May negatively regulate cell cycle progression. May act at least in part via inhibition of the cyclin-D1/CDK4 complex, thereby preventing phosphorylation of RB1 and blocking E2F-dependent transcription (By similarity). May be required for hepatocyte proliferation. Interacts with CCND1 and GRAP2. May also interact with COPS5, RPLP0, SIRT6, SYF2 and TCF3. Expressed at high levels in brain, intestine, muscle and ovary and at lower levels in heart, kidney, liver, lung, spleen and testis. Highly expressed in the unfertilized egg. Expression is reduced at the two cell and blastocyst stages. Expressed in the liver, CNS and dorsal root ganglia throughout organogenesis. Also expressed in the intestine, kidney, lung, nasal cavities and thymus from 13 dpc. Expression is induced by partial hepatectomy. Phosphorylated. Belongs to the CCNDBP1 family.