Fig. 6: HURP promotes microtubule growth in the presence of vinorelbine.

a A representative kymograph show a microtubule grown from X-rhodamine-labeled GMPCPP-stabilized seeds with HiLyte Fluor^TM647 tubulin without addition of vinorelbine and GFP-HURP FL. b–e Under the same experimental setting as in (a), representative kymographs show microtubules grown in the presence of 250 nM vinorelbine without and with the indicated concentration of GFP-HURP FL. Plus and minus ends of microtubules are indicated. Vertical scale bar = 90 sec, and horizontal scale bar = 10 μm. f–k Quantification of microtubule dynamicity, including (f) polymerization rate, (g) depolymerization rate, (h) catastrophe frequency, (i) rescue frequency, (j) ratio of rescue and catastrophe frequency, and (k) microtubule length, as a function of vinorelbine with the indicated GFP-HURP FL concentrations. Control experiment (no addition of vinorelbine and GFP-HURP FL protein) is indicated. Data are mean ± SD from three independent experiments (n = 26 (control, vinorelbine only, 250 nM) and n = 20 (500 nM and 1 µM) microtubules). Two-tailed Student’s t test; Statistical differences: *, P < 0.05; **, P < 0.001; ****, P < 0.0001; n.s., not significant. l A representative image shows microtubules grown from X-rhodamine-labeled GMPCPP-stabilized seeds (red) with HiLyte Fluor^TM 647 tubulin (blue) without addition of vinorelbine and GFP-HURP FL (left panel). Under the same experimental setting, representative images show microtubules grown in the presence of vinorelbine without and with GFP-HURP FL. Incubation time is 40 minutes. Scale bars, 10 μm. m Quantification of length of dynamic microtubule (blue), as a function of vinorelbine with and without GFP-HURP FL in the indicated time points. Data are mean ± SD from three independent experiments (n = 59 microtubules for each condition). Two-tailed Student’s t test; Statistical differences: ****, P < 0.0001; n.s., not significant.