ERBB2 is a target for USP8-mediated deubiquitination
ERBB2 is a target for USP8-mediated deubiquitination
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DOI：
10.1016/j.cellsig.2010.10.023
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发表时间：
2011-02-01
影响因子：
4.8
通讯作者：
van Leeuwen, Jeroen E. M.
中科院分区：
文献类型：
--
作者：
Meijer, Inez M. J.;van Leeuwen, Jeroen E. M.
ErbB受体酪氨酸激酶的过度表达和下调与增强的信号和肿瘤的发生有关。表皮生长因子受体(EGFR)信号的减弱是由E3连接酶Cb1的内吞和泛素化所介导的。在通向溶酶体的过程中，但在将EGFR整合到MVB的内部小泡之前，EGFR经历了Usp8介导的去泛素化。ERBB2显示出增强的循环回到细胞表面，因此我们假设Usp8不是ErbB2运输途径的一部分。在这里，我们证明，在嵌合的EGFR-ErbB2受体的背景下，(I)EGF诱导EGFR-ErbB2的pY1091 Cbl结合位点依赖的K63-多泛素化，(Ii)Cb1在EGFR-ErbB2wt和Y1091F突变受体的刺激下被酪氨酸磷酸化，(Iii)EGF诱导的EGFR-ErbB2的激活诱导Usp8酪氨酸磷酸化，以及(Iv)在EGF存在和不存在的情况下，催化失活的Usp8-C748A的共表达增强了EGFR-ErbB2 wt和Y1091F的泛素化。我们进一步证明，在EGFR-ErbB2的刺激下，Usp8的酪氨酸磷酸化是(A)独立于Y1091，(B)依赖于Src-和EGFR-ErbB2-激酶的活性，(C)通过Usp8-C748A的共表达而增强。和(D)部分依赖于USP8的微管相互作用和运输(MIT)结构域。我们的研究结果表明，Usp8是ErbB2内体转运途径的一部分。(C)2010 Elsevier Inc.保留所有权利。
Overexpression and poor downregulation of ErbB receptor tyrosine kinases are associated with enhanced signaling and tumorigenesis. Attenuation of EGF-receptor (EGFR) signaling is mediated by endocytosis and ubiquitination by the E3-ligase Cbl. En route to lysosomes, but before incorporation of the EGFR into internal vesicles of MVBs, the EGFR undergoes Usp8-mediated deubiquitination. ErbB2 displays enhanced recycling back to the cell surface, and therefore we hypothesized that Usp8 is not part of the ErbB2 trafficking pathway. Here, we demonstrate, in the context of a chimeric EGFR-ErbB2 receptor, that (i) EGF induces pY1091 Cbl binding site-dependent K63-polyubiquitination of EGFR-ErbB2, (ii) Cbl is tyrosine phosphorylated upon stimulation of EGFR-ErbB2 wt and Y1091F mutant receptor, (iii) EGF-induced activation of EGFR-ErbB2 induces Usp8 tyrosine phosphorylation, and (iv) ubiquitination of the EGFR-ErbB2 wt and Y1091F mutant is enhanced upon coexpression of catalytically inactive Usp8-C748A in the presence and absence of EGF. We further show that Usp8 tyrosine phosphorylation upon stimulation of EGFR-ErbB2 is (a) independent of Y1091, (b) dependent on Src- and EGFR-ErbB2-kinase activity, (c) enhanced upon coexpression of Usp8-C748A. and (d) partly dependent on the Microtubule Interacting and Transport (MIT) domain of Usp8. Our findings demonstrate that Usp8 is part of the ErbB2 endosomal trafficking pathway. (C) 2010 Elsevier Inc. All rights reserved.