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| | ==Crystal structure of the G202A mutant of human G-alpha-i1== | | ==Crystal structure of the G202A mutant of human G-alpha-i1== |
| - | <StructureSection load='3ums' size='340' side='right' caption='[[3ums]], [[Resolution|resolution]] 2.34Å' scene=''> | + | <StructureSection load='3ums' size='340' side='right'caption='[[3ums]], [[Resolution|resolution]] 2.34Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3ums]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=2pz2 2pz2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3UMS OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3UMS FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3ums]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=2pz2 2pz2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3UMS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3UMS FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">GNAI1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])</td></tr> | + | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">GNAI1 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ums FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ums OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ums RCSB], [http://www.ebi.ac.uk/pdbsum/3ums PDBsum]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3ums FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ums OCA], [https://pdbe.org/3ums PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ums RCSB], [https://www.ebi.ac.uk/pdbsum/3ums PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ums ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/GNAI1_HUMAN GNAI1_HUMAN]] Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. The G(i) proteins are involved in hormonal regulation of adenylate cyclase: they inhibit the cyclase in response to beta-adrenergic stimuli. The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. May play a role in cell division.<ref>PMID:17635935</ref> <ref>PMID:17264214</ref> | + | [[https://www.uniprot.org/uniprot/GNAI1_HUMAN GNAI1_HUMAN]] Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. The G(i) proteins are involved in hormonal regulation of adenylate cyclase: they inhibit the cyclase in response to beta-adrenergic stimuli. The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. May play a role in cell division.<ref>PMID:17635935</ref> <ref>PMID:17264214</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> |
| | </div> | | </div> |
| - | | + | <div class="pdbe-citations 3ums" style="background-color:#fffaf0;"></div> |
| - | ==See Also== | + | |
| - | *[[Guanine nucleotide-binding protein|Guanine nucleotide-binding protein]]
| + | |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Homo sapiens]] | + | [[Category: Human]] |
| | + | [[Category: Large Structures]] |
| | [[Category: Cappell, S D]] | | [[Category: Cappell, S D]] |
| | [[Category: Johnston, C A]] | | [[Category: Johnston, C A]] |
| Structural highlights
Function
[GNAI1_HUMAN] Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. The G(i) proteins are involved in hormonal regulation of adenylate cyclase: they inhibit the cyclase in response to beta-adrenergic stimuli. The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. May play a role in cell division.[1] [2]
Publication Abstract from PubMed
G-protein heterotrimers, composed of a guanine nucleotide-binding G alpha subunit and an obligate G betagamma dimer, regulate signal transduction pathways by cycling between GDP- and GTP-bound states. Signal deactivation is achieved by G alpha-mediated GTP hydrolysis (GTPase activity) which is enhanced by the GTPase-accelerating protein (GAP) activity of "regulator of G-protein signaling" (RGS) proteins. In a cellular context, RGS proteins have also been shown to speed up the onset of signaling, and to accelerate deactivation without changing amplitude or sensitivity of the signal. This latter paradoxical activity has been variably attributed to GAP/enzymatic or non-GAP/scaffolding functions of these proteins. Here, we validated and exploited a G alpha switch-region point mutation, known to engender increased GTPase activity, to mimic in cis the GAP function of RGS proteins. While the transition-state, GDP x AlF(4)(-)-bound conformation of the G202A mutant was found to be nearly identical to wild-type, G alpha(i1)(G202A) x GDP assumed a divergent conformation more closely resembling the GDP x AlF(4)(-)-bound state. When placed within Saccharomyces cerevisiae G alpha subunit Gpa1, the fast-hydrolysis mutation restored appropriate dose-response behaviors to pheromone signaling in the absence of RGS-mediated GAP activity. A bioluminescence resonance energy transfer (BRET) readout of heterotrimer activation with high temporal resolution revealed that fast intrinsic GTPase activity could recapitulate in cis the kinetic sharpening (increased onset and deactivation rates) and blunting of sensitivity also engendered by RGS protein action in trans. Thus G alpha-directed GAP activity, the first biochemical function ascribed to RGS proteins, is sufficient to explain the activation kinetics and agonist sensitivity observed from G-protein-coupled receptor (GPCR) signaling in a cellular context.
Regulators of G-protein signaling accelerate GPCR signaling kinetics and govern sensitivity solely by accelerating GTPase activity.,Lambert NA, Johnston CA, Cappell SD, Kuravi S, Kimple AJ, Willard FS, Siderovski DP Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):7066-71. Epub 2010 Mar 29. PMID:20351284[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Cho H, Kehrl JH. Localization of Gi alpha proteins in the centrosomes and at the midbody: implication for their role in cell division. J Cell Biol. 2007 Jul 16;178(2):245-55. PMID:17635935 doi:10.1083/jcb.200604114
- ↑ Johnston CA, Siderovski DP. Structural basis for nucleotide exchange on G alpha i subunits and receptor coupling specificity. Proc Natl Acad Sci U S A. 2007 Feb 6;104(6):2001-6. Epub 2007 Jan 30. PMID:17264214
- ↑ Lambert NA, Johnston CA, Cappell SD, Kuravi S, Kimple AJ, Willard FS, Siderovski DP. Regulators of G-protein signaling accelerate GPCR signaling kinetics and govern sensitivity solely by accelerating GTPase activity. Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):7066-71. Epub 2010 Mar 29. PMID:20351284 doi:10.1073/pnas.0912934107
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