Nedd4-2 Modulates Renal Na+-Cl− Cotransporter via the Aldosterone-SGK1-Nedd4-2 Pathway

作者：Juan Pablo Arroyo, Dagmara Lagnaz, Caroline Ronzaud, Norma Hilda Vázquez, Benjamin S. Ko, Lauren Moddes, Dorothée Ruffieux-Daidié, Pierrette Hausel, Robert Koesters, Baoli Yang, John B. Stokes, Robert S. Hoover, Gerardo Gamba, Olivier Staub · 发表于：Journal of the American Society of Nephrology · 年份：2011 · DOI：10.1681/asn.2011020132 · 被引用次数：168 · 研究领域：Ion Transport and Channel Regulation、Hormonal Regulation and Hypertension、Pancreatic function and diabetes

Regulation of renal Na(+) transport is essential for controlling blood pressure, as well as Na(+) and K(+) homeostasis. Aldosterone stimulates Na(+) reabsorption by the Na(+)-Cl(-) cotransporter (NCC) in the distal convoluted tubule (DCT) and by the epithelial Na(+) channel (ENaC) in the late DCT, connecting tubule, and collecting duct. Aldosterone increases ENaC expression by inhibiting the channel's ubiquitylation and degradation; aldosterone promotes serum-glucocorticoid-regulated kinase SGK1-mediated phosphorylation of the ubiquitin-protein ligase Nedd4-2 on serine 328, which prevents the Nedd4-2/ENaC interaction. It is important to note that aldosterone increases NCC protein expression by an unknown post-translational mechanism. Here, we present evidence that Nedd4-2 coimmunoprecipitated with NCC and stimulated NCC ubiquitylation at the surface of transfected HEK293 cells. In Xenopus laevis oocytes, coexpression of NCC with wild-type Nedd4-2, but not its catalytically inactive mutant, strongly decreased NCC activity and surface expression. SGK1 prevented this inhibition in a kinase-dependent manner. Furthermore, deficiency of Nedd4-2 in the renal tubules of mice and in cultured mDCT(15) cells upregulated NCC. In contrast to ENaC, Nedd4-2-mediated inhibition of NCC did not require the PY-like motif of NCC. Moreover, the mutation of Nedd4-2 at either serine 328 or 222 did not affect SGK1 action, and mutation at both sites enhanced Nedd4-2 activity and abolished SGK1-depend...