FEATURES

FAMILY

DESCRIPTION

Also known as CDN1B_HUMAN, CDKN1B, KIP1. Important regulator of cell cycle progression. Inhibits the kinase activity of CDK2 bound to cyclin A, but has little inhibitory activity on CDK2 bound to SPDYA (PubMed:28666995). Involved in G1 arrest. Potent inhibitor of cyclin E- and cyclin A-CDK2 complexes. Forms a complex with cyclin type D-CDK4 complexes and is involved in the assembly, stability, and modulation of CCND1-CDK4 complex activation. Acts either as an inhibitor or an activator of cyclin type D-CDK4 complexes depending on its phosphorylation state and/or stoichometry. Forms a ternary complex composed of CCNE1, CDK2 and CDKN1B. Interacts directly with CCNE1; the interaction is inhibited by CDK2-dependent phosphorylation on Thr-187. Interacts with COPS5, subunit of the COP9 signalosome complex; the interaction leads to CDKN1B degradation. Interacts with NUP50; the interaction leads to nuclear import and degradation of phosphorylated CDKN1B. Interacts with CCND1 and SNX6 (By similarity). Interacts (Thr-198-phosphorylated form) with 14-3-3 proteins, binds strongly YWHAQ, weakly YWHAE and YWHAH, but not YWHAB nor YWHAZ; the interaction with YWHAQ results in translocation to the cytoplasm (PubMed:14504289). Interacts with AKT1 and LYN; the interactions lead to cytoplasmic mislocation, phosphorylation of CDKN1B and inhibition of cell cycle arrest (PubMed:12042314, PubMed:12244301, PubMed:17254966). Forms a ternary complex with CCNA2 and CDK2; CDKN1B inhibits the kinase activity of CDK2 through conformational rearrangements. Interacts (unphosphorylated form) with CDK2. Forms a complex with CDK2 and SPDYA, but does not directly interact with SPDYA (PubMed:12972555, PubMed:28666995). Forms a ternary complex composed of cyclin D, CDK4 and CDKN1B. Interacts (phosphorylated on Tyr-88 and Tyr-89) with CDK4; the interaction is required for cyclin D and CDK4 complex assembly, induces nuclear translocation and activates the CDK4 kinase activity. Interacts with GRB2 (PubMed:16195327). Interacts with PIM1 (PubMed:18593906). Identified in a complex with SKP1, SKP2 and CKS1B (PubMed:16209941). Interacts with UHMK1; the interaction leads to cytoplasmic mislocation, phosphorylation of CDKN1B and inhibition of cell cycle arrest (PubMed:12093740). Interacts also with CDK1 (PubMed:16007079). Dephosphorylated on Thr-187 by PPM1H, leading to CDKN1B stability (PubMed:22586611).

EXTERNAL LINKS

CDKN1B

Cyclin-dependent kinase inhibitor 1B

CDKN1B

Molecular Synopsis