Source:http://linkedlifedata.com/resource/umls/id/C0659150
NCI: CHK1 Checkpoint Homolog, encoded by the human CHEK1 gene, is a serine/threonine protein kinase that is required for the DNA damage checkpoint. This protein is involved in cell cycle arrest when DNA damage has occurred or when unligated DNA is present. It binds to and phosphorylates CDC25A, CDC25B and CDC25C. Phosphorylation of CDC25C on serine-216 creates a binding site for 14-3-3 protein which inhibits CDC25C. This prevents activation of the CDC2-Cyclin B complex and prevents mitotic entry. This protein is expressed ubiquitously with the most abundant expression in thymus, testis, small intestine, and colon. (From LocusLink, Swiss-Prot, PubMed and NCI)