P2RY1 belongs to the family of G protein-coupled receptors. This family has several receptor subtypes with different pharmacological selectivity, which overlaps in some cases, for various adenosine and uridine nucleotides. P2RY1 functions as a receptor for extracellular ATP and ADP. In platelets, binding to ADP leads to mobilization of intracellular calcium ions via activation of phospholipase C. ADP binding also may lead to a change in platelet shape and possible platelet aggregation.