Cell turnover is a fundamental feature in metazoans. Cells can die passively, as a consequence of severe damage to their structural integrity, or actively, owing to a more confined biological disruption such as DNA damage. Passive cell death is uncontrolled and often harmful to the organism. In contrast, active cell death is tightly regulated and serves to support the organism's life. Apoptosis-the primary form of regulated cell death-is relatively well defined. Necroptosis-an alternative, distinct kind of regulated cell death discovered more recently-is less well understood. Apoptosis and necroptosis can be triggered either from within the cell or by extracellular stimuli. Certain signaling components, including several death ligands and receptors, can regulate both processes. Whereas apoptosis is triggered and executed via intracellular proteases called caspases, necroptosis is suppressed by caspase activity. Here we highlight current understanding of the key signaling mechanisms that control regulated cell death.

中文翻译：

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受调控的细胞死亡：信号和机制。

细胞更新是后生动物的一个基本特征。细胞可以被动死亡，因为其结构完整性受到严重破坏，或者由于更有限的生物破坏（如 DNA 损伤）而主动死亡。被动细胞死亡是不受控制的，通常对生物体有害。相比之下，主动细胞死亡受到严格监管，并用于支持生物体的生命。细胞凋亡——受调节的细胞死亡的主要形式——相对明确。坏死性凋亡——一种最近发现的另一种独特的受调节细胞死亡——人们不太了解。细胞凋亡和坏死性凋亡可以从细胞内或由细胞外刺激触发。某些信号成分，包括几个死亡配体和受体，可以调节这两个过程。细胞凋亡是通过称为 caspase 的细胞内蛋白酶触发和执行的，而坏死性凋亡则被 caspase 活性抑制。在这里，我们强调目前对控制调节细胞死亡的关键信号机制的理解。