CDKN1A
Description
The CDKN1A (cyclin dependent kinase inhibitor 1A) is a protein-coding gene located on chromosome 6.
CDKN1A, also known as p21, is a cyclin-dependent kinase inhibitor (CKI) that plays a significant role in cell cycle regulation and DNA damage response. It inhibits the activity of various cyclin/CDK complexes, particularly CDK2. CDKN1A is a key downstream target of the tumor suppressor p53 and its expression is induced in response to DNA damage, leading to cell cycle arrest. The gene encoding CDKN1A, CDKN1A, is located on chromosome 6 in humans.
CDKN1A plays a crucial role in regulating cell cycle progression and halting cell division in response to DNA damage, particularly during the G2 phase. This protein is involved in p53-mediated suppression of cell growth when DNA damage occurs, as well as in p53-independent G2 arrest mediated by CREB3L1, particularly in astrocytes and osteoblasts. CDKN1A directly binds to and inhibits cyclin-dependent kinases (CDKs), preventing the phosphorylation of key CDK substrates, thereby halting cell cycle progression. It contributes to the nuclear localization and assembly of the cyclin D-CDK4 complex, promoting its kinase activity toward RB1. However, at higher concentrations, it can inhibit the kinase activity of the cyclin D-CDK4 complex. Additionally, CDKN1A interferes with DNA synthesis by DNA polymerase delta by competing with POLD3 for binding to PCNA.
CDKN1A is also known as CAP20, CDKN1, CIP1, MDA-6, P21, SDI1, WAF1, p21CIP1.
