Agonist-promoted desensitization and phosphorylation of. cap alpha. /sub 1/-adrenergic receptors coupled to stimulation of phosphatidylinositol metabolism

Conference · Wed Mar 05 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6859428

Leeb-Lundberg, L M.F.; Cotecchia, S; Caron, M G; Lefkowitz, R J

In the DDT/sub 1/ MF-2 hamster vas deferens smooth muscle cell line the ..cap alpha../sub 1/-adrenergic receptor (..cap alpha../sub 1/-AR) agonist norepinephrine (NE) promotes rapid attenuation of ..cap alpha../sub 1/-AR-mediated phosphatidylinositol (PI) metabolism which is paralleled by rapid phosphorylation of the ..cap alpha../sub 1/-AR. Cells were labeled by incubation with /sup 32/P/sub i/. Coincubation with NE (100 ..mu..M) significantly increases the rate of /sup 32/P-labeling of both PI and phosphatidic acid. Pretreatment of cells with 100 ..mu..M NE (in the presence of 1 ..mu..M propranolol to prevent ..beta..-AR interactions) results in a drastic attenuation of the NE response on PI metabolism. ..cap alpha../sub 1/-AR from labeled cells can be solubilized and purified by affinity chromatography on Affigel-A55414 and wheat germ agglutinin agarose chromatography. SDS-PAGE of purified ..cap alpha../sub 1/-AR shows a NE-promoted increase in phosphorylation of the M/sub r/ 80K ligand binding peptide. Stoichiometry of phosphorylation increases from approx. 1 mol phosphate/mol ..cap alpha../sub 1/-AR in the basal condition to approx. 2.5 after NE treatment. Both desensitization and phosphorylation are rapid being maximal within 10-20 min of agonist exposure. These results together with previous findings that phorbol esters promote rapid ..cap alpha../sub 1/-AR uncoupling and phosphorylation suggest that receptor phosphorylation is an important mechanism of regulation of ..cap alpha../sub 1/-AR receptor responsiveness.

• Research Organization: Duke Univ. Medical Center, Durham
• OSTI ID: 6859428
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:4
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTROPHORESIS
ESTERS
HAMSTERS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
MAMMALS
MEMBRANE PROTEINS
METABOLISM
MUSCLES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHOLIPIDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PROTEINS
RADIOISOTOPES
RECEPTORS
RODENTS
STOICHIOMETRY
SYMPATHOMIMETICS
TRACER TECHNIQUES
VERTEBRATES