scholarly journals Stat1 associates with c-kit and is activated in response to stem cell factor

1997 ◽  
Vol 327 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Candy DeBERRY ◽  
Sherry MOU ◽  
Diana LINNEKIN

Interaction of stem cell factor (SCF), a haematopoietic growth factor, with the receptor tyrosine kinase c-kit leads to autophosphorylation of c-kit as well as tyrosine phosphorylation of various substrates. Little is known about the role of the JAK/STAT pathway in signal transduction via receptor tyrosine kinases, although this pathway has been well characterized in cytokine receptor signal transduction. We recently found that the Janus kinase Jak2 associates with c-kit and that SCF induces rapid and transient phosphorylation of Jak2. Here we present evidence that SCF activates the transcription factor Stat1. Phosphorylated c-kit co-immunoprecipitates with Stat1 within 1 min of SCF stimulation of the human cell line MO7e. Co-precipitation experiments using glutathione S-transferase fusion proteins indicate that association with c-kit is mediated by the Stat1 SH2 domain. Stat1 is rapidly tyrosine-phosphorylated in response to SCF in MO7e cells, the murine cell line FDCP-1 and normal progenitor cells. SCF-induced phosphorylation of Jak2 and Stat1 was also observed in murine 3T3 fibroblasts stably transfected with full-length human c-kit receptor. Furthermore c-kit directly phosphorylates Stat1 fusion proteins in in vitro kinase assays. Electrophoretic mobility-shift assays with nuclear extracts from SCF-stimulated cell lines and normal progenitor cells indicate that activated Stat1 binds the m67 oligonucleotide, a high-affinity SIE promoter sequence. These results demonstrate that Stat1 is activated in response to SCF, and suggest that Stat1 is a component of the SCF signal-transduction pathway.

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke

Abstract Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.


Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4100-4108 ◽  
Author(s):  
N Okumura ◽  
K Tsuji ◽  
Y Ebihara ◽  
I Tanaka ◽  
N Sawai ◽  
...  

We investigated the effects of stem cell factor (SCF) on the migration of murine bone marrow hematopoietic progenitor cells (HPC) in vitro using a modification of the checkerboard assay. Chemotactic and chemokinetic activities of SCF on HPC were evaluated by the numbers of HPC migrated on positive and negative gradients of SCF, respectively. On both positive and negative gradients of SCF, HPC began to migrate after 4 hours incubation, and their numbers then increased time- dependently. These results indicated that SCF functions as a chemotactic and chemokinetic agent for HPC. Analysis of types of colonies derived from the migrated HPC showed that SCF had chemotactic and chemokinetic effects on all types of HPC. When migrating activities of other cytokines were examined, interleukin (IL)-3 and IL-11 also affected the migration of HPC, but the degrees of each effect were lower than that of SCF. The results of the present study demonstrated that SCF is one of the most potent chemotactic and chemokinetic factors for HPC and suggest that SCF may play an important role in the flow of HPC into bone marrow where stromal cells constitutively produce SCF.


Blood ◽  
1999 ◽  
Vol 93 (8) ◽  
pp. 2569-2577 ◽  
Author(s):  
Huei-Mei Huang ◽  
Jian-Chiuan Li ◽  
Yueh-Chun Hsieh ◽  
Hsin-Fang Yang-Yen ◽  
Jeffrey Jong-Young Yen

Abstract In vitro proliferation of hematopoietic stem cells requires costimulation by multiple regulatory factors whereas expansion of lineage-committed progenitor cells generated by stem cells usually requires only a single factor. The distinct requirement of factors for proliferation coincides with the differential temporal expression of the subunits of cytokine receptors during early stem cell differentiation. In this study, we explored the underlying mechanism of the requirement of costimulation in a hematopoietic progenitor cell line TF-1. We found that granulocyte-macrophage colony-stimulating factor (GM-CSF) optimally activated proliferation of TF-1 cells regardless of the presence or absence of stem cell factor (SCF). However, interleukin-5 (IL-5) alone sustained survival of TF-1 cells and required costimulation of SCF for optimal proliferation. The synergistic effect of SCF was partly due to its anti-apoptosis activity. Overexpression of the IL-5 receptor  subunit (IL5R) in TF-1 cells by genetic selection or retroviral infection also resumed optimal proliferation due to correction of the defect in apoptosis suppression. Exogenous expression of an oncogenic anti-apoptosis protein, Bcl-2, conferred on TF-1 cells an IL-5–dependent phenotype. In summary, our data suggested SCF costimulation is only necessary when the expression level of IL5R is low and apoptosis suppression is defective in the signal transduction of IL-5. Expression of Bcl-2 proteins released the growth restriction of the progenitor cells and may be implicated in leukemia formation.


