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  • Tyrosine Binding Protein Sites Regulate the Intracellular Trafficking and Processing of Amyloid Precursor Protein through a Novel Lysosome-Directed Pathway.

Tyrosine Binding Protein Sites Regulate the Intracellular Trafficking and Processing of Amyloid Precursor Protein through a Novel Lysosome-Directed Pathway.

PloS one (2016-10-25)
Joshua H K Tam, M Rebecca Cobb, Claudia Seah, Stephen H Pasternak
ABSTRACT

The amyloid hypothesis posits that the production of β-amyloid (Aβ) aggregates leads to neurodegeneration and cognitive decline associated with AD. Aβ is produced by sequential cleavage of the amyloid precursor protein (APP) by β- and γ-secretase. While nascent APP is well known to transit to the endosomal/ lysosomal system via the cell surface, we have recently shown that APP can also traffic to lysosomes intracellularly via its interaction with AP-3. Because AP-3 interacts with cargo protein via interaction with tyrosine motifs, we mutated the three tyrosines motif in the cytoplasmic tail of APP. Here, we show that the YTSI motif interacts with AP-3, and phosphorylation of the serine in this motif disrupts the interaction and decreases APP trafficking to lysosomes. Furthermore, we show that phosphorylation at this motif can decrease the production of neurotoxic Aβ 42. This demonstrates that reducing APP trafficking to lysosomes may be a strategy to reduce Aβ 42 in Alzheimer's disease.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-Amyloid Precursor Protein, C-Terminal antibody produced in rabbit, IgG fraction of antiserum, buffered aqueous solution
Sigma-Aldrich
Monoclonal Anti-HA antibody produced in mouse, clone HA-7, ascites fluid
Sigma-Aldrich
DCP-LA, ≥95% (HPLC), oil
Sigma-Aldrich
Adenosine 3′,5′-cyclic monophosphate tris salt, ≥97% (HPLC), powder