 The mechanisms by which glypicans regulate cellular pathways are not entirely clear.One commonly proposed mechanism suggests that glypicans behave as co-receptors which bind both the ligand and the receptor.Wnt recognizes a heparan sulfate structure on GPC3, which contains IdoA2S and GlcNS6S, and that the 3-O-sulfation in GlcNS6S3S enhances the binding of Wnt to the heparan sulfate glypican.