Table 1.

The main characteristics of glycosaminoglycans

GAG	Structure	Function [references]
HA	D-glucuronate + GlcNAc	Stabilization of the connective tissue [11]
		Organization of the ECM [11]
		Hydration and water homeostasis [11]
		Receptor-mediated signalling [12]
		Morphogenesis and tissue homeostasis [13,14]
		Regulation of the inflammatory response [15]
		Tissue modelling and remodelling [72]
		Cellular migration and fagocytosis [5]
DS	L-iduronate + GalNAc-4-sulphate	Collagen organization [18]
		Regulation of TGF-β activity [5]
		Stabilization of the basement membrane [18]
		Regulation of cell-cell and cell-matrix interactions [5]
CS	D-glucuronate + GalNAc-4- or 6-sulphate	Prevention of inflammation [55]
		Immune modulation [43]
		Maintenance of the structure and function of cartilage [55]
		Cartilage shock-absorbing properties [55]
		Regulation of cell adhesion to the ECM [55]
HS	D-glucuronate-2-sulphate (or iduronate-2-sulphate) + N-sulfo-D-glucosamine-6-sulphate	Interaction with cytokines, chemokines and interleukins [18,44-52]
		Morphogenesis, development and organogenesis [19]
		Coreceptors for various receptor tyrosine kinases [27]
Heparin	D-glucuronate-2-sulphate (or iduronate-2-sulphate) + N-sulfo-D-glucosamine-6-sulphate	Anticoagulant effects [19]
		Stabilization of some mast cell tryptases [22]
		Modulation of the activity of various mast cell chymases [59]
		Regulation of the inflammatory response [57]
		Remodelling of the airway wall in asthma [58]
KS	Galactose + GlcNAc-6-sulphate	Tissue hydration [115]
		Cell biology [115]
		Most abundant GAG in airway secretion [116]

CS, chondroitin sulphate; DS, dermatan sulphate; ECM, extracellular matrix; EGF, epidermal growth factor; FGF, fibroblast growth factor; GAG, glycosaminoglycan; GalNAc, N-acetylgalactosamine; GlcNAc, N-acetylglucosamine; HA, hyaluronic acid; HGF, hepatocyte growth factor; HS, heparan sulphate; KS, keratan sulphate; PDGF, platelet-derived growth factor; TGF, transforming growth factor; VEGF, vascular endothelial growth factor.