title: How does the TOM complex mediate insertion of precursor proteins into the mitochondrial outer membrane?
abstract: A multisubunit translocase of the outer mitochondrial membrane (TOM complex) mediates both the import of mitochondrial precursor proteins into the internal compartments of the organelle and the insertion of proteins residing in the mitochondrial outer membrane. The proposed beta-barrel structure of Tom40, the pore-forming component of the translocase, raises the question of how the apparent uninterrupted beta-barrel topology can be compatible with a role of Tom40 in releasing membrane proteins into the lipid core of the bilayer. In this review, I discuss insertion mechanisms of proteins into the outer membrane and present alternative models based on the opening of a multisubunit beta-barrel TOM structure or on the interaction of outer membrane precursors with the outer face of the Tom40 beta-barrel structure.
authors.affiliation: Institute for Physiological Chemistry, Ludwig-Maximilians University, 81377 Munich, Germany. rapaport@med.uni-muenchen.de
authors.forename: Doron
authors.initials: D
authors.lastname: Rapaport
mesh_terms: D000818:Animals; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D008954:Models, Biological; D011498:Protein Precursors / Q000378:metabolism*; D017433:Protein Structure, Secondary; D021381:Protein Transport
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011498:Protein Precursors