a protein kinase of the CDK family. Important for cell cycle G1 phase progression and G1/S transition. The activity of this kinase first appears in mid-G1 phase, controlled by the regulatory subunits including D-type cyclins and members of INK4 family of CDK inhibitors. Phosphorylates and regulates the activity of the Rb tumor suppressor protein. Overexpressed and/or disrupted by translocation in leukemias, lymphomas and other cancers and amplified in gliomas and rodent cancers. Note: This description may include information from UniProtKB.
Protein type: CDK family; CDK/CDK4 subfamily; CDK4 subfamily; CMGC group; Cell cycle regulation; EC 188.8.131.52; Kinase, protein; Protein kinase, CMGC; Protein kinase, Ser/Thr (non-receptor)