Skip to main content
  • Submit
  • About
    • Editorial Board
    • PNAS Staff
    • FAQ
    • Accessibility Statement
    • Rights and Permissions
    • Site Map
  • Contact
  • Journal Club
  • Subscribe
    • Subscription Rates
    • Subscriptions FAQ
    • Open Access
    • Recommend PNAS to Your Librarian
  • Log in
  • My Cart

Main menu

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
  • About
    • Editorial Board
    • PNAS Staff
    • FAQ
    • Accessibility Statement
    • Rights and Permissions
    • Site Map
  • Contact
  • Journal Club
  • Subscribe
    • Subscription Rates
    • Subscriptions FAQ
    • Open Access
    • Recommend PNAS to Your Librarian

User menu

  • Log in
  • My Cart

Search

  • Advanced search
Home
Home

Advanced Search

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses

New Research In

Physical Sciences

Featured Portals

  • Physics
  • Chemistry
  • Sustainability Science

Articles by Topic

  • Applied Mathematics
  • Applied Physical Sciences
  • Astronomy
  • Computer Sciences
  • Earth, Atmospheric, and Planetary Sciences
  • Engineering
  • Environmental Sciences
  • Mathematics
  • Statistics

Social Sciences

Featured Portals

  • Anthropology
  • Sustainability Science

Articles by Topic

  • Economic Sciences
  • Environmental Sciences
  • Political Sciences
  • Psychological and Cognitive Sciences
  • Social Sciences

Biological Sciences

Featured Portals

  • Sustainability Science

Articles by Topic

  • Agricultural Sciences
  • Anthropology
  • Applied Biological Sciences
  • Biochemistry
  • Biophysics and Computational Biology
  • Cell Biology
  • Developmental Biology
  • Ecology
  • Environmental Sciences
  • Evolution
  • Genetics
  • Immunology and Inflammation
  • Medical Sciences
  • Microbiology
  • Neuroscience
  • Pharmacology
  • Physiology
  • Plant Biology
  • Population Biology
  • Psychological and Cognitive Sciences
  • Sustainability Science
  • Systems Biology
Research Article

Binding of cardiotonic steroids to Na+,K+-ATPase in the E2P state

View ORCID ProfileRyuta Kanai, View ORCID ProfileFlemming Cornelius, View ORCID ProfileHaruo Ogawa, Kanna Motoyama, View ORCID ProfileBente Vilsen, and View ORCID ProfileChikashi Toyoshima
PNAS January 5, 2021 118 (1) e2020438118; https://doi.org/10.1073/pnas.2020438118
Ryuta Kanai
aInstitute for Quantitative Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Ryuta Kanai
Flemming Cornelius
bDepartment of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Flemming Cornelius
Haruo Ogawa
aInstitute for Quantitative Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Haruo Ogawa
Kanna Motoyama
aInstitute for Quantitative Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Bente Vilsen
bDepartment of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Bente Vilsen
Chikashi Toyoshima
aInstitute for Quantitative Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Chikashi Toyoshima
  • For correspondence: ct@iqb.u-tokyo.ac.jp
  1. Contributed by Chikashi Toyoshima, November 12, 2020 (sent for review October 1, 2020; reviewed by Kathleen J. Sweadner and Howard S. Young)

  • Article
  • Figures & SI
  • Info & Metrics
  • PDF
Loading

Significance

Cardiotonic steroids (CTSs) are specific inhibitors of Na+,K+-ATPase and have been studied over a long period of time because of their potential therapeutic use in heart failure, hypertension, and cancers. Their affinities and binding kinetics are vastly different and seemingly rather inconsistent in the literature. Recent development of nonconventional CTSs with unexpected behaviors has revived interest in CTSs as potential drugs. In this report, we carried out a systematic study on various CTSs, including rostafuroxin and istaroxime, using kinetics and X-ray crystallography of their complexes with Na+,K+-ATPase, and explain how CTSs block the reaction cycle and why such large differences in inhibitory behaviors arise. The analysis suggests how isoform specificity may be achieved in order to improve their clinical usability.

Abstract

The sodium pump (Na+, K+-ATPase, NKA) is vital for animal cells, as it actively maintains Na+ and K+ electrochemical gradients across the cell membrane. It is a target of cardiotonic steroids (CTSs) such as ouabain and digoxin. As CTSs are almost unique strong inhibitors specific to NKA, a wide range of derivatives has been developed for potential therapeutic use. Several crystal structures have been published for NKA-CTS complexes, but they fail to explain the largely different inhibitory properties of the various CTSs. For instance, although CTSs are thought to inhibit ATPase activity by binding to NKA in the E2P state, we do not know if large conformational changes accompany binding, as no crystal structure is available for the E2P state free of CTS. Here, we describe crystal structures of the BeF3− complex of NKA representing the E2P ground state and then eight crystal structures of seven CTSs, including rostafuroxin and istaroxime, two new members under clinical trials, in complex with NKA in the E2P state. The conformations of NKA are virtually identical in all complexes with and without CTSs, showing that CTSs bind to a preformed cavity in NKA. By comparing the inhibitory potency of the CTSs measured under four different conditions, we elucidate how different structural features of the CTSs result in different inhibitory properties. The crystal structures also explain K+-antagonism and suggest a route to isoform specific CTSs.

