Protein transport machineries for precursor translocation across the inner mitochondrial membrane.
The mitochondrial inner membrane has a central function for the energy metabolism of the cell. The respiratory chain generates a proton gradient across the inner mitochondrial membrane, which is used to produce ATP by the F1Fo-ATPase. To maintain the electrochemical gradient, the inner membrane represents an efficient permeability barrier for small molecules. Nevertheless, metabolites as well as polypeptide chains need to be transported across the inner membrane while the electrochemical gradient is retained. While specialized metabolite carrier proteins mediate the transport of small molecules, dedicated protein translocation machineries in the inner mitochondrial membrane (so called TIM complexes) transport precursor proteins across the inner membrane. Here we describe the organization of the TIM complexes and discuss the current models as to how they mediate the posttranslational import of proteins across and into the inner mitochondrial membrane.
Wagner
Karina
K
Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, D-79104 Freiburg, Germany.
Mick
David U
DU
Rehling
Peter
P
D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism; D008954:Models, Biological; D011498:Protein Precursors / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011498:Protein Precursors; D021122:Protein Subunits; C474451:F1F0-ATP synthase; D025261:Mitochondrial Proton-Translocating ATPases