Check point kinase 1 (Chk1)

Check point kinase 1 (Chk1) is a serine / threonine protein kinase and a key mediator in the DNA damage-induced checkpoint network. Chk1 is an evolutionarily conserved protein kinase that functions to ensure genomic integrity upon genotoxic stress. When the G2 or S checkpoint is abrogated by the inhibition of Chk1, p53– deficient cancer cells undergo mitotic catastrophe and eventually apoptosis, whereas normal cells are still arrested in the G1 phase. Thus, Chk1 inhibitors can preferentially potentiate the efficacy of DNA damaging agents in cancer cells, and Chk1 is an attractive therapeutic target for cancer treatment, especially since approximately 50% of all human cancers are p53-deficient.