Structure-function relationship of NFkB p65

我们以前已经证明，在丝氨酸536磷酸化的p65差异招募选择性启动子细胞活化后。 我们最近证明，p65结合位点和特定基因转录起始位点之间的距离决定了p65是否需要在丝氨酸536上磷酸化。 p65的磷酸化不参与增强体的形成，其中需要组蛋白修饰酶募集到近端启动子。 这些发现表明，p65的磷酸化和启动子的顺式作用元件调节各种NF κ B应答基因。 我们目前正在研究p65的各种磷酸化位点在控制p65反应基因周围的染色质结构中的作用。 我们还研究了各种IkB成员如何调节磷酸化p65的核转位。除了丝氨酸536之外，p65的丝氨酸529的磷酸化已经显示出调节转录活性。 我们目前正在研究丝氨酸529和536的磷酸化在调节染色质结构中的关系。 我们以前已经表明，p65在丝氨酸536磷酸化导致Csf 2基因表达的增加。最近，已经表明IKKa对p65在丝氨酸536处的磷酸化是由小鼠成纤维细胞中的光敏素-β受体（LTbR）信号传导诱导的。 我们已经观察到，用激动性抗LTbR抗体处理3 T3成纤维细胞导致p65在丝氨酸536处磷酸化，但不表达Csf 2基因。 然而，引发与抗LTbR抗体导致TNF介导的Csf 2表达的协同增加。协同增强需要NIK的激活和通过替代NFkB途径的信号传导。此外，在TNF介导的Csf 2基因表达的LTbR引发过程中，观察到p65和RelB的核转位和向Csf 2启动子的募集。我们目前正在研究启动机制。

We have previously demonstrated that the phosphorylation of p65 at serine 536 was differentially recruited to selective promoters following cell activation. We have recently demonstrated that the distance between the site of p65 binding and the transcription start site of a particular gene determines if p65 needs to be phosphorylated on serine 536. The phosphorylation of p65 was not involved in the formation of an enhanceosome, where the recruitment of histone modifying enzymes to proximal promoters was required. These findings suggested that the phosphorylation of p65 and the cis-acting elements of the promoter regulate the various NFkB responsive genes. We are currently investigating the role of various phosphorylation sites of p65 in controling the chromatin architecture surrounding p65 responsive genes. We are also examining how the various IkB members regulate the nuclear translocation of phosphorylated p65. In addition to serine 536, the phosphorylation of serine 529 of p65 has been shown to regulate transcriptional activity. We are currently investigating the relationship between the phosphorylation of serines 529 and 536 in regulating the chromatin architecture. We have shown previously that the phosphorylation of p65 at serine 536 resulted in an increase in Csf2 gene expression. Recently, it has been shown that the phosphorylation of p65 at serine 536 by IKKa was induced by lymphotoxin-beta receptor (LTbR) signaling in mouse fibroblast. We have observed that the treatment of 3T3 fibroblast cells with agonistic anti-LTbR antibody resulted in the phosphorylation of p65 at serine 536, but no expression of Csf2 gene. However, priming with anti-LTbR antibody resulted in a synergistic increase of TNF-mediated Csf2 expression. The synergistic enhancement required the activation of NIK and signaling through the alternative NFkB pathway. Furthermore, the nuclear translocation and recruitment of both p65 and RelB to the Csf2 promoter were observed during the LTbR priming of TNF-mediated Csf2 gene expression. We are currently examining the mechanism of priming.