Receptor for ADP. Coupled to G(i)-proteins. May play a role in hematopoiesis and the immune system.
Subcellular locations: Cell membrane
Strong expression in spleen and adult brain. Lower expression in placenta, lung, liver, spinal cord, thymus, small intestine, uterus, stomach, testis, fetal brain, and adrenal gland. Not detected in pancreas, heart, kidney, skeletal muscle, ovary or fetal aorta. Clearly detected in lymph node and bone marrow, weakly detected in peripheral blood mononuclear cells (PBMC) and in peripheral blood leukocytes (PBL), but not detected in polymorphonuclear cells (PMN). In the brain, detected in all brain regions examined.