Exhibits calcium-dependent phospholipid binding properties. May function in membrane trafficking. Regulates synaptic levels of nicotinic acetylcholine receptor subunit lev-1 and unc-38 in the nerve cord. Involved in nicotinic acetylcholine receptor (nAChR)-mediated sensitivity to nicotine and levamisole. Affects directional sperm motility. Interacts with nicotinic acetylcholine receptor. C2 domains are necessary for calcium-dependent cell membrane association. C2 domains are necessary for neuronal progenitor cell differentiation in a calcium-independent manner. Belongs to the copine family.