Inhibition of protein synthesis initiation by oxidized glutathione: Activation of a protein kinase that phosphorylates the α subunit of eukaryotic initiation factor 2

Ernst, Vivian; Levin, Daniel H.; London, Irving M.

doi:10.1073/pnas.75.9.4110

Cited by 83 publications

(22 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dried moss regains more than 99% of its original fresh weight within 2 min of rehydration (RS Dhindsa, unpublished data) and the rapidly dried moss exhibits extensive membrane leakiness on rehydration (10, 1 1). The Studies of protein synthesis in rabbit reticulocyte lysate show that GSSG causes a rapid inhibition of the initiation step of protein synthesis (13,17) and that sugar phosphates and other NADPH-generating systems and thiol-reducing chemicals can reverse the GSSG-induced inhibition (15). In the present study, DTT did not stimulate protein synthesis, in contrast to the findings on rabbit reticulocyte lysate (15 (16).…”

Section: Resultscontrasting

confidence: 56%

Protein Synthesis during Rehydration of Rapidly Dried Tortula ruralis

Dhindsa

1987

Plant Physiol.

View full text Add to dashboard Cite

Rapidly dried Tortula ruralis, a drought-tolerant moss, is known to synthesize proteins on rehydration at a much lower rate than the slowly dried moss. The reasons for this low rate of protein synthesis are unclear. We have found that during rehydration of rapidly dried moss, there is a negative correlation between the rate of protein synthesis and the tissue levels of oxidized glutathione (GSSG) and lipid peroxidation. When rapidly dried moss, which is known to show extensive solute leakage, is rehydrated in the presence of 100 millimolar K+, 5 millimolar Mg2", 1 millimolar ATP, and 1 millimolar GTP, either separately or together, there is no stimulation of protein synthesis. When it is hydrated in the presence of either 5 millimolar glucose-6-phosphate or 0.1 millimolar NADPH, protein synthesis is stimulated but the stimulation is transitory. A second addition of either of these two chemicals causes a second transient stimulation of protein synthesis. A transitory decrease in the rate ofGSSG accumulation is observed during rehydration in the presence of glucose-6-phosphate or NADPH. Both glucose-6-phosphate and NADPH are known to reverse GSSG-induced inhibition of protein synthesis in rabbit reticulocyte lysate. Results of the present study suggest that the rate of protein synthesis during rehydration of rapidly dried moss is not limited by the availability of ions or energy sources. Since exogenously applied GSSG has been shown to inhibit in vivo and in vitro protein synthesis and since it is known to accumulate during rehydration of rapidly dried, but not slowly dried, moss, it is suggested that the low rate of protein synthesis during rehydration of the rapidly dried moss is, at least in part, due to endogenous GSSG.The drought-tolerant moss, Tortula ruralis, is able to recover from drying to less than 20% of its original fresh weight (2). However, the rate of recovery during rehydration is much lower following rapid drying than following slow drying. For protein synthesis on rehydration of the rapidly dried moss. We have recently suggested (7) that oxidized glutathione, which rapidly accumulates on rehydration of the rapidly dried moss and which inhibits in vivo and in vitro protein synthesis, is the underlying cause of the low rate of protein synthesis.In this paper, we have examined the possibility that the lower rate of protein synthesis may be due to a deficiency of ATP, GTP, and ions, such as K+ and Mg2", brought about through solute leakage. Since the rapidly dried moss shows extensive membrane 'leakiness,' it is likely that chemicals which are normally not expected to be taken up by cells in appreciable quantities, would be taken up rapidly with the mass flow of water during rehydration. Thus, we have also examined the effects of glucose-6-P, DTT, and NADPH since it has been shown (15) that GSSG2-induced inhibition of in vitro protein synthesis can be reversed by sugar phosphates and thiol-reducing compounds. The results obtained show that the low rate of protein synthesis is not due to a ...

show abstract

Section: Resultscontrasting

confidence: 56%

Protein Synthesis during Rehydration of Rapidly Dried Tortula ruralis

Dhindsa

1987

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Changes in the redox state are known to influence the DNA-binding activity of several transcription factors, such as Oxy R (69), AP-1 (70), NF-κB (71), Egr-1 (72), Ets (73), Myb (74) and v-Rel. A redox mechanism is also known to contribute to cell cycle progression (76), hormone receptor interactions (77), bacteriophage DNA replication (78), light signal transduction (78,79), regulation of iron metabolism (80), protein-RNA and protein-DNA interactions and RNA transcription (81)(82)(83) and protein translation regulation (78,84). It is also known that ROS and H 2 O 2 can induce single-strand breaks in cellular DNA, oxidation of DNA bases, chromosomal aberrations and DNA-protein crosslinks (13,85,86).…”

