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PMID: 10427088 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Biogenesis of Tom40, core component of the TOM complex of mitochondria.

The Journal of cell biology ·Vol. 146 ·No. 2 ·1999-07-26 ·Pages 321-31

Rapaport D, Neupert W

Abstract

Tom40 is an essential component of the preprotein translocase of the mitochondrial outer membrane (TOM complex) in which it constitutes the core element of the protein conducting pore. We have investigated the biogenesis of Tom40. Tom40 is inserted into the outer membrane by the TOM complex. Initially, Tom40 is bound as a monomer at the mitochondrial surface. The import receptor Tom20 is involved in this initial step; it stimulates both binding and efficient insertion of the Tom40 precursor. This step is followed by the formation of a further intermediate at which the Tom40 precursor is partially inserted into the outer membrane. Finally, Tom40 is integrated into preexisting TOM complexes. Efficient import appears to require the Tom40 precursor to be in a partially folded conformation. Neither the NH(2) nor the COOH termini are necessary to target Tom40 to the outer membrane. However, the NH(2)-terminal segment is required for Tom40 to become assembled into the TOM complex. A model for the biogenesis of Tom40 is presented.

MeSH Terms
Biological Transport Cross-Linking Reagents Endopeptidases/metabolism Intracellular Membranes/chemistry,metabolism Kinetics Membrane Proteins/chemistry,genetics,metabolism Membrane Transport Proteins Mitochondria/enzymology,metabolism Mitochondrial Membrane Transport Proteins Models, Biological Molecular Weight Multienzyme Complexes/chemistry,metabolism Neurospora crassa Peptide Fragments/chemistry,metabolism Protein Binding Protein Conformation Protein Denaturation Protein Folding Protein Precursors/chemistry,genetics,metabolism Protein Processing, Post-Translational Protein Sorting Signals/chemistry,genetics,metabolism Receptors, Cytoplasmic and Nuclear Saccharomyces cerevisiae Proteins Sequence Deletion Temperature
Chemicals
Cross-Linking Reagents Membrane Proteins Membrane Transport Proteins Mitochondrial Membrane Transport Proteins Multienzyme Complexes Peptide Fragments Protein Precursors Protein Sorting Signals Receptors, Cytoplasmic and Nuclear Saccharomyces cerevisiae Proteins TOM20 protein, S cerevisiae Tom40 protein, S cerevisiae Endopeptidases
Authors & Affiliations
2 authors, click to expand affiliations / ORCID
Rapaport D
Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie der Universität München, 80336 München, Germany.
Neupert W
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Article Info
Journal
The Journal of cell biology
Abbr.
J Cell Biol
ISSN
0021-9525
DOI
10.1083/jcb.146.2.321
Published
1999-07-26
Pages
321-31
Language
English
Region
United States
NLM ID
0375356
PMCID
PMC2156174
Subset
IM
External Links
PubMed source DOI: 10.1083/jcb.146.2.321 PMC Full Text View journal details
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