Fig. 6. Time-lapse imaging of CD47 trans-endocytosis. (A-J) CHO-Ras cells, which were transfected with an expression vector for either SHPS-1–CFP or CD47-YFP, were cocultured, and CFP and YFP images were acquired every minute for 75 minutes. Images obtained at the indicated times between 0 and 60 minutes are shown. Filled white (A,B) and open (C,D) arrowheads indicate lamellipodium-like and filopodium-like protrusions, respectively, formed by a CD47-YFP-expressing cell. White arrows (E-H) indicate vesicle-like structures labeled with both CFP and YFP in a cell expressing SHPS-1–CFP. Endocytosis of vesicles at the contact site was followed by retraction of the filopodium-like protrusion by the CD47-exressing cell and the near disruption of cell-cell contact (yellow arrowheads; I,J). Also see Movie 1 in supplementary material. (K-N) CHO-Ras cells were treated as in A-J with the exception that an expression vector for dynamin 1(K44A) was introduced together with that for SHPS-1–CFP. CFP and YFP images were acquired as in A-J. Images obtained at 0, 10, 20 and 60 minutes are shown. Also see Movie 2 in supplementary material. Bars, 20 µm.