The dynamical behavior of the target protein in the three signaling systems.

Abstract

<p>(A) The IP3 concentration of the GPCR pathway over time by deleting individual feedback modules from the full network. All feedback modules in red act at different time scales and in different ways. (B) The ERK-PP concentration over time by deleting individual feedback modules from the whole MAPK network. Different feedback modules carry out different but synergetic functional duties during cell signaling. (C) The change of the (STAT1n*)₂ concentration over time by deleting individual feedbacks from the whole JAK/STAT network. The upstream local feedback (R09) delays the response significantly, and the feedback module (Module 3) directly linked to the target attenuates the output signal. (D) The change of Ca²⁺ concentration over time in the GPCR signaling system. Note that the faster the increase of [IP3], the shorter the response time and the higher the amplitude of the Ca²⁺ spark. A quick time response of IP3 determines the profile of the Ca²⁺ spark; and the amplitude of IP3 concentration does not seem to be of primary importance.</p