Inhibition of Protein Synthesis by Nitric Oxide Correlates with Cytostatic Activity: Nitric Oxide Induces Phosphorylation of Initiation Factor eIF-2α
Inhibition of Protein Synthesis by Nitric Oxide Correlates with Cytostatic Activity: Nitric Oxide Induces Phosphorylation of Initiation Factor eIF-2α
复制标题
一氧化氮对蛋白质合成的抑制与细胞抑制活性相关：一氧化氮诱导起始因子 eIF-2α 磷酸化
作者：
Young;K. Son;S. Hong;A. Green;Jane;E. Tzeng;C. Hierholzer;T. Billiar
研究背景一氧化氮（NO）具有抑制细胞增殖、抑制微生物生长和下调特定蛋白质合成的作用。进行了研究，以确定NO抑制总蛋白质合成的机制，以及是否与建立的细胞抑制活性的NO.Materials and MethodsIn体外实验中，各种类型的细胞暴露于NO使用供体或诱导型NO合酶（iNOS）的表达。NO抑制总蛋白质合成的能力，通过将35 S-甲硫氨酸掺入蛋白质中来测量，与NO抑制细胞增殖、病毒复制或iNOS表达的能力相关。结果NO供体和iNOS的表达均抑制L929细胞和A2008人卵巢癌细胞的总蛋白质合成，并伴有细胞增殖抑制。抑制的蛋白质合成也被证明与小鼠腹腔巨噬细胞中的iNOS依赖性方式的牛痘病毒增殖减少相关。此外，iNOS在胰岛或RAW264.7细胞中的表达几乎完全抑制总蛋白质合成，这表明蛋白质合成的非特异性抑制可能是NO抑制特定蛋白质如胰岛素或iNOS本身合成的机制。在RAW264.7细胞中证实了这种可能性，其中总蛋白合成的抑制与iNOS蛋白的减少相关。蛋白质水平的降低没有发生在iNOS mRNA水平的变化，这意味着抑制翻译。结论NO通过刺激eIF-2 α磷酸化抑制RAW264.7细胞的蛋白质合成。此外，我们的观察表明，蛋白质合成的非特异性抑制可能是暴露于高水平NO的细胞的一般性反应，蛋白质合成的抑制可能有助于许多所描述的NO的细胞抑制作用。
BackgroundNitric oxide (NO) is cytostatic for proliferating cells, inhibits microbial growth, and down-regulates the synthesis of specific proteins. Studies were undertaken to determine the mechanism by which NO inhibits total protein synthesis and whether the inhibition correlates with established cytostatic activities of NO.Materials and MethodsIn in vitro experiments, various cell types were exposed to NO using either donors or expression of inducible NO synthase (iNOS). The capacity of NO to suppress total protein synthesis, measured by incorporation of 35S-methionine into protein, was correlated with the capacity of NO to suppress cell proliferation, viral replication, or iNOS expression. Phosphorylation of eIF-2α was examined as a possible mechanism for the suppressed protein synthesis by NO.ResultsBoth NO donors and expression of the iNOS suppressed total protein synthesis in L929 cells and A2008 human ovarian tumor cells in parallel with decreased cell proliferation. Suppressed protein synthesis was also shown to correlate with decreased vaccinia virus proliferation in murine peritoneal macrophages in an iNOS-dependent manner. Furthermore, iNOS expression in pancreatic islets or RAW264.7 cells almost completely inhibited total protein synthesis, suggesting that nonspecific inhibition of protein synthesis may be the mechanism by which NO inhibited the synthesis of specific proteins such as insulin or iNOS itself. This possibility was confirmed in RAW264.7 cells where the inhibition of total protein synthesis correlated with the decreased iNOS protein. The decrease in protein levels occurred without changes in iNOS mRNA levels, implicating an inhibition of translation. Mechanistic studies revealed that iNOS expression in RAW264.7 cells resulted in the phosphorylation of eEF-2α and inhibition of the 80S ribosomal complex formation.ConclusionsThese results suggest that NO suppresses protein synthesis by stimulating the phosphorylation of eIF-2α. Furthermore, our observations indicate that nonspecific inhibition of protein synthesis may be a generalized response of cells exposed to high levels of NO and that inhibition of protein synthesis may contribute to many of the described cytostatic actions of NO.
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影响因子：
3.9
作者：
STADLER, J;BERGONIA, HA;LANCASTER, JR
通讯作者：
LANCASTER, JR
DOI：
10.1016/s0021-9258(18)52994-x
发表时间：
1993-04
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Charles E. Samuel
通讯作者：
Charles E. Samuel
影响因子：
56.9
作者：
KARUPIAH, G;XIE, QW;MACMICKING, JD
通讯作者：
MACMICKING, JD
DOI：
10.1016/s0021-9258(18)54642-1
发表时间：
1991-11
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
J. A. Corbett;Jack R. Lancaster;M. Sweetland;M. L. McDaniel
通讯作者：
J. A. Corbett;Jack R. Lancaster;M. Sweetland;M. L. McDaniel
DOI：
10.1073/pnas.90.5.1731
发表时间：
1993-03-01
影响因子：
11.1
作者：
CORBETT, JA;SWEETLAND, MA;MCDANIEL, ML
通讯作者：
MCDANIEL, ML