Dual role of the receptor Tom20 in specificity and efficiency of protein import into mitochondria

Mitochondria import most of their resident proteins from the cytosol, and the import receptor Tom20 of the outer-membrane translocator TOM40 complex plays an essential role in specificity of mitochondrial protein import. Here we analyzed the effects of Tom20 binding on NMR spectra of a long mitochon...

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Published inProceedings of the National Academy of Sciences - PNAS Vol. 108; no. 1; pp. 91 - 96
Main Authors Yamamoto, Hayashi, Itoh, Nobuka, Kawano, Shin, Yatsukawa, Yoh-ichi, Momose, Takaki, Makio, Tadashi, Matsunaga, Mayumi, Yokota, Mihoko, Esaki, Masatoshi, Shodai, Toshihiro, Kohda, Daisuke, Aiken Hobbs, Alyson E, Jensen, Robert E, Endo, Toshiya
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 04.01.2011
National Acad Sciences
Subjects
Amino acids
Binding sites
Binding Sites - genetics
Biological Sciences
crosslinking
cytosol
Immunoprecipitation
Imports
in vitro studies
Membranes
Mitochondria
Mitochondria - metabolism
Mitochondrial Membrane Transport Proteins - metabolism
Models, Molecular
nuclear magnetic resonance spectroscopy
Nuclear Magnetic Resonance, Biomolecular
P branes
Protein Binding - genetics
Protein Binding - physiology
Protein precursors
Protein transport
Protein Transport - physiology
Proteins
Proton-Translocating ATPases - genetics
Proton-Translocating ATPases - metabolism
Receptors
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins - metabolism
T cell receptors
Translocation
Yeasts
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Summary:Mitochondria import most of their resident proteins from the cytosol, and the import receptor Tom20 of the outer-membrane translocator TOM40 complex plays an essential role in specificity of mitochondrial protein import. Here we analyzed the effects of Tom20 binding on NMR spectra of a long mitochondrial presequence and found that it contains two distinct Tom20-binding elements. In vitro import and cross-linking experiments revealed that, although the N-terminal Tom20-binding element is essential for targeting to mitochondria, the C-terminal element increases efficiency of protein import in the step prior to translocation across the inner membrane. Therefore Tom20 has a dual role in protein import into mitochondria: recognition of the targeting signal in the presequence and tethering the presequence to the TOM40 complex to increase import efficiency.
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2Present address: Frontier Research Center, Tokyo Institute of Technology, Nagatsuta-cho 4259-S2, Midori-ku, Yokohama 226-8503, Japan.
3Present address: Department of Cell Biology, University of Alberta, Edmonton, AB, Canada T6G 2H7.
4Present address: Division of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
Author contributions: H.Y., N.I., S.K., M.E., and T.E. designed research; H.Y., N.I., S.K., Y.Y., T. Momose, T. Makio, M.M., M.Y., and T.S. performed research; H.Y., N.I., S.K., Y.Y., T. Momose, T. Makio, M.M., M.Y., and D.K. analyzed data; A.E.A.H. and R.E.J. contributed new reagents/analytic tools; and H.Y., N.I., S.K., and T.E. wrote the paper.
1H.Y. and N.I. contributed equally to this work.
Edited by Walter Neupert, University of Munich, Munich, Germany, and accepted by the Editorial Board November 13, 2010 (received for review October 5, 2010)
ISSN:0027-8424
1091-6490
1091-6490
DOI:10.1073/pnas.1014918108