HSPA5 and Machado-Joseph disease: In comparison to the P3WT+QBP1 SCR and P3MT5+QBP1 single-treatment groups, the P3WT+QBP1 co-treatment group was found to yield the most marked suppression of both expanded-CAG-RNA and -polyQ-protein toxicities as evidenced by both the significant restoration of rRNA defects and the reduction of BiP mRNA induction/XBP1S production in HEK293 cells (Fig. 4A,B,D,E), as well as in MJD-patient-derived fibroblasts (Fig. 4C,F).