Endosomal signaling of epidermal growth factor receptor stimulates signal transduction pathways leading to cell survival
Endosomal signaling of epidermal growth factor receptor stimulates signal transduction pathways leading to cell survival
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DOI：
10.1128/mcb.22.20.7279-7290.2002
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发表时间：
2002-10-01
影响因子：
5.3
通讯作者：
Wang, ZX
中科院分区：
文献类型：
--
作者：
Wang, Y;Pennock, S;Wang, ZX
尽管人们加强了对来自内体的细胞信号的理解，但没有直接证据表明内体信号足以激活信号转导途径，也没有证据表明内体信号能够产生生物学结果。缺乏突破的部分原因是缺乏在没有质膜信号的情况下产生内体信号的手段。在这篇文章中，我们报道了一种系统的建立，以特异性激活表皮生长因子(EGF)受体(EGFR)，当它进入内吞体内时。我们在特定的EGFR酪氨酸激酶抑制剂AG-1478和莫能菌素的存在下用EGF处理细胞，莫能菌素阻止EGFR的循环。这种处理导致未激活的EGF-EGFR复合体内化到内吞体内。然后通过去除AG-1478和莫能菌素来激活内体相关的EGFR。在这个过程中，我们没有观察到任何表面EGFR的磷酸化。我们还在不使用莫能菌素的情况下实现了内体相关EGFR的特异性激活。通过使用该系统，我们提供了原始证据表明：(I)内体可以作为信号复合体形成的成核部位，(Ii)内体EGFR信号足以激活导致细胞增殖和生存的主要信号通路，以及(Iii)内体EGFR信号足以抑制血清提取诱导的细胞凋亡。
In spite of intensified efforts to understand cell signaling from endosomes, there is no direct evidence demonstrating that endosomal signaling is sufficient to activate signal transduction pathways and no evidence to demonstrate that endosomal signaling is able to produce a biological outcome. The lack of breakthrough is due in part to the lack of means to generate endosomal signals without plasma membrane signaling. In this paper, we report the establishment of a system to specifically activate epidermal growth factor (EGF) receptor (EGFR) when it endocytoses into endosomes. We treated cells with EGF in the presence of AG-1478, a specific EGFR tyrosine kinase inhibitor, and monensin, which blocks the recycling of EGFR. This treatment led to the internalization of nonactivated EGF-EGFR complexes into endosomes. The endosome-associated EGFR was then activated by removing AG-1478 and monensin. During this procedure we did not observe any surface EGFR phosphorylation. We also achieved specific activation of endosome-associated EGFR without using monensin. By using this system, we provided original evidence demonstrating that (i) the endosome can serve as a nucleation site for the formation of signaling complexes, (ii) endosomal EGFR signaling is sufficient to activate the major signaling pathways leading to cell proliferation and survival, and (iii) endosomal EGFR signaling is sufficient to suppress apoptosis induced by serum withdrawal.