The adenosine A2A receptor functions by encoding a protein whose activity is mediated by G proteins, a family of proteins that act as molecular switches inside cells.
The gene encodes a protein which is one of several receptor subtypes for adenosine. The activity of the encoded protein, a G protein-coupled receptor family member, is mediated by G proteins which activate adenylyl cyclase, which induce synthesis of intracellular cAMP. G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. 
