Convergent extension requires adhesion-dependent biomechanical integration of cell crawling and junction contraction.

Convergent extension (CE) is an evolutionarily conserved collective cell movement that elongates several organ systems during development. Studies have revealed two distinct cellular mechanisms, one based on cell crawling and the other on junction contraction. Whether these two behaviors collaborate is unclear. Here, using live-cell imaging, we show that crawling and contraction act both independently and jointly but that CE is more effective when they are integrated via mechano-reciprocity. We thus developed a computational model considering both crawling and contraction. This model recapitulates the biomechanical efficacy of integrating the two modes and further clarifies how the two modes and their integration are influenced by cell adhesion. Finally, we use these insights to understand the function of an understudied catenin, Arvcf, during CE. These data are significant for providing interesting biomechanical and cell biological insights into a fundamental morphogenetic process that is implicated in human neural tube defects and skeletal dysplasias.