A dominant negative erythropoietin (EPO) receptor inhibits EPO-dependent growth and blocks F-gp55-dependent transformation.
The erythropoietin receptor (EPO-R), a member of the cytokine receptor superfamily, can be activated to signal cell growth by binding either EPO or F-gp55, the Friend spleen focus-forming virus glycoprotein. Activation by F-gp55 results in constitutive EPO-R signalling and the first stage of Friend virus-induced erythroleukemia. We have generated a truncated form of the EPO-R polypeptide [EPO-R(T)] which lacks the critical cytoplasmic signal-transducing domain of the EPO-R required for EPO- or F-gp55-induced cell growth. EPO-R(T) specifically inhibited the EPO-dependent growth of EPO-R-expressing Ba/F3 cells without changing the interleukin-3-dependent growth of these cells. In addition, Ba/F3 cells that coexpressed wild-type EPO-R and EPO-R(T) were resistant to transformation by F-gp55 despite efficient expression of the F-gp55 transforming oncoprotein in infected cells. EPO-R(T) inhibited the EPO-dependent tyrosine phosphorylation of wild-type EPO-R, the tyrosine kinase (JAK2), and the SH2 adaptor protein (Shc). In conclusion, the EPO-R(T) polypeptide is a dominant negative polypeptide which specifically interferes with the early stages of EPO-R-mediated signal transduction and which prevents Friend virus transformation of erythroblasts.
Barber
D L
DL
Division of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
DeMartino
J C
JC
Showers
M O
MO
D'Andrea
A D
AD
D000818:Animals; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002471:Cell Transformation, Neoplastic; D002999:Clone Cells; D017077:Culture Media, Conditioned; D004921:Erythropoietin / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D053614:Janus Kinase 2; D007700:Kinetics; D051379:Mice; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D017467:Receptors, Erythropoietin / Q000096:biosynthesis / Q000502:physiology*; D015398:Signal Transduction; D013155:Spleen Focus-Forming Viruses / Q000235:genetics*; D014162:Transfection; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000378:metabolism*
D017077:Culture Media, Conditioned; D007377:Interleukin-3; D011518:Proto-Oncogene Proteins; D017467:Receptors, Erythropoietin; D014759:Viral Envelope Proteins; C078780:glycoprotein gp55, Friend spleen focus-forming virus; D004921:Erythropoietin; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2