IDEAS home Printed from https://ideas.repec.org/a/nat/natcom/v5y2014i1d10.1038_ncomms4948.html
   My bibliography  Save this article

Physiological sodium concentrations enhance the iodide affinity of the Na+/I− symporter

Author

Listed:
  • Juan P. Nicola

    (Yale University School of Medicine
    Present address: Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba 5000, Argentina)

  • Nancy Carrasco

    (Yale University School of Medicine)

  • L. Mario Amzel

    (Johns Hopkins University School of Medicine)

Abstract

The Na+/I− symporter (NIS) mediates active I− transport—the first step in thyroid hormonogenesis—with a 2Na+:1I− stoichiometry. NIS-mediated 131I− treatment of thyroid cancer post-thyroidectomy is the most effective targeted internal radiation cancer treatment available. Here to uncover mechanistic information on NIS, we use statistical thermodynamics to obtain Kds and estimate the relative populations of the different NIS species during Na+/anion binding and transport. We show that, although the affinity of NIS for I− is low (Kd=224 μM), it increases when Na+ is bound (Kd=22.4 μM). However, this Kd is still much higher than the submicromolar physiological I− concentration. To overcome this, NIS takes advantage of the extracellular Na+ concentration and the pronounced increase in its own affinity for I− and for the second Na+ elicited by binding of the first. Thus, at physiological Na+ concentrations, ~79% of NIS molecules are occupied by two Na+ ions and ready to bind and transport I−.

Suggested Citation

  • Juan P. Nicola & Nancy Carrasco & L. Mario Amzel, 2014. "Physiological sodium concentrations enhance the iodide affinity of the Na+/I− symporter," Nature Communications, Nature, vol. 5(1), pages 1-10, September.
    • Handle: RePEc:nat:natcom:v:5:y:2014:i:1:d:10.1038_ncomms4948
    DOI: 10.1038/ncomms4948
    as

    Download full text from publisher

    File URL: https://www.nature.com/articles/ncomms4948
    File Function: Abstract
    Download Restriction: no
    File URL: https://libkey.io/10.1038/ncomms4948?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    More about this item

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:nat:natcom:v:5:y:2014:i:1:d:10.1038_ncomms4948. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Sonal Shukla or Springer Nature Abstracting and Indexing (email available below). General contact details of provider: http://www.nature.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.