DP mutants increase sensitivity of MTs to demecolcine and decrease MT polymerization rates. (A) DP and MT immunostaining, and thresholded MT images, in demecolcine-treated cells expressing DP mutants. (n > 35 cell fields for each condition from three independent experiments). (A, bottom) Tubulin intensities during demecolcine treatment. (B) Immunolocalization of keratin and GFP in cells expressing DPII-GFP constructs and treated with demecolcine. (C) MT polymerization rates and frequency of pausing events for cells expressing DPII-GFP constructs (n > 127 EB3 tracks for each condition compiled from n > 4 fields from more than four movies for each condition). All data are from SCC9s. Bars, 10 µm. Error bars indicate SEM.