p21 Antibody

Cyclin-dependent kinase inhibitor 1 (p21) is an important intermediate by which p53/TP53 mediates its role as an inhibitor of cellular proliferation in response to DNA damage. P21 binds to and inhibits cyclin-dependent kinase activity, preventing phosphorylation of critical cyclin-dependent kinase substrates and blocking cell cycle progression. p21 functions in the nuclear localization and assembly of the cyclin D-CDK4 complex and promotes its kinase activity towards RB1. At higher stoichiometric ratios, p21 inhibits the kinase activity of the cyclin D-CDK4 complex.