May act as a signaling scaffold protein that senses intracellular calcium. Can modulate ligand-induced internalization of ADORA2A and coupling efficiency of mGluR5/GRM5; for both receptors may regulate signaling activity such as promoting MAPK1/3 (ERK1/2) activation. Interacts (calcium-dependent) with ADORA2A and GRM5. Colocalizes with ADORA2A and/or mGluR5/GRM5 at the plasma membrane (By similarity). Found in neuronal somata (PubMed:26843217). Detected in the cytoplasm of striatal neurons, at postsynaptic sites, filling dendritic shafts and spines, and at presynaptic sites, filling axon terminals (By similarity). Expressed in the iris, in the ciliary margin of the retina and in the inner portion of the neural retina. Expressed in the spinal dorsal horn with especially strong expression in lamina IIi; found in excitory synaptic boutons (at protein level). Expressed in retina, retinal pigmented epithelium, Rathke's pouch, corneal epithelium, the infundibulum and olfactory placodes at 10.5 dpc (at protein level). Expressed in the inner region of the neural retina, including the ganglion cell layer at 17.5 dpc (at protein level). Expressed in the optic sulcus and in the pre-tectum at 8.5 dpc. Expressed in the optic vesicle, in the midline position in the roof of the midbrain and in the pre-tectum at 9.0-9.5 dpc. Expressed in the olfactory placodes at 10.5 dpc. Expressed in retinal-pigmented epithelium and in the neural retina, with strong expression in the ciliary margin at 12.5-13.5 dpc. Up-regulated by PAX6.