Alladi Ramakrishnan Hall

Signalling Networks: Uncovering the Cellular Digital Computer

Soumyadip Banerjee

IMSc Chennai

Biological cells have to rely on signalling networks to make fast, complex decisions in real time. These decisions often are in binary form, for example, the choice to divide or not. While these decisions may seem to result from a logical computation at a superficial level, the mechanisms associated with such computations are not clear at the signalling network level. As a proof of concept, using the Huang-Ferrell model of a Mitogen-Activated Protein Kinase signalling cascade, we show that by directly controlling the phosphatase level of two different layers of the cascade, a two-input NOR gate can be obtained. The gate fires only when both inputs are low. Further, to test the hypothesis, we used kinase inhibitors as inputs to emulate the action of phosphatases and found a similar NOR-like response. These findings may help us understand how complex logical operations are executed at the signalling network level.