Emergent versus Individual-based Chemotaxis in Cell Clusters

Sensing and migration occur in development, morphogenesis, cancer metastasis, and countless other multicellular processes. Although collective cell sensing and migration have been studied in the context of many different biological systems, universal limits to the precision of the different collective migratory mechanisms observed have yet to be quantified. Here we develop and compare two model forms of collective sensing and migration: one in which cells individually choose their polarization direction (“individual-based” chemotaxis), and the other in which collective migration emerges from intercellular interactions within the cluster (“emergent” chemotaxis). The limits to the migratory precision of these two classes of collective migration are presented. We show how the chemotactic index (CI) and chemotactic ratio (CR) are simple functions of migratory precision giving us predictive power on how CI and CR depend on system parameters such as chemical concentration, gradient, and cell cluster size. Ongoing cell migration experiments to test these predictions are discussed.