Acts as a negative regulator of osteoclast differentiation in basal and inflammatory conditions by regulating TNFSF11-induced Ca (2+) fluxes, thereby controlling the induction of NFATC1 (PubMed:26644563). Interacts with STIM1. Highly expressed in the bone and its expression increases during osteoclastogenesis. Mice are osteopenic and are more susceptible to inflammatory bone loss, owing to enhanced osteoclast formation. Belongs to the TMEM178 family.