Inhibition of Protein Synthesis by Nitric Oxide Correlates with Cytostatic Activity: Nitric Oxide Induces Phosphorylation of Initiation Factor eIF-2α

Kim, Young‐Myeong; Son, Kyonghee; Hong, Sun-Joo; Green, Angela; Chen, Jane-Jane; Tzeng, Edith; Hierholzer, Christian; Billiar, Timothy R.

doi:10.1007/bf03401915

Cited by 75 publications

(59 citation statements)

References 42 publications

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“…We previously showed that when hepatocytes were recovered in fresh medium for 24 h after pretreatment with SNAP for 8 h, stimulation with cytokines increased iNOS-mediated NO production compared with untreated control by increasing tetrahydrobiopterin production without changing iNOS gene expression (Park et al, 2002). However, it has been reported that cotreatment with the NO-donor SNAP and cytokines (including LPS) suppresses iNOS expression and NO production in hepatocytes (Taylor et al, 1997), macrophages (Sheffler et al, 1995;Kim et al,1998) and epithelial cells (Cavicchi et al, 2000). These results indicate that there present both negative and A B positive feedback regulatory mechanisms for NO production during NO generation and after recovery of a certain time period following exposure to NO, respectively.…”

Section: Discussionmentioning

confidence: 99%

Nitric oxide suppresses inducible nitric oxide synthase expression by inhibiting post-translational modification of IκB

Chang

Lee²,

Cheong³

et al. 2004

Exp Mol Med

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Section: Discussionmentioning

confidence: 99%

Nitric oxide suppresses inducible nitric oxide synthase expression by inhibiting post-translational modification of IκB

Chang

Lee²,

Cheong³

et al. 2004

Exp Mol Med

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“…There are reports that NO inhibits protein synthesis (40)(41)(42) at the level of translation initiation. Translation initiation depends mainly on the activity of eukaryotic initiation factors (eIFs).…”

Section: Discussionmentioning

confidence: 99%

“…Initiation factor eIF2␣ (43) promotes the expression of cyclins A, E, and D1 (41), whereas eIF4E promotes the expression of cyclin D and ornithine decarboxylase (44,45). It has been suggested that a NO-induced increase in the phosphorylation of eIF-2␣ may lead to the activation of an eIF-2␣ kinase or inhibition of a phosphatase as a likely mechanism for the nonspecific inhibition of protein synthesis (41). This action of NO in inhibiting protein synthesis was found to be guanylate cyclase-dependent (41).…”

Section: Discussionmentioning

confidence: 99%

Nitric oxide-induced cytostasis and cell cycle arrest of a human breast cancer cell line (MDA-MB-231): Potential role of cyclin D1

Pervin

Singh

Chaudhuri

2001

Proc. Natl. Acad. Sci. U.S.A.

161

115

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DETA-NONOate, a nitric oxide (NO) donor, induced cytostasis in the human breast cancer cells MDA-MB-231, and the cells were arrested in the G 1 phase of the cell cycle. This cytostatic effect of the NO donor was associated with the down-regulation of cyclin D1 and hypophosphorylation of the retinoblastoma protein. No changes in the levels of cyclin E or the catalytic partners of these cyclins, CDK2, CDK4, or CDK6, were observed. This NO-induced cytostasis and decrease in cyclin D1 was reversible for up to 48 h of DETA-NONOate (1 mM) treatment. DETA-NONOate (1 mM) produced a steady-state concentration of 0.5 M of NO over a 24-h period. Synchronized population of the cells exposed to DETANONOate remained arrested at the G 1 phase of the cell cycle whereas untreated control cells progressed through the cell cycle after serum stimulation. The cells arrested at the G 1 phase after exposure to the NO donor had low cyclin D1 levels compared with the control cells. The levels of cyclin E and CDK4, however, were similar to the control cells. The decline in cyclin D1 protein preceded the decrease of its mRNA. This decline of cyclin D1 was due to a decrease in its synthesis induced by the NO donor and not due to an increase in its degradation. We conclude that down-regulation of cyclin D1 protein by DETA-NONOate played an important role in the cytostasis and arrest of these tumor cells in the G 1 phase of the cell cycle.A ctivated macrophages produce large amounts of nitric oxide (NO), which induces cytostasis and cytotoxicity to tumor cells both in vitro and in vivo (1-8). Macrophages also play a significant role in host resistance to tumors (7-9). Tumor cells cocultured with activated macrophages rapidly develop cytostasis, which precedes the cytotoxic effects (5, 10).It has been reported that NO-induced early cytostasis begins with a rapid and reversible inhibition of ribonucleotide reductase (RR) (10). However, the possibility of targets other than RR being involved in the NO-induced long-lasting cytostasis was suggested by other investigators (10). Hydroxyurea, a specific inhibitor of RR (10), decreased thymidine incorporation in cultured cells and, after its removal, the thymidine incorporation rapidly returned to control values. The rate of recovery was much faster after withdrawal of hydroxyurea when compared with the rate of recovery observed in cells that initially were exposed either to activated macrophages or to a NO donor and then kept in a NO-free environment. On this basis, it was suggested that targets other than RR may be responsible for producing long-lasting cytostasis in target cells exposed to NO (5,10,11). This long-lasting cytostasis, therefore, would be associated with metabolic alterations in target cells, producing long-lasting growth inhibition and requiring a longer time for these cells to resume their normal rate of proliferation.Because the precise mechanism(s) by which NO induces this long-lasting cytostasis is not completely known, the present work was undertaken to assess this mechanism(s)...

