Operating regimes of signaling cycles: statics, dynamics, and noise filtering.

ABSTRACT: A ubiquitous building block of signaling pathways is a cycle of covalent modification (e.g., phosphorylation and dephosphorylation in MAPK cascades). Our paper explores the kind of information processing and filtering that can be accomplished by this simple biochemical circuit. Signaling cycles are particularly known for exhibiting a highly sigmoidal (ultrasensitive) input-output characteristic in a certain steady-state regime. Here, we systematically study the cycle's steady-state behavior and its response to time-varying stimuli. We demonstrate that the cycle can actually operate in four different regimes, each with its specific input-output characteristics. These results are obtained using the total quasi-steady-state approximation, which is more generally valid than the typically used

SUBMITTER: Gomez-Uribe C 

PROVIDER: S-EPMC2230677 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature