Fig. 9.
A p21 construct, phosphomimetic at the Mirk phosphorylation site, is twice as effective as wild-type p21 in blocking the activation of caspase 3. C2C12 myoblasts were transfected with Flag-p21 wild-type, Flag-p21-S153A, Flag-p21-S153D, or vector for 24 hours, cultured in differentiation medium for 16 hours, and then analyzed by SDS-PAGE and western blotting for activated caspase 3, normalized by western blotting for tubulin and the expression of exogenous Flag-p21 by western blotting for Flag. Mean +/− SD shown of 2 experiments.