MAPK8 and Alzheimer disease: Indeed, although the precise p75 signaling is not completely understood, p75 can induce apoptosis through a neurotrophin-dependent activation of the sphingomyelinase/ceramide and JNK/p53 pathways followed by induction of Bax and Fas L, thus involving the activation of the mitochondrial intrinsic cascade and, perhaps, also an extrinsic apoptotic pathway, given that Fas and FasL have been found in senile plaques in AD and suggested to participate Aβ-induced neuronal death [63].