Phosphorylates proteins on serine, threonine, and tyrosine (By similarity). Involved in mitotic cell cycle checkpoint control. Required for fin and heart regeneration. Required to prevent chromosome segregation errors during meiosis. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Barely detectable in adult somatic tissues. Expressed in immature germ cells that have not completed meiosis. In ovary, expressed predominantly in previtellogenic oocytes. In testis, expressed in primary and secondary spermatocytes, but not mature spermatozoa. Strongly induced in a subpopulation of cells in the proximal blastema during regenerative outgrowth. Mutants show anomalies in the chromosome number of male germ cells, leading to aneuploidy and severe developmental defects in their progeny. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.