PTPN1 and Alzheimer disease: Quite recently, loss of REST causes upregulation of miR-124 and downregulation of its target protein phosphatase 1 (PTPN1) and disrupted miR-124/PTPN1 signaling that induces AD-like tau pathology in mice via activation of glycogen synthase kinase 3 (GSK-3) and inactivation of protein phosphatase 2A (PP2A) [134].