The Xenopus laevis centrosome aurora/Ipl1-related kinase.
The cDNA encoding the protein kinase pEg2 was originally cloned through a differential screening performed during the early development of Xenopus laevis. pEg2 orthologues were found in various organisms and were classified in a new family of oncogenic mitotic protein kinases named 'aurora/Ipl1-related kinases' after the Drosophila melanogaster gene aurora and the Saccharomyces cerevisiae gene Ipl1. The catalytic activity of pEg2 is necessary for the mitotic microtubule spindle formation in Xenopus laevis egg extracts. The addition of a dominant negative form of pEg2 to in vitro spindle assembly assays leads to monopolar spindles generated by a defect of centrosome separation. In Xenopus cultured cells, pEg2 was confined around the pericentriolar material once centrosomes were duplicated. The centrosome localization does not depend on the presence of microtubules. However, in vitro, the protein binds to taxol-stabilized microtubules independently of its kinase activity. During mitosis the location of the protein changes, in metaphase the kinase localizes on the microtubules at the poles of the mitotic spindle whereas it is not present on astral microtubules. This localization persists until the segregation of the chromosomes is completed. The presence of the kinase on the spindle may reveal another yet unknown function.
Giet
R
R
CNRS UPR41, Université de Rennes 1, faculté de Médecine, France.
Uzbekov
R
R
Kireev
I
I
Prigent
C
C
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D064127:Aurora Kinases; D015153:Blotting, Western; D018797:Cell Cycle Proteins; D018385:Centrosome / Q000201:enzymology* / Q000648:ultrastructure; D018076:DNA, Complementary; D019084:Fluorescent Antibody Technique, Indirect; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D017239:Paclitaxel / Q000494:pharmacology; D011494:Protein Kinases / Q000032:analysis / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000378:metabolism*; D029867:Xenopus Proteins; D014982:Xenopus laevis
D000972:Antineoplastic Agents, Phytogenic; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D029867:Xenopus Proteins; D011494:Protein Kinases; C112134:AURKA protein, Xenopus; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D017239:Paclitaxel