N-glycosylation of human nicastrin is required for interaction with the lectins from the secretory pathway calnexin and ERGIC-53

Vanessa A. Morais, Catarina Brito, Donald S. Pijak, Adam S. Crystal, Ryan R. Fortna, Tong Li, Phil C. Wong, Robert W. Doms, Júlia Costa

Research output: Contribution to journalArticlepeer-review

Abstract

The γ-secretase complex, composed of four non-covalently bound transmembrane proteins Presenilin, Nicastrin (NCT), APH-1 and PEN-2, is responsible for the intramembranous cleavage of amyloid precursor protein (APP), Notch and several other type I transmembrane proteins. γ-Secretase cleavage of APP releases the Aβ peptides, which form the amyloid plaques characteristic of Alzheimer's disease brains, and cleavage of Notch releases an intracellular signalling peptide that is critical for numerous developmental processes. NCT, a type I membrane protein, is the only protein within the complex that is glycosylated. The importance of these glycosylation sites is not fully understood. Here, we have observed that NCT N-linked oligosaccharides mediated specific interactions with the secretory pathway lectins calnexin and ERGIC-53. In order to investigate the role played by N-glycosylation, mutation of each site was performed. All hNCT mutants interacted with calnexin and ERGIC-53, indicating that the association was not mediated by any single N-glycosylation site. Moreover, the interaction with ERGIC-53 still occurred in PS1/2 double knockout cells as detected in immunoprecipitation as well as confocal immunofluorescence microscopy studies, which indicated that NCT interacted with ERGIC-53 prior to its association with the active γ-secretase complex.

Original languageEnglish (US)
Pages (from-to)802-810
Number of pages9
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1762
Issue number9
DOIs
StatePublished - Sep 2006

Keywords

  • Alzheimer's disease
  • Calnexin
  • ERGIC-53
  • N-glycosylation
  • Nicastrin
  • γ-secretase complex

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

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