FIGURE 5.

Plasmin, thrombin, and cathepsin D cleavage sites in OPN. A, cleavage sites for plasmin (P), thrombin (T), and cathepsin D (CD) are indicated with black arrows. Previously identified cleavage sites for MMPs (15) are shown with gray arrows. The RGD motif is highlighted in boldface, and the SVVYGLR sequence is underlined. B, alignment of mammalian OPN sequences. The region containing the identified cleavage sites in human milk is boxed. The integrin-binding motifs RGD and SVVYGLR are highlighted in gray. Glycosylation sites identified in human milk OPN (31) are indicated with a diamond, and corresponding residues in other OPN species are highlighted in black.