Acts as a ligand for the urokinase plasminogen activator surface receptor. Plays a role in angiogenesis by inducing endothelial cell migration and the formation of vascular network (cords). Involved in cellular migration and adhesion. Increases the phosphorylation levels of FAK. Interacts with and increases the mitogenic activity of HGF. Promotes synapse formation. May have a role in the perisylvian region, critical for language and cognitive development. Forms homooligomers (By similarity). Interacts with PLAUR (via the UPAR/Ly6 domains), ADAMTS4 and CTSB. Interacts with HGF; the interaction increases the mitogenic activity of HGF. Expressed in neurons of the rolandic area of the brain (at protein level). Highly expressed in the brain, placenta, lung, trachea, uterus, adrenal gland, heart, ovary and placenta. Weakly expressed in the peripheral blood, brain and bone marrow. Expressed in numerous cancer cell lines and in gastrointestinal cancer cells. Higher levels found in colorectal cancers than in normal colonic mucosa. Contains chondroitin sulfate chains. The disease may be caused by variants affecting the gene represented in this entry.