title: Electron tomography reveals the endoplasmic reticulum as a membrane source for autophagosome formation.
abstract: The origin and source of autophagosomal membranes are long-standing questions. By electron microscopy, we show that the endoplasmic reticulum (ER) associates with early autophagic structures called isolation membranes (IM) or phagophores in mammalian culture cells. Overexpression of a mutant of Atg4B, which causes defects in autophagosome formation, caused accumulation of ER-IM complexes. Electron tomography revealed the ER-IM complex as a subdomain of the ER forming a cradle encircling the IM, and showed that both ER and isolation membranes are interconnected.
authors.affiliation: Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Hayashi-Nishino
authors.forename: Naonobu
authors.initials: N
authors.lastname: Fujita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Noda
authors.forename: Akihito
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Yoshimori
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism; D055032:Electron Microscope Tomography; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D010588:Phagosomes / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D003546:Cysteine Endopeptidases