- Chondroitin sulfate chains on syndecan-1 and syndecan-4 from normal murine mammary gland epithelial cells are structurally and functionally distinct and cooperate with heparan sulfate chains to bind growth factors. A novel function to control binding of midkine, pleiotrophin, and basic fibroblast growth factor. Deepa, S.S., Yamada, S., Zako, M., Goldberger, O., Sugahara, K. J. Biol. Chem. (2004)