Mechanism for removal of tumor necrosis factor receptor 1 from the cell surface by the adenovirus RIDα/β complex
Mechanism for removal of tumor necrosis factor receptor 1 from the cell surface by the adenovirus RIDα/β complex
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DOI：
10.1128/jvi.79.21.13606-13617.2005
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发表时间：
2005-11-01
影响因子：
5.4
通讯作者：
Horwitz, MS
中科院分区：
文献类型：
--
作者：
Chin, YR;Horwitz, MS
编码在腺病毒早期区域3的蛋白具有重要的免疫调节特性。我们最近发现，E3-10.4K/14.5K(RIDα/β)复合体下调了肿瘤坏死因子受体I(TNFR1)在质膜上的表达。为了研究RIDβ酪氨酸分选基序在去除表面TNFR1中的作用，将RIDβ上的酪氨酸122突变为丙氨酸或苯丙氨酸。这两个RIDβ突变不仅取消了表面TNFR1的下调，而且矛盾地增加了表面TNFR1的水平。RID还下调其他死亡受体，如Fas；然而，RIDβ突变体并没有增加表面Fas的表达，这表明RID对TNFR1和Fas的调节在机制上是不同的。在混合实验中，野生型(WT)RID介导的TNFR1下调在RIDβ突变体的存在下被部分抑制，表明突变体竞争TNFR1的访问。事实上，免疫共沉淀显示了RIDβ和TNFR1之间的关联。相反，突变体不影响野生型RID诱导的Fas表达下调。这些差异效应支持一种模型，即RID与细胞膜上的TNFR1相关，而RID可能与细胞质中的Fas相关。通过使用针对接头蛋白2的mu2亚基的小干扰RNA，显性负动蛋白构建K44A，以及溶酶体增效剂巴菲罗星A1和氯化铵，我们还证明了表面TNFR1被RID内化是通过涉及mu2和Dynamin的依赖于笼蛋白的过程，然后是通过内体/溶酶体途径降解TNFR1。
Proteins encoded in adenovirus early region 3 have important immunoregulatory properties. We have recently shown that the E3-10.4K/14.5K (RID alpha/beta) complex downregulates tumor necrosis factor receptor I (TNFR1) expression at the plasma membrane. To study the role of the RID beta tyrosine sorting motif in the removal of surface TNFR1, tyrosine 122 on RID beta was mutated to alanine or phenylalanine. Both RID beta mutations not only abolished the downregulation of surface TNFR1 but paradoxically increased surface TNFR1 levels. RID also downregulates other death receptors, such as FAS; however, surface FAS expression was not increased by RID beta mutants, suggesting that regulation of TNFR1 and that of FAS by RID are mechanistically different. In the mixing experiments, the wild-type (WT) RID-mediated TNFR1 downregulation was partially inhibited in the presence of RID beta mutants, indicating that the mutants compete for TNFR1 access. Indeed, an association between RID beta and TNFR1 was shown by coimmunoprecipitation. In contrast, the mutants did not affect the WT RID-induced downregulation of FAS. These differential effects support a model in which RID associates with TNFR1 on the plasma membrane, whereas RID probably associates with FAS in a cytoplasmic compartment. By using small interfering RNA against the mu 2 subunit of adaptor protein 2, dominant negative dynamin construct K44A, and the lysosomotropic agents bafilomycin A1 and ammonium chloride, we also demonstrated that surface TNFR1 was internalized by RID by a clathrin-dependent process involving mu 2 and dynamin, followed by degradation of TNFR1 via an endosomal/lysosomal pathway.