MTOR and Huntington disease: Dysfunctional kinase signaling pathways involving AKT [37, 51–53], YAP [54], ERK (extracellular signal-related kinase; [55, 56]), mTOR (mechanistic target of rapamycin; [57]), GSK3 (Glycogen synthase kinase 3; [58]), and CDK5 (cyclin-dependent kinase 5; [59, 60]) were proposed to contribute to HD pathogenesis.