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

Functional Analysis of a Tryptophan-Less P-glycoprotein: A Tool for Tryptophan Insertion and Fluorescence Spectroscopy

Tony Kwan, Helen Loughrey, Martine Brault, Samantha Gruenheid, Ina L. Urbatsch, Alan E. Senior and Philippe Gros
Molecular Pharmacology July 2000, 58 (1) 37-47; DOI: https://doi.org/10.1124/mol.58.1.37
Tony Kwan
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Helen Loughrey
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Martine Brault
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Samantha Gruenheid
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Ina L. Urbatsch
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Alan E. Senior
1 2 3
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Philippe Gros
1 2 3
  • 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

P-glycoprotein (Pgp) functions as an ATP-dependent drug efflux pump to confer multidrug resistance to tumor cells. In the absence of a high-resolution structure for this protein, several important and intriguing aspects of Pgp structure and function remain poorly understood. Fluorescence spectroscopy of endogenous or genetically engineered tryptophan residues represents a potentially powerful method to probe static and dynamic aspects of Pgp at high resolution. We have used site-directed mutagenesis to modify the wild-type (WT) mousemdr3 Pgp for tryptophan fluorescence spectroscopy by replacement of all 11 tryptophan residues individually with phenylalanine. None of the 11 tryptophans were found to be absolutely essential for Pgp activity, because Chinese hamster ovary cells transfected and overexpressing this mutant Trp-less mdr3 cDNA (mdr3F1–11) become multidrug-resistant and can carry out active transport of vinblastine, colchicine, and Calcein-AM. The mdr3F1–11 mutant has reduced activity compared with WT Mdr3, and shows a unique pattern of drug resistance clearly distinct from WT and, as opposed to the latter, can neither confer FK-506 resistance nor functionally complementste6 in yeast. Studies with Pgp mutants containing either single or double tryptophan residues or with chimeric molecules constructed between wild-type Pgp andmdr3F1–11 indicated that no single tryptophan residue was responsible for the reduced activity of themdr3F1–11 mutant. Likewise, all but one chimeric Pgp preserved the unique drug resistance profile of themdr3F1–11 mutant. Altogether, we show that a Trp-less Pgp is functionally active and can be used as a molecular backbone for insertion of tryptophans in strategic locations to probe various aspects of Pgp function.

Footnotes

    • Received October 4, 1999.
    • Accepted March 7, 2000.
  • Philippe Gros, Department of Biochemistry, McGill University, 3655 Drummond St., Montreal, Quebec, H3G 1Y6 Canada. E-mail: gros{at}med.mcgill.ca

  • This work was supported in part by a grant (to P.G.) from the Medical Research Council (MRC) of Canada and by National Institutes of Health Grant GM50516 (to A.E.S.). T.K. was supported by a studentship from la Formation de Chercheurs et l'Aide à la Recherche, and P.G. was supported by a senior Scientist Award from the MRC.

  • 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: 58 (1)
Molecular Pharmacology
Vol. 58, Issue 1
1 Jul 2000
  • Table of Contents
  • About the Cover
  • Index by author
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.
Functional Analysis of a Tryptophan-Less P-glycoprotein: A Tool for Tryptophan Insertion and Fluorescence Spectroscopy
(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

Functional Analysis of a Tryptophan-Less P-glycoprotein: A Tool for Tryptophan Insertion and Fluorescence Spectroscopy

Tony Kwan, Helen Loughrey, Martine Brault, Samantha Gruenheid, Ina L. Urbatsch, Alan E. Senior and Philippe Gros
Molecular Pharmacology July 1, 2000, 58 (1) 37-47; DOI: https://doi.org/10.1124/mol.58.1.37

Citation Manager Formats

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

Share
Research ArticleArticle

Functional Analysis of a Tryptophan-Less P-glycoprotein: A Tool for Tryptophan Insertion and Fluorescence Spectroscopy

Tony Kwan, Helen Loughrey, Martine Brault, Samantha Gruenheid, Ina L. Urbatsch, Alan E. Senior and Philippe Gros
Molecular Pharmacology July 1, 2000, 58 (1) 37-47; DOI: https://doi.org/10.1124/mol.58.1.37
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

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

Related Articles

Cited By...

More in this TOC Section

  • Effects of Small Molecule Ligands on ACKR3 Receptors
  • Michaelis-Menten Quantification of GPCR-G Protein Signaling
  • Anti-aromatase activity of exemestane phase II metabolites
Show more Article

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 © 2022 by the American Society for Pharmacology and Experimental Therapeutics