Structural Robustness and Fragility of Biochemical Networks
Stockholm Bioinformatics Center Seminars
Wednesday 04 February 2009
to 17:00 at
Elling Jacobsen (KTH)
Robustness, the ability to maintain functionality in the presence
of internal and external perturbations, is a fundamental property
of biological systems. Uncovering the system level principles and
architectures underlying biological robustness can be a key to
understand the design principles of complex biochemical networks.
In this talk I will present a control theoretic approach to robustness
analysis of biochemical network models that can serve to identify
mechanisms underlying a given function and its robustness. Essentially,
we consider the impact of adding general type dynamic perturbations to
the direct network interactions and determine the smallest distance
to a perturbed network with a qualitatively different behavior.
Important advantages over more traditional approaches to robustness
analysis, such as parametric sensitivity analysis, is that information
on the importance of specific interactions is obtained and that the
potential impact of unmodelled phenomena can be accounted for.
Furthermore, specific network fragilities can be identified. The focus
will be on functions related to bistable switches and sustained
oscillations, and I will demonstrate the method through application to
circadian clocks and MAPK signaling cascades.