Monnier A, Bellé R, Morales J, Cormier P, Boulben S, Mulner-Lorillon O
Station Biologique de Roscoff, Université Pierre et Marie Curie (UFR 937), Centre National de la Recherche Scientifique (UPR 9042), Institut National des Sciences de l'Univers, BP 74, 29682 Roscoff Cedex, France.
Nucleic Acids Res. 2001 Apr 1;29(7):1453-7. doi: 10.1093/nar/29.7.1453.
Eukaryotic elongation factor 1 (eEF-1) contains the guanine nucleotide exchange factor eEF-1B that loads the G protein eEF-1A with GTP after each cycle of elongation during protein synthesis. Two features of eEF-1B have not yet been elucidated: (i) the presence of the unique valyl-tRNA synthetase; (ii) the significance of target sites for the cell cycle protein kinase CDK1/cyclin B. The roles of these two features were addressed by elongation measurements in vitro using cell-free extracts. A poly(GUA) template RNA was generated to support both poly(valine) and poly(serine) synthesis and poly(phenylalanine) synthesis was driven by a poly(uridylic acid) template. Elongation rates were in the order phenylalanine > valine > serine. Addition of CDK1/cyclin B decreased the elongation rate for valine whereas the rate for serine and phenylalanine elongation was increased. This effect was correlated with phosphorylation of the eEF-1delta and eEF-1gamma subunits of eEF-1B. Our results demonstrate specific regulation of elongation by CDK1/cyclin B phosphorylation.
真核生物延伸因子1（eEF-1）包含鸟嘌呤核苷酸交换因子eEF-1B，在蛋白质合成过程中的每个延伸循环后，该因子会将GTP加载到G蛋白eEF-1A上。eEF-1B的两个特征尚未阐明：（i）独特的缬氨酰-tRNA合成酶的存在；（ii）细胞周期蛋白激酶CDK1/细胞周期蛋白B的靶位点的意义。通过使用无细胞提取物进行体外延伸测量来研究这两个特征的作用。生成了聚（GUA）模板RNA以支持聚（缬氨酸）和聚（丝氨酸）的合成，聚（苯丙氨酸）的合成由聚（尿苷酸）模板驱动。延伸速率的顺序为苯丙氨酸>缬氨酸>丝氨酸。添加CDK1/细胞周期蛋白B会降低缬氨酸的延伸速率，而丝氨酸和苯丙氨酸的延伸速率会增加。这种效应与eEF-1B的eEF-1δ和eEF-1γ亚基的磷酸化相关。我们的结果证明了CDK1/细胞周期蛋白B磷酸化对延伸的特异性调节。
