Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Biol Chem
2018 Mar 09;29310:3675-3684. doi: 10.1074/jbc.RA117.000604.
Show Gene links
Show Anatomy links
Mapping allosteric linkage to channel gating by extracellular domains in the human epithelial sodium channel.
Shobair M
,
Popov KI
,
Dang YL
,
He H
,
Stutts MJ
,
Dokholyan NV
.
???displayArticle.abstract???
The epithelial sodium channel (ENaC) mediates sodium absorption in lung, kidney, and colon epithelia. Channels in the ENaC/degenerin family possess an extracellular region that senses physicochemical changes in the extracellular milieu and allosterically regulates the channel opening. Proteolytic cleavage activates the ENaC opening, by the removal of specific segments in the finger domains of the α- and γ ENaC-subunits. Cleavage causes perturbations in the extracellular region that propagate to the channel gate. However, it is not known how the channel structure mediates the propagation of activation signals through the extracellular sensing domains. Here, to identify the structure-function determinants that mediate allosteric ENaC activation, we performed MD simulations, thiol modification of residues substituted by cysteine, and voltage-clamp electrophysiology recordings. Our simulations of an ENaC heterotetramer, α1βα2γ, in the proteolytically cleaved and uncleaved states revealed structural pathways in the α-subunit that are responsible for ENaC proteolytic activation. To validate these findings, we performed site-directed mutagenesis to introduce cysteine substitutions in the extracellular domains of the α-, β-, and γ ENaC-subunits. Insertion of a cysteine at the α-subunit Glu557 site, predicted to stabilize a closed state of ENaC, inhibited ENaC basal activity and retarded the kinetics of proteolytic activation by 2-fold. Our results suggest that the lower palm domain of αENaC is essential for ENaC activation. In conclusion, our integrated computational and experimental approach suggests key structure-function determinants for ENaC proteolytic activation and points toward a mechanistic model for the allosteric communication in the extracellular domains of the ENaC/degenerin family channels.
Aleksandrov,
Allosteric modulation balances thermodynamic stability and restores function of ΔF508 CFTR.
2012, Pubmed
Aleksandrov,
Allosteric modulation balances thermodynamic stability and restores function of ΔF508 CFTR.
2012,
Pubmed
Aleksandrov,
Regulatory insertion removal restores maturation, stability and function of DeltaF508 CFTR.
2010,
Pubmed
Azad,
Mutations in the amiloride-sensitive epithelial sodium channel in patients with cystic fibrosis-like disease.
2009,
Pubmed
,
Xenbase
Baconguis,
X-ray structure of acid-sensing ion channel 1-snake toxin complex reveals open state of a Na(+)-selective channel.
2014,
Pubmed
Baker,
Genetic variation of αENaC influences lung diffusion during exercise in humans.
2011,
Pubmed
Ben-Shahar,
Sensory functions for degenerin/epithelial sodium channels (DEG/ENaC).
2011,
Pubmed
Berman,
Interacting domains in the epithelial sodium channel that mediate proteolytic activation.
2015,
Pubmed
,
Xenbase
Bhalla,
Mechanisms of ENaC regulation and clinical implications.
2008,
Pubmed
Dagliyan,
Rational design of a ligand-controlled protein conformational switch.
2013,
Pubmed
Dawson,
Structure of the acid-sensing ion channel 1 in complex with the gating modifier Psalmotoxin 1.
2012,
Pubmed
Della Vecchia,
Gating transitions in the palm domain of ASIC1a.
2013,
Pubmed
,
Xenbase
del Sol,
Residues crucial for maintaining short paths in network communication mediate signaling in proteins.
2006,
Pubmed
del Sol,
The origin of allosteric functional modulation: multiple pre-existing pathways.
2009,
Pubmed
Ding,
Ab initio folding of proteins with all-atom discrete molecular dynamics.
2008,
Pubmed
Dokholyan,
Controlling Allosteric Networks in Proteins.
2016,
Pubmed
Dokholyan,
Discrete molecular dynamics studies of the folding of a protein-like model.
1998,
Pubmed
Doncheva,
Topological analysis and interactive visualization of biological networks and protein structures.
2012,
Pubmed
Garty,
Epithelial sodium channels: function, structure, and regulation.
1997,
Pubmed
Jasti,
Structure of acid-sensing ion channel 1 at 1.9 A resolution and low pH.
2007,
Pubmed
Kashlan,
Allosteric inhibition of the epithelial Na+ channel through peptide binding at peripheral finger and thumb domains.
2010,
Pubmed
,
Xenbase
Kota,
The N-terminal domain allosterically regulates cleavage and activation of the epithelial sodium channel.
2014,
Pubmed
Moreau,
Biophysics, pathophysiology, and pharmacology of ion channel gating pores.
2014,
Pubmed
Pedersen,
Cell volume regulation in epithelial physiology and cancer.
2013,
Pubmed
Proctor,
Applications of Discrete Molecular Dynamics in biology and medicine.
2016,
Pubmed
Proctor,
Rational Coupled Dynamics Network Manipulation Rescues Disease-Relevant Mutant Cystic Fibrosis Transmembrane Conductance Regulator.
2015,
Pubmed
Ramaswamy,
Proton-mediated conformational changes in an acid-sensing ion channel.
2013,
Pubmed
Rauh,
A mutation of the epithelial sodium channel associated with atypical cystic fibrosis increases channel open probability and reduces Na+ self inhibition.
2010,
Pubmed
,
Xenbase
Rauh,
A mutation in the β-subunit of ENaC identified in a patient with cystic fibrosis-like symptoms has a gain-of-function effect.
2013,
Pubmed
,
Xenbase
Ritz,
Pathways on demand: automated reconstruction of human signaling networks.
2016,
Pubmed
Rocks,
Designing allostery-inspired response in mechanical networks.
2017,
Pubmed
Rossier,
Epithelial sodium transport and its control by aldosterone: the story of our internal environment revisited.
2015,
Pubmed
Roy,
Molecular determinants of desensitization in an ENaC/degenerin channel.
2013,
Pubmed
Scardoni,
Finding the shortest path with PesCa: a tool for network reconstruction.
2015,
Pubmed
Scardoni,
Finding the shortest path with PesCa: a tool for network reconstruction.
2017,
Pubmed
Sharma,
Multiscale modeling of nucleosome dynamics.
2007,
Pubmed
Sherwood,
Structure and activity of the acid-sensing ion channels.
2012,
Pubmed
Shirvanyants,
Discrete molecular dynamics: an efficient and versatile simulation method for fine protein characterization.
2012,
Pubmed
Shobair,
Gain-of-Function Mutation W493R in the Epithelial Sodium Channel Allosterically Reconfigures Intersubunit Coupling.
2016,
Pubmed
Stockand,
Insight toward epithelial Na+ channel mechanism revealed by the acid-sensing ion channel 1 structure.
2008,
Pubmed
Swain,
Coupling of proton binding in extracellular domain to channel gating in acid-sensing ion channel.
2013,
Pubmed
Yang,
Conformational sampling on acid-sensing ion channel 1 (ASIC1): implication for a symmetric conformation.
2009,
Pubmed
Yang,
Inherent dynamics of the acid-sensing ion channel 1 correlates with the gating mechanism.
2009,
Pubmed
