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Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System

While many of the proteins required for autophagy have been identified, the source of the membrane of the autophagosome is still unresolved with the endoplasmic reticulum (ER), endosomes, and mitochondria all having been evoked. The integral membrane protein Atg9 is delivered to the autophagosome du...

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Detalles Bibliográficos
Autores principales: Ohashi, Yohei, Munro, Sean
Formato: Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982105/
https://www.ncbi.nlm.nih.gov/pubmed/20861302
http://dx.doi.org/10.1091/mbc.E10-05-0457
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author Ohashi, Yohei
Munro, Sean
author_facet Ohashi, Yohei
Munro, Sean
author_sort Ohashi, Yohei
collection PubMed
description While many of the proteins required for autophagy have been identified, the source of the membrane of the autophagosome is still unresolved with the endoplasmic reticulum (ER), endosomes, and mitochondria all having been evoked. The integral membrane protein Atg9 is delivered to the autophagosome during starvation and in the related cytoplasm-to-vacuole (Cvt) pathway that occurs constitutively in yeast. We have examined the requirements for delivery of Atg9-containing membrane to the yeast autophagosome. Atg9 does not appear to originate from mitochondria, and Atg9 cannot reach the forming autophagosome directly from the ER or early Golgi. Components of traffic between Golgi and endosomes are known to be required for the Cvt pathway but do not appear required for autophagy in starved cells. However, we find that pairwise combinations of mutations in Golgi-endosomal traffic components apparently only required for the Cvt pathway can cause profound defects in Atg9 delivery and autophagy in starved cells. Thus it appears that membrane that contains Atg9 is delivered to the autophagosome from the Golgi-endosomal system rather than from the ER or mitochondria. This is underestimated by examination of single mutants, providing a possible explanation for discrepancies between yeast and mammalian studies on Atg9 localization and autophagosome formation.
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spelling pubmed-29821052011-01-30 Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System Ohashi, Yohei Munro, Sean Mol Biol Cell Articles While many of the proteins required for autophagy have been identified, the source of the membrane of the autophagosome is still unresolved with the endoplasmic reticulum (ER), endosomes, and mitochondria all having been evoked. The integral membrane protein Atg9 is delivered to the autophagosome during starvation and in the related cytoplasm-to-vacuole (Cvt) pathway that occurs constitutively in yeast. We have examined the requirements for delivery of Atg9-containing membrane to the yeast autophagosome. Atg9 does not appear to originate from mitochondria, and Atg9 cannot reach the forming autophagosome directly from the ER or early Golgi. Components of traffic between Golgi and endosomes are known to be required for the Cvt pathway but do not appear required for autophagy in starved cells. However, we find that pairwise combinations of mutations in Golgi-endosomal traffic components apparently only required for the Cvt pathway can cause profound defects in Atg9 delivery and autophagy in starved cells. Thus it appears that membrane that contains Atg9 is delivered to the autophagosome from the Golgi-endosomal system rather than from the ER or mitochondria. This is underestimated by examination of single mutants, providing a possible explanation for discrepancies between yeast and mammalian studies on Atg9 localization and autophagosome formation. The American Society for Cell Biology 2010-11-15 /pmc/articles/PMC2982105/ /pubmed/20861302 http://dx.doi.org/10.1091/mbc.E10-05-0457 Text en © 2010 by The American Society for Cell Biology This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
spellingShingle Articles
Ohashi, Yohei
Munro, Sean
Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title_full Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title_fullStr Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title_full_unstemmed Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title_short Membrane Delivery to the Yeast Autophagosome from the Golgi–Endosomal System
title_sort membrane delivery to the yeast autophagosome from the golgi–endosomal system
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982105/
https://www.ncbi.nlm.nih.gov/pubmed/20861302
http://dx.doi.org/10.1091/mbc.E10-05-0457
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