Receptor for platelet activating factor, a chemotactic phospholipid mediator that possesses potent inflammatory, smooth-muscle contractile and hypotensive activity. Seems to mediate its action via a G protein that activates a phosphatidylinositol-calcium second messenger system.

Expressed in the placenta, lung, left and right heart ventricles, heart atrium, leukocytes and differentiated HL-60 granulocytes.

Belongs to the G-protein coupled receptor 1 family.

Cell membrane.