Organization of the pre-autophagosomal structure responsible for autophagosome formation

Mol Biol Cell. 2008 May;19(5):2039-50. doi: 10.1091/mbc.e07-10-1048. Epub 2008 Feb 20.

Abstract

Autophagy induced by nutrient depletion is involved in survival during starvation conditions. In addition to starvation-induced autophagy, the yeast Saccharomyces cerevisiae also has a constitutive autophagy-like system, the Cvt pathway. Among 31 autophagy-related (Atg) proteins, the function of Atg17, Atg29, and Atg31 is required specifically for autophagy. In this study, we investigated the role of autophagy-specific (i.e., non-Cvt) proteins under autophagy-inducing conditions. For this purpose, we used atg11Delta cells in which the Cvt pathway is abrogated. The autophagy-unique proteins are required for the localization of Atg proteins to the pre-autophagosomal structure (PAS), the putative site for autophagosome formation, under starvation condition. It is likely that these Atg proteins function as a ternary complex, because Atg29 and Atg31 bind to Atg17. The Atg1 kinase complex (Atg1-Atg13) is also essential for recruitment of Atg proteins to the PAS. The assembly of Atg proteins to the PAS is observed only under autophagy-inducing conditions, indicating that this structure is specifically involved in autophagosome formation. Our results suggest that Atg1 complex and the autophagy-unique Atg proteins cooperatively organize the PAS in response to starvation signals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy
  • Gene Deletion
  • Phagosomes / metabolism*
  • Protein Binding
  • Protein Transport
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism

Substances

  • Saccharomyces cerevisiae Proteins