CCL5-CCR5-mediated apoptosis in T cells - Requirement for glycosaminoglycan binding and CCL5 aggregation
CCL5-CCR5-mediated apoptosis in T cells - Requirement for glycosaminoglycan binding and CCL5 aggregation
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DOI：
10.1074/jbc.m603912200
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Fish, Eleanor N.
中科院分区：
文献类型：
--
作者：
Murooka, Thomas T.;Wong, Mark M.;Fish, Eleanor N.
CCL 5（RANTES（调节正常T细胞表达和分泌的活化））及其同源受体CCR 5已经涉及T细胞活化。CCL 5与细胞表面或细胞外基质中的糖胺聚糖（GAG）结合螯合CCL 5，从而固定CCL 5以提供定向信号。在两个表达CCR 5的人T细胞系中，PM 1.在人外周血来源的T细胞中，微摩尔浓度的CCL 5诱导细胞凋亡。CCL 5诱导的细胞死亡涉及细胞色素c的胞质释放、半胱天冬酶-9和半胱天冬酶-3的活化以及聚（ADP-核糖）聚合酶裂解。CCL 5诱导的细胞凋亡是CCR 5依赖性的，因为缺乏CCR 5表达的天然PM 1和MOLT 4细胞对CCL 5诱导的细胞死亡具有抗性。此外，我们牵连酪氨酸339作为一个关键的残基参与CCL 5诱导的细胞凋亡，因为PM 1细胞表达的酪氨酸突变体受体，CCR 5 Y339 F，不经历凋亡。我们发现CCL 5-CCR 5介导的凋亡依赖于细胞表面GAG结合。加入外源性肝素和硫酸软骨素以及从细胞表面消化GAG可保护细胞免于凋亡。此外，非GAG结合变体（44 AANA 47）-CCL 5不能诱导细胞凋亡。为了说明聚集在CCL 5介导的细胞凋亡中的作用，利用了在微摩尔浓度下形成二聚体的非聚集性CCL 5突变体E66 S和形成四聚体的E26 A。与天然CCL 5不同，E66 S突变体不能诱导细胞凋亡，这表明四聚体是CCL 5诱导细胞凋亡所需的最小的高阶CCL 5聚集体。总之，这些数据表明，CCL 5-GAG结合和CCL 5聚集对于T细胞中的CCL 5活性是重要的，特别是在CCR 5介导的细胞凋亡的背景下。
CCL5 (RANTES (regulated on activation normal T cell expressed and secreted)) and its cognate receptor, CCR5, have been implicated in T cell activation. CCL5 binding to glycosaminoglycans (GAGs) on the cell surface or in extracellular matrix sequesters CCL5, thereby immobilizing CCL5 to provide the directional signal. In two CCR5-expressing human T cell lines, PM1. CCR5 and MOLT4.CCR5, and in human peripheral blood-derived T cells, micromolar concentrations of CCL5 induce apoptosis. CCL5-induced cell death involves the cytosolic release of cytochrome c, the activation of caspase-9 and caspase-3, and poly(ADP-ribose) polymerase cleavage. CCL5-induced apoptosis is CCR5-dependent, since native PM1 and MOLT4 cells lacking CCR5 expression are resistant to CCL5-induced cell death. Furthermore, we implicate tyrosine 339 as a critical residue involved in CCL5-induced apoptosis, since PM1 cells expressing a tyrosine mutant receptor, CCR5Y339F, do not undergo apoptosis. We show that CCL5-CCR5-mediated apoptosis is dependent on cell surface GAG binding. The addition of exogenous heparin and chondroitin sulfate and GAG digestion from the cell surface protect cells from apoptosis. Moreover, the non-GAG binding variant, (44AANA47)-CCL5, fails to induce apoptosis. To address the role of aggregation in CCL5-mediated apoptosis, nonaggregating CCL5 mutant E66S, which forms dimers, and E26A, which form tetramers at micromolar concentrations, were utilized. Unlike native CCL5, the E66S mutant fails to induce apoptosis, suggesting that tetramers are the minimal higher ordered CCL5 aggregates required for CCL5-induced apoptosis. Viewed altogether, these data suggest that CCL5-GAG binding and CCL5 aggregation are important for CCL5 activity in T cells, specifically in the context of CCR5-mediated apoptosis.