Impaired MT disassembly and abnormal cell morphology in TTL KO–cultured neurons. (A and B) WT or TTL KO hippocampal neurons 2 d after plating. Neurons were incubated in the absence (control; A) or presence of 20 µM nocodazole (B), permeabilized in saponin-based buffer to extract free tubulin molecules, and double labeled for F-actin (red) and tubulin (green). (C) Quantitative analysis of nocodazole effects. The axonal MT signal was expressed as the ratio of MT signals measured after nocodazole treatment versus control conditions (mean values ± SEM). MT signals were estimated for a minimum of 50 axons from three independent experiments. (D–G) Cell morphology in WT or TTL KO neurons showing length, number of primary or of higher order collaterals, and total length of collaterals. Mean values ± SEM for 93 WT neurons and 123 TTL KO neurons from three independent experiments are shown. (H) Depolymerizing activity of the neck + motor construct of KIF2A on tyrosinated or detyrosinated MTs. The assay was performed as in Fig. 2 C. Mean values ± SEM for 75 cells are shown. ***, P < 0.001 with a t test. Bars, 20 µm.