Mechanism of MDCK II cell polarization during the cell division: A computational study

Some epithelial cells form a monolayer and individual cell in the monolayer is polarized with respect to the membrane protein location and the intracellular structure. It is observed that mitosis and cytokinesis occur in parallel to the monolayer plane so that the monolayer structure is maintained. The centrosome locations of non-mitotic cells, however, are not necessarily positioned to lead the parallel cell division. Therefore, there must be mechanisms by which centrosomes get relocated, for example in MDCK II cells, from the apical domain to lateral domain to have a proper mitosis and moved back to the apical domain after the cytokinesis. The mechanisms, however, remain poorly understood, especially the mechanical part. A computational model is constructed for centriolic microtubule asters which are driven by localized molecular motors on the cortical layer. This model shows that the interaction between the cortical bound molecular motors and microtubules can lead the two-way relocation of the centrosome. The model also shows that the microtubule dynamic instability plays an important role in initiating the relocation, the tight junction is a key element in positioning the centrosome, and the swelling nucleus can accelerate the movement of centrosome to the lateral side.