Download MendeleyStructure of yeast Ape1 and its role in autophagic vesicle formation.
Su, M.Y., Peng, W.H., Ho, M.R., Su, S.C., Chang, Y.C., Chen, G.C., Chang, C.I.(2015) Autophagy 11: 1580-1593
- PubMed: 26208681
- DOI: https://doi.org/10.1080/15548627.2015.1067363
- Primary Citation of Related Structures:
4R8F - PubMed Abstract:
In Saccharomyces cerevisiae, a constitutive biosynthetic transport pathway, termed the cytoplasm-to-vacuole targeting (Cvt) pathway, sequesters precursor aminopeptidase I (prApe1) dodecamers in the form of a large complex into a Cvt vesicle using autophagic machinery, targeting it into the vacuole (the yeast lysosome) where it is proteolytically processed into its mature form, Ape1, by removal of an amino-terminal 45-amino acid propeptide. prApe1 is thought to serve as a scaffolding cargo critical for the assembly of the Cvt vesicle by presenting the propeptide to mediate higher-ordered complex formation and autophagic receptor recognition. Here we report the X-ray crystal structure of Ape1 at 2.5 Å resolution and reveal its dodecameric architecture consisting of dimeric and trimeric units, which associate to form a large tetrahedron. The propeptide of prApe1 exhibits concentration-dependent oligomerization and forms a stable tetramer. Structure-based mutagenesis demonstrates that disruption of the inter-subunit interface prevents dodecameric assembly and vacuolar targeting in vivo despite the presence of the propeptide. Furthermore, by examining the vacuolar import of propeptide-fused exogenous protein assemblies with different quaternary structures, we found that 3-dimensional spatial distribution of propeptides presented by a scaffolding cargo is essential for the assembly of the Cvt vesicle for vacuolar delivery. This study describes a molecular framework for understanding the mechanism of Cvt or autophagosomal biogenesis in selective macroautophagy.
Organizational Affiliation:
a Institute of Biological Chemistry; Academia Sinica ; Taipei , Taiwan.
