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Thrombopoietin is known to be essential for megakaryocytopoiesis and thrombopoiesis. Recently, we and others have shown that thrombopoietin induces rapid tyrosine phosphorylation of Jak2 and other proteins in human platelets and BaF3 cells, genetically engineered to express c-Mpl, a receptor for thrombopoietin. The Jak family of tyrosine kinases are known to mediate some of the effects of cytokines or hematopoietic growth factors by recruitment and tyrosine phosphorylation of a variety of Stat (signal transducers and activators of transcription) proteins. Hence, we have investigated whether Stat proteins are present in platelets and, if so, whether they become tyrosine phosphorylated in response to thrombopoietin. We immunologically identified Stat1, Stat2, Stat3, and Stat5 in human platelet lysates. Thrombopoietin induced tyrosine phosphorylation of Stat3 and Stat5 in these cells. Thrombopoietin also induced tyrosine phosphorylation of Stat3 and Stat5 in FDCP-2 cells genetically engineered to constitutively express human c-Mpl. Thus, our data indicate that Stat3 and Stat5 may be involved in signal transduction after ligand binding to c-Mpl and that this event may have a role in megakaryopoiesis/thrombopoiesis or possibly a mature platelet function such as aggregation.
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
August 1995,
FEBS letters,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
December 1998,
Blood,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
January 1998,
Thrombosis and haemostasis,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
October 1995,
FEBS letters,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
December 1995,
Biochemical and biophysical research communications,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
June 1995,
Blood,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
December 1994,
European journal of immunology,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
June 1996,
Molecular and cellular biochemistry,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
May 1998,
Biochemical and biophysical research communications,
Y Miyakawa, and
A Oda, and
B J Druker, and
H Miyazaki, and
M Handa, and
H Ohashi, and
Y Ikeda
September 1995,
Proceedings of the National Academy of Sciences of the United States of America,
