Cyclin D2 is involved in the phosphorylation of tumor suppressor protein Rb and functions as a regulatory subunit of CDK4 or CDK6.
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. 
