Journal of Neuroscience, Vol 12, 2597-2608, Copyright © 1992 by Society for Neuroscience
A cell-surface heparan sulfate proteoglycan mediates neural cell adhesion and spreading on a defined sequence from the C-terminal cell and heparin binding domain of fibronectin, FN-C/H II
PK Haugen, PC Letourneau, SL Drake, LT Furcht and JB McCarthy
Department of Cell Biology, University of Minnesota, Minneapolis 55455.
FN-C/H II is a heparin binding synthetic peptide from the C-terminal cell
and heparin binding domain of fibronectin (FN) that mediates neuronal cell
adhesion, spreading, and neurite outgrowth. Cellular interactions with
FN-C/H II are inhibited by soluble heparin, suggesting that a cell-surface
proteoglycan may mediate interactions with FN-C/H II (Haugen et al., 1990).
To test this hypothesis further, heparan sulfate (HS) or chondroitin
sulfate (CS) was removed from the cell surface by enzyme treatment.
Heparitinase but not chondroitinase treatment of cells inhibited rat B104
neuroblastoma cell adhesion and spreading on FN-C/H II. Additionally,
heparitinase treatment decreased the spreading of cells on the 33/66 kDa
fragments containing the C- terminal heparin binding domain of FN.
Furthermore, antibodies generated against a mouse melanoma HS proteoglycan
(HSPG) inhibited B104 cell adhesion to FN-C/H II and the 33/66 kDa FN
fragments. 35S- HSPG isolated from B104 cells directly bound to FN-C/H II
both in solid phase assays and by affinity chromatography, but failed to
bind to a control peptide from this region, CS1. The binding of 35S-HSPG
was predominantly mediated by the HS and not the core protein of the HSPG.
SDS-PAGE of iodinated HSPG demonstrated a single 78 kDa core protein
following heparitinase digestion, which migrated at 51 kDa under
nonreducing conditions. Anti-HSPG antibodies recognized the 78 kDa core
protein by immunoblotting, and stained the surface of rat B104
neuroblastoma cells and cells of the primary neonatal rat nervous system.
These results identify a cell-surface HSPG that likely mediates neuronal
cell binding interactions with FN-C/H II.