期刊
BIOCHEMICAL JOURNAL
卷 394, 期 -, 页码 427-435出版社
PORTLAND PRESS LTD
DOI: 10.1042/BJ20051560
关键词
beta(2)-adrenoceptor; cAMP-dependent protein kinase (PKA); G-protein receptor kinase 2 (GRK2); phosphodiesterase 4 (PDE4); rolipram
资金
- Medical Research Council [G8604010] Funding Source: researchfish
- MRC [G8604010] Funding Source: UKRI
- Medical Research Council [G8604010] Funding Source: Medline
- Wellcome Trust Funding Source: Medline
Membrane-recruitment of GRK2 (G-protein receptor kinase 2) provides a fundamental step in the desensitization process controlling GPCRs (G-protein-coupled receptors), such as the beta(2)AR (beta(2)-adrenergic receptor). In the present paper, we show that challenge of HEK-293 beta 2 [human embryonic kidney cells stably overexpressing the FLAG-tagged beta(2)AR-GFP (green fluorescent protein)] cells with the beta-adrenoceptor agonist, isoprenaline, causes GRK2 to become phosphorylated by PKA (cAMP-dependent protein kinase). This action is facilitated when cAMP-specific PDE4 (phosphodiesterase-4) activity is selectively inactivated, either chemically with rolipram or by siRNA (small interfering RNA)-mediated knockdown of PDE4B and PDE4D. PDE4-selective inhibition by rolipram facilitates the isoprenaline-induced membrane translocation of GRK2, phosphorylation of the beta(2)AR by GRK2, membrane translocation of beta-arrestin and internalization of beta(2)ARs. PDE4-selective inhibition also enhances the ability of isoprenaline to trigger the PKA phosphorylation of GRK2 in cardiac myocytes. In the absence of isoprenaline, rolipram-induced inhibition of PDE4 activity in HEK-293 beta 2 cells acts to stimulate PKA phosphorylation of GRK2, with consequential effects on GRK2 membrane recruitment and GRK2-mediated phosphorylation of the beta(2)AR. We propose that a key role for PDE4 enzymes is: (i) to gate the action of PKA on GRK2, influencing the rate of GRK2 phosphorylation of the beta(2)AR and consequential recruitment of beta-arrestin subsequent to beta-adrenoceptor agonist challenge, and (ii) to protect GRK2 from inappropriate membrane recruitment in unstimulated cells through its phosphorylation by PKA in response to fluctuations in basal levels of cAMP.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据