Studies on the role of protein synthesis in the regulation of corticosterone production by adrenocorticotropic hormone in vivo.

The ability of chloroplasts isolated from Acetabulana mediterranea to synthesize the protein amino acids has been investigated. When this chloroplast isolate was presented with 14CO2 for periods of 6–8 hr, tracer was found in essentially all amino acid species of their hydrolyzed protein Phenylalanine labeling was not detected, probably due to technical problems, and hydroxyproline labeling was not tested for The incorporation of 14CO2 into the amino acids is driven by light and, as indicated by the amount of radioactivity lost during ninhydrin decarboxylation on the chromatograms, the amino acids appear to be uniformly labeled. The amino acid labeling pattern of the isolate is similar to that found in plastids labeled with 14CO2 in vivo. The chloroplast isolate did not utilize detectable amounts of externally supplied amino acids in light or, with added adenosine triphosphate (ATP), in darkness. It is concluded that these chloroplasts are a tight cytoplasmic compartment that is independent in supplying the amino acids used for its own protein synthesis. These results are discussed in terms of the role of contaminants in the observed synthesis, the "normalcy" of Acetabularia chloroplasts, the synthetic pathways for amino acids in plastids, and the implications of these observations for cell compartmentation and chloroplast autonomy.

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Key role of l-alanine in the control of hepatic protein synthesis

Biochemical Journal ◽

10.1042/bj2410491 ◽

1987 ◽

Vol 241 (2) ◽

pp. 491-498 ◽

Cited By ~ 26

Author(s):

D Pérez-Sala ◽

R Parrilla ◽

M S Ayuso

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Physiological Role ◽

Chain Elongation ◽

Liver Protein ◽

Isolated Liver Cells ◽

Metabolic Transformation ◽

Hepatic Protein Synthesis

We investigated the effects of administration of single amino acids to starved rats on the regulation of protein synthesis in the liver. Of all the amino acids tested, only alanine, ornithine and proline promoted statistically significant increases in the extent of hepatic polyribosome aggregation. The most effective of these was alanine, whose effect of promoting polyribosomal aggregation was accompanied by a decrease in the polypeptide-chain elongation time. The following observations indicate that alanine plays an important physiological role in the regulation of hepatic protein synthesis. Alanine was the amino acid showing the largest decrease in hepatic content in the transition from high (fed) to low (starved) rates of protein synthesis. The administration of glucose or pyruvate is also effective in increasing liver protein synthesis in starved rats, and their effects were accompanied by an increased hepatic alanine content. An increase in hepatic ornithine content does not lead to an increased protein synthesis, unless it is accompanied by an increase of alanine. The effect of alanine is observed either in vivo, in rats pretreated with cycloserine to prevent its transamination, or in isolated liver cells under conditions in which its metabolic transformation is fully impeded.

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Citrulline directly modulates muscle protein synthesis via the PI3K/MAPK/4E-BP1 pathway in a malnourished state: evidence from in vivo, ex vivo, and in vitro studies

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00203.2016 ◽

2017 ◽

Vol 312 (1) ◽

pp. E27-E36 ◽

Cited By ~ 16

Author(s):

Servane Le Plénier ◽

Arthur Goron ◽

Athanassia Sotiropoulos ◽

Eliane Archambault ◽

Chantal Guihenneuc ◽

...

Keyword(s):

