Granzyme A loading induces rapid cytolysis and a novel form of DNA damage independently of caspase activation
Granzyme A loading induces rapid cytolysis and a novel form of DNA damage independently of caspase activation
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DOI：
10.1016/s1074-7613(00)80058-8
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发表时间：
1999-05-01
期刊：
影响因子：
32.4
通讯作者：
Lieberman, J
中科院分区：
文献类型：
--
作者：
Beresford, PJ;Xia, ZN;Lieberman, J
细胞毒性淋巴细胞通过释放穿孔素和颗粒酶(Grn)来启动细胞凋亡。GrnB激活caspase凋亡途径，但对gRNA诱导的细胞死亡知之甚少。用穿孔素将重组gRNA、GrnB和酶失活变异体装载到靶细胞中。GRNA诱导单链DNA断裂，可以用Klenow聚合酶标记并在碱性凝胶上显示。GRNA引起的DNA损伤而不是细胞溶解需要gRNA蛋白降解。半胱氨酸天冬氨酸氨基转移酶的阻断不影响gRNA诱导的膜扰动、核浓缩和DNA损伤。GRNA不能诱导caspase-3、lamin B、Rho-GTPase或PARP的切割。在过表达bcl2的Jurkat细胞中，gRNA诱导的细胞毒性和Phap II(先前发现的gRNA底物)的切割没有受到损害。因此，gRNA激活了一条新的细胞凋亡途径。
Cytotoxic lymphocytes trigger apoptosis by releasing perforin and granzymes (Grn). GrnB activates the caspase apoptotic pathway, but little is known about GrnA-induced cell death. Perforin was used to load recombinant GrnA and GrnB and enzymatically inactive variants into target cells. GrnA induces single-strand DNA breaks that can be labeled with Klenow polymerase and visualized on alkaline gels. GrnA-induced DNA damage but not cytolysis requires GrnA proteolysis. GrnA-induced membrane perturbation, nuclear condensation, and DNA damage are unimpaired by caspase blockade. GrnA fails to induce cleavage of caspase-3, lamin B, rho-GTPase, or PARP. GrnA-induced cytotoxicity and cleavage of PHAP II, a previously identified GrnA substrate, are unimpaired in Jurkat cells that overexpress bcl-2. Therefore, GrnA activates a novel apoptotic pathway.