GLYCOBIOLOGY AND EXTRACELLULAR MATRICES
Sequence Analysis of Heparan Sulfate Epitopes with Graded Affinities for Fibroblast Growth Factors 1 and 2*

https://doi.org/10.1074/jbc.M102628200Get rights and content
Under a Creative Commons license
open access

Proteins that belong to the fibroblast growth factor (FGF) family regulate proliferation, migration, and differentiation of many cell types. Several FGFs, including the prototype factors FGF-1 and FGF-2, depend on interactions with heparan sulfate (HS) proteoglycans for activity. We have assessed tissue-derived HS fragments for binding to FGF-1 and FGF-2 to identify the authentic saccharide motifs required for interactions. Sequence information on a range of N-sulfated HS octasaccharides spanning from low to high affinity for FGF-1 was obtained. All octasaccharides with high affinity for FGF-1 (≥0.5 m NaCl required for elution) contained an internal IdoUA(2-OSO3)-GlcNSO3(6-OSO3)-IdoUA(2-OSO3)-trisaccharide motif. Octasaccharides with a higher overall degree of sulfation but lacking the specific trisaccharide motif showed lower affinity for FGF-1. FGF-2 was shown to bind to a mono-O-sulfated HS 6-mer carrying a single internal IdoUA(2-OSO3)-unit. However, a di-O-sulfated -IdoUA(2-OSO3)-GlcNSO3-IdoUA(2-OSO3)-trisaccharide sequence within a HS 8-mer gave stronger binding. These findings show that not only the number but also the positions of individual sulfate groups determine affinity of HS for FGFs. Our findings support the notion that FGF-dependent processes can be modulatedin vivo by regulated expression of distinct HS sequences.

Cited by (0)

Published, JBC Papers in Press, June 13, 2001, DOI 10.1074/jbc.M102628200

4

Unit 1 is invariably GlcUA in all oligosaccharides generated by theN-deacetylation/deamination process, because the -GlcNAc-GlcUA- sequence (cleaved in this process) is not a substrate for the C-5 epimerase that converts GlcUA to IdoUA during heparin/HS biosynthesis (44).

5

Dependent on the charge density of the saccharide analyzed, removal of terminal IdoUA monosaccharide or GlcUA-GlcNSO3 disaccharide units variously affected the elution position in anion-exchange chromatograms. Generally, parental fragments eluted before 50 min were shifted to the left, and those emerging between 50 and 70 min were only slightly affected, whereas components appearing after 70 min were shifted to the right.

*

This work was supported by European Comission Grants QLK-CT-1999.00536 (Program “Biologically Active Novel Glycosaminoglycans”) and BIO4-CT98-0538 (Program “Heparan Sulfate Sequencing Demonstration”), Medical Research Council Grant K96-03P,K99-03X,2309, Swedish Cancer Society Grant 3919-B97, and by funds from the Finnish Cancer Union, the Sigrid Juselius Foundation, and Polysackaridforskning AB.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.