Figure 6.

tau mutants in the N and C termini had differential effects on MT binding. A, diagram shows N- and C-terminal tau mutants. B–F, MT-binding assay was performed in the presence of paclitaxel as described under “Experimental procedures.” HEK293T cells were transfected with WT or the indicated tau mutations. Both the R5H and R5L tau mutants in the N terminus significantly increased MT binding, whereas the mutants near the C terminus, K369I and R406W, decreased MT binding. Immunoblots were probed with anti-β-tubulin antibody TUB 2.1 or total tau antibody 3026 as indicated. S = supernatants; P = pellet fractions. The relative molecular masses of protein markers are indicated on the left. On the right, FL is for full-length tau, and the brace indicates degradative tau bands. G, one-way ANOVA with Dunnett's test was performed with n = 18 for WT and n = 3 for each tau mutant. **, p < 0.01; ****, p < 0.0001.