Protein synthesis and activities of tRNALeu and leucyl-tRNA synthetase in mouse liver under acute lead and zinc exposure

2005 ◽  
Vol 22 (10) ◽  
pp. 288-291
Author(s):  
H. Rodovicius ◽  
D. Viezeliene ◽  
I. Sadauskiene ◽  
L. Ivanov
Keyword(s):  
Protein Synthesis ◽  
Mouse Liver ◽  
Trna Synthetase ◽  
Lead And Zinc ◽  
Zinc Exposure

scholarly journals Subacute effects of cadmium and zinc ions on protein synthesis and cell death in mouse liver

Medicina ◽  
2008 ◽  
Vol 44 (2) ◽  
pp. 131 ◽  
Author(s):  
Inga Stanevièienë ◽  
Ilona Sadauskienë ◽  
Vaiva Lesauskaitë ◽  
Laima Ivanovienë ◽  
Artûras Kaðauskas ◽  
...  
Keyword(s):  
Cell Death ◽  
Body Weight ◽  
Protein Synthesis ◽  
Zinc Sulfate ◽  
Mouse Liver ◽  
Sulfate Solution ◽  
Trna Synthetase ◽  
Zinc Ions ◽  
Zinc Sulfate Solution ◽  
Acceptor Activity

Objective. The aim of this study was to evaluate in vivo the effects of cadmium and zinc ions on translational machinery and death of mouse liver cells. Material and methods. Outbred mice received intraperitoneal injections of cadmium chloride solution (1.4 μmoles cadmium per 1 kg of body weight) and/or zinc sulfate solution (4.8 μmoles zinc per kg of body weight) three times per week for six weeks. Analogical volume of saline solution was injected to the control mice. Protein synthesis was evaluated by incorporation of [14C]-labeled leucine into peptides and proteins. Total tRNAs were isolated using deproteinized extract of liver tissue. Postmitochondrial supernatant was as a source of leucyl-tRNA synthetase. Activities of tRNALeu and leucyl-tRNA synthetase were measured by an aminoacylation reaction using [14C]-labeled leucine. Liver cell apoptosis was detected by TUNEL assay using in situ cell death detection kit. Results. A decrease in incorporation of [14C]-labeled leucine into proteins was detected in liver, kidney, and heart as well as diminution of tRNALeu acceptor activity in cadmium-exposed liver. Cadmium caused activation of the leucyl-tRNA synthetase and induced liver cell apoptosis. Pretreatment of mice with zinc sulfate solution favored to protection of protein synthesis and acceptor activity of tRNALeu against cadmium-induced inhibition. Under co-exposure of mouse liver to cadmium and zinc, activity of the leucyl-tRNA synthetase was at the level of control. Zinc did not influence TUNEL-positive cell number in cadmium-exposed mouse liver. Conclusions. Under subacute intoxication of mice by cadmium, zinc ions protect the translation machinery against inhibition, but do not decrease the number of apoptotic cells in the liver.

Effects of repeated dose administration of lead and zinc ions on protein synthesis in mouse liver

2013 ◽  
Vol 30 (01) ◽  
pp. 18-23
Author(s):  
Jurgita Sulinskiene ◽  
Rasa Bernotiene ◽  
Ilona Sadauskiene ◽  
Arunas Liekis
Keyword(s):  
Protein Synthesis ◽  
Mouse Liver ◽  
Repeated Dose ◽  
Zinc Ions ◽  
Dose Administration ◽  
Lead And Zinc

scholarly journals Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 674
Author(s):  
Francesco Capriglia ◽  
Francesca Rizzo ◽  
Giuseppe Petrosillo ◽  
Veronica Morea ◽  
Giulia d’Amati ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Molecular Mechanisms ◽  
Mitochondrial Protein ◽  
Trna Synthetase ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Translation ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Mitochondrial Functions ◽  
Carboxy Terminal

