Nedd4-2 induces endocytosis and degradation of proteolytically cleaved epithelial Na+ channels

Rajesh Kabra; Kristin K Knight; Ruifeng Zhou; Peter M Snyder

doi:10.1074/jbc.M708555200

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Nedd4-2 induces endocytosis and degradation of proteolytically cleaved epithelial Na+ channels

Journal article

Open access

Peer reviewed

Nedd4-2 induces endocytosis and degradation of proteolytically cleaved epithelial Na+ channels

Rajesh Kabra, Kristin K Knight, Ruifeng Zhou and Peter M Snyder

The Journal of biological chemistry, Vol.283(10), pp.6033-6039

03/07/2008

DOI: 10.1074/jbc.M708555200

PMID: 18174164

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Abstract

As a pathway for Na(+) reabsorption, the epithelial Na(+) channel ENaC is critical for Na(+) homeostasis and blood pressure control. Na(+) transport is regulated by Nedd4-2, an E3 ubiquitin ligase that decreases ENaC expression at the cell surface. To investigate the underlying mechanisms, we proteolytically cleaved/activated ENaC at the cell surface and then quantitated the rate of disappearance of cleaved channels using electrophysiological and biochemical assays. We found that cleaved ENaC channels were rapidly removed from the cell surface. Deletion or mutation of the Nedd4-2 binding motifs in alpha, beta, and gammaENaC dramatically reduced endocytosis, whereas a mutation that disrupts a YXXØ endocytosis motif had no effect. ENaC endocytosis was also decreased by silencing of Nedd4-2 and by expression of a dominant negative Nedd4-2 construct. Conversely, Nedd4-2 overexpression increased ENaC endocytosis in human embryonic kidney 293 cells but had no effect in Fischer rat thyroid epithelia. In addition to its effect on endocytosis, Nedd4-2 also increased the rate of degradation of the cell surface pool of cleaved alphaENaC. Together the data indicate that Nedd4-2 reduces ENaC surface expression by altering its trafficking at two distinct sites in the endocytic pathway, inducing endocytosis of cleaved channels and targeting them for degradation.

Cell Line

Epithelium - metabolism

Endosomal Sorting Complexes Required for Transport

Humans

Rats, Inbred F344

Ubiquitin-Protein Ligases - metabolism

Rats

Epithelial Sodium Channels - metabolism

Sodium - metabolism

Protein Processing, Post-Translational - physiology

Endocytosis - physiology

Animals

Epithelial Sodium Channels - genetics

Gene Deletion

Nedd4 Ubiquitin Protein Ligases

Amino Acid Motifs - genetics

Ion Transport - physiology

Thyroid Gland - metabolism

Ubiquitin-Protein Ligases - genetics

Details

Title: Subtitle: Nedd4-2 induces endocytosis and degradation of proteolytically cleaved epithelial Na+ channels
Creators: Rajesh Kabra - Departments of Internal Medicine and Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA 52242, USA
Kristin K Knight
Ruifeng Zhou
Peter M Snyder
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.283(10), pp.6033-6039
DOI: 10.1074/jbc.M708555200
PMID: 18174164
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Publisher: United States
Language: English
Date published: 03/07/2008
Academic Unit: Molecular Physiology and Biophysics; Cardiovascular Medicine; Medicine Administration; Internal Medicine
Record Identifier: 9984025573602771

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