Blood ◽  
1999 ◽  
Vol 93 (8) ◽  
pp. 2569-2577 ◽  
Author(s):  
Huei-Mei Huang ◽  
Jian-Chiuan Li ◽  
Yueh-Chun Hsieh ◽  
Hsin-Fang Yang-Yen ◽  
Jeffrey Jong-Young Yen

In vitro proliferation of hematopoietic stem cells requires costimulation by multiple regulatory factors whereas expansion of lineage-committed progenitor cells generated by stem cells usually requires only a single factor. The distinct requirement of factors for proliferation coincides with the differential temporal expression of the subunits of cytokine receptors during early stem cell differentiation. In this study, we explored the underlying mechanism of the requirement of costimulation in a hematopoietic progenitor cell line TF-1. We found that granulocyte-macrophage colony-stimulating factor (GM-CSF) optimally activated proliferation of TF-1 cells regardless of the presence or absence of stem cell factor (SCF). However, interleukin-5 (IL-5) alone sustained survival of TF-1 cells and required costimulation of SCF for optimal proliferation. The synergistic effect of SCF was partly due to its anti-apoptosis activity. Overexpression of the IL-5 receptor  subunit (IL5R) in TF-1 cells by genetic selection or retroviral infection also resumed optimal proliferation due to correction of the defect in apoptosis suppression. Exogenous expression of an oncogenic anti-apoptosis protein, Bcl-2, conferred on TF-1 cells an IL-5–dependent phenotype. In summary, our data suggested SCF costimulation is only necessary when the expression level of IL5R is low and apoptosis suppression is defective in the signal transduction of IL-5. Expression of Bcl-2 proteins released the growth restriction of the progenitor cells and may be implicated in leukemia formation.


Stem Cells ◽  
1997 ◽  
Vol 15 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Clara Cesana ◽  
Carmelo Carlo‐Stella ◽  
Lina Mangoni ◽  
Ester Regazzi ◽  
Daniela Garau ◽  
...  

1991 ◽  
Vol 148 (3) ◽  
pp. 503-509 ◽  
Author(s):  
Giovanni Migliaccio ◽  
Anna Rita Migliaccio ◽  
Maurice L. Druzin ◽  
Patricia-Jane V. Giardina ◽  
Krisztina M. Zsebo ◽  
...  

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke

Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.


Blood ◽  
1996 ◽  
Vol 87 (2) ◽  
pp. 447-455 ◽  
Author(s):  
M Lubbert ◽  
W Brugger ◽  
R Mertelsmann ◽  
L Kanz

Expression of tissue- and development-specific genes is coordinately regulated during maturation of hematopoietic precursor cells toward functional, end-stage peripheral blood (PB) cells. To study the expression and methylation of several myeloid-specific genes during in vitro differentiation of normal hematopoietic progenitor cells, we used a model of CD34+ selected PB progenitor cells (PBPCs). PBPCs from six patients with solid tumors were recruited by standard-dose chemotherapy and subsequent administration of recombinant granulocyte colony-stimulating factor (G-CSF). PBPCs were collected and CD34+ cells selected by immunoadsorption columns using a biotinylated anti-CD34 monoclonal antibody. Enriched cells contained between 78% and 90% (median, 84%) CD34+ cells as determined by fluorescence-activated cell sorting analysis. Cell preparations were cultured in the presence of interleukin-1 beta (IL-1 beta), IL-3, IL-6 and stem cell factor and with or without G-CSF for various time intervals up to 20 days. Genes for CD34 surface antigen, lysozyme (LZM) and myeloperoxidase (MPO) were examined by RNA and DNA analyses. A rapid and early downregulation of CD34 transcripts was observed, with concomitant, time-dependent upregulation of expression of both the LZM and MPO genes. These effects were enhanced in the presence of G-CSF. Analysis of the DNA methylation status at key sites within these genes showed a pattern of differentiation- and expression-associated demethylation of the LZM gene, which was also enhanced by G-CSF, and constitutive and unaltered demethylation at key regions of the CD34 and MPO genes. In conclusion, the genes for CD34, LZM, and MPO are regulated during in vitro culture of very immature PBPCs in the presence of stem cell factor, IL-1, IL-3, IL-6; their effects are enhanced by G-CSF.


2002 ◽  
Vol 195 (12) ◽  
pp. 1599-1611 ◽  
Author(s):  
Laura Velazquez ◽  
Alec M. Cheng ◽  
Heather E. Fleming ◽  
Caren Furlonger ◽  
Shirly Vesely ◽  
...  

The adaptor protein Lnk, and the closely related proteins APS and SH2B, form a subfamily of SH2 domain-containing proteins implicated in growth factor, cytokine, and immunoreceptor signaling. To elucidate the physiological function of Lnk, we derived Lnk-deficient mice. Lnk−/− mice are viable, but display marked changes in the hematopoietic compartment, including splenomegaly and abnormal lymphoid and myeloid homeostasis. The in vitro proliferative capacity and absolute numbers of hematopoietic progenitors from Lnk−/− mice are greatly increased, in part due to hypersensitivity to several cytokines. Moreover, an increased synergy between stem cell factor and either interleukin (IL)-3 or IL-7 was observed in Lnk−/− cells. Furthermore, Lnk inactivation causes abnormal modulation of IL-3 and stem cell factor–mediated signaling pathways. Consistent with these results, we also show that Lnk is highly expressed in multipotent cells and committed precursors in the erythroid, megakaryocyte, and myeloid lineages. These data implicate Lnk as playing an important role in hematopoiesis and in the regulation of growth factor and cytokine receptor–mediated signaling.


Sign in / Sign up

Export Citation Format

Share Document