title: Atg20- and Atg24-family proteins promote organelle autophagy in fission yeast.
abstract: Autophagy cargos include not only soluble cytosolic materials but also bulky organelles, such as ER and mitochondria. In budding yeast, two proteins that contain the PX domain and the BAR domain, Atg20 and Atg24 (also known as Snx42 and Snx4, respectively) are required for organelle autophagy and contribute to general autophagy in a way that can be masked by compensatory mechanisms. It remains unclear why these proteins are important for organelle autophagy. Here, we show that in a distantly related fungal organism, the fission yeast Schizosaccharomyces pombe, autophagy of ER and mitochondria is induced by nitrogen starvation and is promoted by three Atg20- and Atg24-family proteins - Atg20, Atg24 and SPBC1711.11 (named here as Atg24b). These proteins localize at the pre-autophagosomal structure, or phagophore assembly site (PAS), during starvation. S. pombe Atg24 forms a homo-oligomer and acts redundantly with Atg20 and Atg24b, and the latter two proteins can form a hetero-oligomer. The organelle autophagy defect caused by the loss of these proteins is associated with a reduction of autophagosome size and a decrease in Atg8 accumulation at the PAS. These results provide new insights into the autophagic function of Atg20- and Atg24-family proteins.
authors.affiliation: PTN Graduate Program, School of Life Sciences, Peking University, Beijing 100871, China.|National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Xiao-Man
authors.initials: XM
authors.lastname: Liu
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Zhong-Qiu
authors.initials: ZQ
authors.lastname: Yu
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Sun
authors.affiliation: National Institute of Metrology, Beijing 100013, China.
authors.forename: Xingchuang
authors.initials: X
authors.lastname: Xiong
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China.
authors.forename: Meng-Qiu
authors.initials: MQ
authors.lastname: Dong
authors.affiliation: National Institute of Biological Sciences, Beijing 102206, China dulilin@nibs.ac.cn.
authors.forename: Li-Lin
authors.identifier: 0000-0002-1028-7397
authors.initials: LL
authors.lastname: Du
mesh_terms: D000071182:Autophagosomes / Q000378:metabolism / Q000648:ultrastructure; D001343:Autophagy; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009584:Nitrogen / Q000172:deficiency; D015388:Organelles / Q000378:metabolism*; D055503:Protein Multimerization; D012568:Schizosaccharomyces / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C000621623:Atg20 protein, S pombe; C000621624:Atg24 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D009584:Nitrogen
keywords: Atg20; Atg24; Autophagosome; Autophagy; Fission yeast; PX-BAR; Schizosaccharomyces pombe