Polo Like Kinase 4 (PLK4)

PLK4 encodes a member of the polo family of serine/threonine protein kinases. The protein localizes to centrioles, complex microtubule-based structures found in centrosomes, and regulates centriole duplication during the cell cycle.

Chromosomal segregation during mitosis and meiosis is regulated by kinases and phosphatases. The predicted 970-amino acid STK18 protein shares significant homology with other STKs, particularly to those related to Drosophila 'polo', all of which have an N-terminal kinase domain. Because STK18 is homologous to the murine Sak gene, the authors designated it SAK. Northern blot analysis detected abundant expression of a 4.0-kb STK18 transcript in testis and thymus but not in other tissues or tumors.