ID P35426; PN Cyclin-dependent kinase 4; GN Cdk4; OS 10116; SL Nucleus Position: SL-0178; SL Nucleus Position: SL-0182; SL Comments: Cytoplasm {ECO:0000250|UniProtKB:P11802}. Nucleus {ECO:0000250|UniProtKB:P11802}. Nucleus membrane {ECO:0000250|UniProtKB:P11802}. Note=Cytoplasmic when non-complexed. Forms a cyclin D-CDK4 complex in the cytoplasm as cells progress through G(1) phase. The complex accumulates on the nuclear membrane and enters the nucleus on transition from G(1) to S phase. Also present in nucleoli and heterochromatin lumps. Colocalizes with RB1 after release into the nucleus (By similarity). {ECO:0000250|UniProtKB:P11802}. DR UNIPROT: P35426; DR Pfam: PF00069; DR PROSITE: PS00107; DR PROSITE: PS50011; DR PROSITE: PS00108; DE Function: Ser/Thr-kinase component of cyclin D-CDK4 (DC) complexes that phosphorylate and inhibit members of the retinoblastoma (RB) protein family including RB1 and regulate the cell-cycle during G(1)/S transition. Phosphorylation of RB1 allows dissociation of the transcription factor E2F from the RB/E2F complexes and the subsequent transcription of E2F target genes which are responsible for the progression through the G(1) phase. Hypophosphorylates RB1 in early G(1) phase. Cyclin D-CDK4 complexes are major integrators of various mitogenenic and antimitogenic signals. Also phosphorylates SMAD3 in a cell-cycle-dependent manner and represses its transcriptional activity. Component of the ternary complex, cyclin D/CDK4/CDKN1B, required for nuclear translocation and activity of the cyclin D-CDK4 complex (By similarity). {ECO:0000250|UniProtKB:P11802}. DE Reference Proteome: Yes; GO GO:0005923; GO GO:0000785; GO GO:0097128; GO GO:0097129; GO GO:0097130; GO GO:0000307; GO GO:0005737; GO GO:0016592; GO GO:0031965; GO GO:0005634; GO GO:0048471; GO GO:0032991; GO GO:0005667; GO GO:0005524; GO GO:0030332; GO GO:0004693; GO GO:0016301; GO GO:0004672; GO GO:0106310; GO GO:0004674; GO GO:0044877; GO GO:0008353; GO GO:0060612; GO GO:0031100; GO GO:0051301; GO GO:0032869; GO GO:0071353; GO GO:1904637; GO GO:0071222; GO GO:1904628; GO GO:1904584; GO GO:0007623; GO GO:0000082; GO GO:0002088; GO GO:0043065; GO GO:0008284; GO GO:0045793; GO GO:0050679; GO GO:0048146; GO GO:0010971; GO GO:0045727; GO GO:0006468; GO GO:0051726; GO GO:0042127; GO GO:0010468; GO GO:0046626; GO GO:0046890; GO GO:0050994; GO GO:0040014; GO GO:0061469; GO GO:0055093; GO GO:0010288; GO GO:0010033; GO GO:0033574; GO GO:0009636; GO GO:0009410; GO GO:0007165; TP Membrane Topology: Unknown; Source: UniProt - Sequence Analysis; SQ MATTRYEPVAEIGVGAYGTVYKARDPHSGHFVALKSVRVPNGGAAGGGLPVSTVREVALLRRLEAFEHPNVVRLMDVCAT SQ SRTDRDIKVTLVFEHIDQDLRTYLDKAPPPGLPVETIKDLMRQFLSGLDFLHANCIVHRDLKPENILVTSNGTVKLADFG SQ LARIYSYQMALTPVVVTLWYRAPEVLLQSTYATPVDMWSVGCIFAEMFRRKPLFCGNSEADQLGKIFDLIGLPPEDDWPR SQ EVSLPRGAFSPRGPRPVQSVVPEMEESGAQLLLEMLTFNPLKRISAFRALQHSYLHKEESDPE //