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“…Both NO and CO have high affinity for both protein-bound and free heme-iron (12)(13)(14). Recently, the cytostatic activity of NO was found to correlate with NO-induced increase in eIF2␣ phosphorylation and inhibition of protein synthesis in a number of cell lines (15). However, the mechanism of this NO-induced increase in eIF2␣ phosphorylation was not characterized.…”

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confidence: 99%

The Heme-regulated Eukaryotic Initiation Factor 2α Kinase

Uma

Yun

Matts

2001

Journal of Biological Chemistry

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Nitric oxide (NO) has been reported to inhibit protein synthesis in eukaryotic cells by increasing the phosphorylation of the ␣-subunit of eukaryotic initiation factor (eIF) 2. However, the mechanism through which this increase occurs has not been characterized. In this report, we examined the effect of the diffusible gases nitric oxide (NO) and carbon monoxide (CO) on the activation of the heme-regulated eIF2␣ kinase (HRI) in rabbit reticulocyte lysate. Spectral analysis indicated that both NO and CO bind to the N-terminal heme-binding domain of HRI. Although NO was a very potent activator of HRI, CO markedly suppressed NO-induced HRI activation. The NO-induced activation of HRI was transduced through the interaction of NO with the N-terminal heme-binding domain of HRI and not through S-nitrosylation of HRI. We postulate that the regulation of HRI activity by diffusible gases may be of wider physiological significance, as we further demonstrate that NO generators increase eIF2␣ phosphorylation levels in NT2 neuroepithelial and C2C12 myoblast cells and activate HRI immunoadsorbed from extracts of these non-erythroid cell lines.Over 2 decades ago, the heme-regulated inhibitor (HRI) 1 of protein chain initiation in rabbit reticulocyte lysate (RRL) was identified as a heme-regulated protein kinase that phosphorylated the ␣-subunit of eukaryotic initiation factor eIF2 (reviewed in Refs. 1-3). eIF2 delivers Met-tRNA i in a complex with GTP to 43 S ribosomal initiation complexes and is released as a complex with GDP at the completion of the initiation cycle. Recycling of eIF2⅐GDP and the formation of eIF2⅐GTP⅐Met-tRNA i complexes requires the action of the guanine nucleotide exchange factor, eIF2B. Under heme-deficient conditions, HRI is activated and phosphorylates eIF2. Phosphorylated eIF2 avidly binds eIF2B, sequestering eIF2B in a poorly dissociable complex, which subsequently leads to the inhibition of the initiation of translation, as eIF2⅐GDP complexes that are present in excess of eIF2B fail to recycle. Thus, HRI functions to coordinate globin synthesis with heme availability in RRL.The amino acid sequence deduced from HRI cDNA indicates that it is composed of at least five distinct domains (4). The unique N-terminal domain of HRI contains ϳ165 amino acids. The second and fourth domains contain conserved sequence motifs I-V and motifs VI-XI, which comprise the N-terminal and C-terminal catalytic lobes of protein kinases, respectively. The third and fifth domains are also unique, consisting of ϳ140 amino acids that are inserted between the two conserved kinase lobes and ϳ50 amino acids at the C terminus, respectively.HRI is a hemoprotein that contains two distinct of hemebinding sites (5-7). Heme binding to the first site is stable, and remains associated with purified HRI, whereas heme-binding to the second site is reversible and appears to be responsible for the rapid heme-induced down-regulation of HRI activity . We have recently demonstrated that the N-terminal domain of HRI contains the stable heme-binding...

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Inhibition of Protein Synthesis by Nitric Oxide Correlates with Cytostatic Activity: Nitric Oxide Induces Phosphorylation of Initiation Factor eIF-2α

Cited by 75 publications

References 42 publications

Nitric oxide suppresses inducible nitric oxide synthase expression by inhibiting post-translational modification of IκB

Nitric oxide suppresses inducible nitric oxide synthase expression by inhibiting post-translational modification of IκB

Nitric oxide-induced cytostasis and cell cycle arrest of a human breast cancer cell line (MDA-MB-231): Potential role of cyclin D1

The Heme-regulated Eukaryotic Initiation Factor 2α Kinase

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