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. Author manuscript; available in PMC: 2015 Apr 4.
Published in final edited form as: Prostaglandins Other Lipid Mediat. 2014 Nov 27;0:99–103. doi: 10.1016/j.prostaglandins.2014.11.003

Figure 1. Schematic of PGE2 synthesis, transport, signaling, and metabolism.

Figure 1

The cyclooxygenase-2 (COX-2) enzyme is the rate-limiting step in the production of prostaglandin E2 (PGE2) from arachidonic acid. PGE2 is exported from the cell via multiple drug resistance-associated protein 4 (MRP4). In an autocrine or paracrine manner, extracellular PGE2 binds any of its four cognate EP receptors, EP1-4, and initiates diverse signaling pathways via activation of G-proteins. Alternatively, PGE2 is imported via the prostaglandin transporter (PGT) and inactivated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). The bold arrows indicate members of this pathway up-regulated in cancer while the dotted arrows indicate members of this pathway down-regulated in cancer.