Effect of retroactivity in the dynamics of mixed feedback loop

Application of engineering principles for the redesign of biological systems is well supported by mathematical foundations and computational techniques. Modularity serves as one among such engineering concept adopted for the redesign and synthesis of biological systems. Based on modularity, biological subsystems called modules are engineered to exhibit desired characteristics with the objective to integrate them to form complex systems, as in engineering disciplines. Even though biological modules were engineered successfully, a retroactive effect has been identified when they are integrated. This generates nonlinearities which challenge the predictability of engineered biological systems. Here, we attempt to analyze this retroactive effect on the dynamics of one small biological network called the Mixed Feedback Loop. We successfully modeled and quantified the impact of interconnections between the modules in Mixed Feedback Loop by implementing Cascaded Layering Framework, a general modeling framework for quantifying nonlinearities in modular interconnections.