Figure 1. SIRT1 decreases protein O-GlcNAcylation of tau in cells. (A) pcDNA3.1, pcDNA3.1/Myc-SIRT1 or pcDNA3.1/Myc-H363Y was transfected into GFP-Tau441 overexpressed HEK-293A or COS7 cells. Recombinant human tau441 immunoaffinity-purified with anti-GFP antibody from HEK-293A cells was immunolabeled with anti-GFP to tau, RL2 to O-GlcNAc or anti-Myc to SIRT1. Quantitative analysis of relative O-GlcNAcylation levels of tau after being normalized with total tau is shown as mean ± S.D. (n=3), ***, p < 0.001; (B) shSIRT1 plasmids or its control plasmids were transfected into HEK-293T cells. Recombinant human tau441 was immunoaffinity-purified with anti-GFP antibody from cells. Quantitative analysis of relative O-GlcNAcylation levels of tau after being normalized with total tau is shown as mean ± S.D. (n=3), ***, p < 0.001.