Evidence for a vasopressin receptor-GTP binding protein complex

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5019982

Fitzgerald, T J; Uhing, R J; Exton, J H

Plasma membranes from the livers of rats were able to hydrolyze the ..gamma..-phosphate from guanosine-5'-triphosphate (GTP). The rate of GTP hydrolysis could be decreased to 10% of its initial rate by the addition of adenosine-5'-triphosphate with a concomitant decrease in the K/sub m/ for GTP from approx. 10/sup -3/ M to 10/sup -6/ M. The low K/sub m/ GTPase activity was inhibited by the addition of nonhydrolyzable analogs of GTP. In addition, the GTPase activity was stimulated from 10 to 30% over basal by the addition of vasopressin. A dose dependency curve showed that the maximum stimulation was obtained with 10/sup -8/ M vasopressin. Identical results were obtained from plasma membranes that had been solubilized with 1% digitonin. When membranes that had been solubilized in the presence of (Phenylalanyl-3,4,5-/sup 3/H(N))vasopressin were subjected to sucrose gradient centrifugation, the majority of bound (/sup 3/H)vasopressin migrated with an approximate molecular weight of 300,000. Moreover, there was a GTPase activity that migrated with the bound (/sup 3/H)vasopressin. This peak of bound (/sup 3/H)vasopressin was decreased by 90% when the sucrose gradient centrifugation was run in the presence of 10/sup -5/ M guanosine-5'-O-(3-thiotriphosphate). These results support the conclusion that liver plasma membranes contain a GTP-binding protein that can complex with the vasopressin receptor.

• Research Organization: Vanderbilt Univ. School of Medicine, Nashville, TN
• OSTI ID: 5019982
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AROMATICS
ATP
AZAARENES
BIOCHEMICAL REACTION KINETICS
BODY
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
DECOMPOSITION
DIGESTIVE SYSTEM
DOSE-RESPONSE RELATIONSHIPS
ENZYME ACTIVITY
ENZYMES
ESTERASES
GLANDS
GUANOSINE
HETEROCYCLIC COMPOUNDS
HORMONES
HYDROLASES
HYDROLYSIS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIVER
LYSIS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHATASES
PHOSPHATES
PHOSPHORUS COMPOUNDS
PITUITARY HORMONES
PROTEINS
PURINES
RATS
REACTION KINETICS
RECEPTORS
RIBOSIDES
RODENTS
SOLVOLYSIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VASOPRESSIN
VERTEBRATES