Figure 6.
Microtubule Minus-End-Directed Motor HSET Organizes Asymmetrically Growing Microtubules into Asters and Nematic Networks of Extensile Bundles
(A and B) Confocal fluorescence microscopy images showing time course of (A) HSET-mediated organization of microtubule asters and of (B) a globally contracting microtubule network of CAMSAP3-C-nucleated microtubules at the indicated protein concentrations.
(C) Scheme showing inverted microtubule growth asymmetry in the presence of microtubule plus-end capper DARPin (D1)2.
(D) Kymographs showing fast microtubule minus-end growth using Alexa546-EB3 to visualize microtubule ends growing at 60 μM tubulin from GMPCPP-stabilized microtubule “seeds” (left) or of spontaneously nucleated microtubules (right) in the presence of 2.9 μM DARPin (D1)2.
(E) Microtubule growth speed distribution in the absence (top) and presence (bottom) of 2.9 μM DARPin (D1)2 at 60 μM tubulin. Number of microtubule growth episodes measured: without DARPin (D1)2, 271; with DARPin (D1)2, 328.
(F) Confocal fluorescence microscopy images showing time course of mCherry-HSET-mediated organization of microtubules with inverted growth asymmetry into networks of extensile bundles in the presence of 2.9 μM DARPin (D1)2 at 60 μM tubulin. mCherry-HSET concentration was 100 nM. Temperature was 33°C.