Figure 1.

Examples of pathways that may be activated by EP2R and EP4R. (i) Gα_s may act via cAMP-gated channels to increase Ca²⁺ and Ca²⁺-dependent calcineurin signaling. Gαs may also act via (ii) cAMP to activate PKA or EPAC, leading to activation or inhibition of phosphorylation of extracellular signal-regulated kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family. (iii) Gα_s may also act independently of cAMP to activate the MAPK pathway by transactivating epidermal growth factor receptor (EGFR) via Src. Potential target transcription factors include nuclear factor of activated T-cells (NFAT), cAMP-response element binding protein (CREB) and activator protein-1(AP-1).