ArticleThe Biochemical journal2011
Substrate binding disrupts dimerization and induces nucleotide exchange of the chloroplast GTPase Toc33.
Article in The Biochemical journal, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.
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Who cites it
14 citing papers in PubMed, 31 citations in OpenAlex.
- Septin-mediated coupling of protein import and division during chloroplast evolution.bioRxiv : the preprint server for biology · 2026Article
- Functional Interaction Between Toc75 POTRA1 Domain and Tic22-III in the Intermembrane Space During Chloroplast Protein Import.Plant direct · 2026Article
- Origins, function, and regulation of the TOC-TIC general protein import machinery of plastids.Journal of experimental botany · 2020Article
- The TOC GTPase Receptors: Regulators of the Fidelity, Specificity and Substrate Profiles of the General Protein Import Machinery of Chloroplasts.The protein journal · 2019Review
- Molecular Topology of the Transit Peptide during Chloroplast Protein Import.The Plant cell · 2018Article
- Chloroplast Preproteins Bind to the Dimer Interface of the Toc159 Receptor during Import.Plant physiology · 2017Article
- Interaction of a novel fluorescent GTP analogue with the small G-protein K-Ras.Journal of biochemistry · 2016Article
- Phosphorylation and Dephosphorylation of the Presequence of Precursor MULTIPLE ORGANELLAR RNA EDITING FACTOR3 during Import into Mitochondria from Arabidopsis.Plant physiology · 2015Article
- New insights into the mechanism of chloroplast protein import and its integration with protein quality control, organelle biogenesis and development.Journal of molecular biology · 2015Review
- The C-terminus of Bienertia sinuspersici Toc159 contains essential elements for its targeting and anchorage to the chloroplast outer membrane.Frontiers in plant science · 2014Article
- Border control: selectivity of chloroplast protein import and regulation at the TOC-complex.Frontiers in plant science · 2014Review
- Targeting and assembly of components of the TOC protein import complex at the chloroplast outer envelope membrane.Frontiers in plant science · 2014Review
- The tRNA-modifying function of MnmE is controlled by post-hydrolysis steps of its GTPase cycle.Nucleic acids research · 2013Article
- Chloroplast Omp85 proteins change orientation during evolution.Proceedings of the National Academy of Sciences of the United States of America · 2011Article
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9 authors at 2 institutions in 1 country.
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Abstract
GTPases act as molecular switches to control many cellular processes, including signalling, protein translation and targeting. Switch activity can be regulated by external effector proteins or intrinsic properties, such as dimerization. The recognition and translocation of pre-proteins into chloroplasts [via the TOC/TIC (translocator at the outer envelope membrane of chloroplasts/inner envelope membrane of chloroplasts)] is controlled by two homologous receptor GTPases, Toc33 and Toc159, whose reversible dimerization is proposed to regulate translocation of incoming proteins in a GTP-dependent manner. Toc33 is a homodimerizing GTPase. Functional analysis suggests that homodimerization is a key step in the translocation process, the molecular functions of which, as well as the elements regulating this event, are largely unknown. In the present study, we show that homodimerization reduces the rate of nucleotide exchange, which is consistent with the observed orientation of the monomers in the crystal structure. Pre-protein binding induces a dissociation of the Toc33 homodimer and results in the exchange of GDP for GTP. Thus homodimerization does not serve to activate the GTPase activity as discussed many times previously, but to control the nucleotide-loading state. We discuss this novel regulatory mode and its impact on the current models of protein import into the chloroplast.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.