FIGURE 4.

Deletion of cell-surface uPAR abrogates the observed phagocytic effect due to uPAR expression. a, CS-1 cells were transfected as indicated. The cells were either left untreated or treated with 2 units/ml glycophosphatidylinositol (GPI)-specific phospholipase C (PIPLC) that cleaves uPAR from the cell surface. Cells were then assessed for their phagocytic efficiency. b and c, surface expression of overexpressed proteins in transiently transfected CS-1 cells was confirmed by staining of live cells with primary antibodies followed by fluorescent secondary antibodies and analyzed by flow cytometry. Surface uPAR before and after PIPLC treatment was detected using a rabbit polyclonal 399R antibody (b). Functional αvβ5 heterodimers on the surface were confirmed by mouse monoclonal P1F6 antibody and were found to be intact after PIPLC treatment (c).