Document Detail


Rescue of aberrant gating by a genetically encoded PAS (Per-Arnt-Sim) domain in several long QT syndrome mutant human ether-á-go-go-related gene potassium channels.
MedLine Citation:
PMID:  21536673     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Congenital long QT syndrome 2 (LQT2) is caused by loss-of-function mutations in the human ether-á-go-go-related gene (hERG) voltage-gated potassium (K(+)) channel. hERG channels have slow deactivation kinetics that are regulated by an N-terminal Per-Arnt-Sim (PAS) domain. Only a small percentage of hERG channels containing PAS domain LQT2 mutations (hERG PAS-LQT2) have been characterized in mammalian cells, so the functional effect of these mutations is unclear. We investigated 11 hERG PAS-LQT2 channels in HEK293 cells and report a diversity of functional defects. Most hERG PAS-LQT2 channels formed functional channels at the plasma membrane, as measured by whole cell patch clamp recordings and cell surface biotinylation. Mutations located on one face of the PAS domain (K28E, F29L, N33T, R56Q, and M124R) caused defective channel gating, including faster deactivation kinetics and less steady-state inactivation. Conversely, the other mutations caused no measurable differences in channel gating (G53R, H70R, and A78P) or no measurable currents (Y43C, C66G, and L86R). We used a genetically encoded hERG PAS domain (NPAS) to examine whether channel dysfunction could be corrected. We found that NPAS fully restored wild-type-like deactivation kinetics and steady-state inactivation to the hERG PAS-LQT2 channels. Additionally, NPAS rescued aberrant currents in hERG R56Q channels during a dynamic ramp voltage clamp. Thus, our results reveal a putative "gating face" in the PAS domain where mutations within this region form functional channels with altered gating properties, and we show that NPAS is a general means for rescuing aberrant gating in hERG LQT2 mutant channels and may be a potential biological therapeutic.
Authors:
Elena C Gianulis; Matthew C Trudeau
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-05-02
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  286     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-06-20     Completed Date:  2011-08-30     Revised Date:  2014-05-23    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  22160-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Electric Conductivity
Ether-A-Go-Go Potassium Channels / chemistry*,  genetics,  metabolism*
HEK293 Cells
Humans
Ion Channel Gating / genetics*
Long QT Syndrome / genetics*,  metabolism*
Models, Molecular
Mutation*
Protein Structure, Tertiary / genetics
Grant Support
ID/Acronym/Agency:
HL-083121/HL/NHLBI NIH HHS; T32 AR007592/AR/NIAMS NIH HHS; T32-GM 008181/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Ether-A-Go-Go Potassium Channels
Comments/Corrections

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