Molecular chaperone which facilitates proper subunit assembly and surface trafficking of alpha-7 (CHRNA7) and alpha-8 (CHRNA8) nicotinic acetylcholine receptors (PubMed:12821669, PubMed:15504725, PubMed:16120769, PubMed:18691158, PubMed:32204458). May also promote functional expression of homomeric serotoninergic 5-HT3 receptors, and of heteromeric acetylcholine receptors alpha-3/beta-2, alpha-3/beta-4, alpha-4/beta-2 and alpha-4/beta-4. Monomer and homodimer. Interacts with CHRNA7, CHRNA3, CHRNA4, CHRNB2, CHRNB4 and HTR3A. Broadly expressed, with high levels in muscle, brain, heart, pancreas and testis. In the central nervous system, highest levels are detected in the cerebellum and pituitary gland. Over-expressed in brains from patients with bipolar disease or schizophrenia. Isoform 5 is predominantly expressed in the brain. The coiled-coil domain mediates transient homodimerization with other acetylcholine receptor-bound RIC3 molecules, promoting stepwise ACHR homomeric assembly at the membrane. Belongs to the ric-3 family. Probable cloning artifact.