Unimpaired coupling of phosphorylated, desensitized β‐adrenoceptor to Gs in a reconstitution system

FEBS Letters

Dees, Christian¹  Cooney, Deirdre¹  Hekman, Mirko¹  Holzhöfer, Andreas¹  Keenan, Alan K.¹ 

[1] Dept of Physiological Chemistry, University of Würzburg, Koellikerstraße 2, D-8700 Würzburg, FRG

关键词: β-Adrenoceptor;    Desensitization;    Phosphorylation;    Gs-protein;    Reconstitution;    AppNHp;    adenylyl imidodiphosphate;    SDS-PAGE;    SDS-polyacrylamide gel electrophoresis;    DTT;    dithiothreitol;    CYP;    cyanopindolol;    CGP 12177;    Ciba Geigy Product 12177;    Gs;    guanine nucleotide-binding protein mediating stimulation of adenylate cyclase;   

DOI  :  10.1016/0014-5793(87)80680-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Heterologous desensitization of turkey erythrocyte β-adrenoceptors correlates with receptor phosphorylation and impaired receptor-G^s coupling, as assessed by fusion of purified desensitized receptors with X. laevis erythrocytes [(1984) Science 225, 837-840]. We have purified β-receptors from desensitized and untreated turkey erythrocytes and have compared the abilities of these two receptors to couple with pure turkey erythrocyte G_s in a reconstituted system. Functional receptor-G_s coupling was assessed by measuring hormone-dependent (i) G_s, activation by GTPγS and (ii) GTPase activity. While in membranes prepared from desensitized cells, receptor-G_s, coupling was clearly reduced, this effect was absent when coupling of purified desensitized receptor was measured. We conclude that covalent modification by phosphorylation does not fully explain the functional uncoupling at the membrane level.

【 授权许可】

Unknown