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Abstract Detail



Cell biology

Chi, Zhihai [1], Ambrose, Chris [1].

Microtubule collision-induced catastrophe in Arabidopsis cortical microtubule arrays.

Microtubules (MTs) are polymers of α- and β-tubulin that organize into three-dimensional arrays to direct cell division, expansion and morphogenesis. MT organization is determined by the rates at which MTs grow (polymerize) and shorten, as well as the frequencies of transitions between growth and shortening phases. The switch from growth to shortening is termed catastrophe, and from shortening to growth is rescue. Numerous studies have measured MT catastrophe frequencies, but did not take into account the fact that MT catastrophe occurs in two ways: (1) after collision of a growing MT end with another MT (termed encounter-based catastrophe); and (2) without collision (termed free catastrophe). To test the relative contribution of each catastrophe type, we imaged cotyledons of Arabidopsis plants expressing the MT reporter GFP-TUB6 and quantified the frequencies of free vs encounter-based catastrophes. We found that roughly 90% of catastrophes occur via the encounter-based mechanism. Thus, overall cellular catastrophe frequency is dependent on how frequently MTs collide. Consistent with this, cells with highly ordered, parallel MT arrays showed lower total catastrophe frequencies compared to disorganized net-like arrays. These data show that overall MT organization should be taken into account when measuring catastrophe frequencies.


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1 - University of Saskatchewan, Biology, Rm. 148 W.P. Thompson Building 112 Science Place , Saskatoon, SK, S7N 5E2, CA

Keywords:
cortical microtubule
encounter-based catastrophe
microtubule pause.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PCL010
Abstract ID:1122
Candidate for Awards:None


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