Figure 1. Treatment of SK-N-MC cells with forskolin stimulates phosphorylation of CREB at Ser133, detected by the PathScan ® Phospho-CREB (Ser133) Sandwich ELISA Kit #7385, but does not affect the levels of total CREB detected by PathScan ® Total CREB Sandwich ELISA Kit #7390. SK-N-MC cells (80-90% confluent) were treated with 120 μM forskolin with 0.5 mM IBMX for 30 minutes and lysed. The absorbance readings at 450 nm are shown in the top figure, while the corresponding western blots using CREB (48H2) Rabbit mAb #9197 (left panel) or Phospho-CREB (Ser133) (1B6) Mouse mAb #9196 (right panel) are shown in the bottom figure.