Diacylglycerol-dependent binding recruits PKCθ and RasGRP1 C1 domains to specific subcellular localizations in living T lymphocytes
Diacylglycerol-dependent binding recruits PKCθ and RasGRP1 C1 domains to specific subcellular localizations in living T lymphocytes
复制标题
DOI：
10.1091/mbc.e03-11-0844
复制
发表时间：
2004-06-01
影响因子：
3.3
通讯作者：
Merida, I
中科院分区：
文献类型：
--
作者：
Carrasco, S;Merida, I
二酰基甘油（DAG）信号通路依赖于保守的存在。结构域1 （Cl）在T细胞受体（TCR）触发后，磷脂酶c依赖的DAG的产生对于正确的免疫反应的开始是必不可少的。因此，在T淋巴细胞中表达的两种含cl的蛋白，Ras guanyl核苷酸释放蛋白1 （Ras- grp1）和蛋白激酶CO (PKCtheta)，被证明是T细胞活化和增殖的基础。虽然含有相同的调控结构域，但它们被认为在响应TCR触发时迁移到不同的亚细胞位置。在这里，我们研究了活Jurkat T细胞中RasGRP1和PKCtheta C1结构域的细胞内定位。结果表明，在初级序列没有显著差异的情况下，这些蛋白的C1结构域在细胞内表现出特定的定位，并对药物刺激和TCR触发有不同的反应。这些差异有助于解释包含它们的全长蛋白的不同定位和不同的功能作用。这些DAG绑定模块的属性允许将其描述为区分DAG池的功能标记。最后，我们发现通过结合不同的二酰基甘油形式，不同C1模块的过表达可以减弱来自血浆或细胞膜的dag依赖信号。这是通过分析这两个脂质池对plc依赖的Ras激活响应TCR触发的贡献来证明的。
Diacylglycerol (DAG) signaling relies on the presence of conserved. domain 1 (Cl) in its target proteins. Phospholipase C-dependent generation of DAG after T cell receptor (TCR) triggering is essential for the correct immune response onset. Accordingly, two Cl-containing proteins expressed in T lymphocytes, Ras guanyl nucleotide-releasing protein1 (Ras-GRP1) and protein kinase CO (PKCtheta), were shown to be fundamental for T-cell activation and proliferation. Although containing the same regulatory domain, they are proposed to relocate to distinct subcellular locations in response to TCR triggering. Here we studied intracellular localization of RasGRP1 and PKCtheta C1 domains in living Jurkat T cells. The results demonstrate that, in the absence of significant primary sequence differences, the C1 domains of these proteins show specific localization within the cell and distinct responses to pharmacological stimulation and TCR triggering. These differences help explain the divergent localization and distinct functional roles of the full-length proteins, which contains them. The properties of these DAG-binding modules allow their characterization as functional markers that discriminate between DAG pools. Finally, we show that by binding to different diacylglycerol forms, overexpression of distinct C1 modules can attenuate DAG-dependent signals originating from the plasma or internal membranes. This is shown by analyzing the contribution of these two lipid pools to PLC-dependent Ras activation in response to TCR triggering.