Jump to ContentJump to Main Navigation
Show Summary Details

Biological Chemistry

Editor-in-Chief: Brüne, Bernhard

Editorial Board Member: Buchner, Johannes / Lei, Ming / Ludwig, Stephan / Sies, Helmut / Turk, Boris / Wittinghofer, Alfred

12 Issues per year


IMPACT FACTOR 2015: 2.710
Rank 142 out of 289 in category Biochemistry & Molecular Biology in the 2015 Thomson Reuters Journal Citation Report/Science Edition

SCImago Journal Rank (SJR) 2015: 1.607
Source Normalized Impact per Paper (SNIP) 2015: 0.751
Impact per Publication (IPP) 2015: 2.609

Online
ISSN
1437-4315
See all formats and pricing
Just Accepted

Issues

The Mitochondrial Protein Import Motor

Andreas Strub / Joo Hyun Lim / Nikolaus Pfanner / Wolfgang Voos
Published Online: 2005-07-05 | DOI: https://doi.org/10.1515/BC.2000.115

Abstract

Mitochondrial proteins are synthesized as precursor proteins in the cytosol and are posttranslationally imported into the organelle. A complex system of translocation machineries recognizes and transports the precursor polypeptide across the mitochondrial membranes. Energy for the translocation process is mainly supplied by the mitochondrial membrane potential (∆ψ) and the hydrolysis of ATP. Mitochondrial Hsp70 (mtHsp70) has been identified as the major ATPase driving the membrane transport of the precursor polypeptides into the mitochondrial matrix. Together with the partner proteins Tim44 and Mge1, mtHsp70 forms an import motor complex interacting with the incoming preproteins at the inner face of the inner membrane. This import motor complex drives the movement of the polypeptides in the translocation channel and the unfolding of carboxy-terminal parts of the preproteins on the outside of the outer membrane. Two models of the molecular mechanism of mtHsp70 during polypeptide translocation are discussed. In the ‘trapping’ model, precursor movement is generated by Brownian movement of the polypeptide chain in the translocation pore. This random movement is made vectorial by the interaction with mtHsp70 in the matrix. The detailed characterization of conditional mutants of the import motor complex provides the basis for an extended model. In this ‘pulling’ model, the attachment of mtHsp70 at the inner membrane via Tim44 and a conformational change induced by ATP results in the generation of an inward-directed force on the bound precursor polypeptide. This active role of the import motor complex is necessary for the translocation of proteins containing tightly folded domains. We suggest that both mechanisms complement each other to reach a high efficiency of preprotein import.

About the article

Published Online: 2005-07-05

Published in Print: 2000-09-13


Citation Information: Biological Chemistry, ISSN (Print) 1431-6730, DOI: https://doi.org/10.1515/BC.2000.115. Export Citation

Citing Articles

Here you can find all Crossref-listed publications in which this article is cited. If you would like to receive automatic email messages as soon as this article is cited in other publications, simply activate the “Citation Alert” on the top of this page.

[1]
Diane Jackson-Constan, Mitsuru Akita, and Kenneth Keegstra
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2001, Volume 1541, Number 1-2, Page 102
[2]
Ingo Amm, Thomas Sommer, and Dieter H. Wolf
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2014, Volume 1843, Number 1, Page 182
[3]
Wolfgang Voos
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2013, Volume 1833, Number 2, Page 388
[4]
Sigune Schmidt, Andreas Strub, Karin Röttgers, Nicole Zufall, and Wolfgang Voos
Journal of Molecular Biology, 2001, Volume 313, Number 1, Page 13
[5]
Andreas Strub, Nicole Zufall, and Wolfgang Voos
Journal of Molecular Biology, 2003, Volume 334, Number 5, Page 1087
[7]
Shuntae Williams, Lipi Saha, Ujjal K. Singha, and Minu Chaudhuri
Experimental Parasitology, 2008, Volume 118, Number 3, Page 420
[8]
Geoffrey Duby and Marc Boutry
Plant Science, 2002, Volume 162, Number 4, Page 477
[9]
Wolfgang Voos
Research in Microbiology, 2009, Volume 160, Number 9, Page 718
[10]
Sunil C Kaul, Kazunari Taira, Olivia M Pereira-Smith, and Renu Wadhwa
Experimental Gerontology, 2002, Volume 37, Number 10-11, Page 1157
[11]
Carla M. Koehler
Annual Review of Cell and Developmental Biology, 2004, Volume 20, Number 1, Page 309
[12]
Rona G. Giffard, Ru-Quan Han, John F. Emery, Melissa Duan, and Jean Francois Pittet
Anesthesiology, 2008, Volume 109, Number 2, Page 339
[13]
Renu Wadhwa, Kazunari Taira, and Sunil C. Kaul
Cell Stress & Chaperones, 2002, Volume 7, Number 3, Page 309
[14]
Custer C. Deocaris, Sunil C. Kaul, and Renu Wadhwa
Cell Stress & Chaperones, 2006, Volume 11, Number 2, Page 116

Comments (0)

Please log in or register to comment.
Log in