Speaker
Description
Tissue development and homeostasis rely on cellular decision-making in response to fluctuating environmental signals. The process of cellular decision-making integrates dynamics on different spatial scales ranging from the molecular to the tissue scale, where all spatial scales are subject to fluctuations and consume chemical energy to fuel interactions. How are information and fluctuations propagated in a dynamic multi-scale organisation of non-equilibrium dynamics and how can biological systems exploit this to process environmental information? Here, we show how the dynamics of active organelles suppresses cellular responses to fast fluctuating environmental signals, but facilitates the response to slow biological relevant signals. We demonstrate that active organelle dynamics gives rise to a kinetic low pass filter. Starting from a full stochastic treatment, we derive a generalized Fokker Planck equation in which a localized mode gives rise to a collective degree of freedom. We identify the localization mode in full stochastic simulations, demonstrate how the dynamics of the localization mode builds a kinetic low pass filter, and show how this gives rise to strongly increased sensitivity of selectivity of cellular decisions. We demonstrate our findings in the specific context of the metabolic regulation of cell death focusing on the interplay of Bax protein dynamics with rapid mitochondrial fusion and fission. Our work shows paradigmatically how biological function relies on the integration of non-equilibrium processes on different spatial scales in order to control and respond to fluctuations.
