The Retinoblastoma Protein: More than a Tumor Suppressor

REGULATION OF RB DURING CELL CYCLE PROGRESSION AND DIFFERENTIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Modification of Rb by Phosphorylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Gl Arrest by Overexpression of Rb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Possible Roles for Rb in Other Phases of the Cell Cycle . . . . . . . . . . . . . . . . . . . . . . 8 Interaction of Rb with Cyclin/Cdk Complexes and Protein Phosphatases . . . . . . . . . 8 Importance of Phosphorylation and Dephosphorylation . . . . . . . . . . . . . . . . . . . . . . . 9 Rb Phosphorylation and Cellular Diff erentiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0