Isolation of a neuronal cell surface receptor of heparin binding growth-associated molecule (HB-GAM). Identification as N-syndecan (syndecan-3)

J Biol Chem. 1994 Apr 29;269(17):12999-3004.

Abstract

HB-GAM (heparin binding growth-associated molecule; pleiotrophin) is a secretory, extracellular matrix-associated protein that is strongly expressed in developing nervous tissues and belongs to a novel family of differentiation/growth factors. It promotes axonal growth from perinatal rat brain neurons and is suggested to be mitogenic for some cell types and to display cell-transforming activity. Since the receptors of HB-GAM in cells are unknown, we have started isolation of putative cell surface receptors from brain neurons and from perinatal rat brain. For this purpose, recombinant HB-GAM was produced with the aid of a baculovirus vector and used as an affinity matrix in receptor isolation. A detergent-solubilized component from cultured brain neurons and from brain was identified that binds specifically to HB-GAM and migrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a broad smear with an apparent molecular mass of about 200 kDa. This cell surface component was found to contain heparan sulfate chains, which are bound to a core protein with an apparent molecular mass of 120 kDa. Gel electrophoretic characteristics, immunochemical analysis, and partial peptide sequencing revealed that the cell surface component isolated as an HB-GAM receptor is N-syndecan (syndecan-3). In a solid phase binding assay, N-syndecan was found to bind to HB-GAM in a similar manner as to basic fibroblast growth factor (KD = 0.6 nM). Immunofluorescence microscopy indicated that in brain neurons, N-syndecan occurs at the surface of the cell soma and of the neurites that grow along HB-GAM-coated substrates. Anti-N-syndecan antibodies added to culture media had an inhibitory effect on HB-GAM-induced neurite outgrowth. We suggest that N-syndecan mediates the neurite outgrowth-promoting signal from HB-GAM to the cytoskeleton of growing neurites.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies
  • Brain / cytology
  • Brain / metabolism
  • Carrier Proteins / metabolism*
  • Cytokines / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Fluorescent Antibody Technique
  • Membrane Glycoproteins / immunology
  • Membrane Glycoproteins / isolation & purification*
  • Membrane Glycoproteins / metabolism
  • Molecular Sequence Data
  • Nerve Tissue Proteins / metabolism*
  • Neurites
  • Neurons / metabolism*
  • Proteoglycans / immunology
  • Proteoglycans / isolation & purification*
  • Proteoglycans / metabolism
  • Rats
  • Syndecan-3

Substances

  • Antibodies
  • Carrier Proteins
  • Cytokines
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Proteoglycans
  • Sdc3 protein, rat
  • Syndecan-3
  • pleiotrophin