Disruption of β-catenin binding to parathyroid hormone (PTH) receptor inhibits PTH-stimulated ERK1/2 activation.
Disruption of β-catenin binding to parathyroid hormone (PTH) receptor inhibits PTH-stimulated ERK1/2 activation.
复制标题
β-连环蛋白与甲状旁腺激素 (PTH) 受体结合的破坏抑制 PTH 刺激的 ERK1/2 激活。
DOI：
10.1016/j.bbrc.2015.05.082
复制
发表时间：
2015
影响因子：
3.1
通讯作者：
Wang,Bin
中科院分区：
文献类型：
--
作者：
Yang,Yanmei;Wang,Bin
甲状旁腺激素I型受体(PTH1R)介导甲状旁腺激素及其相关蛋白(PTHrP)对细胞外矿质离子稳态和骨重建的作用。这些作用在一定程度上依赖于细胞外信号调节激酶1和2(ERK1/2)的激活。位于PTH1R羧基末端的序列控制其激活和运输。β-连环蛋白通过与受体的胞内羧基末端区域结合，调节PTH1R信号转导，促进软骨细胞肥大。甲状旁腺素受体与β-连环蛋白的相互作用如何影响甲状旁腺素刺激的ERK1/2尚不清楚。本研究利用不表达甲状旁腺素受体的人胚胎肾293细胞，研究β-连环蛋白与甲状旁腺素受体结合的破坏是否影响甲状旁腺激素刺激的ERK1/2的激活。我们发现β-连环蛋白与野生型PTH1R相互作用，但与突变型PTH1R(L584A/L585A)的相互作用明显减弱。与突变型甲状旁腺激素受体相比，甲状旁腺素对野生型甲状旁腺激素受体诱导的cAMP生成减少，细胞内钙离子浓度升高，提示β-连环蛋白将甲状旁腺素受体信号从GαS激活转换为GαQ信号。此外，转染PTH1R的HEK293细胞中ERK1/2的激活具有时间和浓度依赖性。甲状旁腺激素刺激的ERK1/2激活主要通过GαQ/PLC信号通路介导。重要的是，转导突变型PTH1R通过抑制GαQ介导的信号转导而降低PTH诱导的ERK1/2的激活。本研究首次显示β-连环蛋白与甲状旁腺素受体结合的干扰抑制了甲状旁腺素刺激的ERK1/2的磷酸化。
The type I parathyroid hormone receptor (PTH1R) mediates PTH and PTH-related protein (PTHrP) actions on extracellular mineral ion homeostasis and bone remodeling. These effects depend in part on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Sequences located within or at the carboxyl-terminus of PTH1R control its activation and trafficking. β-catenin regulates PTH1R signaling and promotes chondrocyte hypertrophy through binding to the intracellular carboxyl-terminal region of the receptor. How the interaction of PTH1R with β-catenin affects PTH-stimulated ERK1/2 is unknown. In the present study, human embryonic kidney 293 (HEK293) cells, which do not express the PTH1R, were used to investigate whether the disruption of β-catenin binding to PTH1R affects PTH-stimulated ERK1/2 activation. We demonstrated that β-catenin interacted with wild-type PTH1R but this interaction was markedly reduced with mutant PTH1R (L584A/L585A). PTH stimulated less cAMP formation and increased more intracellular calcium in HEK293 cells transfected with wild-type PTH1R compared with mutant PTH1R, indicating β-catenin switches PTH1R signaling from Gαs activation to Gαq signaling. In addition, ERK1/2 activation in HEK293 cells transfected with PTH1R exhibited time and concentration dependence. PTH-stimulated ERK1/2 activation was mostly mediated through Gαq/PLC signaling pathway. Importantly, transfection of mutant PTH1R decreased PTH-induced ERK1/2 activation by inhibiting Gαq-mediated signaling. This study shows for the first time that the interference of β-catenin binding to PTH1R inhibits PTH-stimulated ERK1/2 phosphorylation.