stepwise vectorial translocation of proteins across the mitochondrial membranes. The complex appears to act as a molecular ratchet which is energetically driven by the hydrolysis of ATP.
authors.affiliation: Institut für Physiologische Chemie der Universität München, Germany.
authors.forename: H C
authors.initials: HC
authors.lastname: Schneider
authors.forename: J
authors.initials: J
authors.lastname: Berthold
authors.forename: M F
authors.initials: MF
authors.lastname: Bauer
authors.forename: K
authors.initials: K
authors.lastname: Dietmeier
authors.forename: B
authors.initials: B
authors.lastname: Guiard
authors.forename: M
authors.initials: M
authors.lastname: Brunner
authors.forename: W
authors.initials: W
authors.lastname: Neupert
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004247:DNA / Q000138:chemical synthesis; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D011498:Protein Precursors / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013388:Succinimides; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D013388:Succinimides; C077016:TIM44 protein, S cerevisiae; D000255:Adenosine Triphosphate; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase; C019358:disuccinimidyl suberate