(C) Representative immunoblot of the HTT (ab-MAB5492) after filter retardation assay from the insoluble cellular fraction upon expression of HTTex1 16Q eGFP or 72Q eGFP or its phosphorylation-incompetent mutants with the indicated kinases for 48 hour in HEK293T cells. (D) Quantification of the fold change in HTT aggregates compared to EV expressing HTTex1 16Q from the experiments like in C. 