(A) Representative western blot of soluble HTT (ab-MAB5492), HTT pS13 (ab-CHDI-90001039-1) and HTT pT3 (ab-CHDI-90001528-1) upon coexpression of HTTex1 16Q eGFP or 72Q eGFP or its phosphorylation-incompetent mutants with the indicated kinases for 48 hour in HEK293T cells. (B) The graph indicates the fold change in HTT in samples like illustrated in A, relative to empty vector controls normalized to GAPDH. 