Abolition of G protein inhibition of alpha 1A and alpha 1B calcium channels by co-expression of the beta 3 subunit

FEBS Lett. 1995 Aug 28;371(1):43-6. doi: 10.1016/0014-5793(95)00860-c.


Three different classes of alpha 1 Ca2+ channel (alpha 1A, alpha 1B, alpha 1C) were expressed in Xenopus oocytes to determine whether G protein-mediated inhibition is an inherent property of the alpha 1 subunit itself, and if so, whether co-expression of auxiliary subunits modulates the inhibition seen. From our data it is apparent that either alpha 1A or alpha 1B Ca2+ channels expressed alone are sufficient for voltage-dependent G protein inhibition. alpha 1C Ca2+ channels expressed alone do not exhibit the G protein inhibition seen in alpha 1A and alpha 1B channels. Additionally, co-expression of the beta 3 subunit abolishes the ability of G proteins to inhibit currents through alpha 1A and alpha 1B Ca2+ channels. Differential sensitivity of alpha 1 as well as modulation of properties by beta 3 provide a potential mechanism for the regulation of G protein-mediated inhibition in neurons.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium Channels / biosynthesis
  • Calcium Channels / physiology*
  • Electrophysiology
  • Ethylmaleimide / pharmacology
  • GTP-Binding Proteins / antagonists & inhibitors
  • GTP-Binding Proteins / physiology*
  • Guanosine Diphosphate / analogs & derivatives
  • Guanosine Diphosphate / pharmacology
  • Membrane Potentials / drug effects
  • Microinjections
  • Oocytes
  • RNA, Complementary
  • Thionucleotides / pharmacology
  • Xenopus laevis


  • Calcium Channels
  • RNA, Complementary
  • Thionucleotides
  • Guanosine Diphosphate
  • guanosine 5'-O-(2-thiodiphosphate)
  • GTP-Binding Proteins
  • Ethylmaleimide