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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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Animals
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Antigens, CD
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Binding Sites
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Cells, Cultured
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Endoglin
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Endothelium, Vascular / metabolism*
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Fibroblasts / metabolism
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Humans
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Immunosorbent Techniques
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Isoquinolines / pharmacology
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism*
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Mice
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Phosphorylation
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Phosphoserine / metabolism
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Phosphothreonine / metabolism
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Piperazines / pharmacology
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Protein Kinase C / antagonists & inhibitors
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Receptors, Cell Surface
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Recombinant Proteins / metabolism
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Transfection
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Transforming Growth Factor beta / metabolism*
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Umbilical Veins
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Vascular Cell Adhesion Molecule-1*
Substances
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Antigens, CD
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ENG protein, human
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Endoglin
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Isoquinolines
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Membrane Glycoproteins
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Piperazines
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Receptors, Cell Surface
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Recombinant Proteins
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Transforming Growth Factor beta
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Vascular Cell Adhesion Molecule-1
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Phosphothreonine
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Phosphoserine
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1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
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Protein Kinase C