STOP proteins.
Microtubules assembled from pure tubulin in vitro are labile, rapidly depolymerized upon exposure to the cold. In contrast, in a number of cell types, cytoplasmic microtubules are stable, resistant to prolonged cold exposure. During the past years, the molecular basis of this microtubule stabilization in cells has been elucidated. Cold stability is due to polymer association with different variants of a calmodulin-regulated protein, STOP protein. The dynamic and hence the physiological consequences of STOP association with microtubules vary in different tissues. In neurons, STOP seems almost permanently associated with microtubules. STOP is apparently a major determinant of microtubule turnover in such cells and is required for normal neuronal differentiation. In cycling cells, only minor amounts of STOP are associated with interphase microtubules and STOP does not measurably affects microtubule dynamics. However, STOP is associated with mitotic microtubules in the spindle. Recent results indicate that such an association could be vital for meiosis and for the long-term fidelity of the mitotic process.
Bosc
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Institut National de la Santé Et de la Recherche Médicale, INSERM Unité 366, Département de Biologie Moléculaire et Structurale, Laboratoire du Cytosquelette, Commissariat à l'Energie Atomique de Grenoble, Grenoble , France.
Oenarier
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Andrieux
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Job
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D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics; D008540:Meiosis / Q000502:physiology; D051379:Mice; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D041681:NIH 3T3 Cells; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D015739:Nocodazole / Q000494:pharmacology; D016716:PC12 Cells; D020033:Protein Isoforms / Q000235:genetics / Q000276:immunology / Q000502:physiology; D051381:Rats; D020080:Tandem Repeat Sequences / Q000235:genetics
D000906:Antibodies; D018076:DNA, Complementary; C113727:Map6 protein, rat; D008869:Microtubule-Associated Proteins; C491893:Mtap6 protein, mouse; D020033:Protein Isoforms; D015739:Nocodazole