Affiliation:
1. Department of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne, Switzerland
Abstract
ABSTRACT
The epithelial Na
+
channel (ENaC) is a heteromeric protein complex playing a fundamental role in Na
+
homeostasis and blood pressure regulation. Specific mutations inactivating PY motifs in ENaC C termini cause Liddle's syndrome, an inherited form of hypertension. Previously we showed that these PY motifs serve as binding sites for the E3 enzyme Nedd4-2, implying ubiquitination as a regulatory mechanism of ENaC. Ubiquitination involves the sequential action of E1, E2, and E3 enzymes. Here we identify the E2 enzyme UBE2E3, which acts in concert with Nedd4-2, and show by coimmunoprecipitation that UBE2E3 and Nedd4-2 interact together. In
Xenopus laevis
oocytes, UBE2E3 reduces ENaC activity marginally, consistent with Nedd4-2 being the rate-limiting factor in this process, whereas a catalytically inactive mutant of UBE2E3 (UBE2E3-CS) causes elevated ENaC activity by increasing cell surface expression. No additive effect is observed when UBE2E3-CS is coexpressed with an inactive Nedd4-2 mutant, and the stimulatory role of UBE2E3-CS depends on the integrity of the PY motifs (Nedd4-2 binding sites) and the ubiquitination sites on ENaC. In renal mpkCCD
cl4
cells, displaying ENaC-dependent transepithelial Na
+
transport, Nedd4-2 and UBE2E3 can be coimmunoprecipitated and overexpression of UBE2E3 affects Na
+
transport, corroborating the concept of a concerted action of UBE2E3 and Nedd4-2 in ENaC regulation.
Publisher
American Society for Microbiology
Subject
Cell Biology,Molecular Biology
Reference72 articles.
1. Abriel, H., E. Kamynina, J.-D. Horisberger, and O. Staub. 2000. Regulation of the cardiac voltage-gated Na+ channel (rH1) by the ubiquitin-protein ligase Nedd4. FEBS Lett. 466 : 377-380.
2. Abriel, H., J. Loffing, J. F. Rebhun, J. H. Pratt, J.-D. Horisberger, D. Rotin, and O. Staub. 1999. Defective regulation of the epithelial Na+ channel (ENaC) by Nedd4 in Liddle's syndrome. J. Clin. Investig. 103 : 667-673.
3. Anan, T., Y. Nagata, H. Koga, Y. Honda, N. Yabuki, C. Miyamoto, A. Kuwano, I. Matusuda, F. Endo, H. Saya, and M. Nakao. 1999. Human ubiquitin-protein ligase Nedd4: expression, subcellular localization, and selective interaction with ubiquitin-conjugating enzymes. Genes Cells 3 : 751-763.
4. Aristarkhov, A., E. Eytan, A. Moghe, A. Admon, A. Hershko, and J. V. Ruderman. 1996. E2-C, a cyclin-selective ubiquitin carrier protein required for the destruction of mitotic cyclins. Proc. Natl. Acad. Sci. USA 93 : 4294-4299.
5. Asher, C., A. Chigaev, and H. Garty. 2001. Characterization of interactions between Nedd4 and β and γENaC using surface plasmon resonance. Biochem. Biophys. Res. Commun. 286 : 1228-1231.
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