CSK controls retinoic acid receptor (RAR) signaling: a RAR-c-SRC signaling axis is required for neuritogenic differentiation
CSK controls retinoic acid receptor (RAR) signaling: a RAR-c-SRC signaling axis is required for neuritogenic differentiation
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DOI：
10.1128/mcb.01352-06
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发表时间：
2007-06-01
影响因子：
5.3
通讯作者：
Durden, Donald L.
中科院分区：
文献类型：
--
作者：
Dey, Nandini;De, Pradip K.;Durden, Donald L.
在这里，我们报告的第一个证据表明，c-SRC是必需的视黄酸（RA）受体（RAR）信号，观察表明，这个家庭的核激素受体的一个新的范例。我们观察到，CSK负调控RAR的功能所需的轴突分化。CSK过表达抑制RA介导的神经突生长，这一结果与SFK c-SRC的抑制相关。与CSK对RAR信号传导和神经突生长的促核作用一致，CSK过表达阻断了RAC 1的下游激活。在LA-N-5细胞中，GDP-RAC 1向GTP-RAC 1的转化与c-SRC的活化平行，早在全反式维甲酸处理后15分钟。免疫荧光染色和共聚焦显微镜证实c-SRC和RAR γ的胞浆共定位。通过表面等离子体共振观察到RAR与SRC的直接和配体依赖性结合，并且共免疫沉淀研究证实了RAR γ与c-SRC的体内结合。删除富含脯氨酸的结构域内RAR γ废除这种相互作用在体内。CSK阻断RAR-RA依赖的SRC激活和LA-N-5细胞中的神经突生长。结果表明，由RA-RAR介导的转录信号事件是必要的，但不足以介导复杂的神经元细胞分化。我们已经阐明了一个非基因组的RAR-SRC相互作用介导的细胞核信号是负调控的CSK和RA诱导的神经元分化所需的。
Herein, we report the first evidence that c-SRC is required for retinoic acid (RA) receptor (RAR) signaling, an observation that suggests a new paradigm for this family of nuclear hormone receptors. We observed that CSK negatively regulates RAR functions required for neuritogenic differentiation. CSK overexpression inhibited RA-mediated neurite outgrowth, a result which correlated with the inhibition of the SFK c-SRC. Consistent with an extranuclear effect of CSK on RAR signaling and neurite outgrowth, CSK overexpression blocked the downstream activation of RAC1. The conversion of GDP-RAC1 to GTP-RAC1 parallels the activation of c-SRC as early as 15 min following all-trans-retinoic acid treatment in LA-N-5 cells. The cytoplasmic colocalization of c-SRC and RAR gamma was confirmed by immunofluorescence staining and confocal microscopy. A direct and ligand-dependent binding of RAR with SRC was observed by surface plasmon resonance, and coimmunoprecipitation studies confirmed the in vivo binding of RAR gamma to c-SRC. Deletion of a proline-rich domain within RAR gamma abrogated this interaction in vivo. CSK blocked the RAR-RA-dependent activation of SRC and neurite outgrowth in LA-N-5 cells. The results suggest that transcriptional signaling events mediated by RA-RAR are necessary but not sufficient to mediate complex differentiation in neuronal cells. We have elucidated a nongenomic extranuclear signal mediated by the RAR-SRC interaction that is negatively regulated by CSK and is required for RA-induced neuronal differentiation.