HTT and Huntington disease: The effect of modifying serine at the site of 1181 and 1201 on mHTT toxicity was further confirmed in the primary neuronal HD cell model as we published in earlier works [36,69,70], where primary cultured cortical/striatal neurons were co-transfected with GFP and constructs expressing full-length huntingtin with either 23Q (FL-23Q) or 82Q (FL-82Q) or modified 82Q (FL-S1181A, FL-S1201A) (Figure 6B).