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Activation of the regulator of G protein signaling 14-G?i1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

ABSTRACT: RGS14 is a brain scaffolding protein that integrates G protein and MAP kinase signaling pathways. Like other RGS proteins, RGS14 is a GTPase activating protein (GAP) that terminates G?i/o signaling. Unlike other RGS proteins, RGS14 also contains a G protein regulatory (also known as GoLoco) domain that binds G?i1/3-GDP in cells and in vitro. Here we report that Ric-8A, a nonreceptor guanine nucleotide exchange factor (GEF), functionally interacts with the RGS14-G?i1-GDP signaling complex to regulate its activation state. RGS14 and Ric-8A are recruited from the cytosol to the plasma membrane in the presence of coexpressed G?i1 in cells, suggesting formation of a functional protein complex with G?i1. Consistent with this idea, Ric-8A stimulates dissociation of the RGS14-G?i1-GDP complex in cells and in vitro using purified proteins. Purified Ric-8A stimulates dissociation of the RGS14-G?i1-GDP complex to form a stable Ric-8A-G?i complex in the absence of GTP. In the presence of an activating nucleotide, Ric-8A interacts with the RGS14-G?i1-GDP complex to stimulate both the steady-state GTPase activity of G?i1 and binding of GTP to G?i1. However, sufficiently high concentrations of RGS14 competitively reverse these stimulatory effects of Ric-8A on G?i1 nucleotide binding and GTPase activity. This observation correlates with findings that show RGS14 and Ric-8A share an overlapping binding region within the last 11 amino acids of G?i1. As further evidence that these proteins are functionally linked, native RGS14 and Ric-8A coexist within the same hippocampal neurons. These findings demonstrate that RGS14 is a newly appreciated integrator of unconventional Ric-8A and G?i1 signaling.

SUBMITTER: Vellano CP

PROVIDER: S-EPMC3087496 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature

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Activation of the regulator of G protein signaling 14-Gαi1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

Vellano Christopher P CP Shu Feng-Jue FJ Ramineni Suneela S Yates Cindee K CK Tall Gregory G GG Hepler John R JR

Biochemistry 20110111 5

RGS14 is a brain scaffolding protein that integrates G protein and MAP kinase signaling pathways. Like other RGS proteins, RGS14 is a GTPase activating protein (GAP) that terminates Gαi/o signaling. Unlike other RGS proteins, RGS14 also contains a G protein regulatory (also known as GoLoco) domain that binds Gαi1/3-GDP in cells and in vitro. Here we report that Ric-8A, a nonreceptor guanine nucleotide exchange factor (GEF), functionally interacts with the RGS14-Gαi1-GDP signaling complex to regu ...[more]

PMID: 21158412

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Dataset Information

Activation of the regulator of G protein signaling 14-G?i1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

Publications

Activation of the regulator of G protein signaling 14-Gαi1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

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