Extracellular signal-regulated kinase 1/2 activation by myometrial oxytocin receptor involves GαqGβγ and epidermal growth factor receptor tyrosine kinase activation
Extracellular signal-regulated kinase 1/2 activation by myometrial oxytocin receptor involves GαqGβγ and epidermal growth factor receptor tyrosine kinase activation
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DOI：
10.1210/en.2002-221039
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发表时间：
2003-07-01
期刊：
影响因子：
4.8
通讯作者：
Sanborn, BM
中科院分区：
文献类型：
--
作者：
Zhong, M;Yang, M;Sanborn, BM
催产素（OT）刺激细胞外信号调节激酶1/2 （ERK1/2）的机制仅部分被理解。OT受体（OTR）信号主要通过Galpha(q)传递，但PHM1肌层细胞中ERK1/2磷酸化（ERK1/2- p）并没有通过抑制下游效应物如磷脂酶C或蛋白激酶C来消除。与Galpha(i)偶联反应不一致的是，百日咳毒素对OT诱导的ERK1/2- p的抑制被蛋白激酶a抑制剂Rp-cAMPS和KT5720逆转。与蛋白激酶A的抑制作用一致，百日咳毒素预处理提高了细胞cAMP， 8-（4-氯苯硫磷）cAMP抑制ot诱导的ERK1/2-P。β -肾上腺素能受体激酶的伽马清道夫羧基末端对OT反应的衰减涉及伽马介导的途径。在过表达OTR的COSM6细胞（OTR-COSM6）和PHM1细胞中，表皮生长因子受体（EGFR）酪氨酸激酶抑制剂AG1478显著降低了ot诱导的ERK1/2-P，而血小板来源的生长因子受体酪氨酸激酶抑制剂AG1296则没有作用。此外，OT增加了OTR-COSM6细胞中EGFR酪氨酸的磷酸化，而AG1478或EGTA + thapsigargin预处理可以抑制这种磷酸化。AG1478不影响OT或蛋白激酶c刺激的ERK1/2-P产生肌醇1,4,5-三磷酸，但完全阻断了离子霉素诱导的ERK1/2-P和EGFR酪氨酸磷酸化。在OTR-COSM6和PHM1细胞中，EGTA降低ot刺激的ERK1/2-P；当thapsigargin + EGTA预处理阻断细胞内钙升高时，未观察到ERK1/2-P。这些数据与肌层和OTR-COSM6细胞中Galpha(q)激活导致ERK1/2-P增加的β - γ介导途径的激活一致。该途径涉及EGFR激活和钙的影响。
The mechanisms by which oxytocin (OT) stimulates extracellular signal-regulated kinase 1/2 (ERK1/2) are only partially understood. OT receptor (OTR) signals predominantly through Galpha(q), but ERK1/2 phosphorylation (ERK1/2-P) in PHM1 myometrial cells was not eliminated by inhibition of downstream effectors such as phospholipase C or protein kinase C. Inconsistent with a Galpha(i)-coupled response, pertussis toxin inhibition of OT-induced ERK1/2-P was reversed by the protein kinase A inhibitors Rp-cAMPS and KT5720. Consistent with an inhibitory role for protein kinase A, pertussis toxin pretreatment raised cellular cAMP and 8-(4-chlorophenylthio)cAMP inhibited OT-induced ERK1/2-P. Attenuation of the OT response by the Gbetagamma scavenger carboxyl terminus of the beta-adrenergic receptor kinase implicated a Gbetagamma-mediated pathway. In both COSM6 cells overexpressing OTR ( OTR-COSM6) and in PHM1 cells, the epidermal growth factor receptor ( EGFR) tyrosine kinase inhibitor AG1478 markedly reduced OT-induced ERK1/2-P, whereas the platelet-derived growth factor receptor tyrosine kinase inhibitor AG1296 had no effect. Furthermore, OT increased EGFR tyrosine phosphorylation in OTR-COSM6 cells, which was inhibited by AG1478 or EGTA plus thapsigargin pretreatment. AG1478 did not affect inositol 1,4,5-triphosphate production by OT or protein kinase C-stimulated ERK1/2-P but completely blocked ionomycin-induced ERK1/2-P and EGFR tyrosine phosphorylation. In both OTR-COSM6 and PHM1 cells, EGTA reduced OT-stimulated ERK1/2-P; no ERK1/2-P was observed when intracellular calcium increases were blocked by pretreatment with thapsigargin plus EGTA. These data are consistent with activation of a Gbetagamma-mediated pathway as a consequence of Galpha(q) activation in myometrium and OTR-COSM6 cells that results in increased ERK1/2-P. This pathway involves both EGFR activation and an influence of calcium.