Abstract
Phagophore maturation is a key step in the macroautophagy pathway, which is critical in many important physiological and pathological processes. Here we identified Drosophila N-ethylmaleimide-sensitive fusion protein 2 (dNSF2) and soluble NSF attachment protein (Snap) as strong genetic modifiers of mutant CHMP2B, an ESCRT-III component that causes frontotemporal dementia and autophagosome accumulation. Among several SNAP receptor (SNARE) genes, Drosophila syntaxin 13 (syx13) exhibited a strong genetic interaction with mutant CHMP2B. Knockdown of syntaxin 13 (STX13) or its binding partner Vti1a in mammalian cells caused LC3-positive puncta to accumulate and blocks autophagic flux. STX13 was present on LC3-positive phagophores induced by rapamycin and was highly enriched on multilamellar structures induced by dysfunctional ESCRT-III. Loss of STX13 also caused the accumulation of Atg5-positive puncta and the formation of multilamellar structures. These results suggest that STX13 is a genetic modifier of ESCRT-III dysfunction and participates in the maturation of phagophores into closed autophagosomes.
Copyright © 2013 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Autophagy*
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Blotting, Western
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism*
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Drosophila melanogaster / genetics
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Drosophila melanogaster / metabolism
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Endosomal Sorting Complexes Required for Transport / genetics
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Endosomal Sorting Complexes Required for Transport / metabolism*
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Eye Abnormalities / genetics
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Eye Abnormalities / metabolism
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Frontotemporal Dementia / genetics
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Frontotemporal Dementia / metabolism
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HEK293 Cells
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HeLa Cells
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Humans
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Microscopy, Confocal
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Microscopy, Immunoelectron
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Microtubule-Associated Proteins / genetics
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Microtubule-Associated Proteins / metabolism
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Mutation
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N-Ethylmaleimide-Sensitive Proteins / genetics
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N-Ethylmaleimide-Sensitive Proteins / metabolism
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Phagosomes / metabolism*
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Phagosomes / ultrastructure
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Phenotype
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Qa-SNARE Proteins / genetics
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Qa-SNARE Proteins / metabolism*
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RNA Interference
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Vesicular Transport Proteins / genetics
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Vesicular Transport Proteins / metabolism*
Substances
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CHMP2B protein, Drosophila
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CHMP2B protein, human
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Drosophila Proteins
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Endosomal Sorting Complexes Required for Transport
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Luminescent Proteins
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MAP1LC3A protein, human
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Microtubule-Associated Proteins
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Nsf2 protein, Drosophila
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Qa-SNARE Proteins
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Vesicular Transport Proteins
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N-Ethylmaleimide-Sensitive Proteins