Impaired TCR signaling through dysfunction of lipid rafts in sphingomyelin synthase 1 (SMS1)-knockdown T cells
Impaired TCR signaling through dysfunction of lipid rafts in sphingomyelin synthase 1 (SMS1)-knockdown T cells
复制标题
鞘磷脂合酶 1 (SMS1) 敲低 T 细胞中脂筏功能障碍导致 TCR 信号传导受损
DOI：
10.1093/intimm/dxn100
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发表时间：
2008-11-01
影响因子：
4.4
通讯作者：
Umehara, Hisanori
中科院分区：
文献类型：
--
作者：
Jin, Zhe-Xiong;Huang, Cheng-Ri;Umehara, Hisanori
在T细胞活化期间，TCR聚集在T细胞-抗原呈递细胞界面的中心，形成中心超分子活化簇。虽然已经提出，鞘脂和胆固醇丰富的微结构域，称为脂筏，形成TCR信号的调节和转导的平台，膜鞘磷脂（SM），脂筏的关键组分的实际作用，还没有报道。在克隆了SM合成基因鞘磷脂合成酶（SMS）1后，我们通过将SMS 1-short-interfering RNA转染到SM膜表达缺陷的Jurkat T细胞中，建立了SM基因敲减细胞系（Jurkat-SMS 1/kd）。在CD 3刺激后，Jurkat-SMS 1/kd细胞中CD 69（最早的白细胞活化抗原）的表达、活化诱导的细胞粘附和增殖以及TCR聚集严重受损。Jurkat-SMS 1/kd细胞中CD 3诱导的酪氨酸磷酸化和用于活化T细胞的连接子与ZAP-70和Grb 2的结合以及蛋白激酶C（PKC）θ的磷酸化也严重受损。最后，Jurkat-SMS 1/kd细胞中TCR、ZAP-70和PKC theta向脂筏的转位明显减少。这些发现表明膜SM对于TCR信号转导至关重要，通过脂筏功能导致完全T细胞活化。
During T cell activation, TCRs cluster at the center of the T cell-antigen-presenting cell interface forming the central supramolecular activation cluster. Although it has been suggested that sphingolipid- and cholesterol-rich microdomains, termed lipid rafts, form platforms for the regulation and transduction of TCR signals, an actual role for membrane sphingomyelin (SM), a key component of lipid rafts, has not been reported. After cloning a gene responsible for SM synthesis, sphingomyelin synthase (SMS) 1, we established a SM-knockdown cell line (Jurkat-SMS1/kd) by transfection of SMS1-short-interfering RNA into Jurkat T cells, which is deficient in membrane expression of SM. Upon CD3 stimulation, expression of CD69 (the earliest leukocyte activation antigen), activation-induced cell adhesion and proliferation as well as TCR clustering was severely impaired in Jurkat-SMS1/kd cells. CD3-induced tyrosine phosphorylation and association of linker for activation of T cell with ZAP-70 and Grb2 and phosphorylation of protein kinase C (PKC) theta were also severely impaired in Jurkat-SMS1/kd cells. Finally, translocation of TCR, ZAP-70 and PKC theta into lipid rafts was markedly decreased in Jurkat-SMS1/kd cells. These findings indicate that membrane SM is crucial for TCR signal transduction, leading to full T cell activation through lipid raft function.