title: Mapping a heparin binding site on ErbB-3 epidermal growth factor receptor.
abstract: Signaling via the ErbB-family of receptors plays an important role in mammalian development and oncogenesis. Here we show that the ErbB-3 receptor, but not other members of this receptor family, binds to immobilized heparin and can be dissociated only at a high ionic strength comparable to that required for fibroblast growth factor receptors. Competition-binding analysis suggests that this interaction is specific and requires highly sulfated species of heparan sulfate. Primary sequence analysis of ErbB-3 identified a basic amino acid cluster (466)KHNRPRR(472) localized to the proximal, cysteine-rich extracellular ligand binding domain of the receptor, with charge density and distribution compatible with, but different to, known linear heparin binding motifs. Site-directed mutagenesis, replacing this sequence with the corresponding residues from ErbB-1, resulted in complete loss of heparin binding activity of the chimeric receptor. Finally, antibodies directed to the putative heparin binding peptide, efficiently bind the native receptor suggesting a novel target for blocking heparin mediated ErbB-3 interactions.
authors.affiliation: Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Adar
authors.forename: A
authors.initials: A
authors.lastname: Yayon
mesh_terms: D000469:Alkaline Phosphatase; D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000906:Antibodies / Q000378:metabolism; D000918:Antibody Specificity; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive / Q000502:physiology; D002460:Cell Line; D016384:Consensus Sequence / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D058851:GPI-Linked Proteins; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics; D008024:Ligands; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000502:physiology; D020893:Receptor, ErbB-3 / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D000469:Alkaline Phosphatase; D000906:Antibodies; D000939:Epitopes; D058851:GPI-Linked Proteins; D006493:Heparin; D006497:Heparan Sulfate; D007141:Immunoglobulin Fc Fragments; D007527:Isoenzymes; D008024:Ligands; D010446:Peptide Fragments; D020893:Receptor, ErbB-3; D011993:Recombinant Fusion Proteins; C019839:alkaline phosphatase, placental