Carboxyl-terminal fragments of Alzheimer beta-amyloid precursor protein accumulate in restricted and unpredicted intracellular compartments in presenilin 1-deficient cells

J Biol Chem. 2000 Nov 24;275(47):36794-802. doi: 10.1074/jbc.M006986200.


Absence of functional presenilin 1 (PS1) protein leads to loss of gamma-secretase cleavage of the amyloid precursor protein (betaAPP), resulting in a dramatic reduction in amyloid beta peptide (Abeta) production and accumulation of alpha- or beta-secretase-cleaved COOH-terminal fragments of betaAPP (alpha- or beta-CTFs). The major COOH-terminal fragment (CTF) in brain was identified as betaAPP-CTF-(11-98), which is consistent with the observation that cultured neurons generate primarily Abeta-(11-40). In PS1(-/-) murine neurons and fibroblasts expressing the loss-of-function PS1(D385A) mutant, CTFs accumulated in the endoplasmic reticulum, Golgi, and lysosomes, but not late endosomes. There were some subtle differences in the subcellular distribution of CTFs in PS1(-/-) neurons as compared with PS1(D385A) mutant fibroblasts. However, there was no obvious redistribution of full-length betaAPP or of markers of other organelles in either mutant. Blockade of endoplasmic reticulum-to-Golgi trafficking indicated that in PS1(-/-) neurons (as in normal cells) trafficking of betaAPP to the Golgi compartment is necessary before alpha- and beta-secretase cleavages occur. Thus, although we cannot exclude a specific role for PS1 in trafficking of CTFs, these data argue against a major role in general protein trafficking. These results are more compatible with a role for PS1 either as the actual gamma-secretase catalytic activity or in other functions indirectly related to gamma-secretase catalysis (e.g. an activator of gamma-secretase, a substrate adaptor for gamma-secretase, or delivery of gamma-secretase to betaAPP-containing compartments).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / metabolism
  • Amyloid Precursor Protein Secretases
  • Amyloid beta-Peptides / metabolism*
  • Amyloid beta-Protein Precursor / metabolism*
  • Animals
  • Aspartic Acid Endopeptidases
  • Biomarkers
  • Brain / metabolism
  • Brain / ultrastructure
  • Cell Compartmentation
  • Electrophoresis, Polyacrylamide Gel
  • Endopeptidases / metabolism
  • Membrane Proteins / deficiency
  • Membrane Proteins / physiology*
  • Mice
  • Mice, Knockout
  • Microscopy, Electron
  • Peptide Fragments / metabolism*
  • Presenilin-1


  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Biomarkers
  • Membrane Proteins
  • Peptide Fragments
  • Presenilin-1
  • amyloid beta-protein (11-40)
  • Amyloid Precursor Protein Secretases
  • Endopeptidases
  • Aspartic Acid Endopeptidases
  • Bace1 protein, mouse