During growth factor-induced cellular regeneration, which transition during cell cycle is controlled by the phosphorylation of the retinoblastoma protein:: (A) G0 to Gl, (B) Gl to S, (C) S to G2, (D) G2 to M
Answer is B. Rb proteins control any extremely impoant check point, the Gi to S transition during the cell cycle. The other checkpoints are regulated by a distinct set of proteins.