Abstract
Previous studies have characterized interactions between the ubiquitin ligase Nedd4-1 and the epithelial Na(+) channel (ENaC). Such interactions control the channel cell surface expression and activity. Recently, evidence has been provided that a related protein, termed Nedd4-2, is likely to be the true physiological regulator of the channel. Unlike Nedd4-1, Nedd4-2 also interacts with the aldosterone-induced channel activating kinase sgk-1. The current study uses surface plasmon resonance to quantify the binding of the four WW domains of Nedd4-2 to synthetic peptides corresponding to the PY motifs of ENaC and sgk-1. The measurements demonstrate that WW3 and WW4 are the only Nedd4-2 domains interacting with both ENaC and sgk-1 and that their binding constants are in the 1-6 microM range.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Motifs
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Amino Acid Sequence
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Animals
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Calcium-Binding Proteins*
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Endosomal Sorting Complexes Required for Transport
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Epithelial Sodium Channels
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Immediate-Early Proteins
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Ligases / chemistry*
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Ligases / metabolism
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Mice
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Molecular Sequence Data
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Nedd4 Ubiquitin Protein Ligases
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Nuclear Proteins*
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Protein Serine-Threonine Kinases / chemistry*
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Protein Serine-Threonine Kinases / metabolism
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Recombinant Proteins / chemistry
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Sodium Channels / chemistry*
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Sodium Channels / metabolism
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Surface Plasmon Resonance
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Ubiquitin-Protein Ligases*
Substances
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Calcium-Binding Proteins
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Endosomal Sorting Complexes Required for Transport
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Epithelial Sodium Channels
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Immediate-Early Proteins
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Nuclear Proteins
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Recombinant Proteins
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Sodium Channels
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Nedd4 Ubiquitin Protein Ligases
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Nedd4l protein, mouse
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Ubiquitin-Protein Ligases
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Protein Serine-Threonine Kinases
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serum-glucocorticoid regulated kinase
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Ligases