GMPCPP abolishes TIP activity of the CLIP-170(H2)–EB1 complex. The movie shows the localization of CLIP-170(H2)–GFP molecules (a carboxyl truncation of the plus end microtubule tracking protein CLIP-170) on GMPCPP microtubules in the presence of unlabeled EB1 (a plus end microtubule tracking protein). In the absence of GTP hydrolysis, the CLIP-170(H2)–EB1 complex does not specifically target growing microtubule plus-ends, but instead binds along the length of the microtubule lattice. (Scale bar, 2 micron.) Microtubule dynamics were visualized at 22 °C using a TIRF microscope fitted on an inverted microscope (Nikon TE-2000U). Images were captured with a backilluminated electron-multiplying CCD camera (Cascade-512B, Photometrics) using time-lapse capture at burst mode at 10 frames per second for the analysis of +TIP dynamics at the single-molecule resolution. This movie corresponds to Video S4 from Proc Natl Acad Sci U S A. 2009 Jan 13;106(2):492-7. Epub 2009 Jan 6.