Granzyme a Pathway of CTL-Mediated Cell Death

颗粒酶是 CTL 介导的细胞死亡的途径

• 批准号: 7254918
• 负责人: Judy Lieberman
• 金额: $ 54.3万
• 依托单位: IMMUNE DISEASE INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7254918
• 关键词: Apoptosis; Apoptotic; Bacteria; Base Excision Repairs; Binding; Caspase; Cell Death; Cell membrane; Cell physiology; Cells; Cleaved cell; Complex; Cytolysis; Cytoplasmic Granules; Cytotoxic T-Lymphocytes; DNA; DNA Damage; DNA Repair Pathway; DNA-(apurinic or apyrimidinic site) lyase; Decompression Sickness; Deoxyribonuclease I; Deoxyribonucleases; Effector Cell; Endoplasmic Reticulum; Excision; Exocytosis; Funding; Goals; Grant; Granzyme; HMGB2 Protein; Histones; Human; Immune response; Killer Cells; Kinetics; Lamin Type B; Lamins; Lymphocyte Activation; Mediating; Mitochondria; Morphology; Mus; NME1 gene; Natural Killer Cells; Nuclear Envelope; Nucleosomes; Pathway interactions; Protein Overexpression; Protein phosphatase; Proteins; Proteoglycan; Rattus; Research; Role; Serine Protease; T-Lymphocyte; T-Lymphocyte and Natural Killer Cell; Transfection; Tumor Suppressor Proteins; Virus; Virus Diseases; Work; base; cytotoxic; granzyme A; granzyme B; immunological synapse; inhibitor/antagonist; novel; perforin; phosphoprotein 32; porin; repaired; research study; trafficking; tumor

DESCRIPTION (provided by applicant): Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells exocytose cytotoxic granules to induce apoptosis of virally infected or tumor targets. Cytotoxic granules contain perforin, a pore-forming protein, and a group of serine proteases, called granzymes (Gzm), in a proteoglycan matrix. Perforin and either GzmA or GzmB is sufficient for granule-mediated lysis by CTL, but mice deficient in either Gzm may be impaired in defense against some viral infections. GzmB activates a ubiquitous apoptotic cascade induced by cleavage of caspases and can also directly cleave some key caspase pathway substrates. However, CTL granule mediated cytolysis is virtually unimpaired in the setting of complete caspase blockade. GzmA, the most abundant Gzm, activates a novel caspase-independent apoptotic pathway. The goal of this proposal is to continue to unravel the mechanism of action of GzmA, building on the research accomplished during the previous funding. GzmA, delivered into target cells via perforin, induces single-stranded DNA damage as Nell as apoptotic morphology and loss of cell membrane integrity. A special target of the GzmA cell death pathway is a 270-440 kDa endoplasmic reticulum-associated complex, called the SET complex, which contains three GzmA substrates, the nucleosome assembly protein SET, the DNA bending protein HMG-2 and the apurinic endonuclease (Ape1) in base excision repair (BER). GzmA cleavage of Ape1 makes target cell repair of GzmA-induced damage unlikely. The SET complex also contains the GzmA-activated DNase, NM23-H1, which is activated when GzmA cleaves its specific inhibitor, the SET protein. The competing renewal of this grant will investigate the kinetics of GzmA-mediated damage within target cells; determine the mitochondrial effects of GzmA; identify the remaining components of the SET complex and seek to understand further the role of the SET complex in normal cellular function and in GzmA-mediated cell death; and investigate the effect of GzmA on other DNA repair pathways, besides BER.

描述（由申请方提供）：细胞毒性T淋巴细胞（CTL）和自然杀伤（NK）细胞外排细胞毒性颗粒，诱导病毒感染或肿瘤靶细胞凋亡。细胞毒性颗粒在蛋白多糖基质中含有穿孔素（一种成孔蛋白）和一组丝氨酸蛋白酶（称为颗粒酶（Gzm））。穿孔蛋白和GzmA或GzmB足以通过CTL进行颗粒介导的裂解，但Gzm缺陷的小鼠可能在防御某些病毒感染方面受损。GzmB激活由半胱天冬酶切割诱导的普遍存在的凋亡级联，并且还可以直接切割一些关键的半胱天冬酶途径底物。然而，CTL颗粒介导的细胞溶解在完全半胱天冬酶阻断的情况下几乎不受损害。GzmA是最丰富的Gzm，激活一种新的非半胱天冬酶依赖性凋亡途径。该提案的目标是在先前资助期间完成的研究的基础上，继续揭示GzmA的作用机制。GzmA通过穿孔素进入靶细胞，诱导单链DNA损伤，如Nell的凋亡形态和细胞膜完整性丧失。GzmA细胞死亡的特殊靶点 GzmA通路是一个270-440 kDa的内质网相关复合物，称为SET复合物，它包含三种GzmA底物，即核小体组装蛋白SET、DNA弯曲蛋白HMG-2和碱基切除修复（BER）中的脱嘌呤核酸内切酶（Ape 1）。GzmA切割Ape 1使得靶细胞不太可能修复GzmA诱导的损伤。SET复合物还含有GzmA激活的DNA酶，NM 23-H1，当GzmA切割其特异性抑制剂SET蛋白时，其被激活。这项资助的竞争性更新将研究靶细胞内GzmA介导的损伤动力学;确定GzmA的线粒体效应;确定SET复合物的剩余组分，并寻求进一步了解SET复合物在正常细胞功能和GzmA介导的细胞死亡中的作用;并研究GzmA对BER以外的其他DNA修复途径的影响。