The non-catalytic domain of the Xenopus laevis auroraA kinase localises the protein to the centrosome.
Aurora kinases are involved in mitotic events that control chromosome segregation. All members of this kinase subfamily possess two distinct domains, a highly conserved catalytic domain and an N-terminal non-catalytic extension that varies in size and sequence. To investigate the role of this variable non-catalytic region we overexpressed and purified Xenopus laevis auroraA (pEg2) histidine-tagged N-terminal peptide from bacterial cells. The peptide has no effect on the in vitro auroraA kinase activity, but it inhibits both bipolar spindle assembly and stability in Xenopus egg extracts. Unlike the full-length protein, the N-terminal domain shows only low affinity for paclitaxel-stabilised microtubules in vitro, but localises to the centrosomes in a microtubule-dependent manner. When expressed in Xenopus XL2 cells, it is able to target the green fluorescent protein to centrosomes. Surprisingly, this is also true of the pEg2 catalytic domain, although to a lesser extent. The centrosome localisation of the N-terminal peptide was disrupted by nocodazole whereas localisation of the catalytic domain was not, suggesting that in order to efficiently localise to the centrosome, pEg2 kinase required the non-catalytic N-terminal domain and the presence of microtubules.
Giet
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Groupe Cycle Cellulaire, UMR 6061 Génétique et Développement, CNRS--Université de Rennes I, IFR 97 Génomique Fonctionnelle et Santé, Faculté de Médecine, 2 avenue du Pr Léon Bernard, CS 34317, 35043 Rennes cedex, France.
Prigent
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D000595:Amino Acid Sequence; D000818:Animals; D064127:Aurora Kinases; D020134:Catalytic Domain; D018797:Cell Cycle Proteins; D002457:Cell Extracts; D018385:Centrosome / Q000737:chemistry / Q000378:metabolism*; D017124:Conserved Sequence; D006801:Humans; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D013077:Sperm Head / Q000378:metabolism; D008941:Spindle Apparatus / Q000737:chemistry / Q000378:metabolism; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000378:metabolism*
D018797:Cell Cycle Proteins; D002457:Cell Extracts; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; D011494:Protein Kinases; C112134:AURKA protein, Xenopus; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D017239:Paclitaxel; D015739:Nocodazole