Time-reversal symmetry breaking in the chemosensory array reveals a general mechanism for dissipation-enhanced cooperative sensing

Chemotaxis signaling in Escherichia coli is a nonequilibrium collective phenomenon: chemoreceptors on the cell surface couple together forming an extended lattice structure which enables cooperative signal propagation via nonequilibrium chemical reactions driven by ATP hydrolysis. Recent experiments provide new insight into the nonequilibrium dynamics underlying this system: even in the absence of external stimuli, cells spontaneously switch between active and inactive signaling states, with switching dynamics that break time-reversal symmetry. To understand this behavior and its implications for signaling function, we introduce a nonequilibrium lattice model of the chemosensory array that combines dissipative chemical reaction cycles with cooperative coupling. Our model explains the origin of the switching asymmetry and elucidates how signaling response is enhanced by the interplay between energy dissipation and the collective behavior of the receptor lattice. We find that cells balance a trade-off between response speed and sensitivity by operating near a critical point of the receptor lattice. This speed-sensitivity trade-off is reduced by energy dissipation, which enables simultaneous rapid and sensitive response over a robust range of lattice coupling strengths. Our lattice modeling framework provides a new platform for exploring emergent collective dynamics and phase transitions in biological systems driven far from equilibrium.