Heparan Sulfates Mediate the Binding of Basic Fibroblast Growth Factor to a Specific Receptor on Neural Precursor Cells

doi:10.1074/jbc.270.42.24941

Heparan Sulfates Mediate the Binding of Basic Fibroblast Growth Factor to a Specific Receptor on Neural Precursor Cells (*)

From the (1)Department of Anatomy and Cell Biology, University of Melbourne, 3052 Australia, the
(2) Department of Pathology, University of Melbourne, 3052 Australia, and
(3) The Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Melbourne, 3050 Australia

^¶ To whom correspondence should be addressed. Tel.: 61-3-9344-5795; Fax: 61-3-9347-4190.

Abstract

Heparan sulfate proteoglycans are thought to be obligatory for receptor binding and subsequent mitogenic activity of basic fibroblast growth factor (FGF-2). In a previous study (Nurcombe V., Ford, M. D., Wildschut, J., Bartlett, P. F.(1993) Science 260, 103-106) we have shown that primary cultures of mouse neuroepithelial cells and a cell line derived from them, 2.3D, secrete a heparan sulfate proteoglycan with a high affinity for FGF-2. In this study, a combination of affinity chromatography and gel chromatography was used to further isolate heparan sulfate side chains with high affinity for FGF-2. These active chains had an average molecular weight of 18,000-20,000. In order to determine whether heparan sulfate chains with specificity for FGF-2 also displayed selectivity for the different FGF receptors, peptides designed to the heparin-binding region of the receptors were used in competitive inhibition studies. The structure of the predicted heparin-binding domain of the FGF receptor 1 was modeled on the basis of its presumed secondary and tertiary structure homology with immunoglobulin loops. These results suggested that many of the basic residues within the second immunoglobulin loop of the FGF receptor 1 form a basic domain in the molecule and therefore form part of a heparin-binding site. Peptides homologous to this region of FGF receptor 1 were shown to inhibit mitogenesis in 2.3D cells, while those to FGF receptor types 2, 3, and 4 did not. A reverse transcriptase-polymerase chain reaction assay designed to detect expression of the four FGF receptors types demonstrated that FGF receptors 1 and 3 were present on the 2.3D cell line but that receptors 2 and 4 were not. These findings indicate that unique heparan sulfate domains interact with specific cell-surface receptors to direct cellular responses.

Footnotes

↵^§ Recipient of an Overseas Postgraduate Research Award and a Melbourne University Postgraduate Scholarship.
↵* This work was supported in part by the National Health and Medical Research Council of Australia, the Australian Research Council and the A.L.S.-Motor Neurone Disease Research Society Inc. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

FGF

fibroblast growth factor

FGF-2

basic FGF

FGF-1

acidic FGF

HS

heparan sulfate

HSPG

heparan sulfate proteoglycan

RT

reverse transcription

PCR

polymerase chain reaction

bp

base pair(s)

FGFR1-A22K

FGFR1 specific peptide

FGFR2-A22K

FGFR2 specific peptide

FGFR3-A22R

FGFR3 specific peptide

FGFR4-A22K

FGFR4 specific peptide.
↵²Y. G. Brickman, M.D. Ford, D. H. Small, P. F. Bartlett, and V. Nurcombe, unpublished data.
↵³Y. G. Brickman, M. D. Ford, and V. Nurcombe, manuscript in preparation.
- Received May 22, 1995.
- Revision received August 11, 1995.