VAPB and frontotemporal dementia: Moreover, TAR DNA binding protein 43 (TDP-43) and fused in sarcoma (FUS), two ALS/frontotemporal dementia (FTD)-associated proteins, were reported to activate the glycogen synthase kinase-3β (GSK-3β), which inhibits VAPB-PTPIP51 binding, ultimately resulting in disrupted Ca2+ homeostasis and reduced ATP production [85,89].