. "Cyclin D:Cdk4 mediated phosphorylation of RB1 releases RB1 from the transcriptional regulator E2F and activates E2F function."^^ . . . . . . "Cyclin D:Cdk4/6 mediated phosphorylation of Rb and dissociation of phospho-Rb from the E2F1/2/3:DP-1 complexes"^^ . "2.7.11.22"^^ . . . . . .