Platelet-Activating Factor Receptor (PAFR)

The platelet-activating factor receptor (PAFR) is a G-protein coupled receptor (GPCR) that binds platelet-activating factor (PAF), a potent phospholipid mediator involved in numerous physiological and pathological processes. PAFR is present in both plasma and nuclear membranes of most cells within the vascular system and innate immune system, participating broadly in inflammatory responses as well as other physiological functions such as reproduction and pulmonary gas exchange. It is implicated in various diseases including inflammation, cancer, and stroke, making it a therapeutic target.

Agonists bind to PAFR, activating Gi/Gq/G12/13 proteins, leading to downstream signaling cascades including PI-calcium second messenger system activation, intracellular calcium mobilization, MAPK/NF-kB pathway activation, cAMP inhibition, and EGF-R transactivation. Antagonists block PAF binding, inhibiting these signaling events.