Tau acetylates and stabilizes β-catenin thereby promoting cell survival (2019)
Figure 1

Fig. 1 Tau acetylates β-catenin at K49 in cells, mice and human brains and phosphorylation further increases its acetyltransferase activity

(A and B) Tau increased β-catenin acetylation (Ace-β-cat) measured by immunoprecipitation using anti-β-cat, or Western blotting using anti-β-cat, anti-acetylated lysine (Ace-lys) and HT7 (probes specifically human total Tau). HEK293 cells transiently transfected with wildtype Tau40 (Tau) or the empty vector (Vec) (n = 3 from three independent experiments).

(C and D) β-cat mutation at K49 (K49R) but not K19 (K19R) abolished Tau-induced acetylation. HEK293 cells were co-transfected with eGFP-β-cat (WT, or K19R, or K49R, or K19R/K49R) and Tau or the empty vector for 48 h, and then immunoprecipitated using anti-GFP and Western blotting using anti-β-cat, anti-Ace-lys and HT7 (n = 3 from three independent experiments).

(E and F) The increased β-cat (K49) acetylation was detected in the hippocampal extracts of human Tau transgenic mice (Tau+) compared with the endogenous Tau knockout mice (Tau-), measured by Western blotting using acetylation site-specific antibody (Ace-β-cat-K49); arrowhead in panel E denoted nonspecific band identified by molecular weight. The remarkably increased levels of phosphorylated Tau at Ser199 (pS199) and AT8 epitopes were detected in Tau+ mice (at least 3 mice per group were used).

(G and H) K18 deletion of Tau (Tau-k18(-)) attenuated Tau-induced β-cat acetylation. HEK293 cells were transfected with empty Vec, or Tau40 or Tau-k18(-) for 48 h, and the ace-β-cat was measured by immunoprecipitation using anti-β-cat and Western blotting using anti-ace-lys, anti-β-cat, and Tau5 (detecting total Tau; n = 3 from three independent experiments).

(I-L) The increased total and Ace-β-cat (K49) levels positively correlated with increased phosphorylated Tau pS199 and AT8 as detected by Western blotting in the hippocampal extracts of AD patients compared with age-matched controls (n=10 each group, detailed information for human brain samples was shown in Appendix Table S1). Pearson analysis was used for correlation analysis (K and L).

(M and N) Expressing pseudo-phosphorylated Tau (TauS199E) further increased the K49-acetylation of β-catenin. N2a cells were transiently transfected with Vec, Tau40 or TauS199E for 48 h, levels of K49-acetylated β-cat, total β-cat and total Tau were detected by Western blotting (n=3 biological replicates each group).

(O and P) Inhibiting acetyltransferases CBP/P300 by TPOP146 (134 nM) or PCAF by L-45 (126 nM) for 24 h did not significantly decrease the K49-acetylated β-cat level in Tau-overexpressing N2a cells (n=3 biological replicates each group).

Data information: Data are presented as mean ± SEM; *, P<0.05; **, P<0.01; ***, P<0.001 vs Vec (B, N and P), or vs β-cat WT (D) , or vs Tau- (F) , or vs Tau (H), or vs Ctrl (J); #, P<0.05, ##, P<0.01, ###, P<0.001 vs β-cat WT plus Tau (D), or vs Tau (N) ; &&, P<0.01, &&&, P<0.001 vs β-cat K19R plus Tau (D); the absence of asterisk indicates that the difference is not significant. Data were analyzed by Student's t test (B, F and J) or one-way ANOVA (D, H, N and P).