Simulations suggest that an optimal level of CheW is required for highly cooperative signaling.

(A) Modeled Hill coefficients for different expression levels of CheW as multiples of its native level [W]0. CheA is modeled at its native level [A]0 for all charts. (B) The relative number of CheA dimers per linker is simulated for the different levels of CheW expression. Results are compared to the native level [W]0. (C) Although increased levels of CheW lead to larger clusters, formation of CheW-only linkers also excludes CheA from signaling. These findings suggest that an optimal CheW level is required to balance signaling sensitivity and magnitude. Model parameters are as in Fig 8.