FIGURE 4.

The best of both worlds: induction of attractant degradation retains the high-concentration responsiveness of self generated gradients and low concentration sensitivity of non-degradable systems. (A–C) Simulation of two-spot assay at 10 μM without degradation (A), with always-on degradation (B), and with degradation induced as an ultrasensitive function of receptor occupancy (C). A simulation is scored as positive if twice as many cells are in the right-half of the cell drop as the left half. (D) Number of tests that score positive for each degradation logic across a range of attractants (out of a total of five).