The Impact of Retroactivity on the Input/Output Static Characteristics of a Signaling Component

In prior work, we have shown that just as in many engineering systems, impedance-like effects appear at the interconnection of biomolecular systems. These effects are called retroactivity, to extend the notion of impedance to biological systems. Signaling components, such as covalent modification cycles, play a central role in the transmission of signals within a cell and from outside the cell. They are typically found in highly interconnected architectures in which a component has several downstream clients. In this paper, we show that retroactivity from downstream targets decreases the sensitivity of response to an input stimulus.