May be involved in the regulation of cell proliferation. Has a cell-proliferation inhibition activity in vitro. . May act as a modulator of nicotinic acetylcholine receptors (nAChRs) activity. In vitro inhibits nicotine-induced signaling probably implicating alpha-3:beta-2- or alpha-7-containing nAChRs. . This is the function of ENSG00000167653 (PSCA, prostate stem cell antigen).