The β₃-adrenergic receptor activates mitogen-activated protein kinase in adipocytes through a G_i-dependent mechanism

作     者：Soeder, KJ Snedden, SK Cao, WH Della Rocca, GJ Daniel, KW Luttrell, LM Collins, S 

作者机构：Duke Univ Med Ctr Dept Psychiat & Behav Sci Durham NC 27710 USA Duke Univ Med Ctr Dept Pharmacol Durham NC 27710 USA Duke Univ Med Ctr Dept Biochem Durham NC 27710 USA Duke Univ Med Ctr Dept Med Durham NC 27710 USA 

出 版 物：《JOURNAL OF BIOLOGICAL CHEMISTRY》 (生物化学杂志)

年 卷 期：1999年第274卷第17期

页      面：12017-12022页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 07[理学] 

基　　金：NIDDK NIH HHS [DK53092  DK46793  DK02352] Funding Source: Medline 

主　　题：3T3细胞 脂细胞/酶学 肾上腺素能β激动剂/药理学 钙-钙调素依赖性蛋白激酶类/代谢 二恶茂类/药理学 酶激活 GTP结合蛋白质α亚单位 Gi-Go/代谢 脂解作用 蛋白质结合 受体 肾上腺素能β/代谢 受体 肾上腺素能β3 动物 人类 小鼠 

摘      要：Promiscuous coupling between G protein-coupled receptors and multiple species of heterotrimeric G;proteins provides a potential mechanism for expanding the diversity of G protein-coupled receptor signaling. We have examined the mechanism and functional consequences of dual G(s)/G(i) protein coupling of the beta(3)-adrenergic receptor (beta(3)AR) in 3T3-F442A adipocytes. The beta(3)AR selective agonist disodium (R,R)-5-[2[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]-1,3-benzodioxole-2,2-dicarboxylate (CL316,243) stimulated a dose-dependent increase in cAMP production in adipocyte plasma membrane preparations, and pretreatment of cells with pertussis toxin resulted in a further a-fold increase in cAMP production by CL316,243, CL316,243 (5 mu M) stimulated the incorporation of 8-azido-[P-32]GTP into G alpha(s) (1.57 +/- 0.12;n = 3) and G alpha(i) (1.68 +/- 0.13;n = 4) in adipocyte plasma membranes, directly demonstrating that beta(3)AR stimulation results in G(i)-GTP exchange. The beta(3)AR-stimulated increase in 8-azido-[P-32]GTP labeling of G alpha(i) was equivalent to that obtained with the A(1)-adenosine receptor agonist N-6-cyclopentyladenosine (1.56 +/- 0.07;n = 4), whereas inclusion of unlabeled GTP (100 mu M) eliminated all binding. Stimulation of the beta(3)AR in 3T3-F442A adipocytes led to a 2-3-fold activation of mitogen-activated protein (MAP) kinase, as measured by extracellular signal-regulated kinase-1 and -2 (ERK1/2) phosphorylation. Pretreatment of cells with pertussis toxin (PTX) eliminated MAP kinase activation by beta(3)AR, demonstrating that this response required receptor coupling to Gi, Expression of the human beta(3)AR in HEK-293 cells reconstituted the PTX-sensitive stimulation of MAP kinase, demonstrating that this phenomenon is not exclusive to adipocytes or to the rodent beta(3)AR, ERK1/2 activation by the beta(3)AR was insensitive to the cAMP-dependent protein kinase inhibitor H-89 but was abolished by genistein and AG1478. These data