Linked Life Data

9038185

Source:http://linkedlifedata.com/resource/pubmed/id/9038185

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1997-4-15
pubmed:abstractText
A GTPase-activating protein (GAP) specific for Galphaz was identified in brain, spleen, retina, platelet, C6 glioma cells, and several other tissues and cells. Gz GAP from bovine brain is a membrane protein that is refractory to solubilization with most detergents but was solubilized with warm Triton X-100 and purified up to 50,000-fold. Activity is associated with at least two separate proteins of Mr approximately 22,000 and 28,000, both of which have similar specific activities. In an assay that measures the rate of hydrolysis of GTP pre-bound to detergent-soluble Galphaz, the GAP accelerates hydrolysis over 200-fold, from 0.014 to 3 min -1 at 15 degrees C, or to >/=20 min-1 at 30 degrees C. It does not alter rates of nucleotide association or dissociation. When co-reconstituted into phospholipid vesicles with trimeric Gz and m2 muscarinic receptor, Gz GAP accelerates agonist-stimulated steady-state GTP hydrolysis as predicted by its effect on the hydrolytic reaction. In the single turnover assay, the Km of the GAP for Galphaz-GTP is 2 nM. Its activity is inhibited by Galphaz-guanosine 5'-O-thiotriphosphate (Galphaz-GTPgammaS) or by Galphaz-GDP/AlF4 with Ki approximately 1.5 nM for both species; Galphaz-GDP does not inhibit. G protein betagamma subunits inhibit Gz GAP activity, apparently by forming a GTP-Galphazbetagamma complex that is a poor GAP substrate. Gz GAP displays little GAP activity toward Galphai1 or Galphao, but its activity with Galphaz is competitively inhibited by both Galphai1 and Galphao at nanomolar concentrations when they are bound to GTPgammaS but not to GDP. Neither phospholipase C-beta1 (a Gq GAP) nor several adenylyl cyclase isoforms display Gz GAP activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5732-40
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:9038185-Animals, pubmed-meshheading:9038185-Brain Chemistry, pubmed-meshheading:9038185-Cattle, pubmed-meshheading:9038185-Chromatography, Gel, pubmed-meshheading:9038185-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:9038185-GTP-Binding Protein alpha Subunits, pubmed-meshheading:9038185-GTP-Binding Proteins, pubmed-meshheading:9038185-GTPase-Activating Proteins, pubmed-meshheading:9038185-Guanosine 5'-O-(3-Thiotriphosphate), pubmed-meshheading:9038185-Guanosine Triphosphate, pubmed-meshheading:9038185-Heterotrimeric GTP-Binding Proteins, pubmed-meshheading:9038185-Kinetics, pubmed-meshheading:9038185-Magnesium, pubmed-meshheading:9038185-Molecular Weight, pubmed-meshheading:9038185-Proteins, pubmed-meshheading:9038185-Receptor, Muscarinic M2, pubmed-meshheading:9038185-Receptors, Muscarinic
pubmed:year
1997
pubmed:articleTitle
A GTPase-activating protein for the G protein Galphaz. Identification, purification, and mechanism of action.
pubmed:affiliation
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9041, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't