Alzheimer mutant speeds APP transport

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Rare familial forms of Alzheimer's disease (AD) are linked to mutations in the amyloid precursor protein (APP).
• Most known APP mutations are located in exons 16 or 17, but the APPS198P mutation is in exon 5.

Purpose of the Study:

• To investigate the impact of the APPS198P mutation on amyloid-beta (Aβ) production.
• To elucidate the cellular mechanisms underlying Aβ generation in APPS198P.

Main Methods:

• Generation of APPS198P transgenic mice.
• Analysis of Aβ levels in mouse brains.
• Cellular studies using cultured cells expressing APPS198P.

Main Results:

• APPS198P transgenic mice exhibit elevated levels of Aβ in their brains.
• In cultured cells, APPS198P undergoes rapid endoplasmic reticulum (ER) folding.
• This accelerated folding leads to premature transport to late endosomal/lysosomal compartments, enhancing Aβ generation.

Conclusions:

• The APPS198P mutation promotes Aβ accumulation through accelerated protein processing and enhanced Aβ production.
• This finding provides new insights into the molecular mechanisms of rare familial Alzheimer's disease.