Role of extracellular subdomains of p185c-neu and the epidermal growth factor receptor in ligand-independent association and transactivation
Role of extracellular subdomains of p185c-neu and the epidermal growth factor receptor in ligand-independent association and transactivation
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DOI：
10.1073/pnas.1633546100
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发表时间：
2003-08-05
影响因子：
11.1
通讯作者：
Greene, MI
中科院分区：
文献类型：
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作者：
Kumagai, T;Katsumata, M;Greene, MI
我们研究了组装和激活的表皮生长因子受体（EGFR）-p185（c-neu）异源二聚体通过使用顺序免疫沉淀方法。使用这种方法，我们检测到异源二聚体，也更高阶的寡聚体复合物。磷酸化的EGFR-p185（c-neu）异二聚体的形式检测在EGF的情况下，但物种成为EGF刺激后高度磷酸化。为了评估异源二聚体的形成和额外的EGF反式激活，我们研究了p185（c-neu）和EGFR的四个胞外亚结构域的作用。EGFR的亚结构域I-IV分别与p185 c-neu的亚结构域I-IV以平行方式二聚化。此外，EGFR的亚结构域I-IV也分别与p185（c-neu）亚结构域III、IV、I和II相关。缺乏一个p185 c-neu富含半胱氨酸的结构域（亚结构域II或IV）导致EGF诱导的反式激活的损失。这些数据表明，两个富含半胱氨酸的结构域在配体依赖性反式激活中起决定性作用，并且这些富含半胱氨酸的胞外亚结构域以及非富含半胱氨酸的胞外亚结构域都参与与EGFR的配体非依赖性相互作用。我们的研究提供了p185（c-neu）富含半胱氨酸结构域在erbB复合物的组装和反式激活中作用的生化证据，并表明这些亚结构域可能是有用的临床靶点。
We investigated the assembly and activation of the epidermal growth factor receptor (EGFR)-p185(c-neu) heterodimer by using a sequential immunoprecipitation methodology. Using this approach we detected heterodimers and also higher-ordered oligomeric complexes. Phosphorylated EGFR-p185(c-neu) heterodimeric forms were detected in the absence of EGF, but the species became highly phosphorylated after EGF stimulation. To evaluate heterodimer formation and additional transactivation by EGF, we investigated the roles of the four extracellular subdomains of p185(c-neu) and the EGFR. Subdomains I-IV of the EGFR dimerized with subdomains I-IV of p185c-neu, respectively, in a parallel manner. In addition, subdomains I-IV of the EGFR also associated with p185(c-neu) subdomains III, IV, I, and II, respectively. A lack of one of the p185c-neu cysteine-rich domains (subdomains II or IV) resulted in a loss of EGF-induced transactivation. These data suggest that two cysteine-rich domains play defining roles in ligand-dependent transactivation and that both of these cysteine-rich extracellular subdomains as well as non-cysteine-rich extracellular subdomains are involved in ligand-independent interactions with the EGFR. Our studies provide biochemical evidence of the role of the cysteine-rich domains of p185(c-neu) in assembly and transactivation of erbB complexes and also indicate that these subdomains might be useful clinical targets.