| First Author | Florek M | Year | 2007 |
| Journal | Cell Tissue Res | Volume | 328 |
| Issue | 1 | Pages | 31-47 |
| PubMed ID | 17109118 | Mgi Jnum | J:168820 |
| Mgi Id | MGI:4938266 | Doi | 10.1007/s00441-006-0324-z |
| Citation | Florek M, et al. (2007) Prominin-2 is a cholesterol-binding protein associated with apical and basolateral plasmalemmal protrusions in polarized epithelial cells and released into urine. Cell Tissue Res 328(1):31-47 |
| abstractText | Prominin-2 is a pentaspan membrane glycoprotein structurally related to the cholesterol-binding protein prominin-1, which is expressed in epithelial and non-epithelial cells. Although prominin-1 expression is widespread throughout the organism, the loss of its function solely causes retinal degeneration. The finding that prominin-2 appears to be restricted to epithelial cells, such as those found in kidney tubules, raises the possibility that prominin-2 functionally substitutes prominin-1 in tissues other than the retina and provokes a search for a definition of its morphological and biochemical characteristics. Here, we have investigated, by using MDCK cells as an epithelial cell model, whether prominin-2 shares the biochemical and morphological properties of prominin-1. Interestingly, we have found that, whereas prominin-2 is not restricted to the apical domain like prominin-1 but is distributed in a non-polarized fashion between the apical and basolateral plasma membranes, it retains the main feature of prominin-1, i.e. its selective concentration in plasmalemmal protrusions; prominin-2 is confined to microvilli, cilia and other acetylated tubulin-positive protruding structures. Similar to prominin-1, prominin-2 is partly associated with detergent-resistant membranes in a cholesterol-dependent manner, suggesting its incorporation into membrane microdomains, and binds directly to plasma membrane cholesterol. Finally, prominin-2 is also associated with small membrane particles that are released into the culture media and found in a physiological fluid, i.e. urine. Together, these data show that all the characteristics of prominin-1 are shared by prominin-2, which is in agreement with a possible redundancy in their role as potential organizers of plasma membrane protrusions. |
