Cell surface proteoglycan that bears heparan sulfate (By similarity). Negatively regulates the hedgehog signaling pathway (By similarity). Positively regulates the canonical and non-canonical Wnt signaling pathways (By similarity). Binds to CD81 which decreases the availability of free CD81 for binding to the transcriptional repressor HHEX, resulting in nuclear translocation of HHEX and transcriptional repression (By similarity). Inhibits the dipeptidyl peptidase activity of DPP4 (By similarity). Plays a role in limb patterning and skeletal development (By similarity). Modulates the effects of growth factors on renal branching morphogenesis (By similarity). Required for coronary vascular development (By similarity). Plays a role in regulating cell movements during gastrulation (PubMed:14610063). Heterodimer; disulfide-linked. Cleavage by a furin-like convertase results in production of alpha and beta chains which form a disulfide-linked heterodimer. Maternally expressed and is almost ubiquitous during blastula and gastrula stages but becomes restricted to the prospective hindbrain by 24 hours post-fertilization. O-glycosylated; contains heparan sulfate. Cleaved intracellularly by a furin-like convertase to generate 2 subunits, alpha and beta, which remain associated through disulfide bonds and are associated with the cell surface via the GPI-anchor (PubMed:14610063). This processing is essential for its role in inhibition of hedgehog signaling (By similarity). A second proteolytic event may result in cleavage of the protein on the cell surface, separating it from the GPI-anchor and leading to its shedding from the cell surface (By similarity). Morpholino knockdown results in severe defects during epiboly with most embryos arrested at 60-80% epiboly. Belongs to the glypican family.