Faculty Collaboration Database

Cytokines and growth factors cross-link heparan sulfate. Open Biol 2015 Aug;5(8)

Date

08/14/2015

Pubmed ID

26269427

Pubmed Central ID

PMC4554917

DOI

10.1098/rsob.150046

Scopus ID

2-s2.0-84942437037   24 Citations

Abstract

The glycosaminoglycan heparan sulfate (HS), present at the surface of most cells and ubiquitous in extracellular matrix, binds many soluble extracellular signalling molecules such as chemokines and growth factors, and regulates their transport and effector functions. It is, however, unknown whether upon binding HS these proteins can affect the long-range structure of HS. To test this idea, we interrogated a supramolecular model system, in which HS chains grafted to streptavidin-functionalized oligoethylene glycol monolayers or supported lipid bilayers mimic the HS-rich pericellular or extracellular matrix, with the biophysical techniques quartz crystal microbalance (QCM-D) and fluorescence recovery after photobleaching (FRAP). We were able to control and characterize the supramolecular presentation of HS chains--their local density, orientation, conformation and lateral mobility--and their interaction with proteins. The chemokine CXCL12α (or SDF-1α) rigidified the HS film, and this effect was due to protein-mediated cross-linking of HS chains. Complementary measurements with CXCL12α mutants and the CXCL12γ isoform provided insight into the molecular mechanism underlying cross-linking. Fibroblast growth factor 2 (FGF-2), which has three HS binding sites, was also found to cross-link HS, but FGF-9, which has just one binding site, did not. Based on these data, we propose that the ability to cross-link HS is a generic feature of many cytokines and growth factors, which depends on the architecture of their HS binding sites. The ability to change matrix organization and physico-chemical properties (e.g. permeability and rigidification) implies that the functions of cytokines and growth factors may not simply be confined to the activation of cognate cellular receptors.

Author List

Migliorini E, Thakar D, Kühnle J, Sadir R, Dyer DP, Li Y, Sun C, Volkman BF, Handel TM, Coche-Guerente L, Fernig DG, Lortat-Jacob H, Richter RP

Author

Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Chemokine CXCL12
Cytokines
Extracellular Matrix
Glycosaminoglycans
Heparitin Sulfate
Humans
Intercellular Signaling Peptides and Proteins
Models, Molecular
Molecular Conformation
Protein Binding