Presenilin-1-mediated retention of APP derivatives in early biosynthetic compartments

Traffic. 2006 Mar;7(3):354-64. doi: 10.1111/j.1600-0854.2006.00388.x.

Abstract

Processing of the amyloid precursor protein (APP) leads to the production of amyloid-beta (Abeta), the major component of extracellular plaques in the brains of Alzheimer's disease (AD) patients. Presenilin-1 (PS-1) plays a key role in the final step of Abeta formation, the gamma-secretase cleavage. Previously, we showed that PS-1 is retained in pre-Golgi compartments by incorporation into COPI-coated membranes of the vesicular tubular clusters (VTCs) between endoplasmic reticulum (ER) and Golgi complex. Here, we show that PS-1 also mediates the retention of the beta-cleavage-derived APP-C-terminal fragment (CTFbeta) and/or Abeta in pre-Golgi membranes. Overexpression of PS-1 increased the percentage of CTFbeta and/or Abeta in VTCs as well as their distribution to COPI-coated VTC membranes. By contrast, overexpression of the dominant-negative aspartate mutant PS-1(D257A) or PS-knockout decreased incorporation of these APP derivatives into COPI-coated membranes. Sorting of APP derivatives to COPI-coated VTC membranes was not depending on the APP cytosolic tail. In post-Golgi compartments, PS-1 expression enhanced the association of full-length APP/APPs with endosomal compartments at the expense of plasma membrane-bound APP. We conclude that PS-1, in addition to its role in gamma-secretase cleavage, is also required for the subcellular routing of APP and its derivatives. Malfunctioning of PS-1 in this role may have important consequences for the progress of AD.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / genetics
  • Alzheimer Disease / metabolism
  • Amyloid beta-Peptides / biosynthesis
  • Amyloid beta-Peptides / ultrastructure
  • Amyloid beta-Protein Precursor / metabolism*
  • Amyloid beta-Protein Precursor / ultrastructure
  • Animals
  • CHO Cells
  • Coat Protein Complex I / metabolism
  • Coat Protein Complex I / ultrastructure
  • Cricetinae
  • Embryo, Mammalian
  • Endoplasmic Reticulum / metabolism*
  • Endoplasmic Reticulum / ultrastructure
  • Endosomes / metabolism
  • Endosomes / ultrastructure
  • Fibroblasts / metabolism
  • Fibroblasts / ultrastructure
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Membrane Proteins / ultrastructure
  • Mice
  • Mice, Knockout
  • Microscopy, Immunoelectron
  • Mutation
  • Peptide Fragments / metabolism
  • Peptide Fragments / ultrastructure
  • Presenilin-1
  • Protein Processing, Post-Translational
  • Protein Transport

Substances

  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Coat Protein Complex I
  • Membrane Proteins
  • PSEN1 protein, human
  • Peptide Fragments
  • Presenilin-1