Some Control Theory Ideas in Systems and Synthetic Biology

A central concern of systems and synthetic biology is that of identifying, and understanding the roles of, signal transduction pathways and feedback loops, whether in natural systems or as an aid to engineer networks that exhibit a desired behavior. This talk will discuss how certain types of network qualitative information can be gleaned from "dynamic phenotypes", a term that we take as encompassing transient characteristics of temporal responses, particularly when using richer classes of probing signals than step inputs. Examples of dynamic phenotypes include fold-change detection (scale invariance), non-monotonic responses, and induced subharmonic oscillations. We will present theorems that relate different behaviors to circuit motifs, and touch upon biological applications at multiple scales, including enzymatic mechanisms, chemosensing, the generation of certain stress responses, and the kinetic recognition of self vs non-self by the immune system.