Evolutionarily Conserved Binding of Translationally Controlled Tumor Protein to Eukaryotic Elongation Factor 1B*
Evolutionarily Conserved Binding of Translationally Controlled Tumor Protein to Eukaryotic Elongation Factor 1B*
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DOI：
10.1074/jbc.m114.628594
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发表时间：
2015-01
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通讯作者：
Huiwen 惠文 Wu 吴;Weibin 维斌 Gong 宫;Xingzhe 形哲 Yao 姚;J. Wang 王;S. Perrett;Yingang 银刚 Feng 冯
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作者：
Huiwen 惠文 Wu 吴;Weibin 维斌 Gong 宫;Xingzhe 形哲 Yao 姚;J. Wang 王;S. Perrett;Yingang 银刚 Feng 冯
背景：TCTP是一种丰富且高度保守的蛋白质，其主要功能尚不清楚。结果：TCTP与真核细胞延伸因子1Bα/β/δ的一个保守的中心酸性区结合。结论：TCTP与真核细胞延伸因子1B的结合在进化上是保守的。意义：与eEF 1B的相互作用代表了TCTP的主要功能。翻译控制肿瘤蛋白（TCTP）是一种在真核生物中高度保守的蛋白质。但其主要功能尚不清楚。人TCTP与多细胞动物特异性真核细胞延伸因子1Bδ（eEF 1B δ）相互作用并抑制其鸟嘌呤核苷酸交换因子（GEF）活性，但其结构机制尚不清楚。通过NMR滴定、结构测定、顺磁弛豫增强、定点突变、等温滴定量热法和HADDOCK对接研究了TCTP与eEF 1B δ的相互作用。我们首先证明了eEF 1B δ的催化GEF结构域不负责与TCTP结合，而是eEF 1B δ中先前未被注意的中心酸性区（CAR）结构域。TCTP-eEF 1B δ CAR结构域复合物的诱变数据和结构模型揭示了关键结合残基。这些残基在真核TCTP和eEF 1B GEF中高度保守，包括真核保守的eEF 1B α，这意味着相互作用可能在所有真核生物中保守。TCTP与人类、裂殖酵母和单细胞光合微藻蛋白的eEF 1B α CAR结构域之间的相互作用得到证实，表明通过与eEF 1B的保守相互作用参与蛋白质翻译是TCTP的主要功能。
Background: The primary function of the abundant and highly conserved protein TCTP is not clear. Results: TCTP binds to a conserved central acidic region of eukaryotic elongation factor 1Bα/β/δ. Conclusion: The binding of TCTP to eukaryotic elongation factor 1B is evolutionarily conserved. Significance: The interaction with eEF1B represents a primary function of TCTP. Translationally controlled tumor protein (TCTP) is an abundant protein that is highly conserved in eukaryotes. However, its primary function is still not clear. Human TCTP interacts with the metazoan-specific eukaryotic elongation factor 1Bδ (eEF1Bδ) and inhibits its guanine nucleotide exchange factor (GEF) activity, but the structural mechanism remains unknown. The interaction between TCTP and eEF1Bδ was investigated by NMR titration, structure determination, paramagnetic relaxation enhancement, site-directed mutagenesis, isothermal titration calorimetry, and HADDOCK docking. We first demonstrated that the catalytic GEF domain of eEF1Bδ is not responsible for binding to TCTP but rather a previously unnoticed central acidic region (CAR) domain in eEF1Bδ. The mutagenesis data and the structural model of the TCTP-eEF1Bδ CAR domain complex revealed the key binding residues. These residues are highly conserved in eukaryotic TCTPs and in eEF1B GEFs, including the eukaryotically conserved eEF1Bα, implying the interaction may be conserved in all eukaryotes. Interactions were confirmed between TCTP and the eEF1Bα CAR domain for human, fission yeast, and unicellular photosynthetic microalgal proteins, suggesting that involvement in protein translation through the conserved interaction with eEF1B represents a primary function of TCTP.