Protein translocation pathways of the mitochondrion.
The biogenesis of mitochondria depends on the coordinated import of precursor proteins from the cytosol coupled with the export of mitochondrially coded proteins from the matrix to the inner membrane. The mitochondria contain an elaborate network of protein translocases in the outer and inner membrane along with a battery of chaperones and processing enzymes in the matrix and intermembrane space to mediate protein translocation. A mitochondrial protein, often with an amino-terminal targeting sequence, is escorted through the cytosol by chaperones to the TOM complex (translocase of the outer membrane). After crossing the outer membrane, the import pathway diverges; however, one of two TIM complexes (translocase of inner membrane) is generally utilized. This review is focused on the later stages of protein import after the outer membrane has been crossed. An accompanying paper by Lithgow reviews the early stages of protein translocation.
Koehler
C M
CM
Department of Chemistry and Biochemistry, Box 951569, University of California, 90095-1569, Los Angeles, CA, USA. koehlerc@chem.ucla.edu
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; C102549:TIM22 protein, S cerevisiae; C083081:TIM23 protein, S cerevisiae