GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND STEEL FACTOR INDUCE PHOSPHORYLATION OF BOTH UNIQUE AND OVERLAPPING SIGNAL TRANSDUCTION INTERMEDIATES IN A HUMAN FACTOR-DEPENDENT HEMATOPOIETIC-CELL LINE
GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND STEEL FACTOR INDUCE PHOSPHORYLATION OF BOTH UNIQUE AND OVERLAPPING SIGNAL TRANSDUCTION INTERMEDIATES IN A HUMAN FACTOR-DEPENDENT HEMATOPOIETIC-CELL LINE
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DOI：
10.1002/jcp.1041530122
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发表时间：
1992-10-01
影响因子：
5.6
通讯作者：
GRIFFIN, JD
中科院分区：
文献类型：
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作者：
HALLEK, M;DRUKER, B;GRIFFIN, JD
钢因子（SF）是原癌基因c-kit的配体，与GM-CSF或IL-3协同作用以支持正常人造血祖细胞的生长。我们研究了SF对GM-CSF或IL-3诱导的人因子依赖性细胞系MO 7增殖的影响。SF支持MO 7细胞增殖以及单独的IL-3或GM-CSF，并且其添加显著增强（三至六倍）最大GM-CSF或IL-3刺激的增殖。SF不增加细胞表面GM-CSF受体的数量或亲和力。我们研究了几个早期事件的信号转导，努力阐明这些因素的协同作用的生化机制。由于这三种细胞因子中的每一种都被认为部分通过激活酪氨酸激酶发挥作用，我们研究了它们对细胞内含磷酸酪氨酸蛋白的影响。每种细胞因子诱导快速，瞬时和浓度依赖性的酪氨酸磷酸化的底物。对于GM-CSF和IL-3，这些磷蛋白是不可区分的（150、125、106、93、80、79、73、44、42和36 kDa），而SF诱导205、140-150、116、106、94、90、80、79、73、44、42、39、36、38、39 32 kDa磷蛋白。已知被GM-CSF和IL-3磷酸化和激活的另外两种信号转导中间体，70-75 kDa Raf-1激酶和p42丝裂原活化蛋白激酶-2（MAPK）也被SF磷酸化。当与单独的任何因子相比时，GM-CSF或IL-3与SF的组合没有进一步增加Raf-1或p42 MAPK的磷酸化。相反，SF，而不是GM-CSF或IL-3，诱导磷脂酶C-γ（PLC-γ）的酪氨酸磷酸化。这些结果表明SF和GM-CSF/IL-3对早期信号转导事件具有部分重叠的作用，以及显著的差异，例如PLC-γ的酪氨酸磷酸化。该细胞系为研究造血生长因子协同作用的复杂过程提供了有用的模型系统。
Steel factor (SF), the ligand for the proto-oncogene c-kit, acts synergistically with GM-CSF or IL-3 to support the growth of normal human hematopoietic progenitor cells. We examined the effects of SF on GM-CSF or IL-3 induced proliferation of a human factor-dependent cell line, MO7. SF supported MO7 cell proliferation as well as IL-3 or GM-CSF alone, and its addition dramatically enhanced (three- to sixfold) maximal GM-CSF or IL-3 stimulated proliferation. SF did not increase the number or affinity of cell surface GM-CSF receptors. We examined several early events of signal transduction in an effort to elucidate the biochemical mechanisms of synergy of these factors. Since each of these three cytokines is believed to function in part through activation of a tyrosine kinase, we examined their effects on cellular phosphotyrosine containing proteins. Each cytokine induced rapid, transient, and concentration dependent tyrosine phosphorylation of a number of substrates. For GM-CSF and IL-3, these phosphoproteins were indistinguishable (150, 125, 106, 93, 80, 79, 73, 44, 42, and 36 kDa), while SF induced major or minor tyrosine phosphorylation of 205, 140-150, 116, 106, 94, 90, 80, 79, 73, 44, 42, 39, 36, 32 kDa phosphoproteins. Two other signal transduction intermediates known to be phosphorylated and activated by GM-CSF and IL-3, the 70-75 kDa Raf-1 kinase, and p42 mitogen-activated protein kinase-2 (MAPK), were also phosphorylated by SF. Combinations of GM-CSF or IL-3 with SF did not further increase the phosphorylation of Raf-1 or p42 MAPK when compared to any of the factors alone. In contrast SF, but not GM-CSF or IL-3, induced tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma). These results indicate that SF and GM-CSF/IL-3 have partially overlapping effects on early signal transducing events, as well as striking differences, such as tyrosine phosphorylation of PLC-gamma. This cell line should provide a useful model system to investigate the complicated process of hematopoietic growth factor synergy.