Sentin, a novel regulator of microtubule dynamics. (A) A shorter metaphase spindle was formed after the simultaneous RNAi knockdown of Sentin and Sak, a factor essential for centrosome formation (± SD; n = 12 and 24). (B) Microtubule plus end dynamics was suppressed by Sentin or EB1 RNAi. (top) A control cell that has many dynamic cytoplasmic microtubules during the interphase (the area encircled with yellow is magnified and the plus ends of two microtubules are marked with pink and green dots). (bottom) Life history plot of a representative microtubule after each RNAi treatment, in which microtubule length from the arbitrary chosen point is plotted over time. Also see Video 1 and Table I. Bars, 5 µm.