Partners for adenosine A(1) receptors

G protein-coupled receptors (GPCRs) are targets for therapy in a variety of neurological diseases. Using adenosine A(2) receptors (A(1)Rs) as paradigm of GPCRs, this review focuses on how protein-protein interactions from monomers to heteromers, can contribute to hormone/neurotransmitter/neuromodulator regulation. The interaction of A(1)Rs with other membrane receptors, enzymes, and adaptor and scaffolding proteins is relevant for receptor traffic, internalization, and desensitization, and A(1)Rs are extremely important in driving signaling through different intracellular pathways. There is even the possibility of linking together GPCR heteromeric complexes with ion channel receptors in a receptor mosaic that might have special integrative value and might constitute the molecular basis for learning and memory.