Osteopontin as potential biomarker and therapeutic target in gastric and liver cancers

Figure 1 Structural features of osteopontin isoforms. Three isoforms of osteopontin (OPN), OPN-a, OPN-b and OPN-c, are known. All of them possess identical domains [aspartate domain, arginine-glycine-aspartate domain, Ser-Val-Val-Tyr-Gly-Leu-Arg (SVVYGLR) domain, thrombin cleavage domain, calcium binding domain and heparin binding domain] that are linked together with various linkers. These isoforms distinguish themselves by having a variable length of the linker between signal peptide and aspartate domain. RGD: Arginine-glycine-aspartate.