These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A betagamma dimer derived from G13 transduces the angiotensin AT1 receptor signal to stimulation of Ca2+ channels in rat portal vein myocytes.
    Author: Macrez N, Morel JL, Kalkbrenner F, Viard P, Schultz G, Mironneau J.
    Journal: J Biol Chem; 1997 Sep 12; 272(37):23180-5. PubMed ID: 9287322.
    Abstract:
    A G protein composed of alpha13, beta1, and gamma3 subunits selectively couples the angiotensin AT1A receptors to increase cytoplasmic Ca2+ concentration ([Ca2+]i) in rat portal vein myocytes (Macrez-Leprêtre, N., Kalkbrenner, F., Morel, J. L., Schultz, G., and Mironneau, J. (1997) J. Biol. Chem. 272, 10095-10102). We show here that Gbetagamma transduces the signal leading to stimulation of L-type Ca2+ channels. Intracellular dialysis through the patch pipette of a carboxyl-terminal anti-betacom antibody and a peptide corresponding to the Gbetagamma binding region of the beta-adrenergic receptor kinase 1 inhibited the stimulation of Ca2+ channels and the increase in [Ca2+]i evoked by angiotensin II. The Gbetagamma binding peptide did not prevent the dissociation of the heterotrimeric G protein into its subunits, as it did not block activation of phospholipase C-beta by Galphaq in response to stimulation of alpha1-adrenoreceptors. Transient overexpression of the beta-adrenergic receptor kinase 1 fragment and of Galpha subunits also inhibited the angiotensin II-induced increase in [Ca2+]i. Both anti-alpha13 antibody and carboxyl-terminal alpha13 peptide abrogated the angiotensin II-induced stimulation of Ca2+ channels. We conclude that activation of angiotensin AT1 receptors requires all three alpha, beta, and gamma subunits of G13 for receptor-G protein interaction, whereas the transduction of the signal to L-type Ca2+ channels is mediated by Gbetagamma.
    [Abstract] [Full Text] [Related] [New Search]