Receptor for extracellular ATP > UTP and ADP. The activity of this receptor is mediated by G proteins which activate a phosphatidylinositol-calcium second messenger system. May be the cardiac P2Y receptor involved in the regulation of cardiac muscle contraction through modulation of L-type calcium currents. Is a receptor for leukotriene B4, a potent chemoattractant involved in inflammation and immune response. Expressed at highest levels in heart, skeletal muscle and at lower levels in brain and liver. High level of expression in lymphoid tissues. Phosphorylated by GRK6 upon leukotriene B4 binding; which promotes desensitization. Belongs to the G-protein coupled receptor 1 family.