Membrane perturbation by lipidated Atg8 underlies autophagosome biogenesis
Membrane perturbation by lipidated Atg8 underlies autophagosome biogenesis
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DOI：
10.1038/s41594-021-00614-5
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发表时间：
2021-07-08
影响因子：
16.8
通讯作者：
Noda, Nobuo N.
中科院分区：
文献类型：
--
作者：
Maruyama, Tatsuro;Alam, Jahangir Md.;Noda, Nobuo N.
自噬体的生物合成是自噬的一个基本特征。Atg 8的脂化在这一过程中起着关键作用。先前的体外研究确定了Atg 8的膜束缚和半融合/融合活性，但在自噬体生物发生中的决定性作用仍然存在争议。在这里，我们研究了Atg 8脂质化对膜结构的影响。非球形巨囊泡上的酿酒酵母Atg 8的脂化诱导囊泡急剧变形成具有外芽的球形。溶液NMR光谱的Atg 8脂化nanodisks确定了两个芳香族膜面临的残基，介导膜面积扩大和破碎的巨大囊泡在体外。这些残基也有助于在裂变酵母中，Atg 8的兼职功能的应力下的片段化液泡形态的体内维持。此外，这些芳香残基对于形成足够数量的自噬体和调节自噬体大小至关重要。总之，这些数据表明Atg 8可以引起膜扰动，从而构成高效自噬体生物发生的基础。脂化Atg 8通过两个芳香族面向膜的残基影响膜形态，这对芽殖酵母和哺乳动物细胞的自噬很重要。
Autophagosome biogenesis is an essential feature of autophagy. Lipidation of Atg8 plays a critical role in this process. Previous in vitro studies identified membrane tethering and hemi-fusion/fusion activities of Atg8, yet definitive roles in autophagosome biogenesis remained controversial. Here, we studied the effect of Atg8 lipidation on membrane structure. Lipidation of Saccharomyces cerevisiae Atg8 on nonspherical giant vesicles induced dramatic vesicle deformation into a sphere with an out-bud. Solution NMR spectroscopy of Atg8 lipidated on nanodiscs identified two aromatic membrane-facing residues that mediate membrane-area expansion and fragmentation of giant vesicles in vitro. These residues also contribute to the in vivo maintenance of fragmented vacuolar morphology under stress in fission yeast, a moonlighting function of Atg8. Furthermore, these aromatic residues are crucial for the formation of a sufficient number of autophagosomes and regulate autophagosome size. Together, these data demonstrate that Atg8 can cause membrane perturbations that underlie efficient autophagosome biogenesis.Lipidated Atg8 affects membrane morphology via two aromatic membrane-facing residues that are important for autophagy in budding yeast and mammalian cells.