title: WIPI2 links LC3 conjugation with PI3P, autophagosome formation, and pathogen clearance by recruiting Atg12-5-16L1.
abstract: Mammalian cell homeostasis during starvation depends on initiation of autophagy by endoplasmic reticulum-localized phosphatidylinositol 3-phosphate (PtdIns(3)P) synthesis. Formation of double-membrane autophagosomes that engulf cytosolic components requires the LC3-conjugating Atg12-5-16L1 complex. The molecular mechanisms of Atg12-5-16L1 recruitment and significance of PtdIns(3)P synthesis at autophagosome formation sites are unknown. By identifying interacting partners of WIPIs, WD-repeat PtdIns(3)P effector proteins, we found that Atg16L1 directly binds WIPI2b. Mutation experiments and ectopic localization of WIPI2b to plasma membrane show that WIPI2b is a PtdIns(3)P effector upstream of Atg16L1 and is required for LC3 conjugation and starvation-induced autophagy through recruitment of the Atg12-5-16L1 complex. Atg16L1 mutants, which do not bind WIPI2b but bind FIP200, cannot rescue starvation-induced autophagy in Atg16L1-deficient MEFs. WIPI2b is also required for autophagic clearance of pathogenic bacteria. WIPI2b binds the membrane surrounding Salmonella and recruits the Atg12-5-16L1 complex, initiating LC3 conjugation, autophagosomal membrane formation, and engulfment of Salmonella.
authors: London Research Institute, Cancer Research UK, 44 Lincolns Inn Fields, London WC2A 3LY, UK.
authors: Hannah C
authors: HC
authors: Dooley
authors: London Research Institute, Cancer Research UK, 44 Lincolns Inn Fields, London WC2A 3LY, UK.
authors: Minoo
authors: M
authors: Razi
authors: London Research Institute, Cancer Research UK, 44 Lincolns Inn Fields, London WC2A 3LY, UK.
authors: Hannah E J
authors: HE
authors: Polson
authors: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
authors: Stephen E
authors: SE
authors: Girardin
authors: The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
authors: Michael I
authors: MI
authors: Wilson
authors: London Research Institute, Cancer Research UK, 44 Lincolns Inn Fields, London WC2A 3LY, UK. Electronic address: sharon.tooze@cancer.org.uk.
authors: Sharon A
authors: SA
authors: Tooze
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001343:Autophagy; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D017124:Conserved Sequence; D057809:HEK293 Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000502:physiology*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010587:Phagocytosis; D010588:Phagosomes / Q000378:metabolism* / Q000382:microbiology; D028044:Phosphate-Binding Proteins; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms / Q000502:physiology; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D012486:Salmonella typhimurium / Q000502:physiology*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism
chemical_list: C466624:ATG12 protein, human; C518959:ATG16L1 protein, human; C502778:ATG5 protein, human; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D028044:Phosphate-Binding Proteins; D018129:Phosphatidylinositol Phosphates; D020033:Protein Isoforms; D025841:Small Ubiquitin-Related Modifier Proteins; C569007:WIPI2 protein, human; C055525:phosphatidylinositol 3-phosphate