Transient and selective NF-κB p65 serine 536 phosphorylation induced by T cell costimulation is mediated by IκB kinase β and controls the kinetics of p65 nuclear import
Transient and selective NF-κB p65 serine 536 phosphorylation induced by T cell costimulation is mediated by IκB kinase β and controls the kinetics of p65 nuclear import
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DOI：
10.4049/jimmunol.172.10.6336
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发表时间：
2004-05-15
影响因子：
4.4
通讯作者：
Schmitz, ML
中科院分区：
文献类型：
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作者：
Mattioli, I;Sebald, A;Schmitz, ML
NF-kappaB的核dna结合形式的完整转录活性需要额外的翻译后修饰。在这项研究中，我们系统地绘制了T细胞共刺激诱导的强反式激活NF-kappaB p65亚基c端一半的磷酸化位点，并确定了丝氨酸536是主要的磷酸化位点。丝氨酸536磷酸化的瞬时动力学与IkappaBalpha和IkappaB激酶（IKK）磷酸化的动力学相似，也反映了T细胞共刺激的原理。tcr诱导的丝氨酸536磷酸化通路受Cot激酶（Tpl2）、受体相互作用蛋白、蛋白激酶CO和nf - kappab诱导激酶的调控，但不依赖于磷脂酰肌醇3-激酶/Akt信号通路。功能丧失和功能获得实验显示IKKbeta磷酸化p65丝氨酸536，但IKKalpha不磷酸化。磷酸化发生在细胞质和完整的NF-kappaB/IkappaBalpha复合体内，需要IkappaBalpha丝氨酸32和36位点的事先磷酸化。重组P65（-/-）细胞，无论是野生型P65还是含有丝氨酸到丙氨酸突变的P65突变体，都揭示了该磷酸化位点对细胞质IkappaBalpha定位和P65核输入动力学的重要性。
Full transcriptional activity of the nuclear, DNA-bound form of NF-kappaB requires additional posttranslational modifications. In this study, we systematically mapped the T cell costimulation-induced phosphorylation sites within the C-terminal half of the strongly trans-activating NF-kappaB p65 subunit and identified serine 536 as the main phosphorylation site. The transient kinetics of serine 536 phosphorylation paralleled the kinetics of IkappaBalpha and IkappaB kinase (IKK) phosphorylation and also mirrored the principle of T cell costimulation. The TCR-induced pathway leading to serine 536 phosphorylation is regulated by the kinases Cot (Tpl2), receptor interacting protein, protein kinase CO, and NF-kappaB-inducing kinase, but is independent from the phosphatidylinositol 3-kinase/Akt signaling pathway. Loss-of-function and gain-of-function experiments showed phosphorylation of p65 serine 536 by IKKbeta, but not by IKKalpha. Phosphorylation occurs within the cytoplasmic and intact NF-kappaB/IkappaBalpha complex and requires prior phosphorylation of IkappaBalpha at serines 32 and 36. Reconstitution of P65(-/-) cells either with wild-type p65 or a p65 mutant containing a serine to alanine mutation revealed the importance of this phosphorylation site for cytosolic IkappaBalpha localization and the kinetics of p65 nuclear import.