Section: Discussionmentioning

confidence: 99%

Tumor promotion by hydrogen peroxide in rat liver epithelial cells

Huang

Hossain

et al. 1999

Carcinogenesis

View full text Add to dashboard Cite

“…The mechanism of GSSG inhibition of in vitro protein synthesis in reticulocyte lysates has been the subject of several studies. It has been shown (11,12) that GSSG activates a translational inhibitor, a protein kinase, which phosphorylates and thereby inactivates the initiation factor eIF-2. It has been suggested that sugar phosphates, NADPH, and thiol-reducing systems are required to maintain a high rate of protein synthesis probably by keeping the inhibitor in the inactive state (13,14).…”

Section: Discussionmentioning

confidence: 99%

Glutathione Status and Protein Synthesis during Drought and Subsequent Rehydration in Tortula ruralis

Dhindsa¹

1987

Plant Physiol.

View full text Add to dashboard Cite

Glutathione status and its relationship to protein synthesis during water deficit and subsequent rehydration have been examined in the drought-tolerant moss, Tortula ruralis. During slow drying there is a small decrease in total glutathione but the percentage of oxidized glutathione (GSSG) increases. During rapid drying there is little change in total glutathione but a small increase in GSSG. On rehydration of slowly dried moss, GSSG rapidly declines to normal level. But when rapidly dried moss is rehydrated, there is an immediate, sharp increase in GSSG as a percentage of total glutathione. After 2 hours of rehydration GSSG starts declining and reaches a normal level in about 6 hours. When an increasing degree of steady state water deficit is imposed on the moss tissue with polyethylene glycol 6000, there is a progressive decrease in protein synthesis but an increase in oxidized glutathione. When 5 milimolar GSSG is supplied exogenously during rehydration of rapidly dried or slowly dried moss, protein synthesis is strongly inhibited. In vitro protein synthesis supported by moss mRNA is also inhibited by more than 85% by 150 micromolar GSSG. The role of glutathione status in water deficit-induced inhibition of protein synthesis is discussed.Drought-tolerant moss, Tortula ruralis, can be dried rapidly or slowly to less than 20% of its original fresh weight without loss of its ability to recover on subsequent rehydration (2). However, the rates of metabolic responses on rehydration vary with the speed of the previous drying. For example, the consumption of 02 ( 17) Administration of Steady State Stress. Polythylene glycol 6000 was used as osmoticum to impose steady state water stress as described previously (7). Five hundred mg fresh moss was placed in 5 ml of PEG solution with varying water potential. After 1.5 h, 20 ,uCi of [4,5-3H]leucine (60 Ci/mmol) was added in experiments when rate of protein synthesis was studied. In a parallel experiment after 1.5 h ofpreincubation ofmoss in PEG solution, the level of GSSG as percent oftotal glutathione was determined.Determination of Total Glutathione and Oxidized Glutathione. Enzymic methods described recently (1) were used to determine total glutathione (GSH + GSSG) in terms of GSH equivalents, and oxidized glutathione (GSSG). Tissue samples consisted of 0.5 g fresh moss or equivalent weight of dried moss. Tissue was homogenized in 2.5 ml of 5% 5-sulfosalicylic acid and a 10,000g supematant was obtained and used to determine total glutathione in GSH equivalents by the DTNB-GSSG reductase method. A standard curve was obtained by using authentic GSH at concentrations of 0 to 5 gM. The assay was monitored by following the rate of formation of TNB2 at 412 nm.For the determination of GSSG, 2-vinylpyridine was used to trap the GSH present in the 5-sulfosalicylic acid supematant 2 Abbreviations: TNB, 5-thio-2-nitrobenzoate; DTNB, 5,5'-dithiobis-(2-nitrobenzoic acid). Figure IA. It can be seen that during slow drying there is a steady increase in GSSG in the first 4 ...

show abstract

Inhibition of protein synthesis initiation by oxidized glutathione: Activation of a protein kinase that phosphorylates the α subunit of eukaryotic initiation factor 2

Cited by 83 publications

References 37 publications

Protein Synthesis during Rehydration of Rapidly Dried Tortula ruralis

Protein Synthesis during Rehydration of Rapidly Dried Tortula ruralis

Tumor promotion by hydrogen peroxide in rat liver epithelial cells

Glutathione Status and Protein Synthesis during Drought and Subsequent Rehydration in Tortula ruralis

Contact Info

Product

Resources

About