Roles of c-Src in alpha1B-adrenoceptor phosphorylation and desensitization.
1 The role of the protein tyrosine kinase, c-Src, on the function and phosphorylation of alpha1B-adrenoceptors (alpha1B-AR) and their association with G-protein-coupled receptor kinase (GRK) isozymes was studied. 2 Inhibitors of this kinase (PP2 and Src Inhibitor II) decreased ( approximately 50-75%) noradrenaline- (NA) and phorbol myristate acetate-mediated receptor phosphorylation. Expression of a dominant-negative mutant of c-Src similarly reduced receptor phosphorylation induced by the natural agonists, active phorbol esters and endothelin-1 (ET-1). 3 c-Src, GRK2, GRK3 and GRK5 coimmunoprecipitate with alpha1B-ARs in the basal state. In cells treated with NA or phorbol myristate acetate the amount of coimmunoprecipitated GRK2 and GRK3 increased ( approximately 2- to 3-fold), while treatment with ET-1 only augmented the amount of coimmunoprecipitated GRK2 ( approximately 2-fold). The Src inhibitor, PP2, markedly attenuated all these increases. 4 Cell pretreatment with PP2 amplified the increase in intracellular-free calcium observed with NA, in the basal state and after the stimulation (desensitization) induced by ET-1. 5 The data suggest a role of c-Src in alpha1B-AR desensitization/phosphorylation and in the interaction of these ARs with GRKs.
Alcántara-Hernández
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R
Departamento de Biología Celular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ap. Postal 70-248, México DF 04510.
Casas-González
P
P
García-Sáinz
J A
JA
D058646:Adrenergic alpha-1 Receptor Agonists; D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000378:metabolism; D002522:Chlorocebus aethiops; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000378:metabolism; D054770:G-Protein-Coupled Receptor Kinase 3 / Q000378:metabolism; D054774:G-Protein-Coupled Receptor Kinase 5 / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D051552:beta-Adrenergic Receptor Kinases / Q000378:metabolism*
C412373:AG 1879; D058646:Adrenergic alpha-1 Receptor Agonists; D019332:Endothelin-1; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D018340:Receptors, Adrenergic, alpha-1; D016392:Proto-Oncogene Proteins pp60(c-src); D054770:G-Protein-Coupled Receptor Kinase 3; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2; D054774:G-Protein-Coupled Receptor Kinase 5; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D009638:Norepinephrine