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Acetylation Stimulates the Epithelial Sodium Channel by Reducing Its Ubiquitination and Degradation
Journal article   Open access   Peer reviewed

Acetylation Stimulates the Epithelial Sodium Channel by Reducing Its Ubiquitination and Degradation

Phillip L. Butler, Alexander Staruschenko and Peter M. Snyder
The Journal of biological chemistry, Vol.290(20), pp.12497-12503
05/15/2015
DOI: 10.1074/jbc.M114.635540
PMCID: PMC4432271
PMID: 25787079
url
https://doi.org/10.1074/jbc.M114.635540View
Published (Version of record) Open Access

Abstract

The epithelial Na+ channel (ENaC) functions as a pathway for Na+ absorption in the kidney and lung, where it is crucial for Na+ homeostasis and blood pressure regulation. ENaC is regulated in part through signaling pathways that control the ubiquitination state of ENaC lysines. A defect in ubiquitination causes Liddle syndrome, an inherited form of hypertension. Here we determined that alpha-, beta-, and gamma ENaC are also substrates for lysine acetylation. Trichostatin A (TSA), a histone deacetylase inhibitor, enhanced ENaC acetylation and increased ENaC abundance in the total cell lysate and at the cell surface. Moreover, TSA increased ENaC current in Fischer rat thyroid and kidney collecting duct epithelia. We found that HDAC7 is expressed in the kidney collecting duct, supporting a potential role for this histone deacetylase in ENaC regulation. HDAC7 overexpression reduced ENaC abundance and ENaC current, whereas ENaC abundance and current were increased by silencing of HDAC7. ENaC and HDAC7 form a complex, as detected by coimmunoprecipitation. We observed a reciprocal relationship between acetylation and ubiquitination; TSA reduced ENaC ubiquitination, whereas HDAC7 increased ubiquitination. By reducing ENaC ubiquitination, TSA decreased the rate of ENaC degradation. Thus, acetylation increases epithelial Na+ absorption by antagonizing ENaC ubiquitination. This stabilizes ENaC, and hence, increases its abundance at the cell surface.
Biochemistry & Molecular Biology Life Sciences & Biomedicine Science & Technology

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