scholarly journals Functional interplay between arginyl-tRNA synthetases and arginyltransferase

2022 ◽  
Author(s):  
Irem Avcilar-Kucukgoze ◽  
Anna Kashina
Keyword(s):  
Amino Acid ◽  
Enzymatic Activity ◽  
Cell Lines ◽  
Posttranslational Modification ◽  
Physiological State ◽  
Comprehensive Analysis ◽  
Peptide Substrates ◽  
Trna Synthetases ◽  
Functional Balance ◽  
Biological Importance

Protein arginylation, mediated by arginyltransferase ATE1, is a posttranslational modification of emerging biological importance that consists of transfer of the amino acid Arg to protein and peptide substrates. ATE1 utilizes charged tRNAArg as the donor of the arginyl group, which depends on the activity of Arg-tRNA synthetases (RARS) and is also utilized in translation. The mechanisms that regulate the functional balance between ATE1, RARS and translation are unknown. Here we addressed the functional interplay between these mechanisms using intracellular arginylation sensor in cell lines with overexpression or deletion of ATE1 and RARS isoforms. We find that arginylation levels depend on the physiological state of the cells but are not directly affected by translation activity or availability of RARS isoforms. However, displacement of RARS from the multi-synthetase complex leads to an increase in intracellular arginylation independently of RARS enzymatic activity. This effect is accompanied by ATE1 redistribution into the cytosol. Our results provide the first comprehensive analysis of the interdependence between translation, arginyl-tRNA synthesis, and arginylation.

Glutamine-181 is crucial in the enzymatic activity and substrate specificity of human endoplasmic-reticulum aminopeptidase-1

2008 ◽  
Vol 416 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Yoshikuni Goto ◽  
Hiroe Tanji ◽  
Akira Hattori ◽  
Masafumi Tsujimoto
Keyword(s):  
Endoplasmic Reticulum ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Enzymatic Activity ◽  
Basic Amino Acid ◽  
Hydrolytic Activity ◽  
Site Directed Mutagenesis ◽  
Peptide Substrates ◽  
Endoplasmic Reticulum Aminopeptidase 1 ◽  
Natural Peptides

ERAP-1 (endoplasmic-reticulum aminopeptidase-1) is a multifunctional enzyme with roles in the regulation of blood pressure, angiogenesis and the presentation of antigens to MHC class I molecules. Whereas the enzyme shows restricted specificity toward synthetic substrates, its substrate specificity toward natural peptides is rather broad. Because of the pathophysiological significance of ERAP-1, it is important to elucidate the molecular basis of its enzymatic action. In the present study we used site-directed mutagenesis to identify residues affecting the substrate specificity of human ERAP-1 and identified Gln181 as important for enzymatic activity and substrate specificity. Replacement of Gln181 by aspartic acid resulted in a significant change in substrate specificity, with Q181D ERAP-1 showing a preference for basic amino acids. In addition, Q181D ERAP-1 cleaved natural peptides possessing a basic amino acid at the N-terminal end more efficiently than did the wild-type enzyme, whereas its cleavage of peptides with a non-basic amino acid was significantly reduced. Another mutant enzyme, Q181E, also revealed some preference for peptides with a basic N-terminal amino acid, although it had little hydrolytic activity toward the synthetic peptides tested. Other mutant enzymes, including Q181N and Q181A ERAP-1s, revealed little enzymatic activity toward synthetic or peptide substrates. These results indicate that Gln181 is critical for the enzymatic activity and substrate specificity of ERAP-1.

scholarly journals Availability of Arg, but Not tRNA, Is a Rate-Limiting Factor for Intracellular Arginylation

2021 ◽  
Vol 23 (1) ◽  
pp. 314
Author(s):  
Irem Avcilar-Kucukgoze ◽  
Brittany MacTaggart ◽  
Anna Kashina
Keyword(s):  
Amino Acid ◽  
Posttranslational Modification ◽  
Cultured Cells ◽  
Limiting Factor ◽  
Strong Binding ◽  
Biological Importance ◽  
Rate Limiting ◽  
In Cells

