Exosome uptake is clustered into filopodia active regions. (a) SPT of exosome uptake dynamics by CLSM live cell imaging of actin (left) or plasma membrane–labeled (right) human primary fibroblasts. Exosomes at 100 pM; 50 s/frame. (b) TIRF live cell microscopy of stable actin-RFP expressing human fibroblasts (black) grown on line substrates. (c) Spatial distribution of cell entry events in the migrating cell with trajectories pseudocolored for absolute time within the movie. (d) Classification of exosome uptake at the front end, back end, or in the lateral region of fibroblasts on line substrates visualized by TIRF imaging (pooled data from seven independent experiments).