A Dynamical Paradigm for Molecular Cell Biology

A fundamental challenge in cell biology is to understand the molecular mechanisms underlying basic functions of a living cell, such as transforming incoming signals to appropriate responses or controlling the rates of DNA replication and cell division. The underlying biochemical and genetic mechanisms of a cell are dynamical systems that evolve in time and space according to well known laws of chemical reaction kinetics, molecular transport, and inevitable stochastic fluctuations in small volumes with limited numbers of molecules. Furthermore, the mechanisms are much too complex to comprehend accurately and dependably by informal, intuitive reasoning. To address this deficiency, I will argue that the methods of 'dynamical systems theory' (phase plane analysis, bifurcation diagrams, numerical simulations, and stochastic modeling) are ideal tools for a more precise, reliable and insightful understanding of molecular cell biology. I will illustrate this paradigm with examples from our models of cell cycle regulation in eukaryotes.