What is the role of Geminin in the cell cycle?
Eukaryotic replication origins must fire exactly once per cell cycle, a requirement enforced by strict licensing control. In G1, origin recognition complex recruits Cdc6 and Cdt1 to load MCM2-7 double hexamer helicases to form pre-replicative complexes. Upon S-phase entry, CDK and DDK activations fire origins and simultaneously trigger elimination of licensing factors to prevent re-assembly. Geminin provides a crucial additional layer independent of phosphorylation. Synthesized from S phase onward and stable through G2 and early mitosis, geminin directly binds coiled-coil domain of Cdt1 with h
Ref: McGarry & Kirschner, Geminin prevents DNA rereplication, Cell 1998; Alberts et al., Molecular Biology of the Cell, Chapter 5, Origin Licensing.
