Architecture of the Atg17 complex as a scaffold for autophagosome biogenesis

Cell. 2012 Dec 21;151(7):1501-1512. doi: 10.1016/j.cell.2012.11.028. Epub 2012 Dec 6.


Macroautophagy is a bulk clearance mechanism in which the double-membraned phagophore grows and engulfs cytosolic material. In yeast, the phagophore nucleates from a cluster of 20-30 nm diameter Atg9-containing vesicles located at a multiprotein assembly known as the preautophagosomal structure (PAS). The crystal structure of a 2:2:2 complex of the earliest acting PAS proteins, Atg17, Atg29, and Atg31, was solved at 3.05 Å resolution. Atg17 is crescent shaped with a 10 nm radius of curvature. Dimerization of the Atg17-Atg31-Atg29 complex is critical for both PAS formation and autophagy, and each dimer contains two separate and complete crescents. Upon induction of autophagy, Atg17-Atg31-Atg29 assembles with Atg1 and Atg13, which in turn initiates the formation of the phagophore. The C-terminal EAT domain of Atg1 was shown to sense membrane curvature, dimerize, and tether lipid vesicles. These data suggest a structural mechanism for the organization of Atg9 vesicles into the early phagophore.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Autophagy
  • Autophagy-Related Proteins
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Crystallography, X-Ray
  • Fungal Proteins / chemistry*
  • Models, Molecular
  • Molecular Sequence Data
  • Multiprotein Complexes / chemistry*
  • Phagosomes / metabolism*
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomycetales / chemistry*
  • Saccharomycetales / cytology*
  • Saccharomycetales / metabolism
  • Sequence Alignment


  • Atg17 protein, S cerevisiae
  • Autophagy-Related Proteins
  • Carrier Proteins
  • Fungal Proteins
  • Multiprotein Complexes
  • Saccharomyces cerevisiae Proteins

Associated data

  • PDB/4HPQ