A new molecular explanation for age-related neurodegeneration: the Tyr682 residue of amyloid precursor protein.

Emerging evidence supports the role for the intracellular domains of amyloid precursor protein (APP) in the physiology and function of APP. In this short report, I discuss the hypothesis that mutation of Tyr682 on the Y682 ENPTY687 C-terminal motif of APP may be directly or indirectly associated with alterations in APP functioning and activity, leading to neuronal defects and deficits. Mutation of Tyr682 induces an early and progressive age-dependent cognitive and locomotor decline that is associated with a loss of synaptic connections, a decrease in cholinergic tone, and defects in NGF signaling. These findings support a model in which APP-C-terminal domain exerts a pathogenic function in neuronal development and decline, and suggest that Tyr682 potentially could modulate the properties of APP metabolites in humans.