Drosophila XMAP215 and EB1 promote MT growth and catastrophe, respectively. (A) Drosophila XMAP215^msps and EB1 recombinants used in this study. (B, top) Kymographs showing constant MT end localization of XMAP215^msps-GFP during growth, shrinkage, and the phase in which no MT growth event took place. Lattice binding was also sometimes observed. (bottom) EB1 exclusively localized to the growing ends of MTs. (C and D) Parameters of MT polymerization dynamics in the presence of 15 µM tubulin and various concentrations of XMAP215^msps-HA or EB1 (untagged). Relative values are plotted in these graphs, whereas the actual values are presented in Tables S1, S2, and S3. The mean values of each experiment are marked in gray, whereas the mean values of all the experiments are indicated by black marks. Representative kymographs are shown on the top. See Fig. S2 for the XMAP215^msps data using 7.5 µM tubulin. Data from a single experiment are marked with the same shape. Bars: (horizontal) 5 µm; (vertical) 1 min.