A Compartmentalized Model to Directional Sensing: How can an Amoeboid Cell Unify Pointwise External Signals as an Integrated Entity?

After being exposed to an external chemical attractant, several internal cellular downstream signal transduction pathways control the chemotactic machinery of eukaryotes. The spatial activation of these pathways ultimately leads to some sort of symmetry breaking around the cell periphery in the form of redistribution of several biochemicals, e.g., polymerized actin at one side of the cell for propulsion and the assembly of myosin II at nearly opposite side for retraction. In this study, we revisit the modeling of this process, which is called directional sensing, with a compartment-based design. In our model, we consider a network of excitable elements around cell circumference which are stimulated occasionally with local colored noise. The exciting elements are capable of sharing information with their close neighbors. We show that the dynamic can distinguish a temporary but enough long-lasting direction, statistically, pointing towards the gradient of external stimulants that can be deemed as the preferred orientation of the cell periphery during the directional sensing process in eukaryotes.