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Updated: Jul 17, 2026

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
Published on: August 28, 2012
Intracellular pH regulates amyloid precursor protein intracellular domain accumulation
Valérie Vingtdeux1, Malika Hamdane, Séverine Bégard
1INSERM U815, Centre Jean-Pierre Aubert, Neurodegenerative Disorders and Neuronal Death, 1, Place de Verdun, F-59045 Lille, France.
Abstract:
The amyloid precursor protein (APP) metabolism is central to pathogenesis of Alzheimer's disease (AD). Parenchymal amyloid deposits, a neuropathological hallmark of AD, are composed of amyloid-beta peptides (Abeta). Abeta derives from the amyloid precursor protein (APP) by sequential cleavages by beta- and gamma-secretases. Gamma-secretase cleavage releases the APP intracellular domain (AICD), suggested to mediate a nuclear signaling. Physiologically, AICD is seldom detected and thus supposed to be rapidly degraded. The mechanisms responsible of its degradation remain unknown. We used a pharmacological approach and showed that several alkalizing drugs induce the accumulation of AICD in neuroblastoma SY5Y cell lines stably expressing APP constructs. Moreover, alkalizing drugs induce AICD accumulation in naive SY5Y, HEK and COS cells. This accumulation is not mediated by the proteasome or metallopeptidases and is not the result of an increased gamma-secretase activity since the gamma-secretase cleavage of Notch1 and N-Cadherin is not affected by alkalizing drug treatments. Altogether, our data demonstrate for the first time that alkalizing drugs induce the accumulation of AICD, a mechanism likely mediated by the endosome/lysosome pathway.
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