FIGURE 4.

ULBP2 and ULBP3 can be recruited to exosomes and have different susceptibility to metalloproteases. A, the exosome fraction and soluble proteins from CHO-ULBP2 and -3 transfectants, either untreated or treated with the metalloprotease inhibitor BB94, were purified as in Fig. 3A. Western blot analysis of ULBP molecules and CD63 is shown. B, CV1-ULBP2 and CV1-ULBP3 transfectants were analyzed by confocal microscopy. Images show a single focal plane across the cell (depth of the plane 0.2035 μm) using the 63× objective. The series of images corresponding to the same cell are shown in supplemental Fig. 2. Scale bar, 25 μm.