Involved in the recognition and selection of protein complexes to exit the endoplasmic reticulum (ER) (PubMed:19609303, PubMed:24567339). In muscles, regulates levamisole-sensitive nicotinic acetylcholine receptor (L-AChR) subunit composition, possibly by allowing only specific L-AChR subunit combinations to exit the ER (PubMed:19609303). Specifically, may promote the inclusion of alpha subunits unc-38 and unc-29 into L-AChR (PubMed:19609303). Regulates L-AChR sensitivity to agonists such as nicotine and levamisole at neuro-muscular junctions (PubMed:15990870, PubMed:19609303). In touch neurons, may prevent ER exit of incorrectly folded mec-4-mec-10 ion channel (PubMed:24567339). May interact with the levamisole-sensitive nicotinic acetylcholine receptor (L-AChR) (PubMed:15990870). May interact with nra-4 in the ER (PubMed:19609303). During the assembly of acetylcholine receptor in muscles, colocalizes with L-AChR component unc-29 in the ER. Expressed in body wall, pharyngeal, and vulval muscles, excretory canal cell, head and motor neurons, and vulval epithelium. RNAi-mediated knockdown causes a moderate resistance to nicotine-induced paralysis (PubMed:15990870). RNAi-mediated knockdown in neurons in a hyperactive mec-10 (A673V) mutant background increases touch neuron (TRN) cell death (PubMed:24567339). Belongs to the nicastrin family. Although it contains a putative aminopeptidase domain, the critical residues for Zn(2+) binding and thus for catalytic activity are not conserved suggesting that nra-2 lacks peptidase activity.