a protein kinase of the CDK family that is important for cell cycle G1 phase progression. Its activity is restricted to the G1-S phase. Controlled by the regulatory subunits D-type cyclins and CDK inhibitor p16(INK4a). Phosphorylates the retinoblastoma gene product (Rb). Point mutations found in somatic and familial melanoma. Amplified in sarcomas, glioma and lymphoma. Amplified, methylated or deleted in head and neck squamous cell carcinoma. Overexpression drives epithelial tumors in mice. Disruption makes mice resistant to cancer. Inhibitor: PD332991. Note: This description may include information from UniProtKB.
Protein type: CDK family; CDK/CDK4 subfamily; CDK4 subfamily; CMGC group; Cell cycle regulation; EC 220.127.116.11; Kinase, protein; Protein kinase, CMGC; Protein kinase, Ser/Thr (non-receptor)
Molecular Function: cyclin binding; cyclin-dependent protein kinase activity; cyclin-dependent protein kinase regulator activity; protein binding
Biological Process: G1/S transition of mitotic cell cycle; positive regulation of cell cycle; positive regulation of cell proliferation; positive regulation of fibroblast proliferation; protein amino acid phosphorylation; regulation of gene expression; response to drug