Cytokines and growth factors cross-link heparan sulfate.
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.
Université Grenoble Alpes, Departement de Chimie Moléculaire (DCM), Grenoble, France CNRS, DCM, Grenoble, France CIC biomaGUNE, San Sebastian, Spain.
Elisa
E
Migliorini
Université Grenoble Alpes, Departement de Chimie Moléculaire (DCM), Grenoble, France CNRS, DCM, Grenoble, France.
Dhruv
D
Thakar
Department of Biophysical Chemistry, University of Heidelberg, Heidelberg, Germany.
Jens
J
Kühnle
Université Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble, France CNRS, IBS, Grenoble, France CEA, IBS, Grenoble, France.
Rabia
R
Sadir
University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA.
Douglas P
DP
Dyer
Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
Yong
Y
Li
Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
Changye
C
Sun
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
Brian F
BF
Volkman
University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA.
Tracy M
TM
Handel
Université Grenoble Alpes, Departement de Chimie Moléculaire (DCM), Grenoble, France CNRS, DCM, Grenoble, France.
Liliane
L
Coche-Guerente
Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
David G
DG
Fernig
Université Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble, France CNRS, IBS, Grenoble, France CEA, IBS, Grenoble, France.
Hugues
H
Lortat-Jacob
Université Grenoble Alpes, Departement de Chimie Moléculaire (DCM), Grenoble, France CNRS, DCM, Grenoble, France CIC biomaGUNE, San Sebastian, Spain Max Planck Institute for Intelligent Systems, Stuttgart, Germany rrichter@cicbiomagune.es.
Ralf P
http://orcid.org/0000-0003-3071-2837
RP
Richter
D054377:Chemokine CXCL12 / Q000737:chemistry / Q000378:metabolism; D016207:Cytokines / Q000737:chemistry / Q000378:metabolism*; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D006025:Glycosaminoglycans / Q000737:chemistry / Q000378:metabolism; D006497:Heparan Sulfate / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D011485:Protein Binding
D054377:Chemokine CXCL12; D016207:Cytokines; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D036341:Intercellular Signaling Peptides and Proteins
chemokine; cytokine; extracellular matrix; glycosaminoglcyan; growth factor; heparan sulfate