1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics
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Quantitative analysis of mammalian GIRK2 channel regulation by G proteins, PIP2 and Na+ in a reconstituted system

  1. Weiwei Wang
  2. Matthew R Whorton
  3. Roderick MacKinnon  Is a corresponding author
  1. The Rockefeller University, Howard Hughes Medical Institute, United States
Research Article
  • Cited 57
  • Views 2,974
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Cite this article as: eLife 2014;3:e03671 doi: 10.7554/eLife.03671

Abstract

GIRK channels control spike frequency in atrial pacemaker cells and inhibitory potentials in neurons. By directly responding to G proteins, PIP2 and Na+, GIRK is under the control of multiple signaling pathways. In this study, the mammalian GIRK2 channel has been purified and reconstituted in planar lipid membranes and effects of Gα, Gβγ, PIP2 and Na+ analyzed. Gβγ and PIP2 must be present simultaneously to activate GIRK2. Na+ is not essential but modulates the effect of Gβγ and PIP2 over physiological concentrations. Gαi1(GTPγS) has no effect, whereas Gαi1(GDP) closes the channel through removal of Gβγ. In the presence of Gβγ, GIRK2 opens as a function of PIP2 mole fraction with Hill coefficient 2.5 and an affinity that poises GIRK2 to respond to natural variations of PIP2 concentration. The dual requirement for Gβγ and PIP2 can help to explain why GIRK2 is activated by Gi/o, but not Gq coupled GPCRs.

Article and author information

Author details

  1. Weiwei Wang

    The Rockefeller University, Howard Hughes Medical Institute, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Matthew R Whorton

    The Rockefeller University, Howard Hughes Medical Institute, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Roderick MacKinnon

    The Rockefeller University, Howard Hughes Medical Institute, New York, United States
    For correspondence
    mackinn@rockefeller.edu
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Richard Aldrich, The University of Texas at Austin, United States

Publication history

  1. Received: June 13, 2014
  2. Accepted: July 17, 2014
  3. Accepted Manuscript published: July 20, 2014 (version 1)
  4. Version of Record published: August 19, 2014 (version 2)

Copyright

© 2014, Wang et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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