title: Degradation of the endoplasmic reticulum by autophagy during endoplasmic reticulum stress in Arabidopsis.
abstract: In this article, we show that the endoplasmic reticulum (ER) in Arabidopsis thaliana undergoes morphological changes in structure during ER stress that can be attributed to autophagy. ER stress agents trigger autophagy as demonstrated by increased production of autophagosomes. In response to ER stress, a soluble ER marker localizes to autophagosomes and accumulates in the vacuole upon inhibition of vacuolar proteases. Membrane lamellae decorated with ribosomes were observed inside autophagic bodies, demonstrating that portions of the ER are delivered to the vacuole by autophagy during ER stress. In addition, an ER stress sensor, INOSITOL-REQUIRING ENZYME-1b (IRE1b), was found to be required for ER stress-induced autophagy. However, the IRE1b splicing target, bZIP60, did not seem to be involved, suggesting the existence of an undiscovered signaling pathway to regulate ER stress-induced autophagy in plants. Together, these results suggest that autophagy serves as a pathway for the turnover of ER membrane and its contents in response to ER stress in plants.
authors.affiliation: Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Yimo
authors.initials: Y
authors.lastname: Liu
authors.forename: Junmarie Soto
authors.initials: JS
authors.lastname: Burgos
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Renu
authors.initials: R
authors.lastname: Srivastava
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Howell
authors.forename: Diane C
authors.initials: DC
authors.lastname: Bassham
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D001692:Biological Transport; D004721:Endoplasmic Reticulum / Q000502:physiology*; D059865:Endoplasmic Reticulum Stress; D016254:Mutagenesis, Insertional; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D036226:Seedlings / Q000235:genetics / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D015398:Signal Transduction; D014617:Vacuoles / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; D011494:Protein Kinases; C446527:Ire1-1 protein, Arabidopsis