• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Mechanisms regulating phosphorylation of the alpha-subunit of eukaryotic intitiation factor-2 during post-ischemic brain reperfusion.
【24h】

Mechanisms regulating phosphorylation of the alpha-subunit of eukaryotic intitiation factor-2 during post-ischemic brain reperfusion.

机译：缺血后脑再灌注过程中调节真核启动因子2的α亚基磷酸化的机制。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Protein synthesis is inhibited at the initiation step in neurons following brain ischemia and reperfusion due to the phosphorylation of the eukaryotic initiation factor 2α (eIF2α). In order to understand the causal mechanism of phosphorylation of this initiation factor, I looked at the following possibilities: (1) deglycosylation (inactivation) of the glycoprotein p67; (2) inactivation of a specific phosphatase; or (3) activation of the eIF2α kinase, PERK.; Using immunocytochemistry and Western Blot analysis, I discovered that the glycosylation state, and total levels of p67 do not change following brain ischemia and reperfusion. Previous work in our lab utilizing individual transgenic knockout mice for three of the four kinases (PKR, HRI and GCN2), had shown that these kinases were not responsible for the phosphorylation of eIF2α. In addition, we found no change in phosphatase activity at 5 minutes reperfusion when eIF2α(P) levels are ∼18-fold greater than normal. So this left activation of PERK as the probably cause of eIF2α phosphorylation. We had recently discovered that PERK undergoes a mobility shift by 10 minutes of reperfusion, as determined by Western Blot analysis, indicating that it was undergoing phosphorylation and thus activation. Indeed, in my study, using three different transgenic PERK knockout mouse models (EMX, CamKII, and RIP), eIF2α phosphorylation is substantially decreased by 85% in EMX, 80% in CamKII, and 99% in RIP mice during reperfusion compared to wild type mice. This confirmed that PERK is responsible for phosphorylation of eIF2α following global brain ischemia and reperfusion. However, recent studies in our lab have shown that by 90 minutes of reperfusion, PERK was degraded ∼80% in the cortex, and ∼50% in the hippocampus and brainstem. Several lines of evidence suggested that this may be due to activation of μ-calpain. We have previously shown that calpain is activated as a consequence of ischemia and reperfusion, thus these experiments were undertaken to determine if PERK is a substrate for μ-calpain. In vitro protease reactions containing PERK together with μ-calpain showed that it is indeed degraded by this enzyme.; These results demonstrate that PERK is the kinase responsible for the phosphorylation of eIF2α(P) following ischemia and reperfusion. They also suggest a possible mechanism for the degradation of PERK by 90 minutes of reperfusion.
机译：由于真核起始因子2α（eIF2α）的磷酸化，在脑缺血和再灌注后神经元的起始步骤蛋白被抑制。为了了解该起始因子磷酸化的原因机制，我研究了以下可能性：（1）糖蛋白p67的去糖基化（失活）; （2）使特定的磷酸酶失活;或（3）激活eIF2α激酶PERK。使用免疫细胞化学和蛋白质印迹分析，我发现在脑缺血和再灌注后，糖基化状态和p67的总水平没有改变。在我们实验室中，利用个别转基因敲除小鼠的四种激酶（PKR，HRI和GCN2）中的三种，先前的研究表明这些激酶与eIF2α的磷酸化无关。此外，当eIF2α（P）水平比正常水平高约18倍时，我们发现再灌注5分钟时磷酸酶活性没有变化。因此，这使PERK的激活成为eIF2α磷酸化的可能原因。我们最近发现，如Western Blot分析所确定，PERK在再灌注10分钟后发生迁移率变化，表明它正在磷酸化并因此被激活。确实，在我的研究中，与野生动物相比，使用三种不同的转基因PERK基因敲除小鼠模型（EMX，CamKII和RIP），EMF中eIF2α的磷酸化在EMX中显着降低了85％，在CamKII中降低了80％，在RIP小鼠中降低了99％型小鼠。这证实了PERK负责全脑缺血和再灌注后eIF2α的磷酸化。但是，我们实验室的最新研究表明，再灌注90分钟后，PERK在皮质中降解约80％，在海马和脑干中降解约50％。有几条证据表明，这可能是由于μ-钙蛋白酶的激活所致。先前我们已经表明，钙蛋白酶是缺血和再灌注的结果，因此，进行了这些实验以确定PERK是否是μ-钙蛋白酶的底物。含PERK和μ-钙蛋白酶的体外蛋白酶反应表明它确实被该酶降解。这些结果表明，PERK是负责缺血和再灌注后eIF2α（P）磷酸化的激酶。他们还提出了90分钟的再灌注可能导致PERK降解的机制。

著录项

  • 作者

    Owen, Cheri.;

  • 作者单位

    Wayne State University.;

  • 授予单位 Wayne State University.;
  • 学科 Biology Neuroscience.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 75 p.
  • 总页数 75
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 神经科学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号