Department of Cellular and Genetic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China.
Mol Med Rep. 2012 Dec;6(6):1423-7. doi: 10.3892/mmr.2012.1070. Epub 2012 Sep 10.
Glucose-regulated protein 75 (Grp75), also known as mortalin/mthsp70/PBP74, is a member of the heat-shock protein 70 (HSP70) family. Grp75 is known to protect cells from stress-induced injury. Previous studies have shown that the expression of Grp75 is upregulated by a low dose of ionizing radiation (IR). To evaluate the protective role of Grp75 on cell proliferation in response to IR, Grp75 was overexpressed in a rat adrenal pheochromocytoma cell line (PC12). It was revealed that Grp75 overexpression desensitized PC12 cells to IR-mediated cell injury. In addition, the expression of topoisomerase IIα (Topo IIα) was downregulated in PC12 cells following γ-ray IR. The effect of Grp75 overexpression on Topo IIα expression was examined. It was revealed that Grp75 overexpression reversed the inhibitory effect of IR on Topo IIα expression. In conclusion, the data indicated that Grp75 overexpression attenuates IR-induced injury in PC12 cells by maintaining the expression of Topo IIα.
葡萄糖调节蛋白 75（Grp75），也称为 mortalin/mthsp70/PBP74，是热休克蛋白 70（HSP70）家族的一员。Grp75 已知可保护细胞免受应激诱导的损伤。先前的研究表明，低剂量电离辐射（IR）可上调 Grp75 的表达。为了评估 Grp75 在应对 IR 时对细胞增殖的保护作用，在大鼠肾上腺嗜铬细胞瘤细胞系（PC12）中过表达 Grp75。结果表明，Grp75 的过表达使 PC12 细胞对 IR 介导的细胞损伤产生抗药性。此外，γ射线 IR 后 PC12 细胞中端粒酶 IIα（Topo IIα）的表达下调。检查了 Grp75 过表达对 Topo IIα 表达的影响。结果表明，Grp75 的过表达逆转了 IR 对 Topo IIα 表达的抑制作用。总之，数据表明 Grp75 的过表达通过维持 Topo IIα 的表达来减轻 PC12 细胞中的 IR 诱导损伤。
