Hayashi-Nishino Mitsuko, Fujita Naonobu, Noda Takeshi, Yamaguchi Akihito, Yoshimori Tamotsu, Yamamoto Akitsugu
Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
Nat Cell Biol. 2009 Dec;11(12):1433-7. doi: 10.1038/ncb1991. Epub 2009 Nov 8.
Autophagy is a bulk degradation process in eukaryotic cells and has fundamental roles in cellular homeostasis.The origin and source of autophagosomal membranes are long-standing questions in the field. Using electron microscopy, we show that, in mammalian culture cells, the endoplasmic reticulum (ER) associates with early autophagic structures called isolation membranes (IMs). Overexpression of an Atg4B mutant, which causes defects in autophagosome formation, induces the accumulation of ER-IM complexes. Electron tomography revealed that the ER-IM complex appears as a subdomain of the ER that formed a cradle encircling the IM, and showed that both ER and isolation membranes are interconnected.
自噬是真核细胞中的一种大量降解过程，在细胞内稳态中具有重要作用。自噬体膜的起源和来源是该领域长期存在的问题。通过电子显微镜，我们发现，在哺乳动物培养细胞中，内质网（ER）与称为隔离膜（IMs）的早期自噬结构相关联。导致自噬体形成缺陷的Atg4B突变体的过表达会诱导内质网-隔离膜复合物的积累。电子断层扫描显示，内质网-隔离膜复合物表现为内质网的一个亚结构域，形成一个环绕隔离膜的支架，并表明内质网和隔离膜是相互连接的。
