Atg38 is required for autophagy-specific phosphatidylinositol 3-kinase complex integrity.

Autophagy is a conserved eukaryotic process of protein and organelle self-degradation within the vacuole/lysosome. Autophagy is characterized by the formation of an autophagosome, for which Vps34-dervied phosphatidylinositol 3-phosphate (PI3P) is essential. In yeast, Vps34 forms two distinct protein complexes: complex I, which functions in autophagy, and complex II, which is ...
involved in protein sorting to the vacuole. Here we identify and characterize Atg38 as a stably associated subunit of complex I. In atg38Δ cells, autophagic activity was significantly reduced and PI3-kinase complex I dissociated into the Vps15-Vps34 and Atg14-Vps30 subcomplexes. We find that Atg38 physically interacted with Atg14 and Vps34 via its N terminus. Further biochemical analyses revealed that Atg38 homodimerizes through its C terminus and that this homodimer formation is indispensable for the integrity of complex I. These data suggest that the homodimer of Atg38 functions as a physical linkage between the Vps15-Vps34 and Atg14-Vps30 subcomplexes to facilitate complex I formation.
Mesh Terms:
Autophagy, Class III Phosphatidylinositol 3-Kinases, Gene Expression Regulation, Fungal, Genotype, Immunoprecipitation, Multiprotein Complexes, Mutation, Phenotype, Protein Interaction Domains and Motifs, Protein Interaction Mapping, Protein Multimerization, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction, Vacuolar Sorting Protein VPS15, Vesicular Transport Proteins
J. Cell Biol.
Date: Oct. 28, 2013
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