Crystal structure of the γ-secretase component nicastrin

Proc Natl Acad Sci U S A. 2014 Sep 16;111(37):13349-54. doi: 10.1073/pnas.1414837111. Epub 2014 Sep 2.


γ-Secretase is an intramembrane protease responsible for the generation of amyloid-β (Aβ) peptides. Aberrant accumulation of Aβ leads to the formation of amyloid plaques in the brain of patients with Alzheimer's disease. Nicastrin is the putative substrate-recruiting component of the γ-secretase complex. No atomic-resolution structure had been identified on γ-secretase or any of its four components, hindering mechanistic understanding of γ-secretase function. Here we report the crystal structure of nicastrin from Dictyostelium purpureum at 1.95-Å resolution. The extracellular domain of nicastrin contains a large lobe and a small lobe. The large lobe of nicastrin, thought to be responsible for substrate recognition, associates with the small lobe through a hydrophobic pivot at the center. The putative substrate-binding pocket is shielded from the small lobe by a lid, which blocks substrate entry. These structural features suggest a working model of nicastrin function. Analysis of nicastrin structure provides insights into the assembly and architecture of the γ-secretase complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid Precursor Protein Secretases / chemistry*
  • Binding Sites
  • Crystallography, X-Ray
  • Dictyostelium / enzymology*
  • Humans
  • Membrane Glycoproteins / chemistry*
  • Models, Molecular
  • Protein Structure, Tertiary
  • Substrate Specificity


  • Membrane Glycoproteins
  • nicastrin protein
  • Amyloid Precursor Protein Secretases

Associated data

  • PDB/4R12