Fig. 3

Cell extremities during cell division and extracellular lipidosomes. A-J FEMX-I (A-F, J) or CD9-deficient FEMX-I (shCD9, G-I) cells growing on poly-L-lysine-coated glass coverslips were processed for SEM using 5-kV (A, B and F, left panel) or 15-kV (C-E, F, right panel, G-J) accelerating voltage. Note the presence of large lipid droplet-filled membrane structures (e.g., numbered 1–3 in B) connected with a membrane bridge containing numerous filopodia (A-C, E, dashed lines) to rounded cell body during cell division (A-H, blue line). Filopodia are barely present in shCD9 cells (G-I). Cell extremities can detach completely from the cells, resulting in the formation of larger EVs containing various lipid droplets (I, J). Some regions of interest indicated by colored boxes (A, B, D, G) have been enlarged (A, E, F, H) as indicated. The yellow arrowhead points to a lipid droplet, while the white arrow points to a microvillar-like structure on extracellular lipidosomes. The symbol # indicates a membrane rupture during sample preparation. Scale bars are indicated