GSK3B and Parkinson disease: Back to meth and considering the above-described robust connexion between GSK3 biology and PD pathogenesis, it is important to note that GSK3β interaction with α-synuclein is itself a very crucial nexus mediating meth-induced neurotoxicity, which leads to the blockage of autophagy-lysosomal degradation pathway and eventually to cellular apoptosis [258].