title: Phosphorylation of the human-transforming-growth-factor-beta-binding protein endoglin.
abstract: Endoglin is an homodimeric membrane antigen with capacity to bind transforming growth factor-beta (TGF-beta). Phosphorylation of human endoglin was demonstrated in endothelial cells as well as in mouse fibroblast transfectants expressing two isoforms, L-endoglin or S-endoglin, with distinct cytoplasmic domains. The extent of L-endoglin phosphorylation was found to be 8-fold higher than that of S-endoglin, and phosphopeptide analyses revealed at least three different phosphorylation sites for L-endoglin, whereas S-endoglin produces only one phosphopeptide. The immunoprecipitated L-endoglin was found to be phosphorylated mainly on serine, and, to a minor extent, on threonine, residues. Treatment of the cells with TGF-beta 1 or the protein kinase C inhibitor H-7 resulted in a reduction of the levels of endoglin phosphorylation.
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Lastres
authors.forename: J
authors.initials: J
authors.lastname: Martín-Perez
authors.forename: C
authors.initials: C
authors.lastname: Langa
authors.forename: C
authors.initials: C
authors.lastname: Bernabéu
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D015703:Antigens, CD; D001665:Binding Sites; D002478:Cells, Cultured; D000071063:Endoglin; D004730:Endothelium, Vascular / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007163:Immunosorbent Techniques; D007546:Isoquinolines / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014471:Umbilical Veins; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D015703:Antigens, CD; C064206:ENG protein, human; D000071063:Endoglin; D007546:Isoquinolines; D008562:Membrane Glycoproteins; D010879:Piperazines; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D019010:Vascular Cell Adhesion Molecule-1; D010769:Phosphothreonine; D010768:Phosphoserine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C