Decrease in heart peptide initiation during head-down tilt may be modulated by HSP-70.
Decrease in heart peptide initiation during head-down tilt may be modulated by HSP-70.
复制标题
低头倾斜期间心脏肽起始的减少可能受到 HSP-70 的调节。
DOI：
10.1152/ajpcell.1995.268.6.c1375
复制
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;Yang,J;Ku,Z;Thomason,DB
本研究探讨了啮齿动物后肢非负重时心肌蛋白质合成迅速减少的机制。悬浮后8小时从大鼠心脏分离的多核糖体显示多核糖体池中的RNA较少，并且多核糖体大小向每mRNA较少的核糖体转移;悬浮后18小时，大小转移持续存在，但是多核糖体池中的RNA量恢复到对照值。这些数据与蛋白质合成起始速率的降低一致。在8和12小时的悬浮液，心脏多聚核糖体显示出78%和93%的增加与新生的多肽伴侣蛋白70 kDa的热休克同源/热休克蛋白（HSC/HSP-70），分别，持续7天后的非承重。由于HSC/HSP-70与未折叠蛋白的解离可以通过ATP调节，我们测量了腺苷核苷酸池，发现悬浮18小时后ATP水平降低了53%。我们提出了一种机制，其中HSC/HSP-70的新生多肽的移位间接抑制蛋白质合成起始。
This study examines the mechanism of the rapid decrease in cardiac muscle protein synthesis during rodent hindlimb non-weight bearing. Polysomes isolated from rat hearts 8 h after suspension show less RNA in the polysome pool and a shift in polysome size toward fewer ribosomes per mRNA; 18 h after suspension, the size shift persists, but the amount of RNA in the polysome pool returns to control values. These data are consistent with a decrease in the rate of initiation of protein synthesis. At both 8 and 12 h of suspension, the cardiac polysomes show a 78 and 93% increase association with the nascent polypeptide chaperone protein 70-kDa heat-shock cognate/heat-shock protein (HSC/HSP-70), respectively, that persists after 7 days of non-weight bearing. Because the dissociation of HSC/HSP-70 from unfolded protein can be modulated by ATP, we measured the adenosine nucleotide pools and found a 53% decrease in ATP levels after 18 h of suspension. We propose a mechanism in which a shift of HSC/HSP-70 to the nascent polypeptide indirectly inhibits protein synthesis initiation.