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- 题目:
- RGS proteins maintain robustness of GPCR-GIRK coupling by selective stimulation of the G protein subunit Gαo.
- 作者:
- Chuang(Huai-hu),Chuang(Alexander Y)
- 状态:
- 发布时间2012-02-22 , 更新时间 2016-05-13
- 期刊:
- Sci Signal
- 摘要:
- Termination of heterotrimeric guanine nucleotide-binding protein (G protein) signaling downstream of activated G protein-coupled receptors (GPCRs) is accelerated by regulator of G protein signaling (RGS) proteins, which act as guanosine triphosphatase (GTPase)-activating proteins (GAPs). Using a Xenopus oocyte expression system, we found that although RGS proteins had a negative effect of accelerating the kinetics of GPCR-coupled potassium ion (K+) channel (GIRK) deactivation, they also had positive effects of increasing the amplitudes and activation kinetics of neurotransmitter-evoked GIRK currents. The RGS box domain alone was sufficient to stimulate neurotransmitter-dependent activation of GIRK currents. Moreover, RGS4 mutants with compromised GAP activity augmented GPCR-GIRK coupling (as assessed by measurement of the GIRK current elicited by neurotransmitter). By accelerating G protein activation kinetics, RGS4 specifically stimulated Gα₀, which stimulated GPCR-GIRK coupling despite its GAP activity. Opposing actions of RGS proteins thus both stimulate and inhibit G proteins to modulate the amplitude and kinetics of neurotransmitter-induced GIRK currents, thereby distinguishing the responses to activation of different G protein isoforms.
- 语言:
- eng
- DOI:
- 10.1126/scisignal.2002202
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