8.A.71.1.1
The RIC3 (RIC-3) protein of 369 aas and 2 TMSs.  Promotes functional expression of homomeric alpha-7 and alpha-8 nicotinic acetylcholine receptors at the cell surface (Castelán et al. 2008). Also promotes 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-4.7.  It interacts directly with the cytoplasmic domain of the serotonin receptor (TC# 1.A.9.2.3) (Nishtala et al. 2016). The artificial intelligence program AlphaFold2 predicted structures for NACHO and RIC-3. NACHO is highly conserved in sequence and structure across species, but RIC-3 is not. How do disordered RIC-3 isoforms from C. elegans to humans interact with alpha7 nAChR subunits despite having little sequence homology across RIC-3 species? Two models from the literature about how RIC-3 assists alpha7 nAChR assembly have been evaluated, considering recent structural information about the receptor and its chaperones (Loring 2022). The binding motifs for RIC-3 in 5-HT3A receptor subunits at two locations have been identified (Do and Jansen 2023).