Regulatory component of the cyclin D3-CDK4 (DC) complex that phosphorylates and inhibits members of the retinoblastoma (RB) protein family including RB1 and regulates the cell-cycle during G1,S transition. Phosphorylation of RB1 allows dissociation of the transcription factor E2F from the RB,E2F complex and the subsequent transcription of E2F target genes which are responsible for the progression through the G1 phase. Hypophosphorylates RB1 in early G1 phase. Cyclin D-CDK4 complexes are major integrators of various mitogenenic and antimitogenic signals. Also substrate for SMAD3, phosphorylating SMAD3 in a cell-cycle-dependent manner and repressing its transcriptional activity. Component of the ternary complex, cyclin D3,CDK4,CDKN1B, required for nuclear translocation and activity of the cyclin D-CDK4 complex.
"Full-length cDNA libraries and normalization."
Li W.B., Gruber C., Jessee J., Polayes D.
Submitted (APR-2003)
Research Topic:Cell Biology