Signal transduction through decay-accelerating factor. Interaction of glycosyl-phosphatidylinositol anchor and protein tyrosine kinases p56lck and p59fyn 1.
Signal transduction through decay-accelerating factor. Interaction of glycosyl-phosphatidylinositol anchor and protein tyrosine kinases p56lck and p59fyn 1.
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DOI：
10.4049/jimmunol.149.11.3535
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发表时间：
1992-12
影响因子：
4.4
通讯作者：
A. Shenoy-Scaria;J. Kwong;T. Fujita;M. Olszowy;A. Shaw;D. Lublin
中科院分区：
文献类型：
--
作者：
A. Shenoy-Scaria;J. Kwong;T. Fujita;M. Olszowy;A. Shaw;D. Lublin
衰变加速因子（DAF或CD55）是一种70 - kDa的糖基磷脂酰肌醇（GPI）锚定蛋白，它通过阻止C3转化酶的形成或使其解离来保护细胞免受补体介导的裂解。先前已有报道，多克隆抗体使人类外周T细胞上的DAF交联会导致淋巴细胞增殖。两种单克隆抗体，都定位于DAF的第三个短共有重复区域，能够触发人类外周T细胞的增殖。为了确定GPI锚在细胞激活中的作用，我们用编码DAF或DAF的跨膜形式（DAF - TM）的cDNA转染EL - 4小鼠胸腺瘤细胞。DAF转染的细胞能够转导晚期激活事件，如白细胞介素 - 2的产生所证明的那样，而DAF - TM转染的细胞则不能。GPI锚定的DAF能够转导早期激活事件，导致一种40 - kDa蛋白和几种85 - 95 kDa范围内的蛋白发生酪氨酸磷酸化——这一事件在DAF - TM转染的细胞中不存在。此外，DAF转染细胞的抗DAF免疫沉淀物含有导致40 - 、56 - 60 - 和85 - kDa蛋白磷酸化的酪氨酸激酶活性，而DAF - TM转染细胞的抗DAF免疫沉淀物没有相关的激酶活性。p56lck和p59fyn都与DAF转染的EL - 4细胞中的DAF相关联。在转染了fyn的HeLa细胞中，DAF与p59fyn相关联。DAF与src家族蛋白酪氨酸激酶的这种复合物需要GPI锚，并提示了一种通过GPI锚定膜蛋白进行信号传导的途径。
Decay-accelerating factor (DAF or CD55) is a 70-kDa glycosyl-phosphatidylinositol (GPI)-anchored protein that protects cells from complement-mediated lysis by either preventing the formation of or dissociating C3 convertases. Cross-linking of DAF on human peripheral T cells by polyclonal antibodies has previously been reported to lead to lymphocyte proliferation. Two mAb, both mapping to the third short consensus repeat region of DAF, were able to trigger proliferation of human peripheral T cells. To determine the role of the GPI anchor in cell activation, we transfected EL-4 murine thymoma cells with cDNA encoding either DAF or a transmembrane form of DAF (DAF-TM). The DAF-transfected cells were able to transduce late activation events as evidenced by IL-2 production, whereas DAF-TM transfected cells were unable to do so. The GPI-anchored DAF was able to transduce early activation events leading to the tyrosine phosphorylation of a 40-kDa protein and several proteins in the 85-95 kDa range--an event absent in DAF-TM-transfected cells. Furthermore, anti-DAF immunoprecipitates of DAF-transfected cells contain tyrosine kinase activity leading to the phosphorylation of 40-, 56-60-, and 85-kDa proteins, whereas anti-DAF immunoprecipitates of DAF-TM-transfected cells did not have an associated kinase activity. Both p56lck and p59fyn were associated with DAF in DAF-transfected EL-4 cells. In HeLa cells transfected with fyn, DAF associated with p59fyn. This complex of DAF with src family protein tyrosine kinases requires the GPI anchor and suggests a pathway for signaling through GPI-anchored membrane proteins.