title: [Granulocyte-macrophage colony-stimulating factor and erythropoietin induce tyrosine phosphorylation and activation of JAK2].
abstract: OBJECTIVE
  In order to identify the tyrosine kinase (s) that may associate with cell proliferation.
  
  
  METHODS
  GM-CSF/Epo responsive cell UT-7 and Epo responsive cell UT-7/Epo were used for study of tyrosine phosphorylation.
  
  
  RESULTS
  The addition of GM CSF and/or Epo to the responsive cells induced rapid tyrosine phosphorylations of 145000, 130000, 80000 and 40000 cellular proteins. The tyrosine phosphorylated 130000 protein was identified as JAK2, a non receptor tyrosine kinase. GM CSF and Epo also activated its tyrosine kinase activity. Tyrosine phosphorylation and activation of JAK2 only occurred in GM-CSF and/or Epo-responsive cells.
  
  
  CONCLUSIONS
  JAK2 signal transduction pathway may play an important role in regulating the proliferation of hematopoietic cells induced by GM-CSF and Epo.
authors.affiliation: Institute of Hematology, People's Hospital, Beijing Medical University, Beijing 100044.
authors.forename: H
authors.initials: H
authors.lastname: Ren
authors.forename: D
authors.initials: D
authors.lastname: Lu
mesh_terms: D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D004921:Erythropoietin; D014443:Tyrosine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D053614:Janus Kinase 2