The m.3243A>G mutation within the mitochondrial mt-tRNALeu(UUR) gene is the most prevalent variant linked to mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. This pathogenic mutation causes severe impairment of mitochondrial protein synthesis due to alterations of the mutated tRNA, such as reduced aminoacylation and a lack of post-transcriptional modification. In transmitochondrial cybrids, overexpression of human mitochondrial leucyl-tRNA synthetase (LARS2) has proven effective in rescuing the phenotype associated with m.3243A>G substitution. The rescuing activity resides in the carboxy-terminal domain (Cterm) of the enzyme; however, the precise molecular mechanisms underlying this process have not been fully elucidated. To deepen our knowledge on the rescuing mechanisms, we demonstrated the interactions of the Cterm with mutated mt-tRNALeu(UUR) and its precursor in MELAS cybrids. Further, the effect of Cterm expression on mitochondrial functions was evaluated. We found that Cterm ameliorates de novo mitochondrial protein synthesis, whilst it has no effect on mt-tRNALeu(UUR) steady-state levels and aminoacylation. Despite the complete recovery of cell viability and the increase in mitochondrial translation, Cterm-overexpressing cybrids were not able to recover bioenergetic competence. These data suggest that, in our MELAS cell model, the beneficial effect of Cterm may be mediated by factors that are independent of the mitochondrial bioenergetics.

scholarly journals Advances in the Role of Leucine-Sensing in the Regulation of Protein Synthesis in Aging Skeletal Muscle

2021 ◽  
Vol 9 ◽  
Author(s):  
Yan Zhao ◽  
Jason Cholewa ◽  
Huayu Shang ◽  
Yueqin Yang ◽  
Xiaomin Ding ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Therapeutic Potential ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Trna Synthetase ◽  
Limiting Factor ◽  
Anabolic Resistance ◽  
Age Related

Skeletal muscle anabolic resistance (i.e., the decrease in muscle protein synthesis (MPS) in response to anabolic stimuli such as amino acids and exercise) has been identified as a major cause of age-related sarcopenia, to which blunted nutrition-sensing contributes. In recent years, it has been suggested that a leucine sensor may function as a rate-limiting factor in skeletal MPS via small-molecule GTPase. Leucine-sensing and response may therefore have important therapeutic potential in the steady regulation of protein metabolism in aging skeletal muscle. This paper systematically summarizes the three critical processes involved in the leucine-sensing and response process: (1) How the coincidence detector mammalian target of rapamycin complex 1 localizes on the surface of lysosome and how its crucial upstream regulators Rheb and RagB/RagD interact to modulate the leucine response; (2) how complexes such as Ragulator, GATOR, FLCN, and TSC control the nucleotide loading state of Rheb and RagB/RagD to modulate their functional activity; and (3) how the identified leucine sensor leucyl-tRNA synthetase (LARS) and stress response protein 2 (Sestrin2) participate in the leucine-sensing process and the activation of RagB/RagD. Finally, we discuss the potential mechanistic role of exercise and its interactions with leucine-sensing and anabolic responses.

scholarly journals Deciphering the in vivo Dynamic Proteomics of Mesenchymal Stem Cells in Critical Limb Ischemia

2021 ◽  
Vol 9 ◽  
Author(s):  
Yipeng Du ◽  
Xiaoting Li ◽  
Wenying Yan ◽  
Zhaohua Zeng ◽  
Dunzheng Han ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Protein Synthesis ◽  
Critical Limb Ischemia ◽  
Click Reaction ◽  
Limb Ischemia ◽  
Trna Synthetase ◽  
Doppler Imaging

ObjectiveRegenerative therapy using mesenchymal stem cells (MSC) is a promising therapeutic method for critical limb ischemia (CLI). To understand how the cells are involved in the regenerative process of limb ischemia locally, we proposed a metabolic protein labeling method to label cell proteomes in situ and then decipher the proteome dynamics of MSCs in ischemic hind limb.Methods and ResultsIn this study, we overexpressed mutant methionyl-tRNA synthetase (MetRS), which could utilize azidonorleucine (ANL) instead of methionine (Met) during protein synthesis in MSCs. Fluorescent non-canonical amino-acid tagging (FUNCAT) was performed to detect the utilization of ANL in mutant MSCs. Mice with hindlimb ischemia (HLI) or Sham surgery were treated with MetRSmut MSCs or PBS, followed by i.p. administration of ANL at days 0, 2 6, and 13 after surgery. FUNCAT was also performed in hindlimb tissue sections to demonstrate the incorporation of ANL in transplanted cells in situ. At days 1, 3, 7, and 14 after the surgery, laser doppler imaging were performed to detect the blood reperfusion of ischemic limbs. Ischemic tissues were also collected at these four time points for histological analysis including HE staining and vessel staining, and processed for click reaction based protein enrichment followed by mass spectrometry and bioinformatics analysis. The MetRSmut MSCs showed strong green signal in cell culture and in HLI muscles as well, indicating efficient incorporation of ANL in nascent protein synthesis. By 14 days post-treatment, MSCs significantly increased blood reperfusion and vessel density, while reducing inflammation in HLI model compared to PBS. Proteins enriched by click reaction were distinctive in the HLI group vs. the Sham group. 34, 31, 49, and 26 proteins were significantly up-regulated whereas 28, 32, 62, and 27 proteins were significantly down-regulated in HLI vs. Sham at days 1, 3, 7, and 14, respectively. The differentially expressed proteins were more pronounced in the pathways of apoptosis and energy metabolism.ConclusionIn conclusion, mutant MetRS allows efficient and specific identification of dynamic cell proteomics in situ, which reflect the functions and adaptive changes of MSCs that may be leveraged to understand and improve stem cell therapy in critical limb ischemia.

