“The MWC equilibrium framework not only has been exploited for thinking about the activity of the chemotaxis receptors but also has served as a null model for the switching behavior of the bacterial flagellar motor. This motor switches between clockwise and counterclockwise rotation, as a result of the binding of CheY-P to the FliM part of the motor. The distribution of duration times in the counterclockwise rotation state of the motor appears to defy description in terms of the MWC model and Ising-type conformational spread model, instead demanding that the system operate out of equilibrium with constant energy dissipation. The emergence of such nonequilibrium effects where the MWC framework breaks down represents one of the most exciting frontiers for thinking about the function of allosteric molecules in the context of living cells.”