IKK-Mediated Regulation of the COP9 Signalosome via Phosphorylation of CSN5
IKK-Mediated Regulation of the COP9 Signalosome via Phosphorylation of CSN5
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IKK 通过 CSN5 磷酸化介导的 COP9 信号小体调节
DOI：
10.1021/acs.jproteome.9b00626
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发表时间：
2020-03-01
影响因子：
4.4
通讯作者：
Fang，Lei
中科院分区：
文献类型：
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作者：
Zhang，Jingzi;Zhao，Ruoyu;Fang，Lei
COP9 信号体 (CSN) 是一种进化上保守的多亚基蛋白质复合物，它通过去甲基化和 cullin-RING 泛素 E3 连接酶 (CRL) 失活来控制蛋白质降解。最近，由于 CSN 复合物与 IKK 复合物的关联，CSN 复合物已与 NF-κB 信号通路联系起来。然而，CSN 复合物在此信号通路中如何受到调节仍不清楚。在这里，我们进行了生化实验并证实了CSN和IKK复合物之间的相互作用。此外，我们还确定 IKKα 或 IKKβ 的过度表达会导致 CSN5 磷酸化增强，CSN5 是 CSN 脱乙酰基酶活性的催化亚基。突变分析表明，CSN5 丝氨酸 201 和苏氨酸 205 的磷酸化会损害体外 CSN 介导的去甲基化活性。有趣的是，TNF-α治疗不仅增强了CSN和IKK之间的相互作用，而且还诱导CSN5丝氨酸201处的IKK依赖性磷酸化，通过IKK将CSN与TNF-α信号传导连接起来。此外，TNF-α治疗会影响全局的CSN相互作用网络，特别是CSN与蛋白酶体复合物、真核翻译起始因子复合物和CRL成分的关联。总的来说，我们的结果为 IKK 介导的与 NF-κB 信号通路相关的 CSN 调节提供了新的见解。
The COP9 signalosome (CSN) is an evolutionarily conserved multisubunit protein complex, which controls protein degradation through deneddylation and inactivation of cullin-RING ubiquitin E3 ligases (CRLs). Recently, the CSN complex has been linked to the NF-κB signaling pathway due to its association with the IKK complex. However, how the CSN complex is regulated in this signaling pathway remains unclear. Here, we have carried out biochemical experiments and confirmed the interaction between the CSN and IKK complexes. In addition, we have determined that overexpression of IKKα or IKKβ leads to enhanced phosphorylation of CSN5, the catalytic subunit for CSN deneddylase activity. Mutational analyses have revealed that phosphorylation at serine 201 and threonine 205 of CSN5 impairs CSN-mediated deneddylation activity in vitro. Interestingly, TNF-α treatment not only enhances the interaction between CSN and IKK but also induces an IKK-dependent phosphorylation of CSN5 at serine 201, linking CSN to TNF-α signaling through IKK. Moreover, TNF-α treatment affects the CSN interaction network globally, especially the associations of CSN with the proteasome complex, eukaryotic translation initiation factor complex, and CRL components. Collectively, our results provide new insights into IKK-mediated regulation of CSN associated with the NF-κB signaling pathway.