The protein import motor of mitochondria.
Proteins that are destined for the matrix of mitochondria are transported into this organelle by two translocases: the TOM complex, which transports proteins across the outer mitochondrial membrane; and the TIM23 complex, which gets them through the inner mitochondrial membrane. Two models have been proposed to explain how this protein-import machinery works -- a targeted Brownian ratchet, in which random motion is translated into vectorial motion, or a 'power stroke', which is exerted by a component of the import machinery. Here, we review the data for and against each model.
Neupert
Walter
W
Institut für Physiologische Chemie, Universität München, Butenandtstrabetae 5, Gebäude B, D-81377 Munich, Germany. neupert@bio.med.uni-muenchen.de
Brunner
Michael
M
D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D021381:Protein Transport / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D020409:Molecular Motor Proteins; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae