Melatonin receptor type 1 signals to extracellular signal-regulated kinase 1 and 2 via Gi and Gs dually coupled pathways in HEK-293 cells.
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.
Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou, Zhejiang 310058, China.
Linjie
L
Chen
Xiaobai
X
He
Yaping
Y
Zhang
Xiaopan
X
Chen
Xiangru
X
Lai
Jiajie
J
Shao
Ying
Y
Shi
Naiming
N
Zhou
D000242:Cyclic AMP / Q000378:metabolism; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008550:Melatonin / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D044122:Receptor, Melatonin, MT1 / Q000235:genetics / Q000502:physiology*; D044123:Receptor, Melatonin, MT2 / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D015398:Signal Transduction
D044122:Receptor, Melatonin, MT1; D044123:Receptor, Melatonin, MT2; D043562:Receptors, G-Protein-Coupled; D000242:Cyclic AMP; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C498819:GNAI3 protein, human; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019205:GTP-Binding Protein alpha Subunits, Gs; D008550:Melatonin