Interaction of anti-proliferative protein Tob with poly(A)-binding protein and inducible poly(A)-binding protein: implication of Tob in translational control
Interaction of anti-proliferative protein Tob with poly(A)-binding protein and inducible poly(A)-binding protein: implication of Tob in translational control
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DOI：
10.1111/j.1365-2443.2005.00826.x
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发表时间：
2005-02-01
期刊：
影响因子：
2.1
通讯作者：
Yamamoto, T
中科院分区：
文献类型：
--
作者：
Okochi, K;Suzuki, T;Yamamoto, T
Tob 是一个新兴的抗增殖蛋白家族的成员，该蛋白在过度表达时会抑制细胞生长。 tob mRNA 在无能 T 细胞中高表达，Tob 的过度表达通过与 Smads 的相互作用抑制白细胞介素 2 (IL-2) 的转录。在这里，我们通过使用 GST-Tob 探针筛选表达 cDNA 文库，鉴定了编码多聚腺苷酸结合蛋白 (PABP) 和诱导型 PABP (iPABP) 的两种 cDNA 克隆。免疫共沉淀和 GST 下拉实验表明 Tob 与 iPABP 的羧基末端区域相关。然后我们发现 iPABP 与 PABP 一样，参与翻译调节：iPABP 在体外增强 IL-2 mRNA 的翻译。 IL-2 mRNA 的增强翻译需要 3'UTR 和 Poly(A) 序列。 Tob 在体外通过与 iPABP 羧基末端区域的相互作用消除了翻译的增强。一致地，在稳定表达外源iPABP的NIH3T3细胞中Tob的过表达导致同时转染的IL-2表达质粒的IL-2产生受到抑制。最后，通过无能刺激诱导表达的 Tob 与人 T 细胞中的 iPABP 进行免疫共沉淀。这些发现表明 Tob 通过与 iPABP 相互作用参与无能 T 细胞中 IL-2 mRNA 的翻译抑制。
Tob is a member of an emerging family of anti-proliferative proteins that suppress cell growth when over-expressed. tob mRNA is highly expressed in anergic T cells and over-expression of Tob suppresses transcription of interleukin-2 (IL-2) through its interaction with Smads. Here, we identified two types of cDNA clones coding for poly(A)-binding protein (PABP) and inducible PABP (iPABP) by screening an expression cDNA library with the GST-Tob probe. Co-immunoprecipitation and GST-pull down experiments showed that Tob associated with the carboxyl-terminal region of iPABP. We then found that iPABP, like PABP, was involved in regulation of translation: iPABP enhanced translation of IL-2 mRNA in vitro. The enhanced translation of IL-2 mRNA required the 3'UTR and poly(A) sequences. Tob abrogated the enhancement of translation through its interaction with carboxyl-terminal region of iPABP in vitro. Consistently, over-expression of Tob in NIH3T3 cells, in which exogenous iPABP was stably expressed, resulted in suppression of IL-2 production from the simultaneously transfected IL-2 expression plasmid. Finally, Tob, whose expression was induced by anergic stimulation, was co-immunoprecipitated with iPABP in human T cells. These findings suggest that Tob is involved in the translational suppression of IL-2 mRNA in anergic T cells through its interaction with iPABP.