title: Atg9A trafficking through the recycling endosomes is required for autophagosome formation.
abstract: Autophagy is an intracellular degradation pathway conserved in eukaryotes. Among core autophagy-related (Atg) proteins, mammalian Atg9A is the sole multi-spanning transmembrane protein, and both of its N- and C-terminal domains are exposed to the cytoplasm. It is known that Atg9A travels through the trans-Golgi network (TGN) and the endosomal system under nutrient-rich conditions, and transiently localizes to the autophagosome upon autophagy induction. However, the significance of Atg9A trafficking for autophagosome formation remains elusive. Here, we identified sorting motifs in the N-terminal cytosolic stretch of Atg9A that interact with the adaptor protein AP-2. Atg9A with mutations in the sorting motifs could not execute autophagy and was abnormally accumulated at the recycling endosomes. The combination of defects in autophagy and Atg9A accumulation in the recycling endosomes was also found upon the knockdown of TRAPPC8, a specific subunit of the TRAPPIII complex. These results show directly that the trafficking of Atg9A through the recycling endosomes is an essential step for autophagosome formation.
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Kenta
authors: 0000-0001-8297-2273
authors: K
authors: Imai
authors: Department of Genetics, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Feike
authors: F
authors: Hao
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors: Naonobu
authors: N
authors: Fujita
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Yasuhiro
authors: Y
authors: Tsuji
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Yukako
authors: Y
authors: Oe
authors: Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Yasuhiro
authors: Y
authors: Araki
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan Department of Genetics, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Maho
authors: M
authors: Hamasaki
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan takenoda@dent.osaka-u.ac.jp tamyoshi@fbs.osaka-u.ac.jp.
authors: Takeshi
authors: 0000-0003-3581-7961
authors: T
authors: Noda
authors: Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan Department of Genetics, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan takenoda@dent.osaka-u.ac.jp tamyoshi@fbs.osaka-u.ac.jp.
authors: Tamotsu
authors: 0000-0001-9787-3788
authors: T
authors: Yoshimori
mesh_terms: D033962:Adaptor Protein Complex 2 / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D000071182:Autophagosomes / Q000378:metabolism*; D001343:Autophagy; D000071183:Autophagy-Related Proteins / Q000737:chemistry / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D018345:Mice, Knockout; D008954:Models, Biological; D021381:Protein Transport; D012475:Salmonella / Q000378:metabolism; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D033962:Adaptor Protein Complex 2; C549015:Atg9A protein, mouse; D000071183:Autophagy-Related Proteins; D008565:Membrane Proteins; D033921:Vesicular Transport Proteins; D014443:Tyrosine
keywords: AP-2; Atg9; Autophagy; Golgi; Recycling endosome; Sorting motif; TRAPP