title: The MIM complex mediates preprotein translocation across the mitochondrial inner membrane and couples it to the mt-Hsp70/ATP driving system.
abstract: We have identified a complex in mitochondria that functions as a part of the preprotein import machinery of the inner membrane (MIM complex). Two known components, MIM23 and MIM17, and two novel components, MIM33 and MIM14, were found as constituents of this complex. In the presence of a translocating chain, the outer membrane import machinery (MOM complex) and the MIM complex form translocation contact sites. On the matrix side, the MIM complex is associated with the mt-Hsp70-MIM44 system. We propose a structure of the import machinery in which the MIM complex constitutes a proteinaceous channel that accepts preproteins from the MOM complex, facilitates their reversible transmembrane movement, and mediates unidirectional transport by linkage to the ATP-dependent mt-Hsp70-MIM44 system.
authors.affiliation: Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Berthold
authors.forename: M F
authors.initials: MF
authors.lastname: Bauer
authors.forename: H C
authors.initials: HC
authors.lastname: Schneider
authors.forename: C
authors.initials: C
authors.lastname: Klaus
authors.forename: K
authors.initials: K
authors.lastname: Dietmeier
authors.forename: W
authors.initials: W
authors.lastname: Neupert
authors.forename: M
authors.initials: M
authors.lastname: Brunner
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli; D005656:Fungal Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D016681:Genome, Fungal; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D011498:Protein Precursors / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C091191:TIM17 protein, S cerevisiae; C083081:TIM23 protein, S cerevisiae; D000255:Adenosine Triphosphate