Plays a role in neuronal proliferation and differentiation (By similarity). Plays a role in the accumulation of cellular cholesterol (PubMed:19179482). Involved in intracellular lipid droplet formation (PubMed:19179482). May contribute to cholesterol homeostasis in neuronal cells (PubMed:19179482). Predominantly localized to cholesterol-enriched domains within membranes (PubMed:19179482). Localizes to cytoplasmic punctate vesicular structures (PubMed:19179482). Expressed in retina, hippocampus and cerebellum (PubMed:19179482). Expressed in the ganglion and bipolar cells of the inner and outer nuclear layers of the retina and in Purkinje cells (at protein level) (PubMed:19179482). Expressed strongly in brain and retina, weakly in testis and bone marrow (PubMed:19179482). Down-regulated by thyroid hormone T3 in retinal ganglion layers during the embryonic development (PubMed:19179482). The SSD (sterol-sensing) domain is necessary for the increase in cellular cholesterol uptake (PubMed:19179482). Belongs to the patched family.