Novel Lys63-linked ubiquitination of IKKβ induces STAT3 signaling.
Novel Lys63-linked ubiquitination of IKKβ induces STAT3 signaling.
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DOI：
10.4161/15384101.2014.988026
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Donoghue DJ
中科院分区：
文献类型：
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作者：
Gallo LH;Meyer AN;Motamedchaboki K;Nelson KN;Haas M;Donoghue DJ
NF κ B信号转导在人类疾病中起重要作用，包括乳腺癌和卵巢癌、胰岛素抵抗、胚胎致死和肝变性、类风湿性关节炎、衰老和多发性骨髓瘤（MM）。κ B（I κ B）激酶β抑制剂（IKK β）调节经典核因子κ B（NF κ B）信号转导，以响应炎症和细胞应激。NF κ B激活需要上游蛋白（例如NEMO或TEK 1）的Lys 63连接（K63连接）遍在化，与膜结合受体形成分子复合物。我们证明IKK β本身经历K63连接的泛素化。在多发性骨髓瘤和其他癌症中发现的IKK β Lys171突变导致激酶活化和K63连接的泛素化显著增加。这些突变还导致STAT3信号传导的持续激活。液相色谱-高质量准确度串联质谱分析确定Lys147、Lys418、Lys555和Lys703为IKK β的主要泛素化位点。特异性抑制负责K63连接的泛素化的UBC13-UEV1A复合物，确立Lys147为K63-泛素结合的主要位点，并负责STAT3活化。因此，IKK β激活导致激酶结构域内的泛素化和K63-泛素缀合的信号传导平台的组装。这些结果与已知在MM和其他癌症中频繁发生的NF κ B信号上调的重要性进行了讨论。
NFκB signaling plays a significant role in human disease, including breast and ovarian carcinoma, insulin resistance, embryonic lethality and liver degeneration, rheumatoid arthritis, aging and Multiple Myeloma (MM). Inhibitor of κB (IκB) kinase β (IKKβ) regulates canonical Nuclear Factor κB (NFκB) signaling in response to inflammation and cellular stresses. NFκB activation requires Lys63-linked (K63-linked) ubiquitination of upstream proteins such as NEMO or TAK1, forming molecular complexes with membrane-bound receptors. We demonstrate that IKKβ itself undergoes K63-linked ubiquitination. Mutations in IKKβ at Lys171, identified in Multiple Myeloma and other cancers, lead to a dramatic increase in kinase activation and K63-linked ubiquitination. These mutations also result in persistent activation of STAT3 signaling. Liquid chromatography (LC)-high mass accuracy tandem mass spectrometry (MS/MS) analysis identified Lys147, Lys418, Lys555 and Lys703 as predominant ubiquitination sites in IKKβ. Specific inhibition of the UBC13-UEV1A complex responsible for K63-linked ubiquitination establishes Lys147 as the predominant site of K63-ubiquitin conjugation and responsible for STAT3 activation. Thus, IKKβ activation leads to ubiquitination within the kinase domain and assemblage of a K63-ubiquitin conjugated signaling platform. These results are discussed with respect to the importance of upregulated NFκB signaling known to occur frequently in MM and other cancers.