Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells
Background Sam68, a member of the signal transduction and activation of RNA metabolism (STAR) family of RNA-binding proteins, has been previously implicated as an adaptor molecule in different signaling systems, including leptin receptor (LEPR) signaling. LEPR activation is known to stimulate JAK-ST...
Guardado en:
| Autor principal: | |
|---|---|
| Publicado: |
2011
|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02681161_v26_n9_p2306_SanchezJimenez http://hdl.handle.net/20.500.12110/paper_02681161_v26_n9_p2306_SanchezJimenez |
| Aporte de: |
| id |
paper:paper_02681161_v26_n9_p2306_SanchezJimenez |
|---|---|
| record_format |
dspace |
| spelling |
paper:paper_02681161_v26_n9_p2306_SanchezJimenez2023-06-08T15:24:09Z Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells Varone, Cecilia Laura LEPR signaling leptin placenta Sam68 trophoblast DNA Janus kinase 2 leptin leptin receptor leucine mitogen activated protein kinase phosphatidylinositol 3 kinase protein Sam68 STAT3 protein tyrosine article cell growth cell proliferation controlled study DNA synthesis down regulation enzyme activation gene overexpression human human cell human cell culture immunoblotting immunoprecipitation protein expression protein phosphorylation protein protein interaction protein synthesis signal transduction trophoblast Background Sam68, a member of the signal transduction and activation of RNA metabolism (STAR) family of RNA-binding proteins, has been previously implicated as an adaptor molecule in different signaling systems, including leptin receptor (LEPR) signaling. LEPR activation is known to stimulate JAK-STAT, MAPK and PI3K signaling pathways, thus mediating the biological effects of leptin in different cell types, including trophoblastic cells. We have recently found that leptin stimulation also promotes the overexpression and tyrosine phosphorylation of Sam68 in human trophoblastic JEG-3 cells, suggesting a role for Sam68 in leptin signaling and action in these cells. In the present work, we have studied the participation of Sam68 in the main signaling pathways activated by LEPR to increase growth and proliferation in trophoblastic JEG-3 cells. Methods We used an antisense strategy to down-regulate Sam68 expression in these cells, and we studied LEPR signaling by immunoprecipitation and poly-U affinity precipitation and by analyzing phosphorylation levels of signaling proteins by immunoblot. The effect of leptin on protein synthesis and proliferation was studied by 3[H]-leucine and 3[H]-thymidine incorporation. Results Sam68 knockdown impaired leptin activation of JAK-STAT, PI3K and MAPK signaling pathways in JEG-3 cells. We have also found that leptin-stimulated Sam68 tyrosine phosphorylation is dependent on JAK-2 activity, since the pharmacological inhibitor AG490 prevents the phosphorylation of Sam68 in JEG-3 cells. Finally, the trophic and proliferative effect of leptin in trophoblastic cells is dependent on Sam68 expression, since its down-regulation impaired the leptin-stimulated DNA and protein synthesis. Conclusions These data demonstrate that Sam68 participates in the main signaling pathways of LEPR to mediate the trophic and proliferative effect of leptin in human trophoblastic cells. © 2011 The Author. Fil:Varone, C.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02681161_v26_n9_p2306_SanchezJimenez http://hdl.handle.net/20.500.12110/paper_02681161_v26_n9_p2306_SanchezJimenez |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
LEPR signaling leptin placenta Sam68 trophoblast DNA Janus kinase 2 leptin leptin receptor leucine mitogen activated protein kinase phosphatidylinositol 3 kinase protein Sam68 STAT3 protein tyrosine article cell growth cell proliferation controlled study DNA synthesis down regulation enzyme activation gene overexpression human human cell human cell culture immunoblotting immunoprecipitation protein expression protein phosphorylation protein protein interaction protein synthesis signal transduction trophoblast |
| spellingShingle |
LEPR signaling leptin placenta Sam68 trophoblast DNA Janus kinase 2 leptin leptin receptor leucine mitogen activated protein kinase phosphatidylinositol 3 kinase protein Sam68 STAT3 protein tyrosine article cell growth cell proliferation controlled study DNA synthesis down regulation enzyme activation gene overexpression human human cell human cell culture immunoblotting immunoprecipitation protein expression protein phosphorylation protein protein interaction protein synthesis signal transduction trophoblast Varone, Cecilia Laura Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| topic_facet |
LEPR signaling leptin placenta Sam68 trophoblast DNA Janus kinase 2 leptin leptin receptor leucine mitogen activated protein kinase phosphatidylinositol 3 kinase protein Sam68 STAT3 protein tyrosine article cell growth cell proliferation controlled study DNA synthesis down regulation enzyme activation gene overexpression human human cell human cell culture immunoblotting immunoprecipitation protein expression protein phosphorylation protein protein interaction protein synthesis signal transduction trophoblast |
| description |
Background Sam68, a member of the signal transduction and activation of RNA metabolism (STAR) family of RNA-binding proteins, has been previously implicated as an adaptor molecule in different signaling systems, including leptin receptor (LEPR) signaling. LEPR activation is known to stimulate JAK-STAT, MAPK and PI3K signaling pathways, thus mediating the biological effects of leptin in different cell types, including trophoblastic cells. We have recently found that leptin stimulation also promotes the overexpression and tyrosine phosphorylation of Sam68 in human trophoblastic JEG-3 cells, suggesting a role for Sam68 in leptin signaling and action in these cells. In the present work, we have studied the participation of Sam68 in the main signaling pathways activated by LEPR to increase growth and proliferation in trophoblastic JEG-3 cells. Methods We used an antisense strategy to down-regulate Sam68 expression in these cells, and we studied LEPR signaling by immunoprecipitation and poly-U affinity precipitation and by analyzing phosphorylation levels of signaling proteins by immunoblot. The effect of leptin on protein synthesis and proliferation was studied by 3[H]-leucine and 3[H]-thymidine incorporation. Results Sam68 knockdown impaired leptin activation of JAK-STAT, PI3K and MAPK signaling pathways in JEG-3 cells. We have also found that leptin-stimulated Sam68 tyrosine phosphorylation is dependent on JAK-2 activity, since the pharmacological inhibitor AG490 prevents the phosphorylation of Sam68 in JEG-3 cells. Finally, the trophic and proliferative effect of leptin in trophoblastic cells is dependent on Sam68 expression, since its down-regulation impaired the leptin-stimulated DNA and protein synthesis. Conclusions These data demonstrate that Sam68 participates in the main signaling pathways of LEPR to mediate the trophic and proliferative effect of leptin in human trophoblastic cells. © 2011 The Author. |
| author |
Varone, Cecilia Laura |
| author_facet |
Varone, Cecilia Laura |
| author_sort |
Varone, Cecilia Laura |
| title |
Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| title_short |
Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| title_full |
Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| title_fullStr |
Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| title_full_unstemmed |
Sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic JEG-3 cells |
| title_sort |
sam68 mediates leptin-stimulated growth by modulating leptin receptor signaling in human trophoblastic jeg-3 cells |
| publishDate |
2011 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02681161_v26_n9_p2306_SanchezJimenez http://hdl.handle.net/20.500.12110/paper_02681161_v26_n9_p2306_SanchezJimenez |
| work_keys_str_mv |
AT varonececilialaura sam68mediatesleptinstimulatedgrowthbymodulatingleptinreceptorsignalinginhumantrophoblasticjeg3cells |
| _version_ |
1768545689291194368 |