title: The thrombopoietin receptor c-MPL activates JAK2 and TYK2 tyrosine kinases.
abstract: Thrombopoietin (TPO) is a growth and differentiation factor for megakaryocyte-lineage cells. The receptor for TPO, c-MPL, is a member of the hematopoietic cytokine receptor family and has previously been shown to rapidly activate one or more cytoplasmic tyrosine kinases after ligand binding. In this study, we found that activation of the TPO receptor rapidly induced tyrosine phosphorylation of two members of the Jak tyrosine kinase family, JAK2 and TYK2, but not JAK1 or JAK3, in two different factor-dependent hematopoietic cell lines. The activation of both JAK2 and TYK2 was dose- and time-dependent and was associated with rapid tyrosine phosphorylation of a series of STAT proteins including STAT1, STAT3, and STAT5. Gel-shift assays indicated that one or more of these STATs is likely to participate in the formation of specific DNA-binding complexes. The activation of tyrosine kinases and signal propagation through tyrosine phosphorylation are likely to represent important initial steps in mediating the activities of TPO in myeloid cells.
authors.affiliation: Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sattler
authors.forename: M A
authors.initials: MA
authors.lastname: Durstin
authors.forename: D A
authors.initials: DA
authors.lastname: Frank
authors.forename: K
authors.initials: K
authors.lastname: Okuda
authors.forename: K
authors.initials: K
authors.lastname: Kaushansky
authors.forename: R
authors.initials: R
authors.lastname: Salgia
authors.forename: J D
authors.initials: JD
authors.lastname: Griffin
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D007700:Kinetics; D008894:Milk Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009838:Oligodeoxyribonucleotides; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000502:physiology*; D018121:Receptors, Cytokine / Q000502:physiology; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000502:physiology*; D053628:Receptors, Thrombopoietin; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; D015398:Signal Transduction; D053634:TYK2 Kinase; D013926:Thrombopoietin / Q000494:pharmacology*; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D008894:Milk Proteins; D009363:Neoplasm Proteins; D009838:Oligodeoxyribonucleotides; D011506:Proteins; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D011971:Receptors, Immunologic; D053628:Receptors, Thrombopoietin; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; C082218:MPL protein, human; D019000:Phosphotyrosine; D014443:Tyrosine; D013926:Thrombopoietin; D011505:Protein-Tyrosine Kinases; C507904:JAK1 protein, human; C507924:JAK2 protein, human; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D053634:TYK2 Kinase; C070139:TYK2 protein, human