Abstract
The beta 2-adrenergic receptor (beta 2AR) can be constitutively activated by mutations in the third intracellular loop. Whereas the wild-type receptor exists predominantly in an inactive conformation (R) in the absence of agonist, the mutant receptor appears to spontaneously adopt an active conformation (R*). We now demonstrate that not only is the mutant beta 2AR constitutively active, it is also constitutively desensitized and down-regulated. To assess whether the mutant receptor can constitutively engage a known element of the cellular desensitization machinery, the receptor was purified and reconstituted into phospholipid vesicles. These preparations retained the essential properties of the constitutively active mutant receptor: agonist-independent activity [to stimulate guanine nucleotide-binding protein (Gs)-GTPase] and agonist-specific increase in binding affinity. Moreover, the purified mutant receptor, in the absence of agonist, was phosphorylated by recombinant beta AR-specific kinase (beta ARK) in a fashion comparable to the agonist-occupied wild-type receptor. Thus, the conformation of the mutated receptor is equivalent to the active conformation (R*), which stimulates Gs protein and is identical to the beta ARK substrate.
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- Benovic J. L., DeBlasi A., Stone W. C., Caron M. G., Lefkowitz R. J. Beta-adrenergic receptor kinase: primary structure delineates a multigene family. Science. 1989 Oct 13;246(4927):235–240. doi: 10.1126/science.2552582. [DOI] [PubMed] [Google Scholar]
- Benovic J. L., Shorr R. G., Caron M. G., Lefkowitz R. J. The mammalian beta 2-adrenergic receptor: purification and characterization. Biochemistry. 1984 Sep 25;23(20):4510–4518. doi: 10.1021/bi00315a002. [DOI] [PubMed] [Google Scholar]
- Benovic J. L., Staniszewski C., Mayor F., Jr, Caron M. G., Lefkowitz R. J. beta-Adrenergic receptor kinase. Activity of partial agonists for stimulation of adenylate cyclase correlates with ability to promote receptor phosphorylation. J Biol Chem. 1988 Mar 15;263(8):3893–3897. [PubMed] [Google Scholar]
- Black J. W., Leff P., Shankley N. P., Wood J. An operational model of pharmacological agonism: the effect of E/[A] curve shape on agonist dissociation constant estimation. Br J Pharmacol. 1985 Feb;84(2):561–571. doi: 10.1111/j.1476-5381.1985.tb12941.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cerione R. A., Codina J., Benovic J. L., Lefkowitz R. J., Birnbaumer L., Caron M. G. The mammalian beta 2-adrenergic receptor: reconstitution of functional interactions between pure receptor and pure stimulatory nucleotide binding protein of the adenylate cyclase system. Biochemistry. 1984 Sep 25;23(20):4519–4525. doi: 10.1021/bi00315a003. [DOI] [PubMed] [Google Scholar]
- Clark A. J. The reaction between acetyl choline and muscle cells. J Physiol. 1926 Aug 6;61(4):530–546. doi: 10.1113/jphysiol.1926.sp002314. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Codina J., Hildebrandt J. D., Sekura R. D., Birnbaumer M., Bryan J., Manclark C. R., Iyengar R., Birnbaumer L. Ns and Ni, the stimulatory and inhibitory regulatory components of adenylyl cyclases. Purification of the human erythrocyte proteins without the use of activating regulatory ligands. J Biol Chem. 1984 May 10;259(9):5871–5886. [PubMed] [Google Scholar]
- Cotecchia S., Exum S., Caron M. G., Lefkowitz R. J. Regions of the alpha 1-adrenergic receptor involved in coupling to phosphatidylinositol hydrolysis and enhanced sensitivity of biological function. Proc Natl Acad Sci U S A. 1990 Apr;87(8):2896–2900. doi: 10.1073/pnas.87.8.2896. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cotecchia S., Ostrowski J., Kjelsberg M. A., Caron M. G., Lefkowitz R. J. Discrete amino acid sequences of the alpha 1-adrenergic receptor determine the selectivity of coupling to phosphatidylinositol hydrolysis. J Biol Chem. 1992 Jan 25;267(3):1633–1639. [PubMed] [Google Scholar]
- Dohlman H. G., Thorner J., Caron M. G., Lefkowitz R. J. Model systems for the study of seven-transmembrane-segment receptors. Annu Rev Biochem. 1991;60:653–688. doi: 10.1146/annurev.bi.60.070191.003253. [DOI] [PubMed] [Google Scholar]
- Hausdorff W. P., Caron M. G., Lefkowitz R. J. Turning off the signal: desensitization of beta-adrenergic receptor function. FASEB J. 1990 Aug;4(11):2881–2889. [PubMed] [Google Scholar]
- Johnston R. F., Pickett S. C., Barker D. L. Autoradiography using storage phosphor technology. Electrophoresis. 1990 May;11(5):355–360. doi: 10.1002/elps.1150110503. [DOI] [PubMed] [Google Scholar]
- Karlin A. On the application of "a plausible model" of allosteric proteins to the receptor for acetylcholine. J Theor Biol. 1967 Aug;16(2):306–320. doi: 10.1016/0022-5193(67)90011-2. [DOI] [PubMed] [Google Scholar]
- Kobilka B. K., Dixon R. A., Frielle T., Dohlman H. G., Bolanowski M. A., Sigal I. S., Yang-Feng T. L., Francke U., Caron M. G., Lefkowitz R. J. cDNA for the human beta 2-adrenergic receptor: a protein with multiple membrane-spanning domains and encoded by a gene whose chromosomal location is shared with that of the receptor for platelet-derived growth factor. Proc Natl Acad Sci U S A. 1987 Jan;84(1):46–50. doi: 10.1073/pnas.84.1.46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lefkowitz R. J. G-protein-coupled receptors. Turned on to ill effect. Nature. 1993 Oct 14;365(6447):603–604. doi: 10.1038/365603a0. [DOI] [PubMed] [Google Scholar]
- Lohse M. J., Benovic J. L., Caron M. G., Lefkowitz R. J. Multiple pathways of rapid beta 2-adrenergic receptor desensitization. Delineation with specific inhibitors. J Biol Chem. 1990 Feb 25;265(6):3202–3211. [PubMed] [Google Scholar]
- Munson P. J., Rodbard D. Ligand: a versatile computerized approach for characterization of ligand-binding systems. Anal Biochem. 1980 Sep 1;107(1):220–239. doi: 10.1016/0003-2697(80)90515-1. [DOI] [PubMed] [Google Scholar]
- Pitcher J. A., Inglese J., Higgins J. B., Arriza J. L., Casey P. J., Kim C., Benovic J. L., Kwatra M. M., Caron M. G., Lefkowitz R. J. Role of beta gamma subunits of G proteins in targeting the beta-adrenergic receptor kinase to membrane-bound receptors. Science. 1992 Aug 28;257(5074):1264–1267. doi: 10.1126/science.1325672. [DOI] [PubMed] [Google Scholar]
- Ren Q., Kurose H., Lefkowitz R. J., Cotecchia S. Constitutively active mutants of the alpha 2-adrenergic receptor. J Biol Chem. 1993 Aug 5;268(22):16483–16487. [PubMed] [Google Scholar]
- Samama P., Cotecchia S., Costa T., Lefkowitz R. J. A mutation-induced activated state of the beta 2-adrenergic receptor. Extending the ternary complex model. J Biol Chem. 1993 Mar 5;268(7):4625–4636. [PubMed] [Google Scholar]