Chk

Chk inhibitors act on checkpoint kinases 1 and 2 (Chk1, Chk2), which halt the cell cycle after DNA damage. In 1997 human Chk1 was shown to link DNA damage to cyclin-dependent kinase (CDK) regulation through cell division cycle 25 (Cdc25) phosphatases. A year later, Chk2 was identified as a kinase that connects the ataxia telangiectasia mutated (ATM) protein to cell cycle control. Prexasertib, rabusertib and SCH 900776 are Chk1 inhibitors used to study replication stress and checkpoint override. PD0166285 also inhibits the Wee1 and membrane-associated tyrosine/threonine kinase 1 (Myt1) enzymes, which act alongside Chk1 at the G2/M transition. The list also holds polo-like kinase (PLK) inhibitors such as BI 2536 and volasertib, which are covered in the sibling category PLK.