RRC ID 19641
Author Fukumoto T, Kubota Y, Kitanaka A, Yamaoka G, Ohara-Waki F, Imataki O, Ohnishi H, Ishida T, Tanaka T.
Title Gab1 transduces PI3K-mediated erythropoietin signals to the Erk pathway and regulates erythropoietin-dependent proliferation and survival of erythroid cells.
Journal Cell. Signal.
Abstract In this study, we examined the biological functions of Gab1 in erythropoietin receptor (EPOR)-mediated signaling in vivo. Knockdown of Gab1 by the introduction of the Gab1 siRNA expression vector into F-36P human erythroleukemia (F-36P-Gab1-siRNA) cells resulted in a reduction of cell proliferation and survival in response to EPO. EPO-induced activation of Erk1/2 but not of Akt was significantly suppressed in F-36P-Gab1-siRNA cells compared with mock-transfected F-36P cells. The co-immunoprecipitation experiments revealed an EPO-enhanced association of Gab1 with the Grb2-SOS1 complex and SHP-2 in F-36P cells. A selective inhibitor of phosphatidylinositol 3-kinase (PI3K) LY294002 and short interfering RNA (siRNA) duplexes targeting the p85 regulatory subunit of PI3K (p85-siRNA) independently suppressed tyrosine phosphorylation of Gab1; its association with Grb2, SHP-2 and p85; and the activation of Erk in EPO-treated F-36P cells. LY294002 inhibited EPO-induced tyrosine phosphorylation of Gab1 and its association with Grb2 in human primary EPO-sensitive erythroid cells. The co-immunoprecipitation experiments using the Jak inhibitor AG490 or siRNA duplexes targeting Jak2 and in vitro binding experiments demonstrated that Jak2 regulated Gab1-mediated Erk activation through tyrosine phosphorylation of Gab1. Taken together, these results suggest that Gab1 couples PI3K-mediated EPO signals with the Ras/Erk pathway and that Gab1 plays an important role in EPOR-mediated signal transduction involved in the proliferation and survival of erythroid cells.
Volume 21(12)
Pages 1775-83
Published 2009-12
DOI 10.1016/j.cellsig.2009.07.013
PII S0898-6568(09)00220-4
PMID 19665053
MeSH Adaptor Proteins, Signal Transducing / genetics Adaptor Proteins, Signal Transducing / metabolism* Apoptosis Cell Line, Tumor Cell Proliferation Chromones / pharmacology Enzyme Inhibitors / pharmacology Erythroid Cells / cytology* Erythroid Cells / metabolism Erythropoietin / metabolism* GRB2 Adaptor Protein / metabolism Gene Knockdown Techniques Humans Janus Kinase 2 / antagonists & inhibitors Janus Kinase 2 / metabolism Leukemia, Erythroblastic, Acute / metabolism Mitogen-Activated Protein Kinase 1 / metabolism* Mitogen-Activated Protein Kinase 3 / metabolism* Morpholines / pharmacology Phosphatidylinositol 3-Kinases / metabolism* Protein Tyrosine Phosphatase, Non-Receptor Type 11 / metabolism Receptors, Erythropoietin / metabolism SOS1 Protein / metabolism
IF 3.388
Times Cited 6
Human and Animal Cells F-36P (RCB0775)