Modulation of the homophilic interaction between the first and second Ig modules of neural cell adhesion molecule by heparin.
The second Ig module (IgII) of the neural cell adhesion molecule (NCAM) is known to bind to the first Ig module (IgI) of NCAM (so-called homophilic binding) and to interact with heparan sulfate and chondroitin sulfate glycoconjugates. We here show by NMR that the heparin and chondroitin sulfate-binding sites (HBS and CBS, respectively) in IgII coincide, and that this site overlaps with the homophilic binding site. Using NMR and surface plasmon resonance (SPR) analyses we demonstrate that interaction between IgII and heparin indeed interferes with the homophilic interaction between IgI and IgII. Accordingly, we show that treatment of cerebellar granule neurons (CGNs) with heparin inhibits NCAM-mediated outgrowth. In contrast, treatment with heparinase III or chondroitinase ABC abrogates NCAM-mediated neurite outgrowth in CGNs emphasizing the importance of the presence of heparan/chondroitin sulfates for proper NCAM function. Finally, a peptide encompassing HBS in IgII, termed the heparin-binding peptide (HBP), is shown to promote neurite outgrowth in CGNs. These observations indicate that neuronal differentiation induced by homophilic NCAM interaction is modulated by interactions with heparan/chondroitin sulfates.
Kulahin
Nikolaj
N
Protein Laboratory, Institute of Molecular Pathology, University of Copenhagen, Copenhagen, Denmark.
Rudenko
Olga
O
Kiselyov
Vladislav
V
Poulsen
Flemming M
FM
Berezin
Vladimir
V
Bock
Elisabeth
E
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002531:Cerebellum / Q000187:drug effects / Q000502:physiology; D002809:Chondroitin Sulfates / Q000378:metabolism; D018920:Coculture Techniques; D005347:Fibroblasts / Q000378:metabolism; D006493:Heparin / Q000378:metabolism* / Q000494:pharmacology; D006497:Heparan Sulfate / Q000737:chemistry / Q000494:pharmacology; D007136:Immunoglobulins / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry* / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D013395:Sucrose / Q000031:analogs & derivatives / Q000378:metabolism; D020349:Surface Plasmon Resonance
D002809:Chondroitin Sulfates; D006493:Heparin; D006497:Heparan Sulfate; D007136:Immunoglobulins; D019006:Neural Cell Adhesion Molecules; D010446:Peptide Fragments; D013395:Sucrose; C053081:sucrose octasulfate