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Catalytic domain of the Serine/Threonine Kinase, Polo-like kinase 3 STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. PLKs 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. PLK3, also called Prk or Fnk (FGF-inducible kinase), 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. The PLK3 subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",