Subcellular Localization : Cell membrane; Lipid-anchor, GPI-anchor; Extracellular side (By similarity). Endosome (By similarity). Note=S-nitrosylated form recycled in endosomes. Localizes to CAV1- containing vesicles close to the cell surface. Cleavage of heparan sulfate side chai
Protein Function : Cell surface proteoglycan that bears heparan sulfate. Binds, via the heparan sulfate side chains, alpha-4 (V) collagen and participates in Schwann cell myelination (By similarity). May act as a catalyst in increasing the rate of conversion of prion protein PRPN (C) to PRNP (Sc) via associating (via the heparan sulfate side chains) with both forms of PRPN, targeting them to lipid rafts and facilitating their interaction. Required for proper skeletal muscle differentiation by sequestering FGF2 in lipid rafts preventing its binding to receptors (FGFRs) and inhibiting the FGF-mediated signaling (By similarity).