Regensburg 2007 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Fibers and Bundles

BP 7.4: Vortrag

Montag, 26. März 2007, 17:00–17:15, H44

Force regulation of microtubule dynamics in living cells — •Christian Tischer¹, Damian Brunner², and Marileen Dogterom¹ — ¹AMOLF, Amsterdam, Niederlande — ²EMBL, Heidelberg, Deutschland

Microtubules are stiff biopolymers that self-assemble from tubulin proteins. Inside cells, microtubules are typically several micrometers long and form networks that are organized in a functional way. A unique property of microtubules is their ability to switch from a polymerizing to a depolymerizing state (so-called "catastrophes"). Investigating the intracellular regulation of this fascinating out-of-equilibrium behavior is crucial in order to understand how microtubules fulfill their important functions during cell division and cell morphogenesis. Here, we use the fission yeast (S. Pombe) to investigate regulation of microtubule catastrophes at the cell boundary. Fission yeast is an excellent model organism: it has a well defined cylindrical shape and contains only few microtubules whose dynamics can be readily followed with live-cell microscopy. Developing specialized image analysis methodology we were able to investigate the spatial and temporal distribution of microtubule catastrophes with unprecedented statistical accuracy. Analyzing thousands of catastrophes in hundreds of cells, we provide strong evidence that compressive polymerization forces, arising from growth of microtubules against the cell boundary, indeed enhance the rate of catastrophes. This effect had been predicted by measurements on purified microtubules growing against artificial boundaries.