Regulatory subunit NEMO promotes polyubiquitin-dependent induction of NF-κB through a targetable second interaction with upstream activator IKK2.
Regulatory subunit NEMO promotes polyubiquitin-dependent induction of NF-κB through a targetable second interaction with upstream activator IKK2.
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DOI：
10.1016/j.jbc.2022.101864
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发表时间：
2022-05
影响因子：
4.8
通讯作者：
Ghosh, Gourisankar
中科院分区：
文献类型：
--
作者：
Ko, Myung Soo;Cohen, Samantha N.;Polley, Smarajit;Mahata, Sushil K.;Biswas, Tapan;Huxford, Tom;Ghosh, Gourisankar
通过κ B激酶抑制剂（IKK）复合物的典型NF-κ B信号传导需要通过其活化环内的特异性磷酸化诱导IKK 2/IKK β亚基催化活性。已知这一过程依赖于辅助泛素（U B）结合亚基NF-κ B必需调节因子（NEMO）/IKK γ以及多聚U B链。然而，多聚Ub结合促进IKK催化活性的机制尚不清楚。在这里，我们发现NEMO/IKK γ与线性poly-Ub的结合促进了NEMO/IKK γ和IKK 2/IKK β之间的第二种相互作用，不同于NEMO/IKK γ N端与IKK 2/IKK β C端的"NEMO结合结构域"的充分表征的相互作用。我们将第二次相互作用的位置定位在人NEMO/IKK γ锌指结构域N端的一段大约6个氨基酸。我们还发现，NEMO/IKK γ这一区域内的氨基酸残基是通过体外次级相互作用与IKK 2/IKK β结合以及培养细胞中IKK 2/IKK β完全激活所必需的。此外，我们在IKK 2/IKK β上的NEMO/IKK γ片段的支架二聚化结构域中，在激酶结构域-Ub样结构域附近，确定了一个对接位点。最后，我们发现来自NEMO/IKK γ这一区域的肽能够特异性干扰转染细胞中典型的NF-κ B信号。这些体外生物化学和细胞培养实验表明，由于NEMO/IKK γ与线性多聚UB结合，因此NEMO/IKK γ在引发IKK 2/IKK β磷酸化中发挥直接作用，并且该过程可被抑制以特异性破坏经典NF-κ B信号传导。
Canonical NF-κB signaling through the inhibitor of κB kinase (IKK) complex requires induction of IKK2/IKKβ subunit catalytic activity via specific phosphorylation within its activation loop. This process is known to be dependent upon the accessory ubiquitin (Ub)-binding subunit NF-κB essential modulator (NEMO)/IKKγ as well as poly-Ub chains. However, the mechanism through which poly-Ub binding serves to promote IKK catalytic activity is unclear. Here, we show that binding of NEMO/IKKγ to linear poly-Ub promotes a second interaction between NEMO/IKKγ and IKK2/IKKβ, distinct from the well-characterized interaction of the NEMO/IKKγ N terminus to the “NEMO-binding domain” at the C terminus of IKK2/IKKβ. We mapped the location of this second interaction to a stretch of roughly six amino acids immediately N-terminal to the zinc finger domain in human NEMO/IKKγ. We also showed that amino acid residues within this region of NEMO/IKKγ are necessary for binding to IKK2/IKKβ through this secondary interaction in vitro and for full activation of IKK2/IKKβ in cultured cells. Furthermore, we identified a docking site for this segment of NEMO/IKKγ on IKK2/IKKβ within its scaffold-dimerization domain proximal to the kinase domain–Ub-like domain. Finally, we showed that a peptide derived from this region of NEMO/IKKγ is capable of interfering specifically with canonical NF-κB signaling in transfected cells. These in vitro biochemical and cell culture–based experiments suggest that, as a consequence of its association with linear poly-Ub, NEMO/IKKγ plays a direct role in priming IKK2/IKKβ for phosphorylation and that this process can be inhibited to specifically disrupt canonical NF-κB signaling.
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影响因子：
44.1
作者：
Hu H;Sun SC
通讯作者：
Sun SC
影响因子：
2.9
作者：
Mulero MC;Shahabi S;Ko MS;Schiffer JM;Huang DB;Wang VY;Amaro RE;Huxford T;Ghosh G
通讯作者：
Ghosh G
影响因子：
56.9
作者：
Delhase, M;Hayakawa, M;Karin, M
通讯作者：
Karin, M
Nemo识别二丁素蛋白的结构基础。
影响因子：
16
作者：
Lo, Yu-Chih;Lin, Su-Chang;Rospigliosi, Carla C.;Conze, Dietrich B.;Wu, Chuan-Jin;Ashwell, Jonathan D.;Eliezer, David;Wu, Hao
通讯作者：
Wu, Hao
影响因子：
20.3
作者：
Nagashima, Kumiko;Sasseville, Vito G.;Fraser, Christopher C.
通讯作者：
Fraser, Christopher C.