GBA1 and proteostasis deficiencies: Studies using human induced-pluripotent stem cells (iPSCs) harboring GBA1 mutations reported ALP dysfunction in dopaminergic (DA) neurons from PD patients and further highlighted its role in PD-associated proteinopathy (Schondorf et al., 2014; Fernandes et al., 2016; Mazzulli et al., 2016).