Figure 2:

Schematic representation of the PGE2 signaling receptors EP2 and EP4, reproduced and modified from [1]. EP2 and EP4 are GPCRs coexpressed in immune cells and bind PGE2. After binding to PGE2, both receptors activate the ${\mathrm{G}}_{{\alpha }_s}$ proteins, which in turn activate AC leading to increased levels of intracellular cAMP. EP4 can additionally activate ${\mathrm{G}}_{{\alpha }_i}$, leading to a modulation of cAMP production.