question: Which genes/proteins have been found to inhibit cyclin dependent kinase 4 (CDK4)?
answer: The p15(ink4b) and p16(ink4a) CDK4 inhibitor genes map within the chromosome band 9p21 region deleted frequently in various cancers.The Cdk4 inhibitor p18(Ink4c) is a tumor suppressor. Recent studies of Cyclin D1/Cdk4 have proposed that p21(Waf1/Cip1/Sdi1) plays a key role as a potent Cdk4 inhibitor. p27KIP1 is also a cdk4 ihibitor.