Polyglutamine Aggregation Inhibitor, PGL-135 is a cell-permeable benzothiazole compound that binds to polyglutamine (PQBP-1, polyQ)-containing β-sheet structures and prevents polyQ-aggregation, a pathological hallmark of Huntington's disease (HD) and related glutamine repeat disorders. Shown to be non-toxic and prevent HDQ51 (FLAG|?|-tag HD exon 1 protein with 51 glutamines)-aggregation in 293 Tet-Off (293 tetracycline-off) cells with an IC|50|of ~ 40 λμM.