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J Physiol. 2000 Jul 15;526 Pt 2:341-7.

A regulator of G protein signalling (RGS) protein confers agonist-dependent relaxation gating to a G protein-gated K+ channel.

Author information

1
Department of Pharmacology II, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.

Abstract

1. The effects of RGS4 on the voltage-dependent relaxation of G protein-gated K+ (KG) channels were examined by heterologous expression in Xenopus oocytes. 2. While the relaxation kinetics was unaffected by the acetylcholine concentration ([ACh]) in the absence of RGS4, it became dependent on [ACh] when RGS4 was co-expressed. 3. Kinetic analyses indicated that RGS4 confers to the KG channel a voltage-independent inhibitory gating mechanism, which was attenuated by ACh in a concentration-dependent fashion. 4. In vitro biochemical studies showed that RGS4 could bind to the protein complex containing KG channel subunits. 5. Since the native cardiac KG channel exhibited similar agonist-dependent relaxation kinetics to that mediated by RGS4, it is suggested that KG channel gating is a novel physiological target of RGS protein-mediated regulation.

PMID:
10896722
PMCID:
PMC2270023
DOI:
10.1111/j.1469-7793.2000.00341.x
[Indexed for MEDLINE]
Free PMC Article

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