Analysis of the impact of ERK5, JNK, and P38 kinase cascades on each other: a systems approach.

The classical concept of linear pathways is being increasingly challenged by network representations, which emphasize the importance of interactions between components of a biological system, and motivates for adopting a system-level approach in biology. We have developed a dynamical system that integrates quantitative, dynamic and topological representation of network of ERK5 (Extracellular signal-regulated kinases 5), JNK(c-Jun N-terminal kinases) and P38 kinase cascades. We have observered that, the transient activation of ERK5, JNK1 and P38beta kinase, and the persistent activation of JNK2, JNK3 and P38 delta kinase does not get affected due to the cross-talks between ERK5, JNK and P38 kinase cascades. But it is due to the cross - talks, the transiently activated P38alpha kinase become inactivated, and the transiently activated P38gamma kinase become persistently activated. The impacts of one-way cross-talks between the cascades are insignificant and differ from the impact of two-way cross-talks. We generate a hypothesis that, signaling pathways should be studied as a system by considering the cross-talks between the two adjacent cascades.