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Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay
11:49

Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay

Published on: July 28, 2014

G-protein beta-subunit specificity in the fast membrane-delimited inhibition of Ca2+ channels

D E García1, B Li, R E García-Ferreiro

  • 1Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA.

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
|November 5, 1998
PubMed

Insights

G-protein beta1 and beta2 subunits mediate voltage-dependent inhibition of N-type calcium channels. These subunits interact with the alpha1 subunit

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Electrophysiology

Background:

  • G-protein coupled receptors modulate N-type calcium channel activity.
  • Specific G-protein beta subunits are implicated in this signaling pathway.

Purpose of the Study:

  • To identify which G-protein beta subunit subtypes mediate voltage-dependent inhibition of N-type calcium channels.
  • To determine the interaction site between G-protein beta subunits and N-type calcium channels.

Main Methods:

  • Electrophysiological recordings of calcium currents in cultured rat superior cervical ganglion neurons.
  • Intranuclear injection of DNA encoding five G-protein beta subunits.
  • Yeast two-hybrid system to assess protein-protein interactions.

Main Results:

  • G-protein beta1 (Gbeta1) and G-protein beta2 (Gbeta2) subunits mimicked the inhibitory effects on calcium channels.
  • Gbeta1 and Gbeta2 showed strong interaction with the intracellular loop (domains I-II) of the calcium channel alpha1 subunit.
  • G-protein beta5 (Gbeta5) showed weak effects and interaction, while Gbeta3 and Gbeta4 were largely inactive.

Conclusions:

  • Gbeta1 and/or Gbeta2 subunits are primarily responsible for the voltage-dependent inhibition of N-type calcium channels.
  • The linker region between domains I and II of the calcium channel alpha1 subunit is a key site for this interaction and inhibition.

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