SYP and Alzheimer disease: AD dysregulation of Aβ metabolism progressively attenuates the expression of proteins regulating (a) presynaptic (e.g., vesicle trafficking by synaptophysin and synaptogyrin, vesicle metabolism by synaptotagmin and syntaxin) and (b) postsynaptic activity (e.g., excitation of the postsynaptic membrane by PSD-95 and drebin) [116].