%0 Journal Article %A Birgisdottir, Åsa Birna %A Mouilleron, Stephane %A Bhujabal, Zambarlal %A Wirth, Martina %A Sjøttem, Eva %A Evjen, Gry %A Zhang, Wenxin %A Lee, Rebecca %A O'Reilly, Nicola %A Tooze, Sharon A %A Lamark, Trond %A Johansen, Terje %D 2019 %T Members of the autophagy class III phosphatidylinositol 3-kinase complex I interact with GABARAP and GABARAPL1 via LIR motifs %U https://crick.figshare.com/articles/journal_contribution/Members_of_the_autophagy_class_III_phosphatidylinositol_3-kinase_complex_I_interact_with_GABARAP_and_GABARAPL1_via_LIR_motifs/11353700 %2 https://crick.figshare.com/ndownloader/files/20153108 %K ATG14 %K Autophagy %K BECN1 %K GABARAP %K LIR %K PIK3C3 %K Tooze FC001187 %K PC %K SB %K FERM-ack %K Biochemistry & Molecular Biology %K 0601 Biochemistry and Cell Biology %X Autophagosome formation depends on a carefully orchestrated interplay between membrane-associated protein complexes. Initiation of macroautophagy/autophagy is mediated by the ULK1 (unc-51 like autophagy activating kinase 1) protein kinase complex and the autophagy-specific class III phosphatidylinositol 3-kinase complex I (PtdIns3K-C1). The latter contains PIK3C3/VPS34, PIK3R4/VPS15, BECN1/Beclin 1 and ATG14 and phosphorylates phosphatidylinositol to generate phosphatidylinositol 3-phosphate (PtdIns3P). Here, we show that PIK3C3, BECN1 and ATG14 contain functional LIR motifs and interact with the Atg8-family proteins with a preference for GABARAP and GABARAPL1. High resolution crystal structures of the functional LIR motifs of these core components of PtdIns3K-C1were obtained. Variation in hydrophobic pocket 2 (HP2) may explain the specificity for the GABARAP family. Mutation of the LIR motif in ATG14 did not prevent formation of the PtdIns3K-C1 complex, but blocked colocalization with MAP1LC3B/LC3B and impaired mitophagy. The ULK-mediated phosphorylation of S29 in ATG14 was strongly dependent on a functional LIR motif in ATG14. GABARAP-preferring LIR motifs in PIK3C3, BECN1 and ATG14 may, via coincidence detection, contribute to scaffolding of PtdIns3K-C1 on membranes for efficient autophagosome formation. Abbreviations: ATG: autophagy-related; BafA1: bafilomycin A1; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GFP: enhanced green fluorescent protein; KO: knockout; LDS: LIR docking site; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; SQSTM1/p62: sequestosome 1; VPS: Vacuolar protein sorting; ULK: unc-51 like autophagy activating kinase. %I The Francis Crick Institute