HSPA5 and Parkinson disease: In animal models and in the brain tissues from patients with PD (Colla et al., 2012a,b), mutant α-syn accumulates in the ER, where it is retained by BIP/GRP78 (Colla et al., 2012a) and can impair protein trafficking by affecting RAB1 (Ras-related protein Rab-1A) and SNAREs function at the ER–Golgi boundary (Cooper et al., 2006; Gitler et al., 2008; Thayanidhi et al., 2010).