Aurora kinase A

Aurora kinase A also known as serine/threonine-protein kinase 6 is an enzyme that in humans is encoded by the AURKA gene. Aurora A is a member of a family of mitotic serine/threonine kinases. It is implicated with important processes during mitosis and meiosis whose proper function is integral for healthy cell proliferation. Aurora A is activated by one or more phosphorylations and its activity peaks during the G2 phase to M phase transition in the cell cycle. The aurora kinases were first identified in 1990 during a cDNA screen of Xenopus eggs. The kinase discovered, Eg2, is now referred to as Aurora A. However, Aurora A's meiotic and mitotic significance was not recognized until 1998. The human genome contains three members of the aurora kinase family: Aurora kinase A, Aurora kinase B and Aurora C kinase. The Xenopus, Drosophila, and Caenorhabditis elegans genomes, on the other hand, contain orthologues only to Aurora A and Aurora B. In all studied species, the three Aurora mitotic kinases localize to the centrosome during different phases of mitosis. The family members have highly conserved C-terminal catalytic domains. Their N-terminal domains, however, exhibit a large degree of variance in the size and sequence. Aurora A and Aurora B kinases play important roles in mitosis. The Aurora kinase A is associated with centrosome maturation and separation and thereby regulates spindle assembly and stability. The Aurora kinase B is a chromosome passenger protein and regulates chromosome segregation and cytokinesis. Although there is evidence to suggest that Aurora C might be a chromosomal passenger protein, the cellular function of it is less clear. Aurora A localizes next to the centrosome late in the G1 phase and early in the S phase. As the cell cycle progresses, concentrations of Aurora A increase and the kinase associates with the mitotic poles and the adjacent spindle microtubules. Aurora A remains associated with the spindles through telophase. Right before mitotic exit, Aurora A relocalizes to the mid-zone of the spindle.