Head-down tilt increases rat cardiac muscle eIF-2 alpha phosphorylation.
Head-down tilt increases rat cardiac muscle eIF-2 alpha phosphorylation.
复制标题
低头倾斜会增加大鼠心肌 eIF-2 α 磷酸化。
DOI：
10.1152/ajpcell.1995.269.3.c802
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Thomason,DB
中科院分区：
文献类型：
--
作者：
Menon,V;Thomason,DB
我们之前证明，大鼠低头倾斜会降低心脏多肽起始率，并提出了一种机制，通过分子伴侣热休克同源/热休克蛋白-70 (HSC/HSP-70) 的重新分布，促进真核起始因子-2 α (eIF-2 α) 的磷酸化。在这项研究中，eIF-2 α 的二维凝胶电泳分析显示对照心脏中没有磷酸化。低头倾斜 8 小时后，总 eIF-2 α 增加了 45%，其中 79% 被磷酸化。 18小时时，eIF-2α增加至对照的142%，其中4%被磷酸化。这与之前的研究一致，在 8 小时时，多核糖体 HSC/HSP-70 增加了 78%，并且多核糖体质心向较轻的多核糖体转移（表明起始减少）。悬浮 18 小时后，多聚体 HSC/HSP-70 水平相对于对照为 24%，并且质心返回到对照。我们得出结论，低头倾斜期间多肽起始的减少是由 HSC/HSP-70 通过 eIF-2 α 磷酸化介导的。
We previously demonstrated that head-down tilt in rats decreases heart polypeptide initiation rate and proposed a mechanism whereby redistribution of the chaperone heat-shock cognate/heat-shock protein-70 (HSC/HSP-70) facilitates the phosphorylation of eukaryotic initiation factor-2 alpha (eIF-2 alpha). In this study, two-dimensional gel electrophoretic analysis of eIF-2 alpha showed no phosphorylation in control hearts. At 8 h of head-down tilt, there was a 45% increase in total eIF-2 alpha, and 79% was phosphorylated. At 18 h, eIF-2 alpha increased to 142% of control, of which 4% was phosphorylated. This is consistent with the previous study where, at 8 h, there was a 78% increase in polysomal HSC/HSP-70 and a shift in the polysome center-of-mass to lighter polysomes (indicating decreased initiation). After 18 h of suspension, polysomal HSC/HSP-70 levels were 24% relative to control, and the center-of-mass returned toward control. We conclude that the decrease in polypeptide initiation during head-down tilt is mediated by HSC/HSP-70 via phosphorylation of eIF-2 alpha.