Prom1

Developmental stage

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.

Function

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.

Post-translational modifications

Acetylation at Lys-226, Lys-258 and Lys-265 by NAT8 and NAT8B may control PROM1 protein expression and its function in cell apoptosis.

Sequence Similarities

Belongs to the prominin family.

Tissue Specificity

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).

Cellular localization

• Apical cell membrane
• Multi-pass membrane protein
• Cell projection
• Microvillus membrane
• Multi-pass membrane protein
• Cell projection
• Cilium
• Photoreceptor outer segment
• Endoplasmic reticulum
• Endoplasmic reticulum-Golgi intermediate compartment
• Found in extracellular membrane particles in various body fluids such as ventricular fluid of the developing brain and urine.

Alternative names

CD133, Prom, Proml1, Prom1, Prominin-1, Antigen AC133 homolog, Prominin-like protein 1

Database links

swissprot:O54990 entrezGene:19126

Other research areas

• Immuno-oncology
• Neuroscience