cyclin d1 is a nuclear protein required for cell cycle progression in g1
Cyclin D1 Cyclin D1 is a protein required for progression through the G1 phase of the cell cycle.[14] During the G1 phase, it is synthesized rapidly and accumulates in the nucleus, and is degraded as the cell enters the S phase.[14] Cyclin D1 is a regulatory subunit of cyclin-dependent kinases CDK4 and CDK6. The protein dimerizes with CDK4/6 to regulate the G1/S phase transition and entry into the S-phase.