PTAFR

Platelet-activating factor receptor (PTAFR), also termed PAF receptor or CD294, is a G protein-coupled receptor that binds platelet-activating factor (PAF), a potent phospholipid mediator. Upon activation, PTAFR couples with Gq and Gi proteins to stimulate phospholipase C (PLC)-dependent inositol triphosphate (IP3) production and calcium mobilization, while simultaneously inhibiting adenylate cyclase. This dual signaling drives pro-inflammatory responses through NF-κB activation and cyclooxygenase-2 (COX-2) induction. The receptor is implicated in pathological inflammation, including sepsis, asthma exacerbations, atherosclerosis, and ischemic organ damage. PTAFR antagonists like rupatadine (dual histamine H1/PAFR antagonist) have shown efficacy in allergic rhinitis, while selective inhibitors such as WEB 2086 demonstrated mixed results in sepsis trials. Recent research explores its role in neuroinflammation and cancer metastasis, with novel PAFR-targeting monoclonal antibodies entering preclinical evaluation for autoimmune disorders. Structural studies reveal conserved residues in the ligand-binding pocket that could guide next-generation inverse agonists.