Playing Polo in G1: A Novel Function of Polo-Like Kinase-2 in Centriole Duplication

Centrosomes contain a pair of centrioles that duplicate once during the cell cycle togive rise to two mitotic spindle poles, each containing one old and one newcentriole. Centrosome duplication initiates at the G1/S transition in mammaliancells, and is completed during S and G2 phase. The localization of a number ofprotein kinases to the centrosome has revealed the importance of proteinphosphorylation in controlling the centrosome duplication cycle. Recent studieshave shown that polo-like kinase-2 is required for centriole duplication inmammalian cells. In this article I discuss the implication of these findings to ourcurrent understanding of centrosome duplication.