[Signal of the cytoplasmic regions of leukemia inhibitory factor receptor (LIFR) alpha-subunit and gp130 involves Stat3 activation in leukemic U937 cells].
OBJECTIVE
In order to understand the mechanism of proliferation and differentiation of leukemia cells, we investigate the relation between the cytoplasmic regions LIFR alpha-subunit and gp130 and the transcription activator Stat3 in human leukemic U937 cells.


METHODS
The cytoplasmic domain was each truncated from the LIFR alpha-subunit and gp130. The truncated forms of LIFR alpha-subunit(gp190EX) and gp130 (gp130EX) which can compete with the wild type receptor for binding to leukemia inhibitory factor (LIF) were expressed on the membrane of U937 cells. The level of Stat 3 and its phosphorylation were estimated by immunoblotting.


RESULTS
The increased level of Stat3 and its decreased tyrosine phosphorylation were detected in each group of gp130EX and gp190EX as compared with that in the wild type receptor subunit group.


CONCLUSIONS
The cytoplasmic domains of both LIFR alpha subunit and gp130 involve the induction of Stat3 phosphorylation in U937 cells.
Liu
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Histology and Embryology Department, Second Military Medical University, Shanghai 200433.
Tang
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Liu
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D015703:Antigens, CD / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism*; D010766:Phosphorylation; D018121:Receptors, Cytokine / Q000145:classification / Q000378:metabolism*; D053606:Receptors, OSM-LIF; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism*; D020298:U937 Cells / Q000166:cytology; D052118:Lysosomal-Associated Membrane Protein 1
D015703:Antigens, CD; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D018121:Receptors, Cytokine; D053606:Receptors, OSM-LIF; D050796:STAT3 Transcription Factor; D015534:Trans-Activators; C494199:IL6ST protein, human; C489116:LAMP1 protein, human; D052118:Lysosomal-Associated Membrane Protein 1; C507840:LIFR protein, human; C494086:STAT3 protein, human