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Targeting and insertion of nuclear‐encoded preproteins into the mitochondrial outer membrane
Author(s) -
Mihara Katsuyoshi
Publication year - 2000
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/(sici)1521-1878(200004)22:4<364::aid-bies6>3.0.co;2-n
Subject(s) - translocase of the inner membrane , translocase of the outer membrane , bacterial outer membrane , microbiology and biotechnology , inner membrane , mitochondrion , mitochondrial carrier , biology , cytosol , transmembrane protein , mitochondrial membrane transport protein , protein targeting , cytoplasm , intermembrane space , biogenesis , membrane protein , inner mitochondrial membrane , membrane transport protein , transport protein , biochemistry , membrane , receptor , gene , enzyme , escherichia coli
Most mitochondrial proteins are synthesized in the cytosol as preproteins with a cleavable presequence and are delivered to the import receptors on the mitochondria by cytoplasmic import factors. The proteins are then imported to the intramitochondrial compartments by the import systems of the outer and inner membranes, TOM and TIM. Mitochondrial outer membrane proteins are synthesized without a cleavable presequence and most of them contain hydrophobic transmembrane domains, which, in conjunction with the flanking segments, function as the mitochondria import signals. Some of the proteins are inserted into the outer membrane by the TOM machinery; the import signal probably arrests further translocation and is released from the translocation channel to the lipid bilayer. The other proteins are inserted into the membrane by a novel pathway independent of the TOM machinery. This article reviews recent developments in the biogenesis of mitochondrial outer membrane proteins. BioEssays 22:364–371, 2000. © 2000 John Wiley & Sons, Inc.