T cell receptor signal initiation induced by low-grade stimulation requires the cooperation of LAT in human T cells.
T cell receptor signal initiation induced by low-grade stimulation requires the cooperation of LAT in human T cells.
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DOI：
10.1371/journal.pone.0015114
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发表时间：
2010-11-30
期刊：
影响因子：
3.7
通讯作者：
Michel F
中科院分区：
文献类型：
--
作者：
Dong S;Corre B;Nika K;Pellegrini S;Michel F
刺激T细胞受体(TCR)后最早的激活事件之一是CD3相关复合体中基于免疫受体酪氨酸的激活基序(ITAM)被Src家族激酶Lck磷酸化。有越来越多的证据表明，大量的Lck在T细胞中具有结构性的活性，但TCR是如何与Lck及其下游信号级联相连的仍不清楚。我们分析了人原始的CD4+T细胞和转化的T细胞系Hut-78中Lck和Fyn的磷酸化状态以及TCR信号转导。后者已被证明在TCR诱导的磷酸化方面与初级T细胞相似，并且可以被RNA干扰高度击倒。在这两种T细胞类型中，都观察到Lck和Fyn在其激活的酪氨酸上的基础磷酸化，尽管这在Hut-78细胞中要明显得多。TCR刺激导致Lck与跨膜接头蛋白LAT(T细胞激活连接物)共沉淀，ERK介导的Lck磷酸化，Lck抑制性酪氨酸未检测到去磷酸化。值得注意的是，在HUT-78细胞中，当LAT被敲除后，我们发现LAT促进了TcR诱导的LCK和FYN激活型酪氨酸的磷酸化，TcRζ链的磷酸化和ZAP-70的激活。值得注意的是，LAT在TCR参与度较低的情况下调节这些事件。我们的结果首次表明，LAT促进了TCR信号的启动，并表明该接头可能有助于在底物附近保持活性的Lck。
One of the earliest activation events following stimulation of the T cell receptor (TCR) is the phosphorylation of the immunoreceptor tyrosine-based activation motifs (ITAMs) within the CD3-associated complex by the Src family kinase Lck. There is accumulating evidence that a large pool of Lck is constitutively active in T cells but how the TCR is connected to Lck and to the downstream signaling cascade remains elusive. We have analyzed the phosphorylation state of Lck and Fyn and TCR signaling in human naïve CD4+ T cells and in the transformed T cell line, Hut-78. The latter has been shown to be similar to primary T cells in TCR-inducible phosphorylations and can be highly knocked down by RNA interference. In both T cell types, basal phosphorylation of Lck and Fyn on their activatory tyrosine was observed, although this was much less pronounced in Hut-78 cells. TCR stimulation led to the co-precipitation of Lck with the transmembrane adaptor protein LAT (linker for activation of T cells), Erk-mediated phosphorylation of Lck and no detectable dephosphorylation of Lck inhibitory tyrosine. Strikingly, upon LAT knockdown in Hut-78 cells, we found that LAT promoted TCR-induced phosphorylation of Lck and Fyn activatory tyrosines, TCRζ chain phosphorylation and Zap-70 activation. Notably, LAT regulated these events at low strength of TCR engagement. Our results indicate for the first time that LAT promotes TCR signal initiation and suggest that this adaptor may contribute to maintain active Lck in proximity of their substrates.
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影响因子：
11.4
作者：
BIFFEN, M;MCMICHAELPHILLIPS, D;ALEXANDER, D
通讯作者：
ALEXANDER, D
影响因子：
3.7
作者：
Bartelt RR;Cruz-Orcutt N;Collins M;Houtman JC
通讯作者：
Houtman JC
影响因子：
30.5
作者：
Irles, C;Symons, A;Acuto, O
通讯作者：
Acuto, O
DOI：
10.1073/pnas.0905039107
发表时间：
2010-06-08
影响因子：
11.1
作者：
Jang, Ihn Kyung;Zhang, Jinping;Gu, Hua
通讯作者：
Gu, Hua
影响因子：
5.3
作者：
ABRAHAM, N;VEILLETTE, A
通讯作者：
VEILLETTE, A