Inhibition of Small G Proteins byClostridium sordelliiLethal Toxin Activates cdc2 and MAP kinase inXenopusOocytes
| Autor: | Michel R. Popoff, Nabila Talbi, René Ozon, Catherine Jessus, Kestutis Suziedelis, Hélène Rime |
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| Přispěvatelé: | Station commune de Recherches en Ichtyophysiologie, Biodiversité et Environnement (SCRIBE), Institut National de la Recherche Agronomique (INRA), Laboratoire de Physiologie de la Reproduction, Université Pierre et Marie Curie - Paris 6 (UPMC)-INRA/ESA-Centre National de la Recherche Scientifique (CNRS), Institut Pasteur [Paris] (IP) |
| Rok vydání: | 1998 |
| Předmět: |
Xenopus
Bacterial Toxins Clostridium difficile toxin B Small G Protein Biology GTP-binding protein regulators GTP-Binding Proteins CDC2 Protein Kinase meiosis Animals [SDV.BDD]Life Sciences [q-bio]/Development Biology Molecular Biology ComputingMilieux_MISCELLANEOUS C. sordelliilethal toxin Clostridium Cyclin-dependent kinase 1 Germinal vesicle Kinase cdc2 kinase Cell Biology Molecular biology Xenopusoocytes Rac GTP-Binding Proteins Enzyme Activation Mitogen-activated protein kinase Calcium-Calmodulin-Dependent Protein Kinases biology.protein Oocytes MAP kinase Female Ras Signal Transduction Developmental Biology |
| Zdroj: | Developmental Biology Developmental Biology, 1998, 204 (2), pp.592-602. ⟨10.1006/dbio.1998.9069⟩ Developmental Biology, Elsevier, 1998, 204, pp.592-602 |
| ISSN: | 0012-1606 1095-564X |
| DOI: | 10.1006/dbio.1998.9069 |
| Popis: | International audience; The lethal toxin (LT) from Clostridium sordellii is a glucosyltransferase that modifies and inhibits small G proteins of the Ras family, Ras and Rap, as well as Rac proteins. LT induces cdc2 kinase activation and germinal vesicle breakdown (GVBD) when microinjected into full-grown Xenopus oocytes. Toxin B from Clostridium difficile, that glucosylates and inactivates Rac proteins, does not induce cdc2 activation, indicating that proteins of the Ras family, Ras and/or Rap, negatively regulate cdc2 kinase activation in Xenopus oocyte. In oocyte extracts, LT catalyzes the incorporation of [C-14]glucose into a group of proteins of 23 kDa and into one protein of 27 kDa. The 23-kDa proteins are recognized by anti-Rap1 and anti-Rap2 antibodies, whereas the 27-kDa protein is recognized by several anti-Ras antibodies and probably corresponds to K-Ras. Microinjection of LT into oocytes together with UDP-[C-14]glucose results in a glucosylation pattern similar to the in vitro glucosylation, indicating that the 23- and 27-kDa proteins are in vivo substrates of LT. In vivo time-course analysis reveals that the 27-kDa protein glucosylation is completed within 2 h, well before cdc2 kinase activation, whereas the 23-kDa proteins are partially glucosylated at GVBD. This observation suggests that the 27-kDa Ras protein could be the in vivo target of LT allowing cdc2 kinase activation. Interestingly, inactivation of Ras proteins does not prevent the phosphorylation of c-Raf1 and the activation of MAP kinase that occurs normally around GVBD. |
| Databáze: | OpenAIRE |
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