To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie 4 Expression of kinase-dead Pak1 in aggregates leads to the formation of chains of underlapping cells. The time lapse recording shows cells underlapping each other, with the lamellipodia pointing in the same direction PDGF-A suppresses contact inhibition during directional collective cell migration Martina Nagel, and Rudolf Winklbauer Development 2018. 145:None-None; doi: 10.1242/dev.162651 Download Original Video