XMAP215^Msps accumulates at the growing tip in a Sentin-dependent manner. (A) Tip accumulation of XMAP215^Msps depends on Sentin. After RNAi of Sentin, XMAP215^Msps-GFP was scarcely detected at the plus ends of growing microtubules. Kymographs are shown at the bottom. Bar, 10 µm. Also see Video 6. (B, left and middle) EB1-GFP or GFP-CLASP localization after Sentin RNAi. Most of the growing microtubules had EB1-GFP or GFP-CLASP signals at the tips after Sentin RNAi. Kymographs are also shown. Bars, 2 µm. (right) GFP-Sentin remains at the growing tip after XMAP215^Msps RNAi. Error bars in each graph show SEM of six cells (each have more than five microtubules analyzed). (C) EB1- and Sentin-mediated regulation of microtubule plus end dynamics. EB1 binds to the growing ends of microtubules via its N-terminal region (N). Sentin is recruited to the plus ends by binding of its C terminus (C) to the C-terminal region of EB1. XMAP215^Msps and tubulin are then efficiently recruited to the plus ends of microtubules. The dissociation of tubulin from the end of the microtubules is also promoted by Sentin, which is not depicted in this cartoon.