Figure 2.

In vivo RB phosphorylation at S780, S795, and S807/S811 using stable low-penetrant transfectants in absence of ectopic cyclins. G418 resistant clones were propagated from stable transfectants using the indicated RB mutant plasmids and lysates were subjected to sequential immunoprecipitation with G3-245 followed by imunoblotting with the indicated pan-RB or phospho-specific antibodies.