Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
Autophagy. 2021 Jul;17(7):1636-1648. doi: 10.1080/15548627.2020.1776474. Epub 2020 Jun 17.
Macroautophagy/autophagy is a key catabolic process in which different cellular components are sequestered inside double-membrane vesicles called autophagosomes for subsequent degradation. In yeast, autophagosome formation occurs at the phagophore assembly site (PAS), a specific perivacuolar location that works as an organizing center for the recruitment of different autophagy-related (Atg) proteins. How the PAS is localized to the vacuolar periphery is not well understood. Here we show that the vacuolar membrane protein Vac8 is required for correct vacuolar localization of the PAS. We provide evidence that Vac8 anchors the PAS to the vacuolar membrane by binding Atg13 and recruiting the Atg1 initiation complex. deletion or mislocalization of the protein reduce autophagy activity, highlighting the importance of both the PAS and the correct vacuolar localization of the Atg1 initiation complex for efficient and robust autophagy. AID: auxin-inducible degradation; Atg: autophagy-related; Cvt: cytoplasm-to-vacuole targeting; DMSO: dimethyl sulfoxide; ER: endoplasmic reticulum; GFP: green fluorescent protein; IAA: 3-indole acetic acid; PAS: phagophore assembly site; RFP: red fluorescent protein.
自噬是一种关键的分解代谢过程，其中不同的细胞成分被隔离在称为自噬体的双层膜泡内，随后被降解。在酵母中，自噬体的形成发生在吞噬体组装位点（PAS），这是一个特殊的液泡周质位置，作为招募不同自噬相关（Atg）蛋白的组织中心。PAS 如何定位于液泡周围还不是很清楚。在这里，我们表明液泡膜蛋白 Vac8 是 PAS 正确液泡定位所必需的。我们提供的证据表明，Vac8 通过结合 Atg13 并募集 Atg1 起始复合物将 PAS 锚定在液泡膜上。该蛋白的缺失或定位错误会降低自噬活性，这突出了 PAS 和 Atg1 起始复合物在液泡中的正确定位对于高效和强大的自噬的重要性。AID：生长素诱导降解；Atg：自噬相关；Cvt：细胞质到液泡靶向；DMSO：二甲基亚砜；ER：内质网；GFP：绿色荧光蛋白；IAA：吲哚乙酸；PAS：吞噬体组装位点；RFP：红色荧光蛋白。
