FIGURE 4.
PKA-mediated phosphorylation of Ccc2 and its variants. A, autoradiograms of the 110-kDa band of representative alkaline gels after SDS-PAGE in the absence (black bars) or presence of 100 nm PKAi5–24 (gray bars) (represented in C) on the regulatory phosphorylation of Ccc2 wt, S258A, S258D, S971A, and S258A/S971A. Regulatory phosphorylation and resolution of the bands in alkaline gels were carried out as described under “Experimental Procedures,” with a simultaneous “reference regulatory phosphorylation” of Ccc2 wt taken as 100%, using media with the same specific activity for [γ-32P]ATP and resolution in the same gel. B, silver staining of the corresponding gels presented in A. C, densitometric representation of >4 experiments (mean ± S.E.). Different lowercase letters above the columns indicate significant differences (p < 0.05).