Collective Cell Migration Strategies: Patterning, Motility, and Directionality of the Posterior Lateral Line Primordium in Zebrafish.

During development and homeostasis, tissues move and rearrange to form organs, seal wounds, or-in the case of cancer-spread in the body. To accomplish this, cells in tissues need to communicate with each other, generate force to push themselves forward, and know where to go to-all of this with little to no error. Here, we discuss how a migrating tissue-the zebrafish posterior lateral line primordium-solves these challenges. We focus on the strategies that ensure signaling within the tissue, enable the tissue to generate and transmit force to its substrate for propulsion, and allow robust directional sensing and migration by the tissue. These strategies include facilitated diffusion and ligand trapping for focal signaling, a self-generated attractant gradient for long-distance migration, clamping of the attractant concentration to the attractant receptor's K _d for most sensitive signaling, mechanical coupling among cells for averaging directional sensing in a tissue, and large rear traction stresses to propel the tissue forward. Many of these strategies likely apply to collectively migrating cells in other contexts and should thus provide insights with direct relevance to human health.