通过工程小分子激活蛋白酶激活特定的亡性卡斯帕斯
Daniel C Gray1, Sami Mahrus, James A Wells
1Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
Cell
|August 21, 2010
概括
研究人员开发了一种选择性激活酶的新方法,揭示了酶-3或-7的激活会诱导亡. 他们还发现caspases分裂蛋白酶子单元,这表明癌症治疗的联合疗法.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 细胞亡是一个由caspases调节的关键细胞过程.
- 了解执行者酶 (酶-3, -6, -7) 的特定作用对于控制细胞死亡至关重要.
- 卡斯帕和蛋白质酶在亡中的相互作用尚未完全阐明.
研究的目的:
- 为了研究在亡过程中子手卡斯帕斯的非冗余功能.
- 在人类细胞中开发一种用于选择性酶异型激活的新系统.
- 探索酶活性与蛋白质酶功能之间的关系.
主要方法:
- 开发一个分裂的烟草蚀刻病毒 (TEV) 蛋白酶系统 (SNIPer) 用于控制的,异型特异的酶激活.
- 基因编码TEV分离点的基因编码为caspase等位基因,用于正交激活.
- 蛋白质组分析以确定26S蛋白质组内的酶基质.
- 评估蛋白质酶抑制和酶激活的协同效应.
主要成果:
- 使用SNIPer系统实现了酶-3,-6和-7的选择性激活.
- 观察到所有三种卡斯帕斯的暂时激活.
- 在激活caspase-3或caspase-7时特别诱导了亡.
- 在26S蛋白质组的33个子单元中,有20个被确定为卡斯帕斯分裂部位.
- 证明了蛋白酶抑制和剂量依赖的酶激活之间的协同效应.
结论:
- -3和-7足以驱动亡,突出显示它们的不同作用.
- 卡斯帕斯可以直接准和分裂蛋白质酶子单元,这表明蛋白质分解的相互负调节.
- 这些发现对开发使用蛋白酶体抑制剂和亲亡药物的联合疗法具有重要意义.
相关概念视频
Caspases
Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
The Extrinsic Apoptotic Pathway
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
Autophagic Cell Death
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Phagocytosis of Apoptotic Cells
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.


