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BP: Fachverband Biologische Physik

BP 42: Cytoskeletal filaments (joint BP/CPP)

BP 42.5: Vortrag

Donnerstag, 19. März 2015, 10:45–11:00, H 1028

Cross-linking proteins facilitate formation of microtubule bundles — •Marcel Prelogovic¹, Lora Winters², Iva Tolić², and Nenad Pavin¹ — ¹Faculty of science , University of Zagreb, Croatia — ²Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

During mitosis, microtubules (MTs) form a spindle which is responsible for proper segregation of chromosomes. In the fission yeast Schizosaccharomyces Pombe, the spindle is a bundle of MTs emanating from two spindle pole bodies and held together by cross-linking proteins. Our goal is to understand the dynamic properties of MTs interacting with cross-linking proteins and the role of cross-linking proteins in the formation of MT bundles. We introduce a theoretical model of MT bundling which describes angular movement of MTs around the spindle pole body driven by thermal forces and forces exerted by cross-linking proteins, described as elastic springs. If the number of cross-linking proteins connecting the MTs is above a critical number, attractive forces exerted by cross-linking proteins dominate over thermal forces at very small angles between MTs, causing MT-s to bundle. We identify stable bundles as the cases where MTs are more likely to be bundled than not. Theory yields bundling probability as a function of length and cross-linking protein concentration and predicts parameters for which stable bundles form. In conclusion, these results provide an explanation for how the angular brownian motion and cross-linking proteins affect the formation of stable MT bundles.