Protein arginylation, mediated by arginyltransferase ATE1, is a posttranslational modification of emerging biological importance that consists of transfer of the amino acid Arg from tRNA to protein and peptide targets. ATE1 can bind tRNA and exhibits specificity toward particular tRNA types, but its dependence on the availability of the major components of the arginylation reaction has never been explored. Here we investigated key intracellular factors that can potentially regulate arginylation in vivo, including several tRNA types that show strong binding to ATE1, as well as availability of free Arg, in an attempt to identify intracellular rate limiting steps for this enzyme. Our results demonstrate that, while modulation of tRNA levels in cells does not lead to any changes in intracellular arginylation efficiency, availability of free Arg is a potentially rate-limiting factor that facilitates arginylation if added to the cultured cells. Our results broadly outline global pathways that may be involved in the regulation of arginylation in vivo.

scholarly journals Hypusination, a Metabolic Posttranslational Modification of eIF5A in Plants during Development and Environmental Stress Responses

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1261
Author(s):  
Péter Pálfi ◽  
László Bakacsy ◽  
Henrietta Kovács ◽  
Ágnes Szepesi
Keyword(s):  
Amino Acid ◽  
Environmental Stress ◽  
Plant Development ◽  
Stress Responses ◽  
Posttranslational Modification ◽  
Proper Function ◽  
Signal Pathways ◽  
Deoxyhypusine Synthase ◽  
Deoxyhypusine Hydroxylase ◽  
Eukaryotic Translation

Hypusination is a unique posttranslational modification of eIF5A, a eukaryotic translation factor. Hypusine is a rare amino acid synthesized in this process and is mediated by two enzymes, deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Despite the essential participation of this conserved eIF5A protein in plant development and stress responses, our knowledge of its proper function is limited. In this review, we demonstrate the main findings regarding how eIF5A and hypusination could contribute to plant-specific responses in growth and stress-related processes. Our aim is to briefly discuss the plant-specific details of hypusination and decipher those signal pathways which can be effectively modified by this process. The diverse functions of eIF5A isoforms are also discussed in this review.

A novel polymorphism of human gene has an amino acid substitution (V365M) that decreases enzymatic activity in vitro and in vivo

2004 ◽  
Vol 76 (6) ◽  
pp. 519-527 ◽  
Author(s):  
T FUKAMI ◽  
M NAKAJIMA ◽  
R YOSHIDA ◽  
Y TSUCHIYA ◽  
Y FUJIKI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Enzymatic Activity ◽  
Amino Acid Substitution ◽  
Human Gene

scholarly journals Comprehensive analysis of the gene expression profiles in human gastric cancer cell lines

Oncogene ◽  
2002 ◽  
Vol 21 (42) ◽  
pp. 6549-6556 ◽  
Author(s):  
Jiafu Ji ◽  
Xin Chen ◽  
Suet Yi Leung ◽  
Jen-Tsan A Chi ◽  
Kent Man Chu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Gastric Cancer Cell ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Comprehensive Analysis ◽  
Human Gastric Cancer ◽  
Gastric Cancer Cell Lines

scholarly journals Pretreatment Effect of Inflammatory Stimuli and Characteristics of Tryptophan Transport on Brain Capillary Endothelial (TR-BBB) and Motor Neuron Like (NSC-34) Cell Lines

Biomedicines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Asmita Gyawali ◽  
Young-Sook Kang
Keyword(s):  
Amino Acid ◽  
Motor Neuron ◽  
Cell Lines ◽  
Amino Acid Transporter ◽  
Mutant Type ◽  
Brain Capillary ◽  
Neuroprotective Drugs ◽  
Acid Transporter ◽  
Tryptophan Uptake ◽  
Tryptophan Transport

Tryptophan plays a key role in several neurological and psychiatric disorders. In this study, we investigated the transport mechanisms of tryptophan in brain capillary endothelial (TR-BBB) cell lines and motor neuron-like (NSC-34) cell lines. The uptake of [3H]l-tryptophan was stereospecific, and concentration- and sodium-dependent in TR-BBB cell lines. Transporter inhibitors and several neuroprotective drugs inhibited [3H]l-tryptophan uptake by TR-BBB cell lines. Gabapentin and baclofen exerted a competitive inhibitory effect on [3H]l-tryptophan uptake. Additionally, l-tryptophan uptake was time- and concentration-dependent in both NSC-34 wild type (WT) and mutant type (MT) cell lines, with a lower transporter affinity and higher capacity in MT than in WT cell lines. Gene knockdown of LAT1 (l-type amino acid transporter 1) and CAT1 (cationic amino acid transporter 1) demonstrated that LAT1 is primarily involved in the transport of [3H]l-tryptophan in both TR-BBB and NSC-34 cell lines. In addition, tryptophan uptake was increased by TR-BBB cell lines but decreased by NSC-34 cell lines after pro-inflammatory cytokine pre-treatment. However, treatment with neuroprotective drugs ameliorated tryptophan uptake by NSC-34 cell lines after inflammatory cytokines pretreatment. The tryptophan transport system may provide a therapeutic target for treating or preventing neurodegenerative diseases.

The Neurospora crassa cyt-20 gene encodes cytosolic and mitochondrial valyl-tRNA synthetases and may have a second function in addition to protein synthesis

1991 ◽  
Vol 11 (8) ◽  
pp. 4022-4035
Author(s):  
A R Kubelik ◽  
B Turcq ◽  
A M Lambowitz
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Neurospora Crassa ◽  
Temperature Sensitivity ◽  
Temperature Sensitive ◽  
Cellular Transport ◽  
Missense Mutations ◽  
Reading Frame ◽  
Trna Synthetases ◽  
Cytosolic Protein

The cyt-20-1 mutant of Neurospora crassa is a temperature-sensitive, cytochrome b- and aa3-deficient strain that is severely deficient in both mitochondrial and cytosolic protein synthesis (R.A. Collins, H. Bertrand, R.J. LaPolla, and A.M. Lambowitz, Mol. Gen. Genet. 177:73-84, 1979). We cloned the cyt-20+ gene by complementation of the cyt-20-1 mutation and found that it contains a 1,093-amino-acid open reading frame (ORF) that encodes both the cytosolic and mitochondrial valyl-tRNA synthetases (vaIRSs). A second mutation, un-3, which is allelic with cyt-20-1, also results in temperature-sensitive growth, but not in gross deficiencies in cytochromes b and aa3 or protein synthesis. The un-3 mutant had also been reported to have pleiotropic defects in cellular transport process, resulting in resistance to amino acid analogs (M.S. Kappy and R.L. Metzenberg, J. Bacteriol. 94:1629-1637, 1967), but this resistance phenotype is separable from the temperature sensitivity in crosses and may result from a mutation in a different gene. The 1,093-amino-acid ORF encoding vaIRSs is the site of missense mutations resulting in temperature sensitivity in both cyt-20-1 and un-3 and is required for the transformation of both mutants. The opposite strand of the cyt-20 gene encodes an overlapping ORF of 532 amino acids, which may also be functional but is not required for transformation of either mutant. The cyt-20-1 mutation in the vaIRS ORF results in severe deficiencies of both mitochondrial and cytosolic vaIRS activities, whereas the un-3 mutation does not appear to result in a deficiency of these activities or of mitochondrial or cytosolic protein synthesis sufficient to account for its temperature-sensitive growth. The phenotype of the un-3 mutant raises the possibility that the vaIRS ORF has a second function in addition to protein synthesis.

scholarly journals Transcriptional hallmarks of cancer cell lines reveal an emerging role of branched chain amino acid catabolism

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Ieva Antanavičiūtė ◽  
Valeryia Mikalayeva ◽  
Ieva Ceslevičienė ◽  
Gintarė Milašiūtė ◽  
Vytenis Arvydas Skeberdis ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Amino Acid Catabolism ◽  
Hallmarks Of Cancer ◽  
Branched Chain Amino Acid ◽  
Branched Chain
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