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

J. Biol. Chem., Vol. 283, Issue 12, 7491-7502, March 21, 2008

This Article Full Text Full Text (PDF) All Versions of this Article: 283/12/7491    most recent M709571200v1 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 Inoue, H. Articles by Akita, M. Search for Related Content PubMed PubMed Citation Articles by Inoue, H. Articles by Akita, M. Social Bookmarking                      What's this?

Three Sets of Translocation Intermediates Are Formed during the Early Stage of Protein Import into Chloroplasts^*

Hitoshi Inoue¹ and Mitsuru Akita^¶2

From the United Graduate School of Agricultural Science and Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan and ^¶Satellite Business Venture, Ehime University, Matsuyama, Ehime 790-8577, Japan

During the early stage of protein import into chloroplasts, precursor proteins synthesized in the cytosol irreversibly bind to chloroplasts to form the early translocation intermediate under stringent energy conditions. Many efforts have been made to identify the components involved in protein import by analyzing the early intermediate. However, the state of the precursor within the intermediate has not been well investigated so far. In this study, an attempt was made to evaluate the extent of translocation of the precursor by determining the state of the precursor in the early intermediate under various conditions and analyzing the fragments generated by limited proteolysis of the precursors docked to chloroplasts. Our results indicate that three different sets of early intermediate are formed based on temperature and the hydrolysis of GTP/ATP. These have been identified based on the size of proteolytic fragments of the precursor as "energy-dependent association," "insertion," and "penetration" states. These findings suggest two individual ATP-hydrolyzing steps during the early stage of protein import, one of which is temperature-sensitive. Our results also demonstrate that translocation through the outer envelope membrane is mainly dependent on internal ATP.

Received for publication, November 26, 2007 , and in revised form, January 16, 2008.

^* This work was supported by a grant from the President's discretionary budget of Ehime University (to M. A.). A portion of this work was undertaken at the Integrated Center for Sciences, Ehime University. 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.

¹ A Research Fellow of the Japan Society for the Promotion of Science.

² To whom correspondence should be addressed. Tel.: 81-89-946-9825; Fax: 81-89-946-9825; E-mail: akita{at}agr.ehime-u.ac.jp.

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

This article has been cited by other articles:

				F. Wang, B. Agne, F. Kessler, and D. J. Schnell The role of GTP binding and hydrolysis at the atToc159 preprotein receptor during protein import into chloroplasts J. Cell Biol., October 6, 2008; 183(1): 87 - 99. [Abstract] [Full Text] [PDF]