title: Receptor-mediated selective autophagy degrades the endoplasmic reticulum and the nucleus.
abstract: Macroautophagy (hereafter referred to as autophagy) degrades various intracellular constituents to regulate a wide range of cellular functions, and is also closely linked to several human diseases. In selective autophagy, receptor proteins recognize degradation targets and direct their sequestration by double-membrane vesicles called autophagosomes, which transport them into lysosomes or vacuoles. Although recent studies have shown that selective autophagy is involved in quality/quantity control of some organelles, including mitochondria and peroxisomes, it remains unclear how extensively it contributes to cellular organelle homeostasis. Here we describe selective autophagy of the endoplasmic reticulum (ER) and nucleus in the yeast Saccharomyces cerevisiae. We identify two novel proteins, Atg39 and Atg40, as receptors specific to these pathways. Atg39 localizes to the perinuclear ER (or the nuclear envelope) and induces autophagic sequestration of part of the nucleus. Atg40 is enriched in the cortical and cytoplasmic ER, and loads these ER subdomains into autophagosomes. Atg39-dependent autophagy of the perinuclear ER/nucleus is required for cell survival under nitrogen-deprivation conditions. Atg40 is probably the functional counterpart of FAM134B, an autophagy receptor for the ER in mammals that has been implicated in sensory neuropathy. Our results provide fundamental insight into the pathophysiological roles and mechanisms of 'ER-phagy' and 'nucleophagy' in other organisms.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mochida
authors.affiliation: Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Oikawa
authors.affiliation: Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: 1] Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8503, Japan [2] CREST, Japan Science and Technology Agency, Saitama 332-0012, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kirisako
authors.affiliation: Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hirano
authors.affiliation: Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ohsumi
authors.affiliation: 1] Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8503, Japan [2] CREST, Japan Science and Technology Agency, Saitama 332-0012, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakatogawa
mesh_terms: D000595:Amino Acid Sequence; D001343:Autophagy; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D002467:Cell Nucleus / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D050296:Microbial Viability; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D009584:Nitrogen / Q000172:deficiency / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism; D010641:Phenotype; D011485:Protein Binding; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: C113757:ATG8 protein, S cerevisiae; C502923:Atg11 protein, S cerevisiae; C000599318:Atg39 protein, S cerevisiae; C000599319:Atg40 protein, S cerevisiae; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; C522691:RETREG1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D009584:Nitrogen