National Institute of Biological Sciences , Beijing, China.
Autophagy. 2020 Nov;16(11):2112-2113. doi: 10.1080/15548627.2020.1816665. Epub 2020 Sep 5.
The endoplasmic reticulum (ER) is a major site of protein folding. Perturbations in the folding capacity of the ER result in ER stress. ER stress triggers autophagic degradation of the ER (reticulophagy). Molecular mechanisms underlying ER stress-induced reticulophagy remain largely unknown. Our recent study identified a soluble protein, Epr1, as an autophagy receptor for ER stress-induced reticulophagy in the fission yeast . Epr1 can interact simultaneously with Atg8 and a VAP family integral ER membrane protein, and thereby act as a bridging molecule between them. VAP family proteins contribute to reticulophagy by not only connecting Atg8 to the ER membrane through Epr1, but also by supporting the ER-plasma membrane contact. The expression of Epr1 is upregulated during ER stress in a manner dependent on the unfolded protein response (UPR) regulator Ire1. Ire1 promotes reticulophagy by upregulating Epr1.
内质网（ER）是蛋白质折叠的主要场所。ER 折叠能力的破坏会导致 ER 应激。ER 应激会触发 ER 的自噬降解（网质体自噬）。ER 应激诱导的网质体自噬的分子机制在很大程度上仍然未知。我们最近的研究在裂殖酵母中发现了一种可溶性蛋白 Epr1，它是 ER 应激诱导的网质体自噬的自噬受体。Epr1 可以同时与 Atg8 和 VAP 家族整合的 ER 膜蛋白相互作用，从而充当它们之间的桥接分子。VAP 家族蛋白通过 Epr1 将 Atg8 连接到 ER 膜上，同时支持 ER-质膜接触，从而有助于网质体自噬。Epr1 的表达在 ER 应激过程中上调，这种上调方式依赖于未折叠蛋白反应（UPR）调节剂 Ire1。Ire1 通过上调 Epr1 促进网质体自噬。
