Apoptosis is characterized by the destruction of essential cell organelles, including the cell nucleus. The nuclear envelope (NE) separates the nuclear interior from the cytosol. During apoptosis, the apoptotic machinery, in particular caspases, increases NE permeability by cleaving its proteins, such as those of the nuclear pore complex (NPC) and the nuclear lamina. This in turns leads to passive diffusion of cytosolic apoptogenic proteins, such as caspases and nucleases, through NPCs into the nucleus and the subsequent breakdown of the NE and destruction of the nucleus. However, NE leakiness at early stages of the apoptotic process can also occur in a caspase-independent manner, where Bax, by a non-canonical action, promotes transient and repetitive localized generation and subsequent rupture of nuclear protein-filled nuclear bubbles. This NE rupture leads to discharge of apoptogenic nuclear proteins from the nucleus to the cytosol, a process that can contribute to the death process. Therefore, the NE may play a role as mediator of cell death at early stages of apoptosis. The NE can also serve as a platform for assembly of complexes that regulate the death process. Thus, the NE should be viewed as both a mediator of the cell death process and a target.

中文翻译：

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核膜：细胞凋亡过程的靶标和介质。

细胞凋亡的特征是基本细胞器（包括细胞核）的破坏。核膜 (NE) 将核内部与胞质溶胶分开。在细胞凋亡过程中，细胞凋亡机制，特别是半胱天冬酶，通过裂解其蛋白质（例如核孔复合物 (NPC) 和核纤层的蛋白质）来增加 NE 通透性。这反过来导致胞质凋亡蛋白（例如半胱天冬酶和核酸酶）通过 NPC 被动扩散到细胞核中，并随后导致 NE 分解和细胞核遭到破坏。然而，细胞凋亡过程早期阶段的 NE 泄漏也可能以不依赖 caspase 的方式发生，其中 Bax 通过非典型作用促进瞬时和重复的局部生成以及随后充满核蛋白的核气泡的破裂。这种 NE 破裂导致凋亡核蛋白从细胞核释放到细胞质中，这一过程可能导致死亡过程。因此，NE可能在细胞凋亡早期发挥细胞死亡介质的作用。NE 还可以作为调节死亡过程的复合物组装的平台。因此，NE 应被视为细胞死亡过程的介质和靶标。