Heparan sulfate binding site

Fig. 1 Schematic representation of the CD44 gene and its encoded proteins. The extracellular domain and cytoplasmic tail of CD44 isoforms vary in size as the result of alternative splicing. The alternatively spliced exons are indicated by open boxes. The human vl exon contains a stop codon. In the model of the protein, all putative glycosylation sites are indicated O-gly-cosylation (open circles) N-glycosylation (closed circles) chondroitin sulfate (open squares) hep-aran sulfate chain (rod). As indicated, the heparan sulfate binding site in exon v3 has the ability to bind growth factors. In addition, the HA-binding sites (double lines) the disulfide bonds (S-S) the ankyrin binding site (...) the ezrin binding sites (—) the phosphorylation sites (P) and the putative interaction sites for SRC family kinases, are indicated.

Fragment 3 (Mr 50K) possessed / structure, appeared globular in electron micrographs, and was found to bind to heparin. It was assumed to be the globular region at the end of the long arm of laminin. This site is one of the main heparin- and heparan sulfate-binding domains in laminin (Ott et al., 1982). 

Esko, J.D. Selleck, S.B. (2002) Order out of chaos assembly of ligand binding sites in heparan sulfate. Annu. Rev. Biochem. 

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