Skip to main content
Advertisement

Main menu

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET

User menu

  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Molecular Pharmacology
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET
  • My alerts
  • Log in
  • My Cart
Molecular Pharmacology

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Visit molpharm on Facebook
  • Follow molpharm on Twitter
  • Follow molpharm on LinkedIn
Research ArticleArticle

Identification of a Second Blocker Binding Site at the Cytoplasmic Mouth of the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore

Chantal N. St. Aubin, Jing-Jun Zhou and Paul Linsdell
Molecular Pharmacology May 2007, 71 (5) 1360-1368; DOI: https://doi.org/10.1124/mol.106.031732
Chantal N. St. Aubin
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jing-Jun Zhou
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Paul Linsdell
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF
Loading

Abstract

Chloride transport by the cystic fibrosis transmembrane conductance regulator (CFTR) Cl– channel is inhibited by a broad range of substances that bind within a wide inner vestibule in the pore and physically occlude Cl– permeation. Binding of many of these so-called open-channel blockers involves electrostatic interactions with a positively charged lysine residue (Lys95) located in the pore. Here, we use site-directed mutagenesis to identify a second blocker binding site located at the cytoplasmic mouth of the pore. Mutagenesis of a positively charged arginine at the cytoplasmic mouth of the pore, Arg303, leads to significant weakening of the blocking effects of suramin, a large negatively charged organic molecule. Apparent suramin affinity is correlated with the side chain charge at this position, consistent with an electrostatic interaction. In contrast, block by suramin is unaffected by mutagenesis of Lys95, suggesting that it does not approach close to this important pore-forming lysine residue. We propose that the CFTR pore inner vestibule contains two distinct blocker binding sites. Relatively small organic anions enter deeply into the pore to interact with Lys95, causing an open-channel block that is sensitive to both the membrane potential and the extracellular Cl– concentration. Larger anionic molecules can become lodged in the cytoplasmic mouth of the pore where they interact with Arg303, causing a distinct type of open-channel block that is insensitive to membrane potential or extracellular Cl– ions. The pore may narrow significantly between the locations of these two blocker binding sites.

Footnotes

  • This work was supported by the Canadian Institutes of Health Research.

  • Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.

  • doi:10.1124/mol.106.031732.

  • ABBREVIATIONS: CFTR, cystic fibrosis transmembrane conductance regulator; BHK, baby hamster kidney; DNDS, 4,4′-dinitrostilbene-2,2′-disulfonic acid; NPPB, 5-nitro-2-(3-phenylpropylamino)benzoic acid; PKA, protein kinase A catalytic subunit; TES, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonate; TLCS, taurolithocholate-3-sulfate.

  • ↵1 Current affiliation: Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada.

    • Received October 16, 2006.
    • Accepted February 8, 2007.
  • The American Society for Pharmacology and Experimental Therapeutics
View Full Text

MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years. 

Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page. 

 

  • Click here for information on institutional subscriptions.
  • Click here for information on individual ASPET membership.

 

Log in using your username and password

Forgot your user name or password?

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.
PreviousNext
Back to top

In this issue

Molecular Pharmacology: 71 (5)
Molecular Pharmacology
Vol. 71, Issue 5
1 May 2007
  • Table of Contents
  • Table of Contents (PDF)
  • About the Cover
  • Index by author
  • Back Matter (PDF)
  • Editorial Board (PDF)
  • Front Matter (PDF)
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for sharing this Molecular Pharmacology article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Identification of a Second Blocker Binding Site at the Cytoplasmic Mouth of the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore
(Your Name) has forwarded a page to you from Molecular Pharmacology
(Your Name) thought you would be interested in this article in Molecular Pharmacology.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Research ArticleArticle

Identification of a Second Blocker Binding Site at the Cytoplasmic Mouth of the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore

Chantal N. St. Aubin, Jing-Jun Zhou and Paul Linsdell
Molecular Pharmacology May 1, 2007, 71 (5) 1360-1368; DOI: https://doi.org/10.1124/mol.106.031732

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
Research ArticleArticle

Identification of a Second Blocker Binding Site at the Cytoplasmic Mouth of the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore

Chantal N. St. Aubin, Jing-Jun Zhou and Paul Linsdell
Molecular Pharmacology May 1, 2007, 71 (5) 1360-1368; DOI: https://doi.org/10.1124/mol.106.031732
Reddit logo Twitter logo Facebook logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Abstract
    • Materials and Methods
    • Results
    • Discussion
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF

Related Articles

Cited By...

More in this TOC Section

  • Pharmacological characterization of the human α6β4 nAChR
  • Mechanism of the selective action of paraherquamide A
  • Fatty Acid Amide Hydrolase in Cisplatin Nephrotoxicity
Show more Articles

Similar Articles

Advertisement
  • Home
  • Alerts
Facebook   Twitter   LinkedIn   RSS

Navigate

  • Current Issue
  • Fast Forward by date
  • Fast Forward by section
  • Latest Articles
  • Archive
  • Search for Articles
  • Feedback
  • ASPET

More Information

  • About Molecular Pharmacology
  • Editorial Board
  • Instructions to Authors
  • Submit a Manuscript
  • Customized Alerts
  • RSS Feeds
  • Subscriptions
  • Permissions
  • Terms & Conditions of Use

ASPET's Other Journals

  • Drug Metabolism and Disposition
  • Journal of Pharmacology and Experimental Therapeutics
  • Pharmacological Reviews
  • Pharmacology Research & Perspectives
ISSN 1521-0111 (Online)

Copyright © 2023 by the American Society for Pharmacology and Experimental Therapeutics