Autophagy is a process in which a myriad membrane structures called autophagosomes are formed de novo in a single cell, which deliver the engulfed substrates into lysosomes for degradation. The size of the autophagosomes is relatively uniform in non-selective autophagy and variable in selective autophagy. It has been recently established that autophagosome formation occurs near the endoplasmic reticulum (ER). In this review, we have discussed recent advances in the relationship between autophagosome formation and endoplasmic reticulum. Autophagosome formation occurs near the ER subdomain enriched with phospholipid synthesizing enzymes like phosphatidylinositol synthase (PIS)/CDP-diacylglycerol-inositol 3-phosphatidyltransferase (CDIPT) and choline/ethanolamine phosphotransferase 1 (CEPT1). Autophagy-related protein 2 (Atg2), which is involved in autophagosome formation has a lipid transfer capacity and is proposed to directly transfer the lipid molecules from the ER to form autophagosomes. Vacuole membrane protein 1 (VMP1) and transmembrane protein 41b (TMEM41b) are ER membrane proteins that are associated with the formation of the subdomain. Recently, we have reported that an uncharacterized ER membrane protein possessing the DNAJ domain, called ERdj8/DNAJC16, is associated with the regulation of the size of autophagosomes. The localization of ERdj8/DNAJC16 partially overlaps with the PIS-enriched ER subdomain, thereby implying its association with autophagosome size determination.

中文翻译：

---

自噬体形成与内质网的关系

自噬是在单个细胞中从头形成无数膜结构（称为自噬体）的过程，该过程将被吞噬的底物输送到溶酶体中进行降解。自噬体的大小在非选择性自噬中相对均匀，而在选择性自噬中则可变。最近已经确定自噬体形成在内质网（ER）附近。在这篇综述中，我们讨论了自噬体形成与内质网之间关系的最新进展。自噬体的形成发生在富含磷脂酰合成酶（如磷脂酰肌醇合酶（PIS）/ CDP-二甘油甘油-肌醇3-磷脂酰转移酶（CDIPT）和胆碱/乙醇胺磷酸转移酶1（CEPT1））的ER亚结构域附近。自噬相关蛋白2（Atg2），自噬体形成过程中涉及的脂质体具有脂质转移能力，并被提议直接从ER中转移脂质分子以形成自噬体。液泡膜蛋白1（VMP1）和跨膜蛋白41b（TMEM41b）是与亚结构域形成相关的ER膜蛋白。最近，我们已经报道了具有DNAJ结构域的未表征的ER膜蛋白，称为ERdj8 / DNAJC16，与自噬体大小的调节有关。ERdj8 / DNAJC16的本地化与PIS丰富的ER子域部分重叠，从而暗示其与自噬体大小确定的关联。液泡膜蛋白1（VMP1）和跨膜蛋白41b（TMEM41b）是与亚结构域形成相关的ER膜蛋白。最近，我们已经报道了具有DNAJ结构域的未表征的ER膜蛋白，称为ERdj8 / DNAJC16，与自噬体大小的调节有关。ERdj8 / DNAJC16的本地化与PIS丰富的ER子域部分重叠，从而暗示其与自噬体大小确定的关联。液泡膜蛋白1（VMP1）和跨膜蛋白41b（TMEM41b）是与亚结构域形成相关的ER膜蛋白。最近，我们已经报道了具有DNAJ结构域的未表征的ER膜蛋白，称为ERdj8 / DNAJC16，与自噬体大小的调节有关。ERdj8 / DNAJC16的本地化与PIS丰富的ER子域部分重叠，从而暗示其与自噬体大小确定的关联。