G protein-coupled receptors (GPCRs) represent a large superfamily of cell-surface receptors that are involved in a multitude of physiological processes such as perception of sensory information, modulation of synaptic transmission, hormone release/actions, regulation of cell contraction/migration and cell growth/differentiation. GPCRs interact with G proteins (heterotrimeric GTPases) to synthesize intracellular second messengers, such as diacylglycerol, cyclic AMP, inositol phosphates and calcium ions. Their diverse biological functions range from vision and olfaction to neuronal and endocrine signaling and are involved in many pathological conditions. GRIN2 (G protein-regulated inducer of neurite outgrowth 2), also known as GPRIN2, is a 458 amino acid protein that is expressed in cerebellum and is thought to play a role in neurite outgrowth. GRIN2 interacts with activated G?oand G?, and is encoded by a gene that maps to human chromosome 10q11.22.