Epithelial Na+ channel activity in human airway epithelial cells: the role of serum and glucocorticoid‐inducible kinase 1
Epithelial Na+ channel activity in human airway epithelial cells: the role of serum and glucocorticoid‐inducible kinase 1
BACKGROUND AND PURPOSE Glucocorticoids appear to control Na+ absorption in pulmonary epithelial cells via a mechanism dependent upon serum and glucocorticoid‐inducible kinase 1 (SGK1), a kinase that allows control over the surface abundance of epithelial Na+ channel subunits (α‐, β‐ and γ‐ENaC). However, not all data support this model and the present study re‐evaluates this hypothesis in order to clarify the mechanism that allows glucocorticoids to control ENaC activity.EXPERIMENTAL APPROACH Electrophysiological studies explored the effects of agents that suppress SGK1 activity upon glucocorticoid‐induced ENaC activity in H441 human airway epithelial cells, whilst analyses of extracted proteins explored the associated changes to the activities of endogenous protein kinase substrates and the overall/surface expression of ENaC subunits.KEY RESULTS Although dexamethasone‐induced (24 h) ENaC activity was dependent upon SGK1, prolonged exposure to this glucocorticoid did not cause sustained activation of this kinase and neither did it induce a coordinated increase in the surface abundance of α‐, β‐ and γ‐ENaC. Brief (3 h) exposure to dexamethasone, on the other hand, did not evoke Na+ current but did activate SGK1 and cause SGK1‐dependent increases in the surface abundance of α‐, β‐ and γ‐ENaC.CONCLUSIONS AND IMPLICATIONS Although glucocorticoids activated SGK1 and increased the surface abundance of α‐, β‐ and γ‐ENaC, these responses were transient and could not account for the sustained activation of ENaC. The maintenance of ENaC activity did, however, depend upon SGK1 and this protein kinase must therefore play an important but permissive role in glucocorticoid‐induced ENaC activation.
- Universiti Malaysia Terengganu Malaysia
- University of North Carolina at Chapel Hill United States
- National University of Malaysia Malaysia
- University of Dundee United Kingdom
- UNC Lineberger Comprehensive Cancer Center United States
570, Time Factors, 610, Respiratory Mucosa, Protein Serine-Threonine Kinases, Dexamethasone, Cell Line, Immediate-Early Proteins, Membrane Potentials, Humans, Enzyme Inhibitors, Phosphorylation, Epithelial Sodium Channels, Glucocorticoids, Phosphoinositide-3 Kinase Inhibitors, Up-Regulation, Enzyme Activation, Protein Subunits, Phosphatidylinositol 3-Kinase, Protein Processing, Post-Translational, Signal Transduction, Transcription Factors
570, Time Factors, 610, Respiratory Mucosa, Protein Serine-Threonine Kinases, Dexamethasone, Cell Line, Immediate-Early Proteins, Membrane Potentials, Humans, Enzyme Inhibitors, Phosphorylation, Epithelial Sodium Channels, Glucocorticoids, Phosphoinositide-3 Kinase Inhibitors, Up-Regulation, Enzyme Activation, Protein Subunits, Phosphatidylinositol 3-Kinase, Protein Processing, Post-Translational, Signal Transduction, Transcription Factors
16 Research products, page 1 of 2
- 2017IsRelatedTo
- 2018IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
chevron_left - 1
- 2
chevron_right
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).20 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Average influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Average impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
