Cell-surface receptor that plays a role in cell-cell interactions, cell adhesion and migration, helping them to sense and respond to changes in the tissue microenvironment. Participates thereby in a wide variety of cellular functions including the activation, recirculation and homing of T-lymphocytes, hematopoiesis, inflammation and response to bacterial infection. Engages, through its ectodomain, extracellular matrix components such as hyaluronan/HA, collagen, growth factors, cytokines or proteases and serves as a platform for signal transduction by assembling, via its cytoplasmic domain, protein complexes containing receptor kinases and membrane proteases (PubMed:8343954, PubMed:25065622). Such effectors include PKN2, the RhoGTPases RAC1 and RHOA, Rho-kinases and phospholipase C that coordinate signaling pathways promoting calcium mobilization and actin-mediated cytoskeleton reorganization essential for cell migration and adhesion (By similarity). Interacts with PKN2 (PubMed:17403031). Interacts with TIAM1 and TIAM2 (PubMed:19893486). Interacts with HA, as well as other glycosaminoglycans, collagen, laminin, and fibronectin via its N-terminal segment (PubMed:24606063). Interacts with UNC119. Interacts with PDPN (via extracellular domain); this interaction is required for PDPN-mediated directional migration and regulation of lamellipodia extension/stabilization during cell spreading and migration (By similarity). Interacts with RDX, EZR and MSN (via FERM domain) (PubMed:9472040, PubMed:18753140). Interacts with EGFR (By similarity). Interacts with CD74; this complex is essential for the MIF-induced signaling cascade that results in B cell survival (PubMed:8343954). Colocalizes with actin in membrane protrusionFs at wounding edges. Co-localizes with RDX, EZR and MSN in microvilli. The lectin-like LINK domain is responsible for hyaluronan binding. N-glycosylated. O-glycosylated; contains chondroitin sulfate glycans which can be more or less sulfated. Phosphorylated; activation of PKC results in the dephosphorylation of Ser-742 (constitutive phosphorylation site), and the phosphorylation of Ser-708. Two allelic forms of this glycoprotein, PGP-1.1 and PGP-1.2, have been reported. The expressed product is PGP-1.1 (Ly-24.1).