Effect of redox balance alterations on cellular localization of LAT and downstream T-cell receptor signaling pathways
Effect of redox balance alterations on cellular localization of LAT and downstream T-cell receptor signaling pathways
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DOI：
10.1128/mcb.22.2.400-411.2002
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发表时间：
2002-01-01
影响因子：
5.3
通讯作者：
Verweij, CL
中科院分区：
文献类型：
--
作者：
Gringhuis, SI;Papendrecht-van der Voort, EAM;Verweij, CL
用于活化T细胞（LAT）的整合膜蛋白接头是T细胞受体（TCR）介导的信号传导途径中的中心衔接蛋白。LAT的细胞定位对细胞内氧化还原平衡的改变极其敏感。抗氧化剂谷胱甘肽（GSH）的细胞内水平降低，慢性氧化应激的标志，导致LAT的膜置换，消除TCR介导的信号传导，从而降低T淋巴细胞的反应性。LAT的膜位移是伴随着一个相当大的差异，在本地和非还原变性聚丙烯酰胺凝胶电泳分析，发现指示构象变化的LAT的流动性。LAT内氧化还原敏感性半胱氨酸残基的靶向突变产生了LAT突变体，这些突变体在慢性氧化应激条件下保持膜锚定。氧化还原不敏感LAT突变体的表达允许恢复TCR介导的信号转导，而CD 28介导的信号途径仍然受损。这些结果表明，作为氧化还原平衡改变的结果，LAT的膜置换是干扰LAT插入质膜的构象变化的结果。总之，这些数据表明LAT作为TCR信号传导敏感性的关键中间体，因此T淋巴细胞对慢性氧化应激的作用。
The integral membrane protein linker for activation of T cells (LAT) is a central adapter protein in the T-cell receptor (TCR)-mediated signaling pathways. The cellular localization of LAT is extremely sensitive to intracellular redox balance alterations. Reduced intracellular levels of the antioxidant glutathione (GSH), a hallmark of chronic oxidative stress, resulted in the membrane displacement of LAT, abrogated TCR-mediated signaling and consequently hyporesponsiveness of T lymphocytes. The membrane displacement of LAT is accompanied by a considerable difference in the mobility of LAT upon native and nonreducing denaturing polyacrylamide gel electrophoresis analysis, a finding indicative of a conformational change. Targeted mutation of redox-sensitive cysteine residues within LAT created LAT mutants which remain membrane anchored under conditions of chronic oxidative stress. The expression of redox-insensitive LAT mutants allows for restoration of TCR-mediated signal transduction, whereas CD28-mediated signaling pathways remained impaired. These results are indicative that the membrane displacement of LAT as a result of redox balance alterations is a consequence of a conformational change interfering with the insertion of LAT into the plasma membrane. Conclusively, the data suggest a role for LAT as a crucial intermediate in the sensitivity of TCR signaling and hence T lymphocytes toward chronic oxidative stress.