Structure and function of yeast Atg20, a sorting nexin that facilitates autophagy induction

Proc Natl Acad Sci U S A. 2017 Nov 21;114(47):E10112-E10121. doi: 10.1073/pnas.1708367114. Epub 2017 Nov 7.


The Atg20 and Snx4/Atg24 proteins have been identified in a screen for mutants defective in a type of selective macroautophagy/autophagy. Both proteins are connected to the Atg1 kinase complex, which is involved in autophagy initiation, and bind phosphatidylinositol-3-phosphate. Atg20 and Snx4 contain putative BAR domains, suggesting a possible role in membrane deformation, but they have been relatively uncharacterized. Here we demonstrate that, in addition to its function in selective autophagy, Atg20 plays a critical role in the efficient induction of nonselective autophagy. Atg20 is a dynamic posttranslationally modified protein that engages both structurally stable (PX and BAR) and intrinsically disordered domains for its function. In addition to its PX and BAR domains, Atg20 uses a third membrane-binding module, a membrane-inducible amphipathic helix present in a previously undescribed location in Atg20 within the putative BAR domain. Taken together, these findings yield insights into the molecular mechanism of the autophagy machinery.

Keywords: autophagy; vacuole; yeast.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Motifs
  • Autophagy / genetics*
  • Autophagy-Related Proteins / chemistry*
  • Autophagy-Related Proteins / genetics
  • Autophagy-Related Proteins / metabolism
  • Binding Sites
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Gene Expression Regulation, Fungal*
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Kinetics
  • Models, Molecular
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction
  • Sorting Nexins / chemistry*
  • Sorting Nexins / genetics
  • Sorting Nexins / metabolism


  • Atg20 protein, S cerevisiae
  • Autophagy-Related Proteins
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • Sorting Nexins