We observed that this aberrant phenotype can be reversed by the expression of the cochaperone BAG1 (Bcl-2-associated athanogene 1), restoring DJ-1 subcellular distribution, dimer formation, and chaperone activity and ameliorating cell survival.; In summary, we present BAG1 as a therapeutic tool modulating key steps in htt toxicity in vitro and ameliorating htt toxicity in vivo.