The phosphorylation state of the wheat translation initiation factors eIF4B, eIF4A, and eIF2 is differentially regulated during seed development and germination
The phosphorylation state of the wheat translation initiation factors eIF4B, eIF4A, and eIF2 is differentially regulated during seed development and germination
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DOI：
10.1074/jbc.273.32.20084
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发表时间：
1998-08-07
影响因子：
4.8
通讯作者：
Gallie, DR
中科院分区：
文献类型：
--
作者：
Le, H;Browning, KS;Gallie, DR
翻译起始因子（eIF）4 B和eIF 2是磷酸化状态在成熟种子和叶之间不同的磷蛋白，我们检测了小麦种子发育和萌发过程中eIF 4 B的亚型和eIF 2的α和β亚基，以确定它们磷酸化状态的差异是否是由于组织-细胞间的差异。特异性调节或伴随着发育过程中蛋白质合成活性的变化而发生。eIF 2 α通过几种中间异构体进行磷酸化，这些异构体与种子发育特征性蛋白质合成活性的增加和随后的减少相关。eIF 2 β和eIF 4 B在早期种子发育过程中以高度磷酸化的同种型存在，在后期发育过程中经历去磷酸化。eIF 4 B在萌发后20 h内迅速磷酸化，而eIF 2 α直到生长48-60 h才发生去磷酸化。第三个因素，eIF 4A，主要是非磷酸化的整个种子发育和萌发。这些观察结果表明，eIF 2 α，eIF 2 β和eIF 4 B的磷酸化状态是以与蛋白质合成活性变化相关的方式发育调节的，但也观察到一些差异。
The translation initiation factors (eIF) 4B and eIF2 are phosphoproteins whose phosphorylation state differs between mature seed and leaves, We examined the isoforms of eIF4B and the alpha and beta subunits of eIF2 during the development and germination of wheat seed to determine whether the differences in their phosphorylation state are because of tissue-specific regulation or occur concomitant with changes in protein synthetic activity during development. eIF2 alpha underwent phosphorylation through several intermediate isoforms that correlated with the increase and subsequent reduction in protein synthetic activity characteristic of seed development. eIF2 beta and eIF4B, present as highly phosphorylated isoforms during early seed development, underwent dephosphorylation during late development. eIF4B was rapidly phosphorylated within 20 h of germination, whereas eIF2 alpha did not undergo dephosphorylation until 48-60 h of growth. A third factor, eIF4A, was predominantly nonphosphorylated throughout most of seed development and germination. These observations suggest that the phosphorylation state of eIF2 alpha, eIF2 beta, and eIF4B is developmentally regulated in a way that correlates with the changes in protein synthetic activity but that some differences were also observed.