%0 Journal Article %1 Pei1994 %A Pei, G. %A Samama, P. %A Lohse, M. %A Wang, M. %A Codina, J. %A Lefkowitz, R. J. %D 1994 %J Proc Natl Acad Sci U S A %K *Mutation *Signal Acid Adrenergic Amino Animals Assay CHO Cricetinae Data Dose-Response Drug Expression GTP Gene Isoproterenol/pharmacology Molecular Phosphohydrolases/analysis Phosphorylation Proteins/metabolism Radioligand Recombinant Regulation Relationship, Sequence Transduction beta-2/drug beta-Agonists effects/genetics/*metabolism Receptor Cell %N 7 %P 2699-702 %T A constitutively active mutant beta 2-adrenergic receptor is constitutively desensitized and phosphorylated %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7908440 %V 91 %X 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.

@article{Pei1994, 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.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Pei, G. and Samama, P. and Lohse, M. and Wang, M. and Codina, J. and Lefkowitz, R. J.}, biburl = {https://www.bibsonomy.org/bibtex/26c025b6758ae2d673c1796e5a89d3b14/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {aee83b4e8562217a0789f1cae5969ad3}, intrahash = {6c025b6758ae2d673c1796e5a89d3b14}, issn = {0027-8424 (Print) 0027-8424 (Linking)}, journal = {Proc Natl Acad Sci U S A}, keywords = {*Mutation *Signal Acid Adrenergic Amino Animals Assay CHO Cricetinae Data Dose-Response Drug Expression GTP Gene Isoproterenol/pharmacology Molecular Phosphohydrolases/analysis Phosphorylation Proteins/metabolism Radioligand Recombinant Regulation Relationship, Sequence Transduction beta-2/drug beta-Agonists effects/genetics/*metabolism Receptor Cell}, month = {Mar 29}, note = {Pei, G Samama, P Lohse, M Wang, M Codina, J Lefkowitz, R J HL16037/HL/NHLBI NIH HHS/United States Research Support, U.S. Gov't, P.H.S. United states Proceedings of the National Academy of Sciences of the United States of America Proc Natl Acad Sci U S A. 1994 Mar 29;91(7):2699-702.}, number = 7, pages = {2699-702}, shorttitle = {A constitutively active mutant beta 2-adrenergic receptor is constitutively desensitized and phosphorylated}, timestamp = {2010-12-14T18:22:42.000+0100}, title = {A constitutively active mutant beta 2-adrenergic receptor is constitutively desensitized and phosphorylated}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7908440}, volume = 91, year = 1994 }