The C-terminal region of ATG101 bridges ULK1 and PtdIns3K complex in autophagy initiation

The initiation of macroautophagy/autophagy is tightly regulated by the upstream ULK1 kinase complex, which affects many downstream factors including the PtdIns3K complex. The phosphorylation of the right position at the right time on downstream molecules is governed by proper complex formation. One...

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Bibliographic Details
Published in:Autophagy 2018-12, Vol.14 (12), p.2104-2116
Main Authors: Kim, Byeong-Won, Jin, Yunjung, Kim, Jiyea, Kim, Jun Hoe, Jung, Juneyoung, Kang, Seongman, Kim, Ick Young, Kim, Joungmok, Cheong, Heesun, Song, Hyun Kyu
Format: Article
Language:English
Subjects:
ATG101
ATG13
Autophagy - physiology
Autophagy-Related Protein-1 Homolog - chemistry
Autophagy-Related Protein-1 Homolog - metabolism
Autophagy-Related Proteins - chemistry
Autophagy-Related Proteins - metabolism
C-terminal region
Class III Phosphatidylinositol 3-Kinases - chemistry
Class III Phosphatidylinositol 3-Kinases - metabolism
Crystallography, X-Ray
HEK293 Cells
Humans
Intracellular Signaling Peptides and Proteins - chemistry
Intracellular Signaling Peptides and Proteins - metabolism
Male
Models, Molecular
Multiprotein Complexes - chemistry
Multiprotein Complexes - metabolism
Protein Binding
Protein Interaction Domains and Motifs - physiology
PtdIns3K complex
Research Paper - Basic Science
Scattering, Small Angle
structure
Tumor Cells, Cultured
ULK1 complex
Vacuolar Sorting Protein VPS15 - metabolism
Vesicular Transport Proteins - chemistry
Vesicular Transport Proteins - metabolism
X-Ray Diffraction
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Summary:The initiation of macroautophagy/autophagy is tightly regulated by the upstream ULK1 kinase complex, which affects many downstream factors including the PtdIns3K complex. The phosphorylation of the right position at the right time on downstream molecules is governed by proper complex formation. One component of the ULK1 complex, ATG101, known as an accessory protein, is a stabilizer of ATG13 in cells. The WF finger region of ATG101 plays an important role in the recruitment of WIPI1 (WD repeat domain, phosphoinositide interacting protein 1) and ZFYVE1 (zinc finger FYVE-type containing 1). Here, we report that the C-terminal region identified in the structure of the human ATG101-ATG13 HORMA complex is responsible for the binding of the PtdIns3K complex. This region adopts a β-strand conformation in free ATG101, but either an α-helix or random coil in our ATG101-ATG13 HORMA complex, which protrudes from the core and interacts with other molecules. The C-terminal deletion of ATG101 shows a significant defect in the interaction with PtdIns3K components and subsequently impairs autophagosome formation. This result clearly presents an additional role of ATG101 for bridging the ULK1 and PtdIns3K complexes in the mammalian autophagy process. Abbreviations: ATG: autophagy related; BECN1: beclin 1; GFP: green fluorescent protein; HORMA: Hop1p/Rev7p/MAD2; HsATG13 HORMA : HORMA domain of ATG13 from Homo sapiens; KO: knockout; MAD2: mitotic arrest deficient 2 like 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PIK3R4/VPS15: phosphoinositide-3-kinase regulatory subunit 4; PtdIns3K: phosphatidylinositol 3-kinase; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SAXS: small-angle X-ray scattering; ScAtg13 HORMA : HORMA domain of Atg13 from Sccharomyces cerevisiae; SEC-SAXS: size-exclusion chromatography with small-angle X-ray scattering; SpAtg13 HORMA : HORMA domain of Atg13 from Schizosaccharomyces pombe; SQSTM1/p62: sequestosome 1; ULK1: unc51-like autophagy activating kinase 1; UVRAG: UV radiation resistance associated; WIPI1: WD repeat domain: phosphoinositide interacting 1; ZFYVE1/DFCP1: zinc finger FYVE-type containing 1
ISSN:1554-8627
1554-8635
DOI:10.1080/15548627.2018.1504716