title: Constitutive activation of the Janus kinase-STAT pathway in T lymphoma overexpressing the Lck protein tyrosine kinase.
abstract: The Lck protein, a Src family tyrosine kinase, plays a critical role in T cell maturation and activation. Dysregulation of Lck expression or Lck kinase activity has been implicated in T cell leukemias from mice to humans, although the mechanism underlying Lck-mediated oncogenesis is still largely unclear. We report here that both DNA binding activities and tyrosine phosphorylation of STAT3 and STAT5, but not STAT1, are constitutively enhanced in the mouse T cell lymphoma LSTRA, which is a well-characterized cell line that overexpresses Lck protein and exhibits high levels of Lck kinase activity. Furthermore, Janus kinase 1 (jak1) and Jak2 protein tyrosine kinases are constantly activated in these cells, as determined by their autophosphorylation in an in vitro kinase assay and increased levels of tyrosine phosphorylation on immunoblots. Therefore, like Src-transformed cells, Lck-overexpressing LSTRA cells also exhibit constitutive activation of distinct Jak and STAT proteins.
authors.affiliation: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Yu
authors.forename: R
authors.initials: R
authors.lastname: Jove
authors.forename: S J
authors.initials: SJ
authors.lastname: Burakoff
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002461:Cell Line, Transformed; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D053616:Janus Kinase 3; D019169:Jurkat Cells; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D016399:Lymphoma, T-Cell / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008894:Milk Proteins; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C507936:Jak3 protein, rat; D008894:Milk Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050799:STAT5 Transcription Factor; C494080:Stat1 protein, mouse; C494081:Stat1 protein, rat; C494087:Stat3 protein, mouse; C494088:Stat3 protein, rat; D015534:Trans-Activators; D004247:DNA; D011505:Protein-Tyrosine Kinases; C507933:JAK3 protein, human; C507935:Jak3 protein, mouse; D053616:Janus Kinase 3; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)