FIGURE 3:

MT bundle flexibility is differently regulated, depending on MAP65 cross-linker. (A) Experimental setup (top). MT seed bundles are immobilized on functionalized bar-shape patterns via biotin–NeutrAvidin link (step 1), and further elongated by perfusing tubulin in presence of MAP65 and fluorescent beads as described in Figure 1 (step 2). The hydrodynamic flow is applied when growing bundles have an average length between 10 and 20 μm (middle pattern; step 3). Time series of a bending bundle that elongates in the presence of tubulin, 100 nM MAP65-4, and fluorescent beads (bottom, left). MTs are in green; MT seeds and beads are in red. Line scan of the MT bundle (bottom, right). MT number in the bundle is determined by the level of fluorescence (right). (B) (a) Time series of bending bundles that elongate in the presence of tubulin and 100 nM MAP65-1. (b) Superposition of images showing the amplitude of the bending (red arrows).