Thrombopoietin induces tyrosine phosphorylation and activation of mitogen-activated protein kinases in a human thrombopoietin-dependent cell line.
Thrombopoietin (TPO) is a cytokine which can support the proliferation and differentiation of megakaryocyte progenitor cells, and the maturation of megakaryocytes. We show here that mitogen-activated protein (MAP) kinases, Erk1 and Erk2, are involved in TPO signal transduction in the human TPO-dependent megakaryocytic cell line, UT-7/TPO. TPO induced tyrosine phosphorylation of Erk1 and Erk2 proteins in a dose and time-dependent manner. Moreover, the activation of MAP kinases was actually induced by TPO. These results suggest that MAP kinase activation is involved in the signalling pathway of TPO, as it is for other cytokines, one of which is erythropoietin.
Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
M
M
Yamada
N
N
Komatsu
K
K
Okada
T
T
Kato
H
H
Miyazaki
Y
Y
Miura
D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology; D006410:Hematopoiesis; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D015398:Signal Transduction; D013926:Thrombopoietin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D004921:Erythropoietin; D014443:Tyrosine; D013926:Thrombopoietin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases