INS and type 2 diabetes mellitus: Dysregulated mitochondrial Ca2+ signaling and Ca2+ homeostasis are involved in the pathogenesis of insulin insensitivity and T2D [201], and altered ER mitochondrial Ca2+ signaling is a crucial aspect in the impairments produced by the mutated PS2 protein that can have a major role in the development of neurodegeneration in FAD cases [202, 203].