| First Author | Wadehra M | Year | 2004 |
| Journal | Mol Biol Cell | Volume | 15 |
| Issue | 5 | Pages | 2073-83 |
| PubMed ID | 14978215 | Mgi Jnum | J:91398 |
| Mgi Id | MGI:3047005 | Doi | 10.1091/mbc.E03-07-0488 |
| Citation | Wadehra M, et al. (2004) The tetraspan protein EMP2 modulates the surface expression of caveolins and glycosylphosphatidyl inositol-linked proteins. Mol Biol Cell 15(5):2073-83 |
| abstractText | Caveolae are a subset of lipid rafts enriched in glycosphingolipids and cholesterol-rich domains, but selectively lacking glycosylphosphatidyl inositol-anchored proteins (GPI-APs). Caveolin proteins are the organizing component of caveolae, but the corresponding proteins for other classes of lipid rafts are poorly defined. Epithelial membrane protein-2 (EMP2), a member of the four-transmembrane superfamily, facilitates plasma membrane delivery of certain integrins. In this study, we found by laser confocal microscopy that EMP2 was associated with GPI-APs (detected by the GPI-AP binding bacterial toxin proaerolysin). Biochemical membrane fractionation and methyl-beta-cyclodextrin treatment demonstrated that this association occurred within lipid rafts. EMP2 did not associate with caveolin-bearing membrane structures, and recombinant overexpression of EMP2 in NIH3T3 cells decreased caveolin-1 and caveolin-2 protein levels while increasing the surface expression of GPI-APs. Conversely, a ribozyme construct that specifically cleaves the EMP2 transcript reduced surface GPI-APs and increased caveolin protein expression. These findings suggest that EMP2 facilitates the formation and surface trafficking of lipid rafts bearing GPI-APs, and reduces caveolin expression, resulting in impaired formation of caveolae. |
