Mechanisms enabling efficient fountain-flow supracellular migration

In a prototypical mode of single-cell migration, retrograde cytoskeletal flow is mechanically coupled to the environment, propels the cell, and is sustained by an anterograde cytosolic flow of disassembled cytoskeletal components. Supracellular collectives also develop fountain-flows to migrate, but the opposing cellular streams interact with the environment producing conflicting forces. To understand the biophysical constraints of fountain-flow supracellular migration, we develop an active gel model of a cell cluster driven by a polarized peripheral contractile cable. While the model develops fountain-flows and directed migration, efficiency and cluster velocity are extremely small compared to observations. We find that patterned friction or cluster-polarized single-cell directed migration, both suggested by contact inhibition of locomotion, rescue robust and efficient supracellular migration.