The carboxyl-terminal domains of gp130-related cytokine receptors are necessary for suppressing embryonic stem cell differentiation. Involvement of STAT3.
Cell type-specific responses to the leukemia inhibitory factor (LIF)/interleukin 6 cytokine family are mediated by dimerization of the LIF receptor alpha-chain (LIFRalpha) with the signal transducer gp130 or of two gp130 molecules followed by activation of the JAK/STAT and Ras/mitogen-activated protein kinase cascades. In order to dissect the contribution of gp130 and LIFRalpha individually, chimeric molecules consisting of the extracellular domain of the granulocyte colony stimulating factor receptor (GCSF-R) and various mutant forms of the cytoplasmic domains of gp130 or LIFRalpha were expressed in embryonic stem (ES) cells to test for suppression of differentiation, or in a factor-dependent plasma cytoma cell line to assess for induction of proliferation. Carboxyl-terminal domains downstream of the phosphatase (SHP2)-binding sites were dispensable for mitogen-activated protein kinase activation and the transduction of proliferative signals. Moreover, carboxyl-terminal truncation mutants which lacked intact Box 3 homology domains showed decreased STAT3 activation, failed to induce Hck kinase activity and suppress ES cell differentiation. Moreover, STAT3 antisense oligonucleotides impaired LIF-dependent inhibition of differentiation. Substitution of the tyrosine residue within the Box 3 region of the GSCF-R abolished receptor-mediated suppression of differentiation without affecting the transduction of proliferative signals. Thus, distinct cytoplasmic domains within the LIFRalpha, gp130, and GCSF-R transduce proliferative and differentiation suppressing signals.
Ernst
M
M
Ludwig Institute for Cancer Research, Melbourne Tumour Biology Branch, P. O. Royal Melbourne Hospital, Victoria, 3050, Australia. matthias.ernst@ludwig.edu.au
Novak
U
U
Nicholson
S E
SE
Layton
J E
JE
Dunn
A R
AR
D015703:Antigens, CD / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D050822:Cytokine Receptor gp130; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006131:Growth Inhibitors; D006801:Humans; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines; D008562:Membrane Glycoproteins / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D010766:Phosphorylation; D018121:Receptors, Cytokine / Q000378:metabolism*; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000737:chemistry / Q000378:metabolism; D053606:Receptors, OSM-LIF; D050796:STAT3 Transcription Factor; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection; D018909:src Homology Domains
D015703:Antigens, CD; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; C494199:IL6ST protein, human; D015850:Interleukin-6; C507837:LIF protein, human; C507840:LIFR protein, human; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines; D008562:Membrane Glycoproteins; D016376:Oligonucleotides, Antisense; D018121:Receptors, Cytokine; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D053606:Receptors, OSM-LIF; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; D050822:Cytokine Receptor gp130