Interaction and inhibitory cross-talk between endothelin and ErbB receptors in the adult heart
Interaction and inhibitory cross-talk between endothelin and ErbB receptors in the adult heart
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DOI：
10.1124/mol.106.027599
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发表时间：
2007-06-01
影响因子：
3.6
通讯作者：
Walker, Jeffery W.
中科院分区：
文献类型：
--
作者：
Chung, Ka Young;Walker, Jeffery W.
内皮素-1 (ET-1) 通过结合 A 型内皮素受体 (ETA) 和 B 型内皮素受体 (ETB) G 蛋白偶联受体来调节哺乳动物心脏的收缩性和生长。为了确定与成人心肌中 ET-1 受体相关的生长信号通路，进行了免疫沉淀/蛋白质组学联合分析。通过基质辅助激光解吸电离/飞行时间质谱法，在 ETA 免疫沉淀物中鉴定出被认为在 ETA 下游起作用的信号蛋白，例如 G α(q)、磷脂酶 C-β 1、蛋白激酶 C (PKC) epsilon 和 PKC δ。同样突出的还有生长因子受体酪氨酸激酶 erbB2 和 erbB4 及其下游生长信号传导效应器磷酸肌醇 3 激酶（PI3 激酶）、Akt、Raf-1、丝裂原激活蛋白激酶激酶 (MEK) 和细胞外信号调节激酶 (Erk)。蛋白质印迹分析证实了 erbB2/4、PI3 激酶和 Akt 与 ETA 的共免疫沉淀，共聚焦显微镜揭示了它们在心脏横管（T 管）中的共定位。 erbB4 受体配体神经调节蛋白-1β (NRG1β) 促进心室肌细胞中的 erbB2/4 酪氨酸磷酸化和 Akt 丝氨酸磷酸化，而 ET-1 治疗则不然。这一观察结果反对成人心肌中通过 erbB2/4 反式激活发生的 ET-1 生长信号传导。然而，ET-1 确实刺激 Erk1/2 磷酸化，并显着削弱了 NRG1 介导的几种作用，包括 erbB2/4 磷酸化、Akt 的丝氨酸磷酸化和负性肌力。 ETA 和 erbB2/4-Akt 途径之间的这种抑制性串扰由佛波酯模拟，并通过 PKC 或 MEK/Erk 的药理抑制来阻断。蛋白质组学分析和随后的受体串扰研究表明，成人心肌细胞与新生儿心肌细胞中 ETA 和 erbB 通路之间的生长信号传导存在根本不同。结果可能与以下因素相关的心肌病有关：1) 长期暴露于 ET-1； 2) T管变性； 3) 针对erbB2抑制的疗法。
Endothelin-1 (ET-1) regulates contractility and growth of the mammalian heart by binding endothelin receptor type A (ETA) and endothelin receptor type B (ETB) G-protein-coupled receptors. To identify growth signaling pathways associated with ET-1 receptors in adult myocardium, a combined immunoprecipitation/ proteomic analysis was performed. Signaling proteins believed to function downstream of ET A such as G alpha(q), phospholipase C-beta 1, protein kinase C (PKC) epsilon, and PKC delta were identified in immunoprecipitates of ETA by matrix-assisted laser desorption ionization/ time of flight mass spectrometry. Also prominent were the growth factor receptor tyrosine kinases erbB2 and erbB4 and their downstream growth signaling effectors phosphoinositide-3 kinase (PI3 kinase), Akt, Raf-1, mitogen-activated protein kinase kinase (MEK), and extracellular signal-regulated kinase (Erk). Western blot analysis confirmed coimmunoprecipitation of erbB2/4, PI3 kinase, and Akt with ETA, and confocal microscopy revealed their colocalization in cardiac transverse tubules (T-tubules). The erbB4 receptor ligand neuregulin-1 beta (NRG1 beta) promoted erbB2/4 tryosine phosphorylation and Akt serine phosphorylation in ventricular myocytes, whereas treatment with ET-1 did not. This observation argues against ET-1 growth signaling occurring via erbB2/ 4 transactivation in adult myocardium. ET-1 did, however, stimulate Erk1/2 phosphorylation and substantially blunted several NRG1 -mediated actions, including erbB2/4 phosphorylation, serine phosphorylation of Akt, and negative inotropy. This inhibitory cross-talk between ET A and erbB2/ 4-Akt pathways was mimicked by a phorbol ester and blocked by pharmacological inhibition of PKC or MEK/ Erk. The proteomic analysis and subsequent investigation of receptor cross-talk indicate that growth signaling between ET A and erbB pathways is fundamentally different in adult versus neonatal cardiac myocytes. The results may be relevant to cardiomyopathies associated with 1) prolonged exposure to ET-1; 2) degeneration of T-tubules; and 3) therapies targeted at erbB2 inhibition.