Energy partitioning in the cell cortex

Authors:
Publisher website
Google Scholar
Abstract
Living systems are driven far from thermodynamic equilibrium through the continuous consumption of ambient energy. In the cell cortex, this energy is invested in the formation of diverse patterns in chemical and mechanical activities, whose spatial and temporal dynamics determine the cell phenotypes and behaviours. How cells partition internal energy between these activities is unknown. Here we measured the entropy production rate of both chemical and mechanical subsystems of the cell cortex across a variety of patterns as the system is driven further from equilibrium. We do this by manipulating the Rho GTPase pathway, which controls the cortical actin filaments and myosin-II. At lower levels of GTPase-activating protein expression, which produce pulses or choppy Rho and actin filament waves, energy is proportionally partitioned between the two subsystems and is subject to the constraint of Onsager reciprocity. Within the range of reciprocity, the entropy production rate is maximized in choppy waves. As the cortex is driven into labyrinthine or spiral travelling waves, reciprocity is broken, marking an increasingly differential partitioning of energy and an uncoupling of chemical and mechanical activities. We further demonstrate that energy partitioning and reciprocity are determined by the competing timescales between chemical reaction and mechanical relaxation.
All Related Versions
Funding Information
  • United States Department of Defense | United States Army | U.S. Army Research, Development and Engineering Command | Army Research Office (W911NF-14-1- 0403)
  • U.S. Department of Health & Human Services | National Institutes of Health (R01 1R01GM126256, U54 CA209992, RO1GM052932)
  • Human Frontier Science Program (RGY0073/2018)
  • National Science Foundation (2132606)

This publication has 60 references indexed in Scilit: