Carsten Conradi: Multistationarity regions for systems that admit a monomial parametrization

Polynomial Ordinary Differential Equations are an important tool in many areas of quantitative biology. Due to high measurement uncertainty, few experimental repetitions and a limited number of measurable components, parameters are subject to high uncertainty and can vary in large intervals. One therefore effectively has to study families of parametrized polynomial ODEs. Multistationarity (i.e. the existence of at least two distinct positive steady states) has been recognized as an important feature of these ODEs. As parameter values are confined to large intervals one is generally interested in parameter conditions that guarantee multistationarity and further constrain the parameter values. The focus of this talk are mass action ODEs that admit a monomial parameterization of positive steady states. For such systems it is straightforward to derive a parameterization of rate constants where multistationarity exists. To this class belong, for example, multisite phosphorylation systems, key players in intracellular signaling and regulation.