Intercellular signalling is limited by the range of cell responsiveness, often mediated by repressors. A recently identified repressor, Sprouty, inhibits MAP kinase signalling in flies, mice and humans and has a conserved function in patterning the airways of these divergent species.
Placzek, M., & Skaer, H. (1999). Airway patterning: A paradigm for restricted signalling. Current Biology, 9(14). https://doi.org/10.1016/S0960-9822(99)80322-4