Melatonin Receptor Type 1 Signals to Extracellular Signal-Regulated Kinase 1 and 2 via Gi and Gs Dually Coupled Pathways in HEK-293 Cells
Melatonin Receptor Type 1 Signals to Extracellular Signal-Regulated Kinase 1 and 2 via Gi and Gs Dually Coupled Pathways in HEK-293 Cells
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褪黑素受体 1 型通过 HEK-293 细胞中的 Gi 和 Gs 双重偶联途径向细胞外信号调节激酶 1 和 2 发出信号。
DOI：
10.1021/bi500092e
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发表时间：
2014-05-06
期刊：
影响因子：
2.9
通讯作者：
Zhou, Naiming
中科院分区：
文献类型：
--
作者：
Chen, Linjie;He, Xiaobai;Zhou, Naiming
松果体激素褪黑激素通过两种G蛋白偶联受体（褪黑激素受体1型（MT 1）和褪黑激素受体2型（MT 2））在多种生理和病理反应中发挥其调节作用，这两种受体已被认为是治疗许多人类疾病和病症的有希望的靶点。MT 1受体在近20年前被发现;然而，MT 1介导的信号传导影响生理学的分子机制仍有待进一步阐明。在这项研究中，使用稳定表达人MT 1受体的HEK 293细胞，褪黑激素诱导细胞外信号调节激酶1和2（ERK 1/2）的浓度依赖性激活。百日咳毒素预处理强烈抑制了褪黑素介导的ERK 1/2磷酸化在较晚时间点（≥5 min）的作用，但仅检测到对ERK 1/2活化在较早时间点（≤2 min）的轻微抑制（如果有的话）。进一步的实验表明，Gβγ亚基、磷酸肌醇3-激酶和钙不敏感蛋白激酶C参与了MT 1在较晚时间点（≥5 min）介导的ERK 1/2激活。此外，来自cAMP测定结合MT 1突变体的结果表明，人MT 1受体也可以与Gs蛋白偶联，刺激细胞内cAMP的形成，并且MT 1诱导的ERK 1/2在早期时间点（≤2 min）的激活是由Gs/cAMP/PKA级联介导的。我们的研究结果可能会提供新的见解的药理作用和生理功能的MT 1介导的ERK 1/2的激活调制。
The pineal gland hormone melatonin exerts its regulatory roles in a variety of physiological and pathological responses through two G protein-coupled receptors, melatonin receptor type 1 (MT1) and melatonin receptor type 2 (MT2), which have been recognized as promising targets in the treatment of a number of human diseases and disorders. The MT1 receptor was identified nearly 20 years ago; however, the molecular mechanisms by which MT1-mediated signaling affects physiology remain to be further elucidated. In this study, using HEK293 cells stably expressing the human MT1 receptor, melatonin induced a concentration-dependent activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2). The melatonin-mediated phosphorylation of ERK1/2 at later time points (≥5 min) was strongly suppressed by pretreatment with pertussis toxin, but only a slight, if any, inhibition of ERK1/2 activation at early time points (≤2 min) was detected. Further experiments demonstrated that the Gβγ subunit, phosphoinositide 3-kinase, and calcium-insensitive protein kinase C were involved in the MT1-mediated activation of ERK1/2 at later time points (≥5 min). Moreover, results derived from cAMP assays combined with a MT1 mutant indicated that the human MT1 receptor could also couple to Gs protein, stimulating intracellular cAMP formation, and that the MT1-induced activation of ERK1/2 at early time points (≤2 min) was mediated by the Gs/cAMP/PKA cascade. Our findings may provide new insights into the pharmacological effects and physiological functions modulated by the MT1-mediated activation of ERK1/2.