Auxin-induced rapid degradation of inhibitor of caspase-activated DNase (ICAD) induces apoptotic DNA fragmentation, caspase activation, and cell death: a cell suicide module.
Auxin-induced rapid degradation of inhibitor of caspase-activated DNase (ICAD) induces apoptotic DNA fragmentation, caspase activation, and cell death: a cell suicide module.
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DOI：
10.1074/jbc.m114.583542
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发表时间：
2014-11-07
期刊：
影响因子：
--
通讯作者：
Earnshaw WC
中科院分区：
文献类型：
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作者：
Samejima K;Ogawa H;Ageichik AV;Peterson KL;Kaufmann SH;Kanemaki MT;Earnshaw WC
背景：caspase激活的脱氧核糖核酸酶(caspase-active DNase，CAD)对细胞凋亡的调控和功能尚不清楚。结果：使用生长素诱导的降解系统快速耗尽CAD抑制物(ICAD)可诱导异位的CAD激活和细胞凋亡。结论：异位CAD激活通过正反馈环触发caspase激活和细胞凋亡。意义：受控的CAD与ICAD的分离是一种消除多余细胞的新方法。半胱氨酸天冬氨酸酶激活的DNA酶(CAD)是一种主要的凋亡核酸酶，在细胞凋亡过程中起DNA断裂和染色质凝聚的作用。由于其抑制分子伴侣ICAD的caspase裂解，CAD通常在细胞凋亡中被激活。人们对CAD监管的其他方面知之甚少。特别是，目前还不清楚在非凋亡活细胞中直接激活CAD是否会引发细胞死亡。利用生长素诱导降解系统(AID)，我们开发了一种自杀系统，通过该系统，ICAD在活细胞中迅速降解，以响应植物激素生长素。我们的研究表明，ICAD的快速耗尽足以激活CAD并诱导DT40和酵母细胞的细胞死亡。在脊椎动物细胞中，异位的CAD激活触发了caspase的激活，以及随后caspase依赖的凋亡变化的特征，包括磷脂酰丝氨酸暴露和核碎裂。这些观察结果不仅表明，CAD的激活通过正反馈回路驱动细胞凋亡，而且还识别了一种独特的自杀系统，可以用于控制基因修饰的生物体。
Background: Regulation and function of the apoptotic nuclease, caspase-activated DNase (CAD), remains obscure. Results: Rapid depletion of the CAD inhibitor (ICAD) using auxin-inducible degron system induces ectopic CAD activation and apoptosis. Conclusion: Ectopic CAD activation triggers caspase activation and apoptosis through a positive feedback loop. Significance: Controlled CAD dissociation from ICAD is applicable as a novel method to eliminate unwanted cells. Caspase-activated DNase (CAD) is a major apoptotic nuclease, responsible for DNA fragmentation and chromatin condensation during apoptosis. CAD is normally activated in apoptosis as a result of caspase cleavage of its inhibitory chaperone ICAD. Other aspects of CAD regulation are poorly understood. In particular, it has been unclear whether direct CAD activation in non-apoptotic living cells can trigger cell death. Taking advantage of the auxin-inducible degron (AID) system, we have developed a suicide system with which ICAD is rapidly degraded in living cells in response to the plant hormone auxin. Our studies demonstrate that rapid ICAD depletion is sufficient to activate CAD and induce cell death in DT40 and yeast cells. In the vertebrate cells, ectopic CAD activation triggered caspase activation and subsequent hallmarks of caspase-dependent apoptotic changes, including phosphatidylserine exposure and nuclear fragmentation. These observations not only suggest that CAD activation drives apoptosis through a positive feedback loop, but also identify a unique suicide system that can be used for controlling gene-modified organisms.