The G protein-gated atrial K+ channel is stimulated by three distinct GIα-subunits
- 1 December 1988
- journal article
- research article
- Published by Springer Nature in Nature
- Vol. 336 (6200) , 680-682
- https://doi.org/10.1038/336680a0
Abstract
The gunanine nucleotide-binding protein, Gi, which inhibits adenylyl cyclase, has recently been shown to have three subtypes of the a-subunit, termed Giα-1, Giα-2 and Giα-3. They share 87–94% amino-acid sequence homology1–10 and so are difficult to separate from one another. Among other functions11,12–14, purified preparations activate K+ channels15–21 but there is confusion over which of the subtypes activates the muscarinic K+ channels of the atrial muscle of the heart: Giα-3, also termed Gk15, has been shown to activate this channel but it is not clear whether Giα-l22 does21 or does not23,24. To clarify this problem, we expressed the subtypes separately in Escherichia coli to eliminate contamination by other subtypes and tested the recombinant α- chains on atrial muscarinic K+ channels. Although we anticipated that only Giα-3 would have Gkactivity, to our surprise all three recombinant subtypes were active, from which we deduce that the Gi subtypes are multifunctional.Keywords
This publication has 17 references indexed in Scilit:
- A small multigene family encodes Gi signal-transduction proteins.Proceedings of the National Academy of Sciences, 1987
- The human genome encodes at least three non‐allellic G proteins with αi‐type subunitsFEBS Letters, 1987
- Molecular cloning of a new human G protein Evidence for two Giα‐like protein familiesFEBS Letters, 1987
- The α Subunit of the GTP Binding Protein G k Opens Atrial Potassium ChannelsScience, 1987
- Reconstitution of Somatostatin and Muscarinic Receptor Mediated Stimulation of K+Channels by Isolated GKProtein in Clonal Rat Anterior Pituitary Cell Membranes *Molecular Endocrinology, 1987
- Human Gi protein α‐subunit: deduction of amino acid structure from a cloned cDNAFEBS Letters, 1987
- Direct Activation of Mammalian Atrial Muscarinic Potassium Channels by GTP Regulatory Protein G kScience, 1987
- Inhibitory and stimulatory G proteins of adenylate cyclase: cDNA and amino acid sequences of the alpha chains.Proceedings of the National Academy of Sciences, 1986
- Molecular cloning and sequence determination of cDNAs for alpha subunits of the guanine nucleotide-binding proteins Gs, Gi, and Go from rat brain.Proceedings of the National Academy of Sciences, 1986
- Primary structure of the α‐subunit of bovine adenylate cyclase‐inhibiting G‐protein deduced from the cDNA sequenceFEBS Letters, 1986