Overexpression of beta-arrestin and beta-adrenergic receptor kinase augment desensitization of beta 2-adrenergic receptors.
Receptor-specific or homologous desensitization of beta 2-adrenergic receptors is thought to be effected via phosphorylation of the receptor by the beta-adrenergic receptor kinase (beta ARK), followed by binding of beta-arrestin. We have generated stably transfected Chinese hamster ovary cell lines overexpressing either of the two regulatory proteins and also expressing low or high levels of beta 2-adrenergic receptors (approximately 80 and approximately 600 fmol/mg of membrane protein). In these cells, we studied the process of desensitization induced by the beta-adrenergic receptor agonist isoproterenol. In cells expressing high levels of beta 2-adrenergic receptors, desensitization to high concentrations of isoproterenol (previously shown to be mediated by both beta ARK and protein kinase A) amounted to approximately 50% in control cells, approximately 80% in beta ARK-overexpressing cells, and approximately 90% in beta-arrestin-overexpressing cells. In cells expressing low levels of beta 2-adrenergic receptors, these values were approximately 50, approximately 60, and approximately 60%, respectively. Desensitization to low concentrations of isoproterenol (previously shown to be essentially protein kinase A-mediated and not receptor-specific, i.e. heterologous) was not affected by overexpression of either beta ARK or beta-arrestin. These data suggest that in cells expressing high levels of beta 2-adrenergic receptors, beta-arrestin and beta ARK become limiting for homologous receptor desensitization. They provide further support for the involvement of these two proteins in the regulation of beta 2-adrenergic receptor function.
Laboratory of Molecular Biology, University of Munich, Max-Planck-Institute of Biochemistry, Martinsried, Federal Republic of Germany.
S
S
Pippig
S
S
Andexinger
K
K
Daniel
M
M
Puzicha
M G
MG
Caron
R J
RJ
Lefkowitz
M J
MJ
Lohse
D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D000941:Antigens / Q000235:genetics / Q000378:metabolism*; D019390:Arrestins; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D007457:Iodine Radioisotopes / Q000378:metabolism; D020120:Iodocyanopindolol; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010761:Phosphorus Radioisotopes; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism; D014162:Transfection; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
D000906:Antibodies; D000941:Antigens; D019390:Arrestins; D005136:Eye Proteins; D007457:Iodine Radioisotopes; D010455:Peptides; D010761:Phosphorus Radioisotopes; D011943:Receptors, Adrenergic, beta; D000071557:beta-Arrestins; D015636:Magnesium Chloride; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D020120:Iodocyanopindolol; D010869:Pindolol; D011494:Protein Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases; D020558:GTP Phosphohydrolases; D000262:Adenylyl Cyclases; D007545:Isoproterenol