Phosphorylation of Nanog is essential to regulate Bmi1 and promote tumorigenesis.
Phosphorylation of Nanog is essential to regulate Bmi1 and promote tumorigenesis.
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新出现的证据表明，Nanog密切参与肿瘤发生，部分是通过调节癌症起始细胞群。然而，Nanog在肿瘤发生中的调节和作用仍然知之甚少。在这项研究中，人Nanog被鉴定为在包括T200和T280在内的多个残基处被人PKCε磷酸化。我们的工作表明，在T200和T280的磷酸化调节Nanog的功能，通过几种调节机制。磷酸化不敏感和磷酸化模拟突变体Nanog的结果表明，在T200和T280磷酸化增强Nanog蛋白的稳定性。此外，磷酸化不敏感的T200 A和T280 A突变体Nanog对内源性Nanog转录活性具有显性负抑制作用。Nanog的失活是由于受损的同源二聚化、DNA结合、启动子占用和p300（转录共激活因子）募集导致靶基因启动子激活缺陷。磷酸化不敏感的T200 A或T280 A突变体Nanog的异位表达减少了头颈部鳞状细胞癌（HNSCC）细胞中的细胞增殖、集落形成、侵袭、迁移和癌症起始细胞群。在表达磷酸化不敏感的T200 A或T280 A突变体Nanog的HNSCC细胞中，体内癌症引发能力严重受损;对照、T200 A和T280 A分别为87.5%（14/16）、12.5%（1/8）和0%（0/8）。Nanog占据Bmi 1启动子直接反式激活和调节Bmi 1。基因消融和拯救实验表明，Bmi 1是Nanog的多效性、促癌作用的关键下游信号节点。总之，我们的研究首次揭示了Nanog的翻译后磷酸化对于调节Bmi 1和促进肿瘤发生至关重要。
Emerging evidence indicates that Nanog is intimately involved in tumorigenesis in part through regulation of the cancer initiating cell population. However, the regulation and role of Nanog in tumorigenesis are still poorly understood. In this study, human Nanog was identified to be phosphorylated by human PKCε at multiple residues including T200 and T280. Our work indicated that phosphorylation at T200 and T280 modulates Nanog function through several regulatory mechanisms. Results with phosphorylation-insensitive and phosphorylation-mimetic mutant Nanog revealed that phosphorylation at T200 and T280 enhance Nanog protein stability. Moreover, phosphorylation-insensitive T200A and T280A mutant Nanog had a dominant-negative function to inhibit endogenous Nanog transcriptional activity. Inactivation of Nanog was due to impaired homodimerization, DNA binding, promoter occupancy, and p300, a transcriptional co-activator, recruitment resulting in a defect in target gene promoter activation. Ectopic expression of phosphorylation-insensitive T200A or T280A mutant Nanog reduced cell proliferation, colony formation, invasion, migration, and the cancer initiating cell population in head and neck squamous cell carcinoma (HNSCC) cells. The in vivo cancer initiating ability was severely compromised in HNSCC cells expressing phosphorylation-insensitive T200A or T280A mutant Nanog; 87.5% (14/16), 12.5% (1/8), and 0% (0/8) for control, T200A, and T280A, respectively. Nanog occupied the Bmi1 promoter to directly transactivate and regulate Bmi1. Genetic ablation and rescue experiments demonstrated that Bmi1 is a critical downstream signaling node for the pleiotropic, pro-oncogenic effects of Nanog. Taken together, our study revealed, for the first time, that post-translational phosphorylation of Nanog is essential to regulate Bmi1 and promote tumorigenesis.
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影响因子：
8
作者：
Bourguignon, L. Y. W.;Earle, C.;Wong, G.;Spevak, C. C.;Krueger, K.
通讯作者：
Krueger, K.
影响因子：
64.5
作者：
Mitsui, K;Tokuzawa, Y;Yamanaka, S
通讯作者：
Yamanaka, S
影响因子：
4.8
作者：
Ho, Baotran;Olson, Gretchen;Golubovskaya, Vita M.
通讯作者：
Golubovskaya, Vita M.
DOI：
10.1073/pnas.1005847107
发表时间：
2010-07-27
影响因子：
11.1
作者：
Moretto-Zita, Matteo;Jin, Hua;Xu, Yang
通讯作者：
Xu, Yang
影响因子：
5.2
作者：
Chang, David F.;Tsai, Steven C.;Lutzko, Carolyn
通讯作者：
Lutzko, Carolyn