Autophagy is initiated by the formation of a phagophore assembly site (PAS), the precursor of autophagosomes. In mammals, autophagosome formation sites form throughout the cytosol in specialized subdomains of the endoplasmic reticulum (ER). In yeast, the PAS is also generated close to the ER, but always in the vicinity of the vacuole. How the PAS is anchored to the vacuole and the functional significance of this localization are unknown. Here, we investigated the role of the PAS-vacuole connection for bulk autophagy in the yeast Saccharomyces cerevisiae We show that Vac8 constitutes a vacuolar tether that stably anchors the PAS to the vacuole throughout autophagosome biogenesis via the PAS component Atg13. S. cerevisiae lacking Vac8 show inefficient autophagosome-vacuole fusion, and form fewer and smaller autophagosomes that often localize away from the vacuole. Thus, the stable PAS-vacuole connection established by Vac8 creates a confined space for autophagosome biogenesis between the ER and the vacuole, and allows spatial coordination of autophagosome formation and autophagosome-vacuole fusion. These findings reveal that the spatial regulation of autophagosome formation at the vacuole is required for efficient bulk autophagy.

中文翻译：

---

Vac8 在空间上限制了酿酒酵母液泡中的自噬体形成。

自噬由吞噬细胞组装位点 (PAS) 的形成启动，该位点是自噬体的前体。在哺乳动物中，自噬体形成位点在内质网 (ER) 的专门亚域中的整个细胞质中形成。在酵母中，PAS 也在 ER 附近产生，但总是在液泡附近。PAS 如何锚定到液泡以及这种定位的功能意义尚不清楚。在这里，我们研究了 PAS-液泡连接在酵母酿酒酵母中大量自噬中的作用我们表明 Vac8 构成了一个液泡系绳，它通过 PAS 成分 Atg13 在整个自噬体生物发生过程中将 PAS 稳定地锚定在液泡上。缺乏 Vac8 的酿酒酵母显示自噬体-液泡融合效率低下，并形成更少和更小的自噬体，这些自噬体通常远离液泡。因此，Vac8 建立的稳定的 PAS-液泡连接为 ER 和液泡之间的自噬体生物发生创造了一个密闭空间，并允许自噬体形成和自噬体-液泡融合的空间协调。这些发现表明，有效的大量自噬需要液泡中自噬体形成的空间调节。