MT dynamic defects after expression of the Tuba1a S140G-mutant construct. (A) Example of a 24-s time-lapse video microscopy sequence of EB3-mCherry tracking in Neuro-2a cells after transfection with control WT Tuba1a, mutant Tuba1a S140G, control WT Tuba8, and combined Tuba1a S140G + Tuba8 WT. The EB3-mCherry spots were tracked every 6 s in two different cellular compartments: in the soma (yellow dots) and in the process (blue dots in the outlined rectangle). Bars, 6.4 µm. (B–E) EB3-mCherry polymerization (polym.) straightness (B and D) is significantly increased in the soma of cells expressing the mutant Tuba1a S140G construct (B, first two bars). EB3-mCherry polymerization speed is not changed with the mutant Tuba1a S140G construct in either the soma or process (C and E). Comparatively, control Tuba8 overexpression decreased EB3-mCherry polymerization straightness both in the soma and the process (B and D) and increased the EB3-mCherry polymerization speed in the soma (C and E). Coexpression of mutant Tuba1a S140G together with Tuba8 did not restore the EB3-mCherry polymerization straightness nor the speed to the control level and gave results similar to Tuba8 alone. *, P < 0.05; ***, P < 0.001. n = 8,253 spots for control Tuba1a; n = 8,933 spots for Tuba1a S140G mutant; n = 8,450 spots for control Tuba8; n = 9,182 for Tuba1a S140G mutant + Tuba8 in the soma; n = 2,185 spots for control Tuba1a; n = 1,450 spots for Tuba1a S140G mutant; n = 2,242 spots for control Tuba8; and n = 3,065 for Tuba1a S140G mutant + Tuba8 in the processes. Data are represented as mean ± SEM.