Biomathematics / Computational Biology Colloquium

Models of microtubule self-organization

Speaker: Aleksandra Plochocka, Center for Computational Biology, Flatiron Institute

Location: Warren Weaver Hall 1314

Date: Tuesday, March 3, 2020, 12:30 p.m.

Synopsis:

Microtubule self-organization is essential to the correct function of cells. We consider two different models of microtubule self-organization motivated by an in-vivo experiment on the Drosophila epithelium and an in-vitro experiment of kinesis-14 and stabilized microtubules.

In Drosophila epithelium the adhesion protein E-cadherin has to be delivered to cell boundaries in order to hold cells together in tissue. This delivery is done along the microtubule cytoskeleton. An outstanding question is how, given a broad range of possible dynamic behaviors of individual microtubules, functional microtubule networks are established and maintained in living cells. We use stochastic simulations to determine that self-organization of the microtubule network is robust in a wide parameter range: microtubule alignment is not affected by the details of their dynamic instability or interactions. We confirm this using genetic manipulations of Drosophila embryonic epithelial cells and develop a minimal model which suggests that the origin of robustness is the generic separation of scales in microtubule dynamics: polymerization and depolymerization predominating over catastrophe and rescue. We demonstrate that the microtubule network self-organization depends only on cell geometry and the distribution of microtubule minus-ends. 

An in-vitro system consisting of kinesin-14 and microtubules demonstrates chirality where kinesin-14 walks antiparallel microtubules around each other in a helical motion. I will discuss our preliminary results for the coarse-graining of microscopic properties of this system.