Solubilization of the vasopressin receptor from rat liver plasma membranes. Evidence for a receptor X GTP-binding protein complex.
The GTPase activity of plasma membranes isolated from rat livers was stimulated 20% over basal by vasopressin. A concentration dependency curve showed that maximal stimulation was obtained with 10(-8) M vasopressin. The vasopressin-stimulated GTPase activity was not inhibited in plasma membranes that had been ADP-ribosylated with either cholera toxin or pertussis toxin. Identical results were obtained from plasma membranes that had been solubilized with 1% digitonin. When membranes that had been solubilized after preincubation with [3H]vasopressin were subjected to sucrose gradient centrifugation, the majority of protein-bound [3H]vasopressin migrated as a single band with a sedimentation constant of 16.8 S. Moreover, there was a GTPase activity that migrated with the bound [3H]vasopressin. This peak of bound [3H]vasopressin was decreased by 90% when the sucrose gradient centrifugation was run in the presence of 10 microM guanosine 5'-O-(thiotriphosphate). When the 16.8 S peak of bound [3H]vasopressin was further purified over a wheat germ lectin-Sepharose column, a GTPase activity co-eluted from the column with the protein-bound [3H]vasopressin. Direct evidence that a GTP-binding protein was present in the 16.8 S peak was obtained by the immunodetection of a 35-kDa beta subunit of a GTP-binding protein. These results support the conclusion that liver plasma membranes contain a GTP-binding protein that can complex with the vasopressin receptor.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D046911:Macromolecular Substances; D051381:Rats; D011945:Receptors, Angiotensin / Q000302:isolation & purification / Q000378:metabolism*; D017483:Receptors, Vasopressin; D012995:Solubility; D014667:Vasopressins / Q000378:metabolism*
D046911:Macromolecular Substances; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; D000246:Adenosine Diphosphate Ribose; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins