Tanaka M, Suda T, Takahashi T, Nagata S
Osaka Bioscience Institute, Japan.
EMBO J. 1995 Mar 15;14(6):1129-35. doi: 10.1002/j.1460-2075.1995.tb07096.x.
Fas is a type I membrane protein which mediates apoptosis. Fas ligand (FasL) is a 40 kDa type II membrane protein expressed in cytotoxic T cells upon activation that belongs to the tumor necrosis factor (TNF) family. Here, we found abundant cytotoxic activity against Fas-expressing cells in the supernatant of COS cells transfected with human FasL cDNA but not with murine FasL cDNA. Using a specific polyclonal antibody against a peptide in the extracellular region of human FasL, a protein of 26 kDa was detected in the supernatant of the COS cells. The signal sequence of granulocyte colony-stimulating factor was attached to the extracellular region of human FasL. COS cells transfected with the cDNA coding for the chimeric protein efficiently secreted the active soluble form of human FasL (sFasL). Chemical crosslinking and gel filtration analysis suggested that human sFasL exists as a trimer. Human peripheral T cells activated with phorbol myristic acetate and ionomycin also produced functional sFasL, suggesting that human sFasL works as a pathological agent in systemic tissue injury.
Fas是一种介导细胞凋亡的I型膜蛋白。Fas配体（FasL）是一种40 kDa的II型膜蛋白，在细胞毒性T细胞激活后表达，属于肿瘤坏死因子（TNF）家族。在此，我们发现在转染了人FasL cDNA而非鼠FasL cDNA的COS细胞上清液中，对表达Fas的细胞具有丰富的细胞毒性活性。使用针对人FasL细胞外区域肽段的特异性多克隆抗体，在COS细胞上清液中检测到一种26 kDa的蛋白质。粒细胞集落刺激因子的信号序列连接到人FasL的细胞外区域。转染了编码嵌合蛋白cDNA的COS细胞有效地分泌了人FasL的活性可溶性形式（sFasL）。化学交联和凝胶过滤分析表明人sFasL以三聚体形式存在。用佛波酯肉豆蔻酸酯和离子霉素激活的人外周血T细胞也产生功能性sFasL，表明人sFasL在系统性组织损伤中作为一种病理因子发挥作用。
