Article
- The EMBO Journal (2006) 25, 1836 - 1847
- doi:10.1038/sj.emboj.7601091
Published online: 13 April 2006
Subject Categories:
The molecular chaperone Hsp90 delivers precursor proteins to the chloroplast import receptor Toc64
Soumya Qbadou1,a, Thomas Becker1,a, Oliver Mirus1, Ivo Tews2, Jürgen Soll1 and Enrico Schleiff1
- Botanik, LMU München, München, Germany
- Biochemistry Center (BZH), Heidelberg, Germany
Correspondence to:
Enrico Schleiff, Botanik, LMU München, Menzinger Str. 67/223, München 80638, Germany. Tel.: +49 89 17861 182; Fax: +49 89 17861 185; E-mail: schleiff@lrz.uni-muenchen.de
aThese authors contributed equally to this work
Received 4 May 2005; Accepted 21 March 2006
Abstract
Precursor protein targeting toward organellar surfaces is assisted by different cytosolic chaperones. We demonstrate that the chloroplast protein translocon subunit Toc64 is the docking site for Hsp90 affiliated preproteins. Thereby, Hsp90 is recognised by the clamp type TPR domain of Toc64. The subsequent transfer of the preprotein from Toc64 to the major receptor of the Toc complex, namely Toc34, is affinity driven and nucleotide dependent. We propose that Toc64 acts as an initial docking site for Hsp90 associated precursor proteins. We outline a mechanism in which chaperones are recruited for a specific targeting event by a membrane-inserted receptor.
Keywords:
- Hsp70,
- Hsp90,
- precursor recognition,
- protein translocation,
- TPR domain
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated
NEWS AND VIEWS
Molecular chaperones Plugging the transport gap
Nature News and Views (20 Feb 2003)
A GTPase gate for protein import into chloroplasts
Nature Structural Biology News and Views (01 Feb 2002)
RESEARCH
Heredity Original Article
Preprotein recognition by the Toc complex
The EMBO Journal Article (11 Feb 2004)
