title: Identification of tyrosines 154 and 307 in the extracellular domain and 653 and 766 in the intracellular domain as phosphorylation sites in the heparin-binding fibroblast growth factor receptor tyrosine kinase (flg).
abstract: Four tyrosine residues have been identified as phosphorylation sites in the tyrosine kinase isoform of the heparin-binding fibroblast growth factor receptor flg (FGF-R1). Baculoviral-insect cell-derived recombinant FGF-R1 was phosphorylated and fragmented with trypsin while immobilized on heparin-agarose beads. Phosphotyrosine peptides were purified by chromatography on immobilized anti-phosphotyrosine antibody and analyzed by Edman degradation and electrospray tandem mass spectrometry. Tyrosine residue 653, which is in a homologous spatial position to major autophosphorylation sites in the catalytic domain of the src and insulin receptor kinases, is the major intracellular FGF-R1 phosphorylation site. Residue 766 in the COOH-terminus outside the kinase domain is a secondary site. Tyrosine residues 154 and 307, which are in the extracellular domain of transmembrane receptor isoforms and are in an unusual sequence context for tyrosine phosphorylation, were also phosphorylated.
authors.affiliation: W. Alton Jones Cell Science Center, Lake Placid, New York 12946.
authors.forename: J
authors.initials: J
authors.lastname: Hou
authors.forename: K
authors.initials: K
authors.lastname: McKeehan
authors.forename: M
authors.initials: M
authors.lastname: Kan
authors.forename: S A
authors.initials: SA
authors.lastname: Carr
authors.forename: M J
authors.initials: MJ
authors.lastname: Huddleston
authors.forename: J W
authors.initials: JW
authors.lastname: Crabb
authors.forename: W L
authors.initials: WL
authors.lastname: McKeehan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D006493:Heparin / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017468:Receptors, Fibroblast Growth Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins; D006493:Heparin; D011505:Protein-Tyrosine Kinases