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

J. Biol. Chem., Vol. 282, Issue 47, 34334-34345, November 23, 2007

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 282/47/34334    most recent M703876200v1 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 Google Scholar Google Scholar Articles by Hageman, J. Articles by Kampinga, H. H. Search for Related Content PubMed PubMed Citation Articles by Hageman, J. Articles by Kampinga, H. H. Social Bookmarking                      What's this?

Comparison of Intra-organellar Chaperone Capacity for Dealing with Stress-induced Protein Unfolding^*

From the Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, 9713 AV, The Netherlands

Molecular chaperones are essential for cells to prevent that partially unfolded proteins form non-functional, toxic aggregates. This requirement is increased when cells experience protein unfolding stresses and such could affect all compartments in the eukaryotic cell. Whether all organelles are equipped with comparable chaperone capacities is largely unknown, mainly due to the lack of suitable reporters that allow such a comparison. Here we describe the development of fluorescent luciferase reporters that are sorted to various cellular locations (nucleus, cytoplasm, endoplasmic reticulum, and peroxisomes) and that differ minimally in their intrinsic thermal stability properties. When heating living cells, the rate of inactivation was most rapid for the nuclear-targeted luciferase, indicating that the nucleus is the most sensitive organelle toward heat-induced denaturing stress. Post-heat re-activation, however, occurred at equal kinetics irrespective of luciferase localization. Also, induction of thermotolerance by a priming heat treatment, that coordinately up-regulates all heat-inducible chaperones, resulted in a transient heat resistance of the luciferase in all organelles in a comparable manner. Overexpression of the main heat-inducible Hsp70 family member, HspA1A, protected only the cytosolic and nuclear, but not the other luciferases. Together, our data suggest that in each compartment investigated, including the peroxisome in which so far no chaperones could be detected, chaperone machines are present and can be induced with activities similar to those present in the cytosolic/nuclear compartment.

Received for publication, May 10, 2007 , and in revised form, September 4, 2007.

^* This work was supported by Innovatiegerichte Onderzoeksprogramma genomics Grant IGE03018. 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 and Table S1.

¹ To whom correspondence should be addressed: Ant. Deusinglaan 1, 9713 AV Groningen, The Netherlands. Tel.: 31-50-3632911; Fax: 31-50-3632913; E-mail: h.h.kampinga{at}med.umcg.nl.

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