Referenced in: none

Automatically associated channels: Cav2.1

Title: [Binding of G alpha o N-terminus is responsible for the voltage-resistant inhibition of alpha 1A (P/Q-type, Cav2.1) Ca2+ channels]

Authors: Mariko Kinoshita

Journal, date & volume: Yakugaku Zasshi, 2002 Aug , 122, 565-72

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12187771

Abstract
G-protein-mediated inhibition of presynaptic voltage-dependent Ca2+ channels is comprised of voltage-dependent and--resistant components. The former is caused by a direct interaction of Ca2+ channel alpha 1 subunits with G beta gamma, whereas the latter has not been well characterized. Here, we show that the N-terminus of G alpha o is critical for the interaction with the C-terminus of the P/Q-type channel subunit, and that the binding induces voltage-resistant inhibition. A P/Q-type C-terminal peptide, an antiserum raised against the G alpha o N-terminus, and a G alpha o N-terminal peptide all attenuated the voltage-resistant inhibition of P/Q-type currents. Furthermore, the N-terminus of G alpha o bound to the C-terminus of alpha 1A in vitro, which was prevented either by the P/Q-type channel C-terminal or G alpha o N-terminal peptide. Although the C-terminal domain of the N-type channel showed similar ability to binding with G alpha o N-terminus, the above-mentioned treatments were ineffective in the N-type channel current. These findings demonstrate that the voltage-resistant inhibition of the P/Q-type channel is caused by the interaction between the C-terminal domain of the Ca2+ channel alpha 1A subunit and the N-terminal region of G alpha o.