TY - JOUR
T1 - E3 ligase FLRF (Rnf41) regulates differentiation of hematopoietic progenitors by governing steady-state levels of cytokine and retinoic acid receptors
AU - Jing, Xin
AU - Infante, Jorge
AU - Nachtman, Ronald G.
AU - Jurecic, Roland
N1 - Funding Information:
We thank Dr. McIntush (Bethyl Inc.) for generously generating and sharing two α-FLRF Abs, and Dr. Sytkowski (Harvard Medical School), and Dr. Kaushansky (UC San Diego School of Medicine) for sharing with us BaF3/EPOR and BaF3/Mpl cell lines. This work was supported by National Institutes of Health grant RO1 RR15242 and American Cancer Society Institutional Grants (R.J.).
PY - 2008/9
Y1 - 2008/9
N2 - Objective: FLRF (Rnf41) gene was identified through screening of subtracted cDNA libraries form murine hematopoietic stem cells and progenitors. Subsequent work has revealed that FLRF acts as E3 ubiquitin ligase, and that it regulates steady-state levels of neuregulin receptor ErbB3 and participates in degradation of IAP protein BRUCE and parkin. The objective of this study was to start exploring the role of FLRF during hematopoiesis. Materials and Methods: FLRF was overexpressed in a murine multipotent hematopoietic progenitor cell line EML, which can differentiate into almost all blood cell lineages, and in pro-B progenitor cell line BaF3. The impact of FLRF overexpression on EML cell differentiation into myeloerythroid lineages was studied using hematopoietic colony-forming assays. The interaction of FLRF with cytokine receptors and receptor levels in control cells and EML and BaF3 cells overexpressing FLRF were examined with Western and immunoprecipitation. Results: Remarkably, overexpression of FLRF significantly attenuated erythroid and myeloid differentiation of EML cells in response to cytokines erythropoietin (EPO) and interleukin-3 (IL-3), and retinoic acid (RA), and resulted in significant and constitutive decrease of steady-state levels of IL-3, EPO, and RA receptor-α (RARα) in EML and BaF3 cells. Immunoprecipitation has revealed that FLRF interacts with IL-3, EPO, and RARα receptors in EML and BaF3 cells, and that FLRF-mediated downregulation of these receptors is ligand binding-independent. Conclusions: The results of this study have revealed new FLRF-mediated pathway for ligand-independent receptor level regulation, and support the notion that through maintaining basal levels of cytokine receptors, FLRF is involved in the control of hematopoietic progenitor cell differentiation into myeloerythroid lineages.
AB - Objective: FLRF (Rnf41) gene was identified through screening of subtracted cDNA libraries form murine hematopoietic stem cells and progenitors. Subsequent work has revealed that FLRF acts as E3 ubiquitin ligase, and that it regulates steady-state levels of neuregulin receptor ErbB3 and participates in degradation of IAP protein BRUCE and parkin. The objective of this study was to start exploring the role of FLRF during hematopoiesis. Materials and Methods: FLRF was overexpressed in a murine multipotent hematopoietic progenitor cell line EML, which can differentiate into almost all blood cell lineages, and in pro-B progenitor cell line BaF3. The impact of FLRF overexpression on EML cell differentiation into myeloerythroid lineages was studied using hematopoietic colony-forming assays. The interaction of FLRF with cytokine receptors and receptor levels in control cells and EML and BaF3 cells overexpressing FLRF were examined with Western and immunoprecipitation. Results: Remarkably, overexpression of FLRF significantly attenuated erythroid and myeloid differentiation of EML cells in response to cytokines erythropoietin (EPO) and interleukin-3 (IL-3), and retinoic acid (RA), and resulted in significant and constitutive decrease of steady-state levels of IL-3, EPO, and RA receptor-α (RARα) in EML and BaF3 cells. Immunoprecipitation has revealed that FLRF interacts with IL-3, EPO, and RARα receptors in EML and BaF3 cells, and that FLRF-mediated downregulation of these receptors is ligand binding-independent. Conclusions: The results of this study have revealed new FLRF-mediated pathway for ligand-independent receptor level regulation, and support the notion that through maintaining basal levels of cytokine receptors, FLRF is involved in the control of hematopoietic progenitor cell differentiation into myeloerythroid lineages.
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U2 - 10.1016/j.exphem.2008.04.001
DO - 10.1016/j.exphem.2008.04.001
M3 - Article
C2 - 18495327
AN - SCOPUS:49349109951
VL - 36
SP - 1110
EP - 1120
JO - Experimental Hematology
JF - Experimental Hematology
SN - 0301-472X
IS - 9
ER -