Molecular Mechanism of Granule-mediated Apoptosis

细胞毒性细胞颗粒介导的细胞凋亡是一种独特的细胞信号传导形式， 通过孔形成蛋白穿孔素递送颗粒相关丝氨酸蛋白酶（颗粒酶）。的 对颗粒分泌途径中遗传缺陷的鉴定已经清楚地确定了颗粒- 介导的细胞凋亡对于免疫稳态至关重要。获得性细胞毒性效应子功能破坏 被病毒蛋白质感染可能会引发淋巴细胞增殖和自身反应，并降低宿主的防御能力 响应能力。病毒感染的细胞或肿瘤细胞也可以通过抑制颗粒介导的细胞凋亡来抵抗颗粒介导的细胞凋亡。 这条路的任何方面。描述了这一鲜为人知的现象的多个步骤 对于理解许多疾病状态的免疫发病机制变得越来越重要。 为了理解穿孔素对颗粒酶的传递，需要对穿孔素的分子特性进行表征。 最接近的步骤-围绕这些结合，内化和早期贩运的事件 颗粒组分。颗粒酶B保持与颗粒相关的蛋白聚糖，sergylycin结合， 由细胞毒性细胞分泌。出乎意料的是，颗粒酶经历了来自serglycin的静电交换， 靶向细胞硫酸化糖胺聚糖，其随后促进与未定义的受体结合， 内化此外，颗粒酶似乎表现出膜溶解活性，如果足够的 实现内体浓缩。标题为穿孔蛋白-颗粒酶联合递送假说-两者 穿孔素和颗粒酶被预测从丝氨酸蛋白酶到细胞表面进行静电交换 并且一起有助于内体溶解递送过程。将先前的努力扩展到糖生物学， 颗粒酶B细胞表面相互作用，并强调成像技术，特别是新的方法， 直接可视化颗粒酶和穿孔素与靶细胞的相互作用，具体目的是： 1.研究丝甘肽向靶细胞表面转移颗粒酶B 2.穿孔素在颗粒酶传递中作用的分子分析 3.评估细胞毒性细胞介导的细胞毒性过程中靶细胞的质膜和内体完整性。 凋亡

Cytotoxic cell granule-mediated apoptosis is a unique form of cell signaling that entails the intracellular delivery of granule-associated serine proteases (granzymes) by the pore forming protein perforin. The identification of genetic defects in the granule secretion pathway have clearly established that granule- mediated apoptosis is crucial for immune homeostasis. Acquired disruption of cytotoxic cell effector function by viral proteins are likely to trigger lymphoproliferation and autoreactivity as well as diminish host defense responsiveness. A virus-infected or tumor cell may also resist granule mediated apoptosis by inhibiting virtually any aspect of this pathway. Delineating the multiple steps of this poorly understood phenomenon has become increasingly important to comprehend the immunopathogenesis of a number of disease states. To achieve an understanding of granzyme delivery by perforin requires molecular characterization of the most proximal steps - the events that surround the binding, internalization and early trafficking of these granule components. Granzyme B remains bound to the granule-associated proteoglycan, serglycin, after secretion by a cytotoxic cell. Unexpectedly, the granzyme undergoes electrostatic exchange from serglycin to target cell sulfated glycosaminoglycans which then facilitate binding to undefined receptor(s) for optimal internalization. In addition, the granzyme appears to manifest membranolytic activity if a sufficient endosomal concentration is achieved. Entitled the conjoined Perforin-Granzyme delivery hypothesis - both perforin and granzymes are predicted to undergo electrostatic exchange to the cell surface from serglycin and together contribute to endosomolytic delivery process. Extending previous efforts to the glycobiology of granzyme B-cell surface interactions and emphasizing imaging techniques, particularly new methods that directly visualize the interaction of the granzyme and perforin with target cells, the Specific Aims are: 1. Study the transfer of granzyme B from serglycin to the target cell surface 2. Ascertain role of perforin in granzyme delivery - a molecular analysis 3. Assess plasma membrane and endosomal integrity of the target cell during cytotoxic cell-mediated apoptosis