Frequency analysis of intracellular signal transduction systems

In this paper, we propose two analysis methods for a complicated and huge biological system. As a practical biological system, we employ a newly published signal transduction system with transcriptional control. For such a system, only few analysis tools such as parameter sensitivity analysis are available. First, we extend the concept of Bode diagram, including the effect of changes of both amplitude are frequency of input signal on output response. Next, we introduce the calculation of the L₂-induced gain. Although it is difficult to find the nominal gain theoretically, we show that the distribution of the gain over various amplitudes and frequencies of input signal provides us some useful information in a biological system.