Chimeric tumor necrosis factor receptors with constitutive signaling activity.
Chimeric tumor necrosis factor receptors with constitutive signaling activity.
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具有组成型信号传导活性的嵌合肿瘤坏死因子受体。
DOI：
10.1073/pnas.92.12.5376
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发表时间：
1995
影响因子：
11.1
通讯作者：
Beutler,B
中科院分区：
文献类型：
--
作者：
Bazzoni,F;Alejos,E;Beutler,B
许多激素和细胞因子受体是通过其特定的配体进行交联的，而多聚化是导致信号产生的关键步骤。在肿瘤坏死因子受体(TNF-Rs)的情况下，抗体诱导的交联足以触发细胞溶解效应。然而，信号的四级结构要求--即二聚体、三聚体或更高阶多聚体的形成--仍然不清楚。此外，目前还不清楚55 kDa或75 kDa的肿瘤坏死因子受体是导致细胞溶解的原因。我们推测，靶向质膜的专性受体二聚体可能会持续发出信号，表明肿瘤坏死因子的存在，尽管实际上没有配体。这种分子插入到适当的载体中，可以用来将受体特异性的“肿瘤坏死因子样”活性投射到体内特定的细胞和组织。因此，我们构建了编码嵌合受体的序列，其中小鼠促红细胞生成素受体(EPO-R)的胞外区与两个小鼠肿瘤坏死因子受体的“茎”、跨膜区和胞内区融合在一起。因此，EPO-R组被用来驱动肿瘤坏死因子-受体胞浆结构域的二聚化。这些嵌合蛋白在多种细胞系中都有很好的表达，并与细胞表面的促红细胞生成素结合。55 kDa和75 kDa EPO/TNF-R嵌合体均具有结构性细胞毒作用，可通过共转染或克隆形成实验检测到。因此，尽管两个肿瘤坏死因子受体的细胞质结构域之间缺乏结构上的同源性，但观察到了相似的信号终点。此外，二聚化(而不是三聚化或更高阶多聚化)足以引发生物反应。
Many hormone and cytokine receptors are crosslinked by their specific ligands, and multimerization is an essential step leading to the generation of a signal. In the case of the tumor necrosis factor (TNF) receptors (TNF-Rs), antibody-induced crosslinking is sufficient to trigger a cytolytic effect. However, the quaternary structural requirements for signaling--i.e., the formation of dimers, trimers, or higher-order multimers--have remained obscure. Moreover, it has not been clear whether the 55-kDa or 75-kDa TNF-R is responsible for initiation of cytolysis. We reasoned that an obligate receptor dimer, targeted to the plasma membrane, might continuously signal the presence of TNF despite the actual absence of the ligand. Such a molecule, inserted into an appropriate vector, could be used to project receptor-specific "TNF-like" activity to specific cells and tissues in vivo. Accordingly, we constructed sequences encoding chimeric receptors in which the extracellular domain of the mouse erythropoietin receptor (Epo-R) was fused to the "stem," transmembrane domain, and cytoplasmic domain of the two mouse TNF-Rs. Thus, the Epo-R group was used to drive dimerization of the TNF-R cytoplasmic domain. These chimeric proteins were well expressed in a variety of cell lines and bound erythropoietin at the cell surface. Both the 55-kDa and the 75-kDa Epo/TNF-R chimeras exerted a constitutive cytotoxic effect detected by cotransfection or clonogenic assay. Thus, despite the lack of structural homology between the cytoplasmic domains of the two TNF-Rs, a similar signaling endpoint was observed. Moreover, dimerization (rather than trimerization or higher-order multimerization) was sufficient for elicitation of a biological response.