Activation of the mitogen-activated protein kinase pathway is involved in and sufficient for megakaryocytic differentiation of CMK cells.
Activation of the mitogen-activated protein (MAP) kinase pathway has been associated with both cell proliferation and differentiation. Constitutively activated forms of Mek (MAP kinase/Erk kinase) and Erk (MAP kinase) have been previously shown capable of inducing differentiation or proliferation in nonhematopoietic cells. To specifically examine the role of Erk activation in megakaryocytic growth and development, we activated the MAP kinase pathway by the transfection of constitutively activated Mek or Erk cDNA into a human megakaryoblastic cell line, CMK, by electroporation. The CMK transfectant clones that expressed constitutively activated Mek or Erk showed morphologic changes of differentiation. Transfected cells also showed expression of mature megakaryocytic cell surface markers. The MAP kinase pathway was also activated by treatment of the hematopoietic cells with a cytokine that activates Erk. The treatment of CMK cells with stem cell factor (SCF ) caused MAP kinase activation and induced differentiation by the expression of mature megakaryocytic cell surface markers. The effects of the SCF treatment were inhibited by pretreatment with a specific inhibitor of the MAP kinase pathway, PD98059. In this report, we conclude that activation of the MAP kinase pathway was both necessary and sufficient to induce differentiation in this megakaryoblastic cell line.
Melemed
A S
AS
James Whitcomb Riley Hospital for Children and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.
Ryder
J W
JW
Vik
T A
TA
D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D004789:Enzyme Activation; D005434:Flow Cytometry; D006801:Humans; D048369:MAP Kinase Kinase 1; D048728:MAP Kinase Kinase Kinase 1; D008533:Megakaryocytes / Q000166:cytology* / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases