The mechanisms underlying turnover of the nuclear pore complex (NPC) and the component nucleoporins (Nups) are still poorly understood. In this study, we found that the budding yeast Saccharomyces cerevisiae triggers NPC degradation by autophagy upon the inactivation of Tor kinase complex 1. This degradation largely depends on the selective autophagy-specific factor Atg11 and the autophagy receptor–binding ability of Atg8, suggesting that the NPC is degraded via receptor-dependent selective autophagy. Immunoelectron microscopy revealed that NPCs embedded in nuclear envelope–derived double-membrane vesicles are sequestered within autophagosomes. At least two pathways are involved in NPC degradation: Atg39-dependent nucleophagy (selective autophagy of the nucleus) and a pathway involving an unknown receptor. In addition, we found the interaction between Nup159 and Atg8 via the Atg8-family interacting motif is important for degradation of this nucleoporin not assembled into the NPC. Thus, this study provides the first evidence for autophagic degradation of the NPC and Nups, which we term “NPC-phagy” and “nucleoporinophagy.”

中文翻译：

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TORC1 失活刺激核孔蛋白和核孔复合物的自噬

核孔复合物（NPC）和核孔蛋白（Nups）成分的转换机制仍然知之甚少。在这项研究中，我们发现出芽酵母酿酒酵母在 Tor 激酶复合物 1 失活后通过自噬触发 NPC 降解。这种降解很大程度上取决于选择性自噬特异性因子 Atg11 和 Atg8 的自噬受体结合能力，这表明NPC 通过受体依赖性选择性自噬被降解。免疫电镜显示，嵌入核膜来源的双膜囊泡中的 NPC 被隔离在自噬体内。NPC 降解至少涉及两条途径：Atg39 依赖性核自噬（细胞核的选择性自噬）和涉及未知受体的途径。此外，我们发现 Nup159 和 Atg8 之间通过 Atg8 家族相互作用基序的相互作用对于未组装到 NPC 中的核孔蛋白的降解非常重要。因此，这项研究为 NPC 和 Nups 的自噬降解提供了第一个证据，我们将其称为“NPC 吞噬”和“核孔道吞噬”。