Depolymerizing activity of MCAK on pure tyrosinated or detyrosinated MTs. (A) Tyrosinated (Tyr) and detyrosinated (Detyr) MTs stained for either total, tyrosinated, or detyrosinated tubulin. (B) Representative pictures of tyrosinated and detyrosinated MT before and after exposure to MCAK for 20 min. (C) Analysis of MT depolymerization in the presence of MCAK. The MT signal is the percentage ± SEM of the area occupied by the MT at time 10 or 20 min versus time 0. A minimum of 20 independent images was measured in each condition. **, P < 0.01; and ***, P < 0.001 with a t test. Bars, 10 µm.