Figure 3
From: Microtubule-binding protein FOR20 promotes microtubule depolymerization and cell migration
FOR20 decreases the microtubule growth rate and increases the depolymerization rate and catastrophe frequency. (a) The schematic of in vitro microtubule dynamics assay depicts microtubules grown from a TAMRA-labeled microtubule seed that was immobilized on a cover glass surface by anti-TAMRA antibody. Tubulin polymerization is imaged by TIRF microscopy. In the kymograph, the vertical distance indicates time and the horizontal distance represents microtubule length. Microtubule length/time is the microtubule growth rate (L/tG) or depolymerization rate (L/tD). Lifetime is tG, and the catastrophe frequency is 1/tG. (b–e) 10% Alexa 488-labeled microtubules (12 μM free tubulin dimers) were grown from 10% TAMRA-labeled microtubule seeds (red) stabilized by GMPCPP (1 mM) in the presence of different concentrations of FOR20 on a cover glass surface coated with anti-TAMRA antibody, and then detected by TIRF microscopy. Kymograph depicts dynamic microtubules from plus (b and c) and minus (d and e) ends during microtubule growing and shrinking. The growing microtubule tip position was measured by ImageJ software (Fiji) to evaluate kinetic parameters of microtubule dynamics. **P<0.01, student’s t-test. Vertical bar, 5 min; horizontal bar, 5 μm. Also see Supplementary Movie S1, Supplementary Movie S2, Supplementary Movie S3.
