Studying the role of cross-linking proteins and microtubule pivoting in formation of parallel bundles by using numerical simulations

Tokom mitoze stanica formira se diobeno vreteno, stanični mehanizam koji ima sposobnost samoorganizacije i odgovoran je za pravilnu segregaciju genetskog materijala. Jedni od elemenata koji tvore diobeno vreteno su mikrotubuli, koji pomoću vezivnih proteina, formiraju paralelene i antiparalelene svežnjeve, stabilne strukture unutar diobenog vretena. Mehanizmi iza formacije svežnjeva još nisu do kraja istraženi. Cilj ovoga rada je proučiti formaciju paralelnih svežanja u stanicama kvasca Schizosaccharomyces pombe. Dosadašnji modeli opisuju djelovanje mikrotubula zbog vezivnih proteina kao kontinuriano polje sila , no proteini su u stvarnosti diskretne čestice. U ovom radu proučavano je kako diskretna priroda sila koje stvaraju vezivni proteini utječe na proces stvaranja paralelnih svežnjeva. Otkrili smo kako za prirodne vremenske skale, raspodjele proteina na mikrotubulima odstupaju od prosjeka, ali njihov efekt ostaje isti. During mitosis, cell forms a spindle, a cellular mechanism that has the ability to self-organise and is responsible for proper segregation of genetic material. Some of the of the elements that form a spindle are microtubules, forming parallel and antiparallel bundles with cross-linking proteins, stable structures in the spindle. Aim of this thesis was to study the formation of parallel bundles in fission yeast (Schizosaccharomyces pombe) cells. Former models describe microtubule interaction as a continuous field of forces, but proteins are discrete particles. In this thesis we have studied how the discrete nature of the forces generated by the cross-linking proteins affects the process of bundle formation and we have discovered that for relevant time scales, protein distribution on microtubules deviate from the average, but their overall effect stays the same.