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Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps

Rapamycin, an antifungal macrolide antibiotic, mimics starvation conditions in Saccharomyces cerevisiae through activation of a general G(0) program that includes widespread effects on translation and transcription. Macroautophagy, a catabolic membrane trafficking phenomenon, is a prominent part of...

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Autores principales: Abeliovich, Hagai, Dunn, William A., Kim, John, Klionsky, Daniel J.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2000
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174351/
https://www.ncbi.nlm.nih.gov/pubmed/11086004
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author Abeliovich, Hagai
Dunn, William A.
Kim, John
Klionsky, Daniel J.
author_facet Abeliovich, Hagai
Dunn, William A.
Kim, John
Klionsky, Daniel J.
author_sort Abeliovich, Hagai
collection PubMed
description Rapamycin, an antifungal macrolide antibiotic, mimics starvation conditions in Saccharomyces cerevisiae through activation of a general G(0) program that includes widespread effects on translation and transcription. Macroautophagy, a catabolic membrane trafficking phenomenon, is a prominent part of this response. Two views of the induction of autophagy may be considered. In one, up-regulation of proteins involved in autophagy causes its induction, implying that autophagy is the result of a signal transduction mechanism leading from Tor to the transcriptional and translational machinery. An alternative hypothesis postulates the existence of a dedicated signal transduction mechanism that induces autophagy directly. We tested these possibilities by assaying the effects of cycloheximide and specific mutations on the induction of autophagy. We find that induction of autophagy takes place in the absence of de novo protein synthesis, including that of specific autophagy-related proteins that are up-regulated in response to rapamycin. We also find that dephosphorylation of Apg13p, a signal transduction event that correlates with the onset of autophagy, is also independent of new protein synthesis. Finally, our data indicate that autophagosomes that form in the absence of protein synthesis are significantly smaller than normal, indicating a role for de novo protein synthesis in the regulation of autophagosome expansion. Our results define the existence of a signal transduction-dependent nucleation step and a separate autophagosome expansion step that together coordinate autophagosome biogenesis.
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spelling pubmed-21743512008-05-01 Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps Abeliovich, Hagai Dunn, William A. Kim, John Klionsky, Daniel J. J Cell Biol Original Article Rapamycin, an antifungal macrolide antibiotic, mimics starvation conditions in Saccharomyces cerevisiae through activation of a general G(0) program that includes widespread effects on translation and transcription. Macroautophagy, a catabolic membrane trafficking phenomenon, is a prominent part of this response. Two views of the induction of autophagy may be considered. In one, up-regulation of proteins involved in autophagy causes its induction, implying that autophagy is the result of a signal transduction mechanism leading from Tor to the transcriptional and translational machinery. An alternative hypothesis postulates the existence of a dedicated signal transduction mechanism that induces autophagy directly. We tested these possibilities by assaying the effects of cycloheximide and specific mutations on the induction of autophagy. We find that induction of autophagy takes place in the absence of de novo protein synthesis, including that of specific autophagy-related proteins that are up-regulated in response to rapamycin. We also find that dephosphorylation of Apg13p, a signal transduction event that correlates with the onset of autophagy, is also independent of new protein synthesis. Finally, our data indicate that autophagosomes that form in the absence of protein synthesis are significantly smaller than normal, indicating a role for de novo protein synthesis in the regulation of autophagosome expansion. Our results define the existence of a signal transduction-dependent nucleation step and a separate autophagosome expansion step that together coordinate autophagosome biogenesis. The Rockefeller University Press 2000-11-27 /pmc/articles/PMC2174351/ /pubmed/11086004 Text en © 2000 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Abeliovich, Hagai
Dunn, William A.
Kim, John
Klionsky, Daniel J.
Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title_full Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title_fullStr Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title_full_unstemmed Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title_short Dissection of Autophagosome Biogenesis into Distinct Nucleation and Expansion Steps
title_sort dissection of autophagosome biogenesis into distinct nucleation and expansion steps
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174351/
https://www.ncbi.nlm.nih.gov/pubmed/11086004
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