Intracellular orphan receptor that binds numerous drugs and which is highly expressed in various proliferating cells. Corresponds to the sigma-2 receptor, which is thought to play important role in regulating cell survival, morphology and differentiation. May play a role as a regulator of cellular cholesterol homeostasis. May function as sterol isomerase. May alter the activity of some cytochrome P450 proteins. Localized at cell membrane and in lysosomes in sterol-depleted cells when expression of endogenous TMEM97 is stimulated. Sigma receptors are classified into two subtypes (Sigma-1 and Sigma-2) based on their different pharmacological profile. Sigma-2 receptors are identified by radioligand-binding studies as a binding site with high affinity for di-o-tolylguanidine (DTG) and haloperidol. Belongs to the TMEM97/sigma-2 receptor family.