Specific in vivo binding of activator of G protein signalling 1 to the G_β1 subunit

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• 作者：Richard Hiskens ; Manu Vatish ; Claire Hill ; John Davey and Graham Ladds
• 关键词：AGS1 ; G_β ; 1 subunit ; Two-hybrid analysis ; Co-immunoprecipitation ; Cationic region ; Propeller structure
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2005
• 出版时间：2005
• 年：2005
• 卷：337
• 期：4
• 页码：1038-1046
• 全文大小：243 K

文摘

Activator of G protein signalling 1 (AGS1) is a Ras-like protein that affects signalling through heterotrimeric G proteins. Previous in vitro studies suggest that AGS1 can bind to G_α-GDP subunits and promote nucleotide exchange, leading to activation of intracellular signalling pathways. This model is consistent with in vivo evidence demonstrating that AGS1 activates both G_α- and G_βγ-dependent pathways in the absence of ligand. However, it does not easily explain how AGS1 blocks G_βγ-dependent, but not G_α-dependent, signalling following receptor activation. We have used yeast two hybrid analysis and co-immunoprecipitation studies in mammalian cells to demonstrate a direct interaction between AGS1 and the G_β1 subunit of heterotrimeric G proteins. The interaction is specific for G_β1 and involves the cationic region of AGS1 and the C-terminal region of G_β1. Possible implications of this novel interaction for the activity of AGS1 are discussed.