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Targeting of an abundant cytosolic form of the protein import receptor at Toc159 to the outer chloroplast membrane
Auteur(s)
Hiltbrunner, Andreas
Bauer, Jörg
Vidi, Pierre-Alexandre
Infanger, Sibylle
Hohwy, Morten
Date de parution
2001
In
Journal of Cell Biology
Vol.
2
No
154
De la page
309
A la page
316
Mots-clés
Résumé
Chloroplast biogenesis requires the large-scale import of cytosolically synthesized precursor proteins. A trimeric translocon (Toc complex) containing two homologous, GTP-binding proteins (atToc33 and atToc159) and a channel protein (atToc75) facilitates protein translocation across the outer envelope membrane. The mechanisms governing function and assembly of the Toc complex are not yet understood. This study demonstrates that atToc159 and its pea orthologue exist in an abundant, previously unrecognized soluble form, and partition between cytosol-containing soluble fractions and the chloroplast outer membrane. We show that soluble atToc159 binds directly to the cytosolic domain of atToc33 in a homotypic interaction, contributing to the integration of atToc159 into the chloroplast outer membrane. The data suggest that the function of the Toc complex involves switching of at Toc159 between a soluble and an integral membrane form.
Identifiants
Type de publication
journal article
