Involved in the regulation of both adhesion and cell morphology and cancer progression. Functions as an anti-adhesive molecule that maintains an open filtration pathway between neighboring foot processes in the podocyte by charge repulsion. Acts as a pro-adhesive molecule, enhancing the adherence of cells to immobilized ligands, increasing the rate of migration and cell-cell contacts in an integrin-dependent manner. Induces the formation of apical actin-dependent microvilli. Involved in the formation of a preapical plasma membrane subdomain to set up initial epithelial polarization and the apical lumen formation during renal tubulogenesis. Plays a role in cancer development and aggressiveness by inducing cell migration and invasion through its interaction with the actin-binding protein EZR. Affects EZR-dependent signaling events, leading to increased activities of the MAPK and PI3K pathways in cancer cells. Monomer; when associated with the membrane raft. Oligomer; when integrated in the apical membrane. Interacts with SLC9A3R2. Interacts (via the C-terminal PDZ-binding motif DTHL) with SLC9A3R1 (via the PDZ domains); the interaction take place early in the secretory pathway and is necessary for its apical membrane sorting (By similarity). Found in a complex with EZR, PODXL and SLC9A3R2. Associates with the actin cytoskeleton through complex formation with EZR and SLC9A3R2. Interacts (via the C-terminal PDZ-binding motif DTHL) with SLC9A3R1 (via the PDZ domains); interaction is not detected in glomerular epithelium cells. Interacts (via the C-terminal PDZ-binding motif DTHL) with SLC9A3R2 (via the PDZ 1 domain); interaction is detected in glomerular epithelium cells. Interacts with EZR. In single attached epithelial cells is restricted to a preapical pole on the free plasma membrane whereas other apical and basolateral proteins are not yet polarized. Colocalizes with SLC9A3R2 at the apical plasma membrane during epithelial polarization. Colocalizes with SLC9A3R1 at the trans-Golgi network (transiently) and at the apical plasma membrane. Its association with the membrane raft is transient. Forms granular, punctuated pattern, forming patches, preferentially adopting a polar distribution, located on the migrating poles of the cell or forming clusters along the terminal ends of filipodia establishing contact with the endothelial cells. Colocalizes with the submembrane actin of lamellipodia, particularly associated with ruffles. Colocalizes with vinculin at protrusions of cells. Colocalizes with ITGB1. Colocalizes with actin filaments, EZR and SLC9A3R1 in a punctate pattern at the apical cell surface where microvilli form (By similarity). Colocalizes with EZR and SLC9A3R2 at the apical cell membrane of glomerular epithelium cells. Colocalizes with PARD3, PRKCI, EXOC5, OCLN, RAB11A and RAB8A in apical membrane initiation sites (AMIS) during the generation of apical surface and luminogenesis (By similarity). Glomerular epithelium cell (podocyte) (at protein level). Both the O-glycan-rich domain of the extracellular domain and the C-terminus PDZ-binding motif (DTHL) in the cytoplasmic tail harbor an apical sorting signal. The cytoplasmic domain is necessary for the apical membrane targeting and renal tubulogenesis. The large highly anionic extracellular domain allows to maintain open filtration pathways between neighboring podocyte foot processes. The cytoplasmic C-terminus PDZ-binding motif (DTHL) is essential for interaction with SLC9A3R1 and for targeting SLC9A3R1 to the apical cell membrane. The extracellular domain is necessary for microvillus formation (By similarity). N- and O-linked glycosylated. Sialoglycoprotein (By similarity). Belongs to the podocalyxin family.