GATA transcription factors inhibit cytokine-dependent growth and survival of a hematopoietic cell line through the inhibition of STAT3 activity
GATA transcription factors inhibit cytokine-dependent growth and survival of a hematopoietic cell line through the inhibition of STAT3 activity
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DOI：
10.1074/jbc.m413461200
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发表时间：
2005-04-01
影响因子：
4.8
通讯作者：
Kanakura, Y
中科院分区：
文献类型：
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作者：
Ezoe, S;Matsumura, I;Kanakura, Y
尽管通过基因靶向实验显示加塔-1和加塔-2对于造血细胞的发育是必需的，但也报道了它们抑制造血细胞的生长。因此，在本研究中，我们检测了加塔-1和加塔-2对细胞因子信号的影响。他莫昔芬诱导型加塔-1（加塔-1/ERT）对IL-3依赖性细胞系Ba/F3的IL-3依赖性生长显示出轻微的抑制作用。另一方面，它大大抑制TPO依赖性生长和gp 130介导的生长/存活的Ba/F3。类似地，雌二醇诱导形式的加塔-2（加塔-2/ER）破坏了Ba/F3的血小板生成素（TPO）依赖性生长和gp 130介导的生长/存活。对于这一机制，我们发现加塔-1和加塔-2在体外和体内都直接与STAT 3结合，并且在凝胶迁移试验和染色质免疫沉淀试验中抑制其DNA结合活性，而它们几乎不影响STAT 5活性。此外，在正常巨核细胞中发现内源性加塔-1与STAT 3相互作用，表明加塔-1可能抑制正常造血细胞中的STAT 3活性。此外，我们发现加塔-1通过其N-锌指结构域抑制STAT 3活性。总之，这些结果表明，除了作为转录因子的作用，加塔家族蛋白通过蛋白质-蛋白质相互作用调节细胞因子信号，从而调节造血细胞的生长和存活。
Although GATA-1 and GATA-2 were shown to be essential for the development of hematopoietic cells by gene targeting experiments, they were also reported to inhibit the growth of hematopoietic cells. Therefore, in this study, we examined the effects of GATA-1 and GATA-2 on cytokine signals. A tamoxifen-inducible form of GATA-1 (GATA-1/ERT) showed a minor inhibitory effect on interleukin-3 (IL-3)-dependent growth of an IL3-dependent cell line Ba/F3. On the other hand, it drastically inhibited TPO-dependent growth and gp130-mediated growth/survival of Ba/F3. Similarly, an estradiol-inducible form of GATA-2 (GATA-2/ER) disrupted thrombopoietin (TPO)-dependent growth and gp130-mediated growth/survival of Ba/F3. As for this mechanism, we found that both GATA-1 and GATA-2 directly bound to STAT3 both in vitro and in vivo and inhibited its DNA-binding activity in gel shift assays and chromatin immunoprecipitation assays, whereas they hardly affected STAT5 activity. In addition, endogenous GATA-1 was found to interact with STAT3 in normal megakaryocytes, suggesting that GATA-1 may inhibit STAT3 activity in normal hematopoietic cells. Furthermore, we found that GATA-1 suppressed STAT3 activity through its N-zinc finger domain. Together, these results suggest that, besides the roles as transcription factors, GATA family proteins modulate cytokine signals through protein-protein interactions, thereby regulating the growth and survival of hematopoietic cells.