Cyclin D2, a protein that in humans is encoded by the CCND2 gene, is involved in the phosphorylation of tumor suppressor protein Rb and functions as a regulatory subunit of CDK4 or CDK6.
G1/S-specific cyclin-D2 is a protein that in humans is encoded by the CCND2 gene. This protein has been shown to interact with and be involved in the phosphorylation of tumor suppressor protein Rb. This cyclin forms a complex with and functions as a regulatory subunit of CDK4 or CDK6, whose activity is required for cell cycle G1/S transition. 
