title: Role of the import motor in insertion of transmembrane segments by the mitochondrial TIM23 complex.
abstract: The TIM23 complex mediates translocation of proteins across, and their lateral insertion into, the mitochondrial inner membrane. Translocation of proteins requires both the membrane-embedded core of the complex and its ATP-dependent import motor. Insertion of some proteins, however, occurs in the absence of ATP, questioning the need for the import motor during lateral insertion. We show here that the import motor associates with laterally inserted proteins even when its ATPase activity is not required. Furthermore, our results suggest a role for the import motor in lateral insertion. Thus, the import motor is involved in ATP-dependent translocation and ATP-independent lateral insertion.
authors.affiliation: Institute for Physiological Chemistry and Centre for Integrated Protein Science, Ludwig-Maximilians University, Butenandtstrasse 5, 81377 Munich, Germany.
authors.forename: Dušan
authors.initials: D
authors.lastname: Popov-Čeleketić
authors.forename: Karin
authors.initials: K
authors.lastname: Waegemann
authors.forename: Koyeli
authors.initials: K
authors.lastname: Mapa
authors.forename: Walter
authors.initials: W
authors.lastname: Neupert
authors.forename: Dejana
authors.initials: D
authors.lastname: Mokranjac
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae; C478853:Tim14 protein, S cerevisiae; D000255:Adenosine Triphosphate