PLK1

Polo-like kinase 1 (PLK1), a serine/threonine kinase encoded by the PLK1 gene, is a master regulator of mitotic progression. Also termed STPK13 or serine/threonine-protein kinase 13, it orchestrates critical cell cycle events including mitotic entry, sister chromatid segregation, and cytokinesis through phosphorylation of substrates like CDC25C, Cyclin B1, and Kizuna. PLK1 activity peaks during G2/M phase, driving centrosome maturation, spindle assembly, and the DNA damage checkpoint. Its overexpression is oncogenic, correlating with poor prognosis in breast, prostate, and non-small cell lung cancers. PLK1 inhibitors (e.g., volasertib, onvansertib) target the kinase's ATP-binding domain, showing antitumor efficacy in clinical trials. While early-phase trials demonstrated partial responses in acute myeloid leukemia and colorectal cancer, challenges persist in therapeutic windows and resistance mechanisms. Combination strategies with PARP inhibitors or immune checkpoint blockers are under investigation to enhance clinical outcomes.