Signaling and Control

Control processes are responsible for maintenance of the organism’s internal environment (homeostasis) and, therefore, inextricable from the very definition of living matter. Optimal homeostasis involves adaptation and relies on processing of signals from the environment. Signaling and control processes are considered that exhibit nonlinear effects such as an all-of-nothing response, switches, modulation of oscillations, and hysteresis. Examples are drawn from intracellular molecular systems, as well as multicellular and inter-organ control networks: protein kinase cascades with feedback, dynamics of the transmembrane electrochemical potential, regulation of gene expression by metabolism, and control of breathing.