May play a role in cell differentiation, proliferation and apoptosis. Binds cholesterol in cholesterol-containing plasma membrane microdomains and may play a role in the organization of the apical plasma membrane in epithelial cells. During early retinal development acts as a key regulator of disk morphogenesis (PubMed:19228982). Involved in regulation of MAPK and Akt signaling pathways. In neuroblastoma cells suppresses cell differentiation such as neurite outgrowth in a RET-dependent manner. Interacts with CDHR1 and with actin filaments. Interacts with NAT8 and NAT8B (By similarity). Found in extracellular membrane particles in various body fluids such as ventricular fluid of the developing brain and urine. Additional isoforms seem to exist. In the submandibular gland, expressed on the apical side of epithelial cells. In the parotid gland, expressed in the intercalated ducts. In the sublingual gland, expressed in intercalated ducts. In the extraorbital lacrimal gland, expressed in the intercalated tubules and larger intralobular ducts. Expressed in the retina. Present in urine within small membrane particles (at protein level). In the embryo, expressed on the apical side of neuroepithelial cells and of other epithelia such as lung buds, gut and ureter buds. In the adult, expressed at the apical side of the kidney tubules and of the ependymal layer of the brain. Not expressed in gut, liver, lung, pituitary, adrenal, heart or spleen. Localized to the nascent disk membranes at the base of the rod outer segment in the retina (at protein level). At birth, is detected at the interface between the developing neuroretina and the retinal pigment epithelium (RPE) layer. In the postnatal retina (P20) detected in photoreceptors, with particular concentration in the region of plasma membrane evaginations at the basal part of the outer segment (OS). Expressed by rod and cone photoreceptor cells, most abundantly between the OS and inner segment (IS), in close proximity to the connecting cilium. Acetylation at Lys-226, Lys-258 and Lys-265 by NAT8 and NAT8B may control PROM1 protein expression and its function in cell apoptosis. Progressive degeneration and functional deterioration of both cone and rod photoreceptors associated with impaired morphogenesis of the disks and OS. Fundus images and light microscopy of retinal sections from transgenic mice expressing mutant PROM1 reveal progressive retinal abnormalities visible as subretinal deposits and photoreceptor atrophy. Belongs to the prominin family.