Development and Characterization of Pepducins as Gs-biased Allosteric Agonists
Development and Characterization of Pepducins as Gs-biased Allosteric Agonists
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DOI：
10.1074/jbc.m114.618819
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发表时间：
2014-12-26
影响因子：
4.8
通讯作者：
Benovic, Jeffrey L.
中科院分区：
文献类型：
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作者：
Carr, Richard, III;Du, Yang;Benovic, Jeffrey L.
β（2）-肾上腺素能受体（β（2）AR）是介导许多激素反应的原型G蛋白偶联受体，包括心血管和肺功能。用于对抗气道平滑肌过度收缩的β激动剂刺激β（2）AR依赖性cAMP的产生，最终促进气道松弛。用于治疗哮喘的长效β受体激动剂对β 2 AR的慢性刺激可促进对激动剂的反应性减弱，并增加致命性哮喘发作的频率。β 2 AR对β激动剂的脱敏作用主要由G蛋白偶联受体激酶和β抑制蛋白介导，后者减弱受体-G（s）偶联并促进β 2 AR内化和降解。可以选择性地刺激G（s）信号传导而不促进受体与G蛋白偶联受体激酶和β-抑制蛋白的相互作用的偏向性激动剂应该作为有利的哮喘治疗剂。为了鉴定这样的分子，我们筛选了类似于50种脂化肽，这些脂化肽来源于β 2 AR的细胞内环，称为肽蛋白。该筛选揭示了两类G（s）-偏向性肽蛋白，受体非依赖性和受体依赖性，以及几种β-抑制蛋白偏向性肽蛋白。受体非依赖性G（s）-偏性肽蛋白通过直接刺激G蛋白活化来起作用。相比之下，受体依赖性G（s）-偏向性肽蛋白似乎稳定了β（2）AR的G（s）-偏向性构象，该构象与G（s）偶联，但不经历G蛋白偶联受体激酶介导的磷酸化或β-抑制蛋白介导的内化。在原代人气道平滑肌细胞中的功能研究表明，G（s）-偏向性肽蛋白不受常规脱敏的影响，因此可能是开发下一代哮喘治疗剂的良好候选者。我们的研究报告了第一个G（s）偏向的β（2）AR激活剂，并为β（2）AR功能的研究提供了有价值的工具。
The beta(2)-adrenergic receptor (beta(2)AR) is a prototypical G protein-coupled receptor that mediates many hormonal responses, including cardiovascular and pulmonary function. beta-Agonists used to combat hypercontractility in airway smooth muscle stimulate beta(2)AR-dependent cAMP production that ultimately promotes airway relaxation. Chronic stimulation of the beta(2)ARby long acting beta-agonists used in the treatment of asthma can promote attenuated responsiveness to agonists and an increased frequency of fatal asthmatic attacks. beta(2)AR desensitization to beta-agonists is primarily mediated by G protein-coupled receptor kinases and beta-arrestins that attenuate receptor-G(s) coupling and promote beta(2)AR internalization and degradation. A biased agonist that can selectively stimulate G(s) signaling without promoting receptor interaction with G protein-coupled receptor kinases and beta-arrestins should serve as an advantageous asthma therapeutic. To identify such molecules, we screened similar to 50 lipidated peptides derived from the intracellular loops of the beta(2)AR, known as pepducins. This screen revealed two classes of G(s)-biased pepducins, receptor-independent and receptor-dependent, as well as several beta-arrestin-biased pepducins. The receptor-independent G(s)-biased pepducins operate by directly stimulating G protein activation. In contrast, receptor-dependent G(s)-biased pepducins appear to stabilize a G(s)-biased conformation of the beta(2)AR that couples to G(s) but does not undergo G protein-coupled receptor kinase-mediated phosphorylation or beta-arrestin-mediated internalization. Functional studies in primary human airway smooth muscle cells demonstrate that G(s)-biased pepducins are not subject to conventional desensitization and thus may be good candidates for the development of next generation asthma therapeutics. Our study reports the first G(s)-biased activator of the beta(2)AR and provides valuable tools for the study of beta(2)AR function.