R4-10 recapitulates the MT-binding characteristics of FL TPX2 in vitro. (A–E) Images and corresponding kymographs showing the behavior of indicated GFP-tagged TPX2 repeat combinations at indicated concentrations on dynamic MTs grown in our standard assay buffer containing 50 mM KCl. Arrows in A indicate the end localization of R8-9. (F) Line-scan intensity profiles of GFP-TPX2 R4-10 (green) and MT (red) corresponding to the white horizontal dashed lines in E. (G) Plots of the average intensity of GFP-TPX2 R4-10 at indicated concentrations on a 2-µm-long segment of GDP-MT as in E (between two vertical dashed lines) against time. The values were normalized to the maximum intensity of 1 µM GFP-TPX2 R4-10. n = 10–20 MTs from two experiments. (H) Quantification of intensities of indicated GFP-tagged TPX2 repeat combinations at 200 nM (top) or 1 µM (bottom) on GMPCPP seeds and GDP-MT lattices. The values were normalized to the intensity of 1 µM GFP-TPX2 R4-10 on GDP-MT lattices. n = 13–14 MTs from two experiments. N.D., not detected. Horizontal scale bars, 2 µm; vertical scale bars, 2 min. Data represent mean ± SD.