. "The formation of CyclinD:CDK4/6 complexes is promoted by two proteins, p21Cip1/Waf1 and p27kip1. Activity of the cyclin-dependent kinases 4 and 6 can be inhibited by the binding of several small CDK-inhibitory proteins (CKIs)."^^ . "Edited: Matthews, L, 2006-07-03 08:41:56"^^ . . . . . . "Formation of Cyclin D:Cdk4/6 complexes"^^ . . . . . . .