Figure 4.
RIMs and synapsins, but not rabphilin, are putative AC1 targets. A, Western blots show that the amount of PKA-phosphorylated RIM (P-RIM) is greatly reduced in brl somatosensory cortex but not the amount of total RIM, PKA phosphorylated rabphilin (P-rab), or total rabphilin (rab). Actin immunoreactivity was used as a loading control. B, Histogram of the normalized ratios of P-RIM/RIM and RIM/actin as fractions of wt values (normalized in pairs). Normalized brl P-RIM/RIM levels are as follows: P4–P6 group, 0.34 ± 0.04, four pairs; P7–P10 group, 0.35 ± 0.07, 13 pairs. Normalized brl RIM/actin levels are as follows: P4–P7 mice, 1.08 ± 0.10, four pairs; P7–P10 mice, 1.11 ± 0.05, eight pairs. C, Histogram of the normalized ratios of P-rab/rab and rab/actin. Normalized brl P-rab/rab levels are as follows: 1.12 ± 0.09 for four pairs of P4–P6 and 0.98 ± 0.11 for four pairs of P7–P10 age groups. Normalized brl rab/actin levels are as follows: 0.94 ± 0.12 for four pairs of P4–P6 and 1.09 ± 0.11 for four pairs of P7–P10. D, Western blots showing a decrease in the amount of PKA-phosphorylated synapsin [P-syn(PKA)] but not the amount of total synapsin (syn) or MAPK-phosphorylated synapsin [P-syn(M1) or P-syn(M2)]. E–G, Histograms summarizing the normalized ratios of P-syn(PKA)/syn (E), P-syn(M1)/syn and P-syn(M2)/syn (F), and syn/actin (G) as fractions of wild-type values. Normalized brl P-syn (PKA)/syn levels are as follows: 0.47 ± 0.13 for six pairs of P4–P6 group and 0.35 ± 0.06 for eight pairs of P7–P11 group. P-syn(M1)/syn is 0.89 ± 0.07 for eight pairs; P-syn(M2)/syn is 1.02 ± 0.08 for eight pairs; syn/actin is 1.08 ± 0.14 for eight pairs of P4–P6 mice and 1.14 ± 0.14 for eight pairs of P7–P10 mice. Asterisks indicate significant difference.