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Abstract Detail

Cell biology

Ambrose, Chris [1].

Plant cell shape and the microtubule cytoskeleton.

By dictating the structure and composition of the cell wall, microtubules play important roles in controlling plant cell shape and differentiation. Cortical microtubules line the plasma membrane and influence the targeting and trajectories of cell wall biosynthetic factors. Because this cortical microtubule array forms and transitions between different arrangements (parallel, random, bundled) it is an important and well-studied system for live imaging of microtubule dynamics (polymerization, depolymerization, catastrophe, rescue, pause) as well as microtubule-microtubule interactions (e.g. bundling, branching, severing). Here we focus on microtubule catastrophe events. We previously showed that when the tip of a growing microtubule encounters a cell edge (the borders separating adjacent sides of the cell) it is unable to pass the edge, and as such, often undergoes catastrophe and depolymerizes. Most studies, however, image microtubule dynamics on the outer periclinal cell cortex, where there is little influence from cell edges. We have found that in this region, microtubule catastrophe events occur primarily when the tip of a growing microtubule collides with another microtubule. Importantly, these collision-induced catastrophes make up roughly ninety percent of catastrophes, while the other ten percent occur freely with no contact. Because the degree to which cortical microtubules line up in parallel influences the likelyhood of inter-microtubule collisions, we found that total cellular catastrophe frequencies are dependent on the degree of microtubule order (i.e. parallelism). Specifically, the more disordered (i.e. low parallelism) the microtubules are, the higher the catastrophe frequency is. In conclusion, several studies have measured microtubule catastrophe rates without considering the the frequency of microtubule collisions, which varies with microtubule orientation. In order to accurately assess the influence of microtubules on cell shape and differention, future studies in the field of microtubule dynamics should take these findings into account.

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1 - University of Saskatchewan, Biology, 112 Science Place, Biology Building; Room 148, saskatoon, Saskatchewan, S7N5E2, Canada

Cell Biology.

Presentation Type: Oral Paper:Papers for Topics
Session: 58
Location: Salon 17/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:45 AM
Number: 58004
Abstract ID:1287
Candidate for Awards:None

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