FIG. 3.
Specific PKCδ kinase inhibitors and activators modulate SRF DNA binding activity. (A) In vitro kinase reactions with SRF(His)6 and kinases supplied from equal amounts of young (Y), senescent (O), or a combination of young- and old-cell nuclear extracts (Y/O) were performed in the presence of [γ-32P]ATP. Control (C) reactions with SRF but without nuclear extract were also incubated in the presence of [γ-32P]ATP (lanes 1, 5, and 9). Parallel sets of reactions were carried out in the presence of either 20 μM rottlerin (lanes 5 to 8) or 50 nM bistratene A (lanes 9 to 12), which inhibit and activate PKCδ, respectively (B). In vitro kinase reactions performed in parallel without radiolabel were used with labeled SRE EMSAs (lanes 13 to 24).