scholarly journals Involvement of Regucalcin in Protein Synthesis and Proteolysis: Regulation of the Enzyme Activity in the Cytoplasm and Nucleus

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
Masayoshi Yamaguchi
Keyword(s):  
Protein Synthesis ◽  
Calcium Binding ◽  
Binding Protein ◽  
Suppressive Effect ◽  
Trna Synthetase ◽  
Calcium Binding Protein ◽  
Proliferation And Apoptosis ◽  
Regucalcin Gene ◽  
Proteolysis Regulation ◽  
Nuclear Deoxyribonucleic Acid

<p>Regucalcin was discovered in 1978 as a novel calcium-binding protein. The name, regucalcin, was proposed for this calcium-binding protein, which regulates various Ca<sup>2+-</sup> or Ca<sup>2+</sup>/calmodulin-dependent enzyme activations. The regucalcin gene (gene symbol;rgn) is localized on the X chromosome. Regucalcin has been demonstrated to play a multifunctional role in the regulation of intracellular calcium homeostasis, signal transduction, gene expression, cell proliferation and apoptosis in various types of cells and tissues. The cytoplasmic regucalcin translocases to the nucleus and suppresses nuclear deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) synthesis. Moreover, regucalcin has been shown to reveal a suppressive effect on protein synthesis and a stimulatory effect on protein degradation. Regucalcin has been found to inhibit aminoacyl-tRNA synthetase and activate thiol protease.  Regucalcin may play a suppressive role in the regulation of protein turnover in cells.</p>

scholarly journals Translation elongation factor 2 depletion by siRNA in mouse liver leads to mTOR-independent translational upregulation of ribosomal protein genes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maxim V. Gerashchenko ◽  
Mikhail V. Nesterchuk ◽  
Elena M. Smekalova ◽  
Joao A. Paulo ◽  
Piotr S. Kowalski ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Mammalian Cells ◽  
Ribosomal Proteins ◽  
Mouse Liver ◽  
Negative Impact ◽  
Elongation Factor ◽  
Ribosome Profiling ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Elongation Factor 2

Abstract Due to breakthroughs in RNAi and genome editing methods in the past decade, it is now easier than ever to study fine details of protein synthesis in animal models. However, most of our understanding of translation comes from unicellular organisms and cultured mammalian cells. In this study, we demonstrate the feasibility of perturbing protein synthesis in a mouse liver by targeting translation elongation factor 2 (eEF2) with RNAi. We were able to achieve over 90% knockdown efficacy and maintain it for 2 weeks effectively slowing down the rate of translation elongation. As the total protein yield declined, both proteomics and ribosome profiling assays showed robust translational upregulation of ribosomal proteins relative to other proteins. Although all these genes bear the TOP regulatory motif, the branch of the mTOR pathway responsible for translation regulation was not activated. Paradoxically, coordinated translational upregulation of ribosomal proteins only occurred in the liver but not in murine cell culture. Thus, the upregulation of ribosomal transcripts likely occurred via passive mTOR-independent mechanisms. Impaired elongation sequesters ribosomes on mRNA and creates a shortage of free ribosomes. This leads to preferential translation of transcripts with high initiation rates such as ribosomal proteins. Furthermore, severe eEF2 shortage reduces the negative impact of positively charged amino acids frequent in ribosomal proteins on ribosome progression.

scholarly journals Stimulation of Protein Synthesis in Mouse Liver by Ecdysterone

1969 ◽  
Vol 17 (1) ◽  
pp. 75-81 ◽  
Author(s):  
TADAHIKO OTAKA ◽  
SEIICHI OKUI ◽  
MITSURU UCHIYAMA
Keyword(s):  
Protein Synthesis ◽  
Mouse Liver ◽  
Stimulation Of
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