| First Author | Raikwar NS | Year | 2010 |
| Journal | Am J Physiol Renal Physiol | Volume | 299 |
| Issue | 2 | Pages | F436-44 |
| PubMed ID | 20504882 | Mgi Jnum | J:162486 |
| Mgi Id | MGI:4819049 | Doi | 10.1152/ajprenal.00674.2009 |
| Citation | Raikwar NS, et al. (2010) Nedd4-2 interacts with occludin to inhibit tight junction formation and enhance paracellular conductance in collecting duct epithelia. Am J Physiol Renal Physiol 299(2):F436-44 |
| abstractText | Nedd4-2, a E3 ubiquitin ligase, regulates epithelial sodium channel-mediated transcellular Na(+) transport in the collecting duct. We investigated the effect of Nedd4-2 on the junctional complex and paracellular conductance in mpkCCD(c14) cells, a collecting duct cell line. We demonstrate that Nedd4-2 coimmunoprecipitated with and reduced the expression of transfected occludin in HEK293 cells. This interaction was mediated via a conserved PY motif in the COOH terminus of occludin and mutation of this PY motif increased the half-life of transfected occludin in HEK293 cells from 6.4 to 11.4 h. We demonstrate that Nedd4-2 ubiquitinates occludin, which was not seen when a catalytically inactive form of Nedd4-2 was used. Overexpression of Nedd4-2 in mpkCCD(c14) cells reduced occludin at the tight junction and transiently increased paracellular conductance in a Ca(2+) switch assay consistent with a delay in the formation of tight junctions. Conversely, siRNA-mediated knockdown of Nedd4-2 increased occludin levels and reduced paracellular conductance. In summary, we demonstrate that Nedd4-2 plays a role in tight junction assembly and the regulation of paracellular conductance in the collecting duct. |
