Fig. 3

Common PKA signaling pathways: Diagram of the MAPK and PKA pathways. Signaling events leading to Elk1-mediated transcription are shown on the left, while those leading to CREB-mediated transcription are shown on the right. Depending on cell context, PKA either positively or negatively regulates Ras-MAPK signaling. Moreover, MAPK indirectly stimulates CREB-mediated transcription via activation of ribosomal protein S6 kinases (RSKs)