PLK3 (polo-like kinase 3) is a serine/threonine-protein kinase involved in cell cycle regulation, response to stress and Golgi disassembly [, , ]. It regulates angiogenesis and responses to DNA damage []. Activated PLK3 mediates Chk2 phosphorylation by ATM and the resulting checkpoint activation []. PLK3 phosphorylates DNA polymerase delta and may be involved in DNA repair. It also inhibits Cdc25c, thereby regulating the onset of mitosis [, ].
PLK3 (polo-like kinase 3) is a serine/threonine-protein kinase involved in cell cycle regulation, response to stress and Golgi disassembly [, , ]. It regulates angiogenesis and responses to DNA damage []. Activated PLK3 mediates Chk2 phosphorylation by ATM and the resulting checkpoint activation []. PLK3 phosphorylates DNA polymerase delta and may be involved in DNA repair. It also inhibits Cdc25c, thereby regulating the onset of mitosis [, ].STKs (serine/threonine-protein kinases) catalyse the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. PLKs (polo-like kinases) play important roles in cell cycle progression and in DNA damage responses. They regulate mitotic entry, mitotic exit, and cytokinesis. In general PLKs contain an N-terminal catalytic kinase domain and a C-terminal regulatory polo box domain (PBD), which is comprised by two bipartite polo-box motifs (or polo boxes) and is involved in protein interactions. There are five mammalian PLKs (PLK1-5) from distinct genes [, , ].
Polo-like kinases (Plks) belong to the serine/threonine kinase subfamily, and are characterized by the presence of the signature motif called Polo-box domain. Plks are key regulators of cell cycle and cell division in eukaryotes [, ]. Unicellular organisms contain one Plk whereas higher eukaryotes have as many as four Plks: Plk1, Plk2, Plk3 andPlk4.Plk4 (also called Sak) is the most structurally divergent member of the Plks. It plays a pivotal role in centriole duplication [, , , , ]and is required for centriolar satellite function and ciliogenesis []. Substrates identified for Plk4 include Cdc25C and Chk2 [, ].
