FIGURE 6.

Thrombin-induced CREB translocation. VSM cells stimulated with thrombin (Thr; 50 nm) were fractionated to separate nuclear and cytosolic fractions. A, aliquots of fractions were resolved by SDS-PAGE and immunoblotted for CREB, CREB-Ser(P)¹⁴², CREB-Ser(P)¹³³, CaMKIIδ, and CaMKIIδ-Thr(P)²⁸⁷. Histone H3 and -α were used as markers of the nuclear and cytosolic fractions, respectively, and to normalize signals for loading. B, quantification of total CREB signals. C, quantification of phospho-Ser¹⁴²-CREB (CREB-pSer142) signals. D, quantification of phospho-Ser¹³³-CREB (CREB-pSer133) signal in nuclear fraction. Signals in Cytosol were undetectable. Mean data are expressed as fold of unstimulated at 0 min. Values shown are mean ± S.E., n = 3, and were analyzed by one-way ANOVA. *, p < 0.05; **, p < 0.01; ***, p < 0.001, by Dunnett's post hoc test.