CLIP-170 tracks growing microtubule ends in X. laevis egg extract in an EB1-dependent manner. (A) Scheme of the domain architecture of CLIP-170 and EB1. (B) TIRF microscopy of CLIP-170–GFP (green) on dynamic Alexa Fluor 568–labeled microtubules (red) in mock-depleted interphasic egg extract: an image of several microtubules (left), a time sequence (middle), and the corresponding kymograph (space-time plot) as overlay and separate channels (right) of a single microtubule are shown. (C) Western blot of mock-depleted (ΔIgG), EB-depleted (ΔEB), and EB-depleted extract with added recombinant EB1 (ΔEB+EB1), probed with an anti-EB1 antibody. (D) Images (top) and kymographs (bottom) of CLIP-170–GFP and dynamic microtubules in EB-depleted interphasic extract (left) and in extract with added recombinant EB1 (right). (E) Image (top) and kymograph (bottom) of EB1-GFP and microtubules in mock-depleted extract. Recombinant CLIP-170–GFP or EB1-GFP was added to a final concentration of 125 nM. Kymographs display a period of 46 s. Bars, 5 μm.