  • cardiotonic steroids
  • Na+,K+-ATPase
  • crystal structures
  • isoform specificity
  • sodium pump

Footnotes

  • ↵1To whom correspondence may be addressed. Email: ct{at}iqb.u-tokyo.ac.jp.
  • Author contributions: F.C., B.V., and C.T. designed research; R.K., F.C., H.O., K.M., B.V., and C.T. performed research; R.K., F.C., H.O., K.M., B.V., and C.T. analyzed data; and F.C. and C.T. wrote the paper.

  • Reviewers: K.J.S., Massachusetts General Hospital/Harvard Medical School; and H.S.Y., University of Alberta.

  • The authors declare no competing interest.

  • This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2020438118/-/DCSupplemental.

Data Deposition.

The atomic coordinates and structure factors have been deposited in the Protein Data Bank (PDB ID codes 7D91–7D94 and 7DDF–7DDL).

Published under the PNAS license.

View Full Text

Log in using your username and password

Forgot your user name or password?

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.
If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.

Purchase access

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

Subscribers, for more details, please visit our Subscriptions FAQ.

Please click here to log into the PNAS submission website.

PreviousNext
Back to top
Article Alerts
Email Article

Thank you for your interest in spreading the word on PNAS.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Binding of cardiotonic steroids to Na+,K+-ATPase in the E2P state
(Your Name) has sent you a message from PNAS
(Your Name) thought you would like to see the PNAS web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Binding of cardiotonic steroids to Na+,K+-ATPase in the E2P state
Ryuta Kanai, Flemming Cornelius, Haruo Ogawa, Kanna Motoyama, Bente Vilsen, Chikashi Toyoshima
Proceedings of the National Academy of Sciences Jan 2021, 118 (1) e2020438118; DOI: 10.1073/pnas.2020438118

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Request Permissions
Share
Binding of cardiotonic steroids to Na+,K+-ATPase in the E2P state
Ryuta Kanai, Flemming Cornelius, Haruo Ogawa, Kanna Motoyama, Bente Vilsen, Chikashi Toyoshima
Proceedings of the National Academy of Sciences Jan 2021, 118 (1) e2020438118; DOI: 10.1073/pnas.2020438118
Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Mendeley logo Mendeley
Proceedings of the National Academy of Sciences: 118 (1)
Table of Contents

Submit

Sign up for Article Alerts

Article Classifications

  • Biological Sciences
  • Biochemistry

Jump to section

  • Article
    • Abstract
    • Results and Discussion
    • Conclusions
    • Methods
    • Data Deposition.
    • Acknowledgments
    • Footnotes
    • References
  • Figures & SI
  • Info & Metrics
  • PDF

You May Also be Interested in

Surgeons hands during surgery
Inner Workings: Advances in infectious disease treatment promise to expand the pool of donor organs
Despite myriad challenges, clinicians see room for progress.
Image credit: Shutterstock/David Tadevosian.
Setting sun over a sun-baked dirt landscape
Core Concept: Popular integrated assessment climate policy models have key caveats
Better explicating the strengths and shortcomings of these models will help refine projections and improve transparency in the years ahead.
Image credit: Witsawat.S.
Double helix
Journal Club: Noncoding DNA shown to underlie function, cause limb malformations
Using CRISPR, researchers showed that a region some used to label “junk DNA” has a major role in a rare genetic disorder.
Image credit: Nathan Devery.
Steamboat Geyser eruption.
Eruption of Steamboat Geyser
Mara Reed and Michael Manga explore why Yellowstone's Steamboat Geyser resumed erupting in 2018.
Listen
Past PodcastsSubscribe
Multi-color molecular model
Enzymatic breakdown of PET plastic
A study demonstrates how two enzymes—MHETase and PETase—work synergistically to depolymerize the plastic pollutant PET.
Image credit: Aaron McGeehan (artist).

Similar Articles

Site Logo
Powered by HighWire
  • Submit Manuscript
  • Twitter
  • Facebook
  • RSS Feeds
  • Email Alerts

Articles

  • Current Issue
  • Special Feature Articles – Most Recent
  • List of Issues

PNAS Portals

  • Anthropology
  • Chemistry
  • Classics
  • Front Matter
  • Physics
  • Sustainability Science
  • Teaching Resources

Information

  • Authors
  • Editorial Board
  • Reviewers
  • Librarians
  • Press
  • Site Map
  • PNAS Updates

Feedback    Privacy/Legal

Copyright © 2021 National Academy of Sciences. Online ISSN 1091-6490