In response to DNA damage, the checkpoint regulates and coordinates many cellular processes critical for genomic stability,
including cell cycle progression, DNA repair, DNA replication, and apoptosis.
Cyclin D is synthesized during the first stage of
cell replication and is believed to help drive the complex, multi-stage process,
including interaction with the retinoblastoma (Rb) protein, whose function is to prevent excessive
cell growth by inhibiting
cell cycle progression until a
cell is ready to divide.