Fructose-1, 6-bisphosphatase 1 interacts with NF-κB p65 to regulate breast tumorigenesis via PIM2 induced phosphorylation
Fructose-1, 6-bisphosphatase 1 interacts with NF-κB p65 to regulate breast tumorigenesis via PIM2 induced phosphorylation
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DOI：
10.7150/thno.46861
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发表时间：
2020-01-01
期刊：
影响因子：
12.4
通讯作者：
Yu, Zhenhai
中科院分区：
文献类型：
--
作者：
Lu, Chao;Ren, Chune;Yu, Zhenhai
基本原理：果糖-1，6-二磷酸酶1（Fructose-1，6-bisphosphatase 1，FBP 1）是一种肿瘤发生的限速酶，近年来发现它具有肿瘤抑制作用，并通过其非经典功能介导多种转录因子的活性。然而，转录后修饰的非经典functionsofFBP1.Methods的潜在机制仍然难以捉摸：我们采用免疫亲和纯化，以确定结合伙伴（S），并使用免疫共沉淀来验证它们的相互作用。激酶反应证实PIM 2可磷酸化FBP 1。使用过表达或敲低蛋白来评估调节p65蛋白稳定性的作用。机制分析涉及蛋白质降解和多聚泛素化测定。结果：在此，我们鉴定了小鼠淋巴瘤2（PIM 2）中的前病毒插入作为FBP 1的新结合伴侣，其可以磷酸化Ser 144上的FBP 1。令人惊讶的是，磷酸化的FBP 1 Ser 144消除了其与NF-κ B p65的相互作用，通过CHIP介导的蛋白酶体途径促进其蛋白质稳定性。此外，在Ser 144上的FBP 1磷酸化增加了p65调节的PD-L1表达。因此，在体外和体内，Ser 144上的FBP 1磷酸化促进乳腺肿瘤生长。结论：PIM 2磷酸化非经典FBP 1是NF-κ B B通路的一种新的调节因子，提示PIM 2抑制剂可作为乳腺癌的治疗药物。
Rationale: Fructose-1, 6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, was recently shown to be a tumor suppressor and could mediate the activities of multiple transcriptional factors via its non-canonical functions. However, the underlying mechanism of posttranscriptional modification on the non-canonical functions of FBP1 remains elusive.Methods: We employed immunoaffinity purification to identify binding partner(s) and used co-immunoprecipitation to verify their interactions. Kinase reaction was used to confirm PIM2 could phosphorylate FBP1. Overexpression or knockdown proteins were used to assess the role in modulating p65 protein stability. Mechanistic analysis was involved in protein degradation and polyubiquitination assays. Nude mice and PIM2-knockout mice was used to study protein functions in vitro and in vivo.Results: Here, we identified Proviral Insertion in Murine Lymphomas 2 (PIM2) as a new binding partner of FBP1, which could phosphorylate FBP1 on Ser144. Surprisingly, phosphorylated FBP1 Ser144 abrogated its interaction with NF-kappa B p65, promoting its protein stability through the CHIP-mediated proteasome pathway. Furthermore, phosphorylation of FBP1 on Ser144 increased p65 regulated PD-L1 expression. As a result, phosphorylation of FBP1 on Ser144 promoted breast tumor growth in vitro and in vivo. Moreover, the levels of PIM2 and pSer144-FBP1 proteins were positively correlated with each other in human breast cancer and PIM2 knockout mice.Conclusions: Our findings revealed that phosphorylation noncanonical FBP1 by PIM2 was a novel regulator of NF-kappa B pathway, and highlights PIM2 inhibitors as breast cancer therapeutics.