Erythropoietin induces the tyrosine phosphorylation of its own receptor in human erythropoietin-responsive cells.
Using the human erythropoietin-responsive hematopoietic cell line UT-7, we showed that erythropoietin (Epo) rapidly and specifically induced the tyrosine phosphorylation of its own receptor (M(r) 75,000) and increased the tyrosine phosphorylation of other proteins of M(r) 140,000, 120,000, 95,000, 60,000, 57,000, and 42,000. Neither granulocyte-macrophage colony-stimulating factor, interleukin 3, interleukin 6, nor the kit ligand induced the phosphorylation of the M(r) 75,000 receptor protein, although these growth factors induced the phosphorylation of other proteins. Cross-linking experiments using 125I-Epo indicated that the UT-7 cells expressed three Epo receptor subunits, of M(r) 100,000, 85,000, and 75,000, among which only the M(r) 75,000 subunit was tyrosine-phosphorylated following activation with Epo.
Dusanter-Fourt
I
I
Institut National de la Santé et de la Recherche Médicale, Unité 152, ICGM, Hopital Cochin, Paris, France.
Casadevall
N
N
Lacombe
C
C
Muller
O
O
Billat
C
C
Fischer
S
S
Mayeux
P
P
D015153:Blotting, Western; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D004921:Erythropoietin / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D010766:Phosphorylation; D011233:Precipitin Tests; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017467:Receptors, Erythropoietin; D019089:Stem Cell Factor; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D003432:Cross-Linking Reagents; D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D015850:Interleukin-6; D011956:Receptors, Cell Surface; D017467:Receptors, Erythropoietin; D019089:Stem Cell Factor; D004921:Erythropoietin; D014443:Tyrosine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor