Fig. 6: Katanin recruitment to the microtubule crossover site does not require Msd1–Wdr8. | Nature Communications

Fig. 6: Katanin recruitment to the microtubule crossover site does not require Msd1–Wdr8.

From: An anchoring complex recruits katanin for microtubule severing at the plant cortical nucleation sites

Fig. 6

a, b Time-lapse confocal microscopy images of katanin recruitment to the crossover sites in wild-type (a) and wdr8 (b) cells. Katanin (magenta) and microtubules (green) are labeled by GFP-KTN1 and mCherry-TUB6, respectively. Open and closed arrowheads respectively indicate the absence and the presence of KTN1 particles. Yellow and white arrows show the growing and shrinking plus ends, whereas blue arrows indicate the shrinking minus ends of cortical microtubules. Kymographs track the dotted blue lines. Microtubule crossover events set the zero time points. Rectangle regions boxed by red lines are enlarged on the right where dotted white lines mark the plus (+) and minus (−) ends of severed microtubules. A total of 54 and 65 similar events were observed in wild-type cells and wdr8 cells, respectively. Bars, 2 µm. c Distribution of GFP-KTN1 signal intensities at the crossover in wild type (720 ROIs from 14 cells) and wdr8 (960 ROIs from 11 cells). d Katanin accumulates at the crossover sites prior to severing in wild type (green; 42 events from 14 cells) and in wdr8 (magenta; 51 events from 11 cells). Detachment of the severed microtubules were visually detected from the confocal images and was set to the time zero. The error bars indicate SD. e, f Time-lapse confocal microscopy images of Msd1a-GFP (e) and Wdr8-GFP (f) (magenta), and mCherry-TUB6-labeled microtubules (green). Open and closed arrowheads respectively indicate the absence and the presence of Msd1/Wdr8 particles. Bars, 2 µm. e A daughter microtubule was formed at a branching nucleation site (labeled by Msd1a-GFP) and crossed bundled microtubules and another microtubule at 148 s, which resulted in severing without prior recruitment of Msd1a (152 s). f A daughter microtubule was formed at a branching nucleation site (labeled by Wdr8-GFP) and crossed a microtubule at 16 s, which resulted in severing in the absence of Wdr8 at 44 s. Nucleation of the daughter microtubule is set to time zero.

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