Regulation of MAP kinase by calcium-sensing receptor in bovine parathyroid and CaR-transfected HEK293 cells
Regulation of MAP kinase by calcium-sensing receptor in bovine parathyroid and CaR-transfected HEK293 cells
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DOI：
10.1152/ajprenal.2001.280.2.f291
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发表时间：
2001-02-01
影响因子：
4.2
通讯作者：
Brown, EM
中科院分区：
文献类型：
--
作者：
Kifor, O;MacLeod, RJ;Brown, EM
在牛甲状旁腺和CaR转染的人胚肾（HEKCaR）细胞中研究了细胞外钙敏感受体（CaR）对细胞外信号调节激酶1和2（ERK 1/2）通路的调节。升高Ca（o）（2+）或加入选择性CaR激活剂CaR-467引起ERK 1/2快速、剂量依赖性磷酸化。这些磷酸化减弱预处理与百日咳毒素（PTX）或治疗与磷酸酪氨酸激酶（PTK）抑制剂染料木素和除莠霉素，磷脂酰肌醇特异性磷脂酶C（PI-PLC）抑制剂U-73122，或蛋白激酶C（PKC）抑制剂GF 109203 X和增强PKC激活剂佛波醇12-肉豆蔻酸酯13-乙酸酯。PTX与PKC和PTK抑制剂联合治疗几乎消除了HEKCaR细胞中高Ca（o）（2+）诱导的ERK 1/2激活，证明了CaR介导的G（q）和G（i）偶联。在甲状旁腺和HEKCaR细胞中，高Ca（o）（2+）增加了85-kDa胞质磷脂酶A（2）（cPLA（2））的丝氨酸磷酸化。选择性的丝裂原活化蛋白激酶（MAPK）抑制剂PD 98059消除了高Ca（o）（2+）诱导的ERK 1/2激活，并减少了两种细胞类型中cPLA（2）的磷酸化，证明了MAPK在cPLA（2）激活中的作用。因此，我们的数据表明，在牛甲状旁腺和HEKCaR细胞中，CaR通过PKC激活MAPK，可能是通过G（q/11）介导的PI-PLC激活，以及通过G（i）和PTK依赖性途径，并表明MAPK在cPLA（2）激活中的重要性。
Regulation of the extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway by the extracellular calcium (Ca(o)(2+))-sensing receptor (CaR) was investigated in bovine parathyroid and CaR-transfected human embryonic kidney (HEKCaR) cells. Elevating Ca(o)(2+) or adding the selective CaR activator NPS R-467 elicited rapid, dose-dependent phosphorylation of ERK1/2. These phosphorylations were attenuated by pretreatment with pertussis toxin (PTX) or by treatment with the phosphotyrosine kinase (PTK) inhibitors genistein and herbimycin, the phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor U-73122, or the protein kinase C (PKC) inhibitor GF109203X and were enhanced by the PKC activator phorbol 12-myristate 13-acetate. Combined treatment with PTX and inhibitors of both PKC and PTK nearly abolished high Ca(o)(2+)-evoked ERK1/2 activation in HEKCaR cells, demonstrating CaR-mediated coupling via both G(q) and G(i). High Ca(o)(2+) increased serine phosphorylation of the 85-kDa cytosolic phospholipase A(2) (cPLA(2)) in both parathyroid and HEKCaR cells. The selective mitogen-activated protein kinase (MAPK) inhibitor PD98059 abolished high-Ca(o)(2+)-induced ERK1/2 activation and reduced cPLA(2) phosphorylation in both cell types, documenting MAPK's role in cPLA(2) activation. Thus our data suggest that the CaR activates MAPK through PKC, presumably through G(q/11)-mediated activation of PI-PLC, as well as through G(i)- and PTK-dependent pathway(s) in bovine parathyroid and HEKCaR cells and indicate the importance of MAPK in cPLA(2) activation.