Serine/threonine-protein kinase that performs several important functions throughout M phase of the cell cycle; including the regulation of centrosome maturation and spindle assembly; the removal of cohesins from chromosome arms; the inactivation of anaphase-promoting complex/cyclosome (APC/C) inhibitors; and the regulation of mitotic exit and cytokinesis. Polo-like kinase proteins acts by binding and phosphorylating proteins are that already phosphorylated on a specific motif recognized by the POLO box domains. Phosphorylates cdc25; pkmyt1/myt1; stag2/sa2; tpx2. Plays multiple essential roles during mitosis. Phosphorylates the N-terminal domain of cdc25; which leads to cyclin b-cdc2 activation and mitotic entry. Also required for organization of bipolar spindles; and for exit from mitosis. Involved in kinetochore functions and sister chromatid cohesion by phosphorylating stag2/sa2. {ECO:0000269|PubMed:10567586; ECO:0000269|PubMed:11931760; ECO:0000269|PubMed:11994303; ECO:0000269|PubMed:15692562; ECO:0000269|PubMed:15964272; ECO:0000269|PubMed:19351716; ECO:0000269|PubMed:19556869; ECO:0000269|PubMed:8703070; ECO:0000269|PubMed:9831560}.