Cyclin D1 (CCND1)

Cyclin D1 is a regulatory protein that plays a central role in cell cycle progression, particularly in the transition from the G1 phase to the S phase. It acts as a regulatory subunit for cyclin-dependent kinases CDK4 and CDK6, forming active complexes that phosphorylate and inactivate members of the retinoblastoma (RB) protein family, including RB1. This phosphorylation releases E2F transcription factors, enabling transcription of genes required for DNA synthesis and entry into S phase. Overexpression of cyclin D1 is frequently observed across multiple tumor types, leading to unchecked proliferation due to loss of normal G₁/S checkpoint control. Cyclin D1 also regulates activity of various transcription factors, coactivators, corepressors involved in chromatin remodeling and histone acetylation, often via both CDK-dependent and independent mechanisms.

Other names

BCL1PRAD1

Inhibition of CDK4/6 kinase activity, leading to cell cycle arrest in G1 phase