RÉSUMÉ
In order to investigate the expression of erythropoietin receptor(EPOR) in leukemic cell line and clarify the mechanism of proliferative signal transduction mediated by EPOR in the leukemic cell line KOCL-33, biotinylated EPO and flow cytometry were used for detection of EPOR expression, (3)H-TdR incoporation for cell proliferation, immunoprecipitation and Western blot analysis were used to investigate the tyrosine phosphorylation of signal transduction proteins as the causation of enhanced proliferation of KOCL-33 cells. There was EPOR expression and the cell proliferation could be stimulated by EPO in KOCL-33 cells. Dimerization and tyrosine phosphorylation of EPOR were found after 1 minute incubated with EPO. Coimmunoprecipitation of SHC and PLC-gamma and enhanced tyrosine phosphorylation following to the stimulation of EPO were found. Our results suggest that dimerization of EPOR and tyrosine phosphorylation were appeared under the stimulation of EPO, and SHC and PLC-gamma play a cooperative effect in EPOR mediated signal tranduction.