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Catalytic domain of the Serine/Threonine kinase, Aurora kinase STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. Aurora kinases are key regulators of mitosis and are essential for the accurate and equal division of genomic material from parent to daughter cells. Yeast contains only one Aurora kinase while most higher eukaryotes have two. Vertebrates contain at least 2 Aurora kinases (A and B); mammals contains a third Aurora kinase gene (C). Aurora-A regulates cell cycle events from the late S-phase through the M-phase including centrosome maturation, mitotic entry, centrosome separation, spindle assembly, chromosome alignment, cytokinesis, and mitotic exit. Aurora-A activation depends on its autophosphorylation and binding to the microtubule-associated protein TPX2. Aurora-B is most active at the transition during metaphase to the end of mitosis. It is critical for accurate chromosomal segregation, cytokinesis, protein localization to the centrosome and kinetochore, correct microtubule-kinetochore attachments, and regulation of the mitotic checkpoint. Aurora-C is mainly expressed in meiotically dividing cells; it was originally discovered in mice as a testis-specific STK called Aie1. Both Aurora-B and -C are chromosomal passenger proteins that can form complexes with INCENP and survivin, and they may have redundant cellular functions. The Aurora subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
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