Special issue: Proteoglycans: signaling, targeting and therapeutics: introduction.

This special issue of FEBS Journal contains 31 review and primary research articles reflecting the advancements covered at the 2012 Proteoglycans Gordon Research Conference and novel aspects from experts in the field. It is mainly focused on current status of the extracellular and cell surface proteoglycans' regulatory roles in cell signaling, molecular targeting, engineering attempts and potential therapeutic approaches.