FIG. 7.

Activation of the p38 MAP kinase pathway leads to CREB Ser-133 phosphorylation in vivo. (A) COS cells were transfected with 1 μg of CMV-Gal4-CREB, together with either the empty vectors (pCMV6 and pcDNA3) or pCMV6-p38 and pcDNA3-MKK6(Glu) (constitutively active) or pcDNA3-MKK6(KA) (dominant negative). Two days after transfection, cell lysates were prepared, separated by SDS-PAGE, and immunoblotted with anti-PCREB (top) or anti-Gal4 (bottom) antibodies. (B) PC12 cells were either not pretreated or pretreated for 1 h with SB 203580 (5 μM) and were then either left untreated or treated for 10 min with NGF (30 ng/ml). Cell lysates were separated by SDS-PAGE and immunoblotted with an anti-PCREB antibody.