Prominin 2 is a 112 kDa glycoporotein structurally related to Prominin 1 (CD133) although amino acid similarity is not more than 30%, but their genomic organization is strikingly similar. Like Prominin 1, the prominin 2 exhibit similar membrane topology with 5 trans-membrane domains and two large glycosylated extracellular domains. Similar to Prominin1 localization, the Prominin 2 is also associated with membrane protrusions of the epithelial cells from adult kidney, and all along the digestive track and other epithelial tissues.
Prominin 2 expression is down-regulated in aggressive prostate cancer cell lines and transient transfection of PROML2 expression vectors has been shown to induce apoptosis in cultured prostate cancer cells, suggesting a tumor suppressive role for Prominin 2. Prominin 2 expression is likely to be involved in growth suppression in the prostate, and down-regulation of Prominin 2 may disrupt normal prostatic homeostasis and lead to uncontrolled prostatic growth.