Self-organization of microtubules and antagonistic mitotic motors. (A) Competition between XCTK2 and wild-type Eg5 in self-organization of microtubules and motors. (left) Time course of the self-organization of mCherry-XCTK2 (red), Eg5-GFP (green), and Cy5-tubulin (blue) into asters with centrally accumulated mCherry-XCTK2; concentrations are as indicated. (right) Time course of self-organization as monitored by image parameters as in Fig. 4 A for the color channels as indicated. (B) Competition between XCTK2 and chimeric Kin-Eg5 in self-organization of microtubules and motors. (left) Time course of the self-organization of mCherry-XCTK2 (red), Kin-Eg5–GFP (green), and Cy5-tubulin (blue) into separate mCherry-XCTK2–containing asters and Kin-Eg5–GFP-containing asters; concentrations are as indicated. (right) Time course of self-organization as monitored by image parameters. All experiments shown were performed in assay buffer containing 50 mM KCl. a.u., arbitrary unit. Bars, 50 µm.