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PMID: 18824565 Published · ppublish English Journal Article Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't

The role of GTP binding and hydrolysis at the atToc159 preprotein receptor during protein import into chloroplasts.

The Journal of cell biology ·Vol. 183 ·No. 1 ·2008-10-06 ·Pages 87-99

Wang F, Agne B, Kessler F, Schnell DJ

Abstract

The majority of nucleus-encoded chloroplast proteins are targeted to the organelle by direct binding to two membrane-bound GTPase receptors, Toc34 and Toc159. The GTPase activities of the receptors are implicated in two key import activities, preprotein binding and driving membrane translocation, but their precise functions have not been defined. We use a combination of in vivo and in vitro approaches to study the role of the Toc159 receptor in the import reaction. We show that atToc159-A864R, a receptor with reduced GTPase activity, can fully complement a lethal insertion mutation in the ATTOC159 gene. Surprisingly, the atToc159-A864R receptor increases the rate of protein import relative to wild-type receptor in isolated chloroplasts by stabilizing the formation of a GTP-dependent preprotein binding intermediate. These data favor a model in which the atToc159 receptor acts as part of a GTP-regulated switch for preprotein recognition at the TOC translocon.

MeSH Terms
Adenosine Triphosphate/metabolism Amino Acid Substitution Arabidopsis/genetics,metabolism Arabidopsis Proteins/genetics,metabolism Chlorophyll/metabolism Chloroplasts/drug effects,metabolism Cross-Linking Reagents/pharmacology Ethylmaleimide/analogs & derivatives,pharmacology GTP Phosphohydrolases/genetics,metabolism Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology Guanosine Diphosphate/analogs & derivatives,pharmacology Guanosine Triphosphate/metabolism Hydrolysis Kinetics Membrane Proteins/genetics,metabolism Plants, Genetically Modified Protein Binding/drug effects Protein Transport/drug effects Thionucleotides/pharmacology Transformation, Genetic
Chemicals
Arabidopsis Proteins Cross-Linking Reagents Membrane Proteins TOC159 protein, Arabidopsis Thionucleotides Chlorophyll Guanosine Diphosphate Guanosine 5'-O-(3-Thiotriphosphate) guanosine 5'-O-(2-thiodiphosphate) dithiobis(N-ethylmaleimide) Guanosine Triphosphate Adenosine Triphosphate GTP Phosphohydrolases Ethylmaleimide
Authors & Affiliations
4 authors, click to expand affiliations / ORCID
Wang Fei
Department of Biochemistry and Molecular Biology and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003, USA.
Agne Birgit
Kessler Felix
Schnell Danny J
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Article Info
Journal
The Journal of cell biology
Abbr.
J Cell Biol
ISSN
1540-8140
DOI
10.1083/jcb.200803034
Published
2008-10-06
Epub
2008-00-29
Pages
87-99
Language
English
Region
United States
NLM ID
0375356
PMCID
PMC2557045
Subset
IM
Grants
NIGMS NIH HHS · R01 GM061893 · United States
NIGMS NIH HHS · GM61893 · United States
External Links
PubMed source DOI: 10.1083/jcb.200803034 PMC Full Text View journal details
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