Cross-Desensitization and Cointernalization of H1 and H2 Histamine Receptors Reveal New Insights into Histamine Signal Integration
Cross-Desensitization and Cointernalization of H1 and H2 Histamine Receptors Reveal New Insights into Histamine Signal Integration
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DOI：
10.1124/mol.112.083394
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发表时间：
2013-05-01
影响因子：
3.6
通讯作者：
Shayo, Carina
中科院分区：
文献类型：
--
作者：
Alonso, Natalia;Fernandez, Natalia;Shayo, Carina
G蛋白偶联受体信号传导不是由蛋白质/酶的线性途径的顺序激活引起的，而是由多个分支信号传导途径的复杂相互作用引起的，即，信令网络在这项工作中，我们提出了一个详尽的研究H1和H2组胺受体（H1 R和H2 R）在U937细胞和中国仓鼠卵巢转染细胞之间的串扰。通过脱敏试验，我们证明了两种受体之间存在不依赖于蛋白激酶A或C的交叉脱敏。H1 R激动剂刺激抑制细胞增殖，诱导U937细胞凋亡48小时后处理。H1 R诱导的抗增殖和凋亡反应被H2 R激动剂抑制，这表明两种受体之间的串扰改变了它们的功能。结合和共聚焦显微镜研究揭示了共内化的两种受体与激动剂治疗后。为了评估受体的潜在异源二聚化，使用H1 R-青色荧光蛋白和H2 R-黄色荧光蛋白在人胚肾293 T细胞中进行敏化发射荧光共振能量转移实验。据我们所知，这些发现可能代表激动剂诱导的H1 R和H2 R异二聚化的第一个证明。此外，我们还表明，抑制的内化过程并没有阻止受体的交叉脱敏，这是由G蛋白偶联受体激酶2介导的。我们的研究为组胺介导的复杂信号网络提供了新的见解，并为其配体的合理使用提供了进一步的知识。
G protein-coupled receptor signaling does not result from sequential activation of a linear pathway of proteins/enzymes, but rather from complex interactions of multiple, branched signaling routes, i.e., signaling networks. In this work we present an exhaustive study of the cross-talk between H1 and H2 histamine receptors (H1R and H2R) in U937 cells and Chinese hamster ovary-transfected cells. By desensitization assays we demonstrated the existence of a crossdesensitization between both receptors independent of protein kinase A or C. H1R-agonist stimulation inhibited cell proliferation and induced apoptosis in U937 cells following treatment of 48 hours. H1R-induced antiproliferative and apoptotic response was inhibited by an H2R agonist suggesting that the cross-talk between both receptors modifies their function. Binding and confocal microscopy studies revealed cointernalization of both receptors upon treatment with the agonists. To evaluate potential heterodimerization of the receptors, sensitized emission fluorescence resonance energy transfer experiments were performed in human embryonic kidney 293T cells using H1R-cyan fluorescent protein and H2R-yellow fluorescent protein. To our knowledge these findings may represent the first demonstration of agonist-induced heterodimerization of the H1R and H2R. In addition, we also show that the inhibition of the internalization process did not prevent receptor crossdesensitization, which was mediated by G protein-coupled receptor kinase 2. Our study provides new insights into the complex signaling network mediated by histamine and further knowledge for the rational use of its ligands.