HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 283, Issue 25, 17139-17146, June 20, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/25/17139    most recent M710037200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bauerschmitt, H. Articles by Herrmann, J. M. Search for Related Content PubMed PubMed Citation Articles by Bauerschmitt, H. Articles by Herrmann, J. M. Social Bookmarking                      What's this?

The Membrane-bound GTPase Guf1 Promotes Mitochondrial Protein Synthesis under Suboptimal Conditions^*

Heike Bauerschmitt, Soledad Funes, and Johannes M. Herrmann¹

From the Institute of Physiological Chemistry, University of Munich, 81377 Munich, Germany and Department of Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany

Recently, the bacterial elongation factor LepA was identified as critical for the accuracy of in vitro translation reactions. Extremely well conserved homologues of LepA are present throughout bacteria and eukaryotes, but the physiological relevance of these proteins is unclear. Here we show that the yeast counterpart of LepA, Guf1, is located in the mitochondrial matrix and tightly associated with the inner membrane. It binds to mitochondrial ribosomes in a GTP-dependent manner. Mutants lacking Guf1 show cold- and heat-sensitive growth defects on non-fermentable carbon sources that are especially pronounced under nutrient-limiting conditions. The cold sensitivity is explained by diminished rates of protein synthesis at low temperatures. At elevated temperatures, Guf1-deficient mutants exhibit defects in the assembly of cytochrome oxidase, suggesting that the polypeptides produced are not functional. Moreover, Guf1 mutants exhibit synthetic growth defects with mutations of the protein insertase Oxa1. These observations show a critical role for Guf1 in vivo. The observed defects in Guf1-deficient mitochondria are consistent with a function of Guf1 as a fidelity factor of mitochondrial protein synthesis.

Received for publication, December 10, 2007 , and in revised form, April 25, 2008.

^* This work was supported by the Deutsche Forschungsgemeinschaft (SFB530, Teilprojekt C15) and the Stiftung für Innovation in Rheinland-Pfalz. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1 and S2.

¹ To whom correspondence should be addressed: Cell Biology, University of Kaiserslautern, Erwin-Schroedingerstrasse 13, 67663 Kaiserslautern, Germany. Tel.: 49-631-205-2406; Fax: 49-631-205-2492; E-mail: hannes.herrmann{at}biologie.uni-kl.de.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. Prestele, F. Vogel, A. S. Reichert, J. M. Herrmann, and M. Ott Mrpl36 Is Important for Generation of Assembly Competent Proteins during Mitochondrial Translation Mol. Biol. Cell, May 15, 2009; 20(10): 2615 - 2625. [Abstract] [Full Text] [PDF]