Cans Christophe, Passer Brent J, Shalak Vyacheslav, Nancy-Portebois Vanessa, Crible Virginie, Amzallag Nathalie, Allanic David, Tufino Rowena, Argentini Manuela, Moras Dino, Fiucci Giusy, Goud Bruno, Mirande Marc, Amson Robert, Telerman Adam
Molecular Engines Laboratories, 20 Rue Bouvier, 75011 Paris, France.
Proc Natl Acad Sci U S A. 2003 Nov 25;100(24):13892-7. doi: 10.1073/pnas.2335950100. Epub 2003 Nov 17.
Recently, we demonstrated that the expression levels of the translationally controlled tumor protein (TCTP) were strongly down-regulated at the mRNA and protein levels during tumor reversion/suppression and by the activation of p53 and Siah-1. To better characterize the function of TCTP, a yeast two-hybrid hunt was performed. Subsequent analysis identified the translation elongation factor, eEF1A, and its guanine nucleotide exchange factor, eEF1Bbeta, as TCTP-interacting partners. In vitro and in vivo studies confirmed that TCTP bound specifically eEF1Bbeta and eEF1A. Additionally, MS analysis also identified eEF1A as a TCTP interactor. Because eEF1A is a GTPase, we investigated the role of TCTP on the nucleotide exchange reaction of eEF1A. Our results show that TCTP preferentially stabilized the GDP form of eEF1A, and, furthermore, impaired the GDP exchange reaction promoted by eEF1Bbeta. These data suggest that TCTP has guanine nucleotide dissociation inhibitor activity, and, moreover, implicate TCTP in the elongation step of protein synthesis.
最近，我们证明了在肿瘤逆转/抑制过程中以及通过p53和Siah-1的激活，翻译调控肿瘤蛋白（TCTP）的表达水平在mRNA和蛋白质水平上均被强烈下调。为了更好地表征TCTP的功能，我们进行了酵母双杂交筛选。后续分析确定翻译延伸因子eEF1A及其鸟嘌呤核苷酸交换因子eEF1Bβ为与TCTP相互作用的伙伴。体外和体内研究证实TCTP与eEF1Bβ和eEF1A特异性结合。此外，质谱分析也确定eEF1A为TCTP的相互作用分子。由于eEF1A是一种GTP酶，我们研究了TCTP在eEF1A核苷酸交换反应中的作用。我们的结果表明，TCTP优先稳定eEF1A的GDP形式，此外，还损害了由eEF1Bβ促进的GDP交换反应。这些数据表明TCTP具有鸟嘌呤核苷酸解离抑制剂活性，而且表明TCTP参与蛋白质合成的延伸步骤。
