Intracellular and extracellular PLP2 plays a crucial role in collective cell migration. Phase-contrast images of migrating control, PLP2KO, PLP2KO cells overexpressing PLP2-mCherry and PLP2KO cells treated with exosomePLP2-GFP (respectively from left to right); 1 frame/ 15 mins for 12 hrs. Scale bars: 50 μm.