Enables taste receptor binding activity. Involved in regulation of intracellular transport. Acts upstream of or within protein transport into membrane raft; sensory perception of bitter taste; and sensory perception of sweet taste. Located in endoplasmic reticulum membrane. Is integral component of plasma membrane. Is expressed in central nervous system; eye; ganglia; incisor; and testis. Human ortholog(s) of this gene implicated in hereditary spastic paraplegia 72. Orthologous to human REEP2 (receptor accessory protein 2). [provided by Alliance of Genome Resources, Apr 2022]