Protein Synthesis ◽

Ex Vivo ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Fold Increase ◽

Underlying Mechanism ◽

Muscle Homeostasis

Citrulline (CIT) is an endogenous amino acid produced by the intestine. Recent literature has consistently shown CIT to be an activator of muscle protein synthesis (MPS). However, the underlying mechanism is still unknown. Our working hypothesis was that CIT might regulate muscle homeostasis directly through the mTORC1/PI3K/MAPK pathways. Because CIT undergoes both interorgan and intraorgan trafficking and metabolism, we combined three approaches: in vivo, ex vivo, and in vitro. Using a model of malnourished aged rats, CIT supplementation activated the phosphorylation of S6K1 and 4E-BP1 in muscle. Interestingly, the increase in S6K1 phosphorylation was positively correlated ( P < 0.05) with plasma CIT concentration. In a model of isolated incubated skeletal muscle from malnourished rats, CIT enhanced MPS (from 30 to 80% CIT vs. Ctrl, P < 0.05), and the CIT effect was abolished in the presence of wortmannin, rapamycin, and PD-98059. In vitro, on myotubes in culture, CIT led to a 2.5-fold increase in S6K1 phosphorylation and a 1.5-fold increase in 4E-BP1 phosphorylation. Both rapamycin and PD-98059 inhibited the CIT effect on S6K1, whereas only LY-294002 inhibited the CIT effect on both S6K1 and 4E-BP1. These findings show that CIT is a signaling agent for muscle homeostasis, suggesting a new role of the intestine in muscle mass control.

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The effects of 6 hours of hypoxia on protein synthesis in rat tissues in vivo and in vitro

Biochemical Journal ◽

10.1042/bj2280179 ◽

1985 ◽

Vol 228 (1) ◽

pp. 179-185 ◽

Cited By ~ 58

Author(s):

V R Preedy ◽

D M Smith ◽

P H Sugden

Keyword(s):

Protein Synthesis ◽

Gastric Emptying ◽

Skeletal Muscles ◽

Rat Tissues ◽

Tissue Nitrogen ◽

The Brain ◽

H Protein

Rates of protein synthesis were measured in vivo in several tissues (heart, skeletal muscles, liver, tibia, skin, brain, kidney, lung) of fed rats exposed to O2/N2 (1:9) for 6 h starting at 08:00-11:00 h. Protein synthesis rates were depressed by 15-35% compared with normoxic controls in all of the tissues studied. The decreases were greatest in the brain and the skin. Although hypoxia inhibited gastric emptying, its effects on protein synthesis could probably not be attributed to its induction of a starved state, because protein-synthesis rates in brain and skin were not decreased by a 15-18 h period of starvation initiated at 23:00 h. Furthermore, we showed that protein synthesis was inhibited by hypoxia in the rat heart perfused in vitro, suggesting a direct effect. The role of hypoxia in perturbing tissue nitrogen balance in various physiological and pathological states is discussed.

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Contractile protein synthesis rates in vivo in the rat jejunum: modulating role of adrenalectomy and thyroidectomy on ethanol-induced changes

Addiction Biology ◽

10.1080/13556219772877 ◽

1997 ◽

Vol 2 (1) ◽

pp. 67-79 ◽

Cited By ~ 12

Author(s):

JASPAUL S. MARWAY ◽

JOHN P. MIELL ◽

JENNY JONES ◽

ADRIAN B. BONNER ◽

MICHAEL A. PREECE ◽

...

Keyword(s):

Protein Synthesis ◽

Contractile Protein ◽

Rat Jejunum ◽

Induced Changes

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In vivo characterization of the role of tissue‐specific translation elongation factor 1 A 2 in protein synthesis reveals insights into muscle atrophy

FEBS Journal ◽

10.1111/febs.12554 ◽

2013 ◽

Vol 280 (24) ◽

pp. 6528-6540 ◽

Cited By ~ 13

Author(s):

Jennifer Doig ◽

Lowri A. Griffiths ◽

David Peberdy ◽

Permphan Dharmasaroja ◽

Maria Vera ◽

...

Keyword(s):

Protein Synthesis ◽

Muscle Atrophy ◽

Elongation Factor ◽

Translation Elongation Factor ◽

Translation Elongation ◽

In Vivo Characterization ◽

Elongation Factor 1

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Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia)

Reproduction Fertility and Development ◽

10.1071/rd9920533 ◽

1992 ◽

Vol 4 (5) ◽

pp. 533 ◽

Cited By ~ 6

Author(s):

G Chaturapanich ◽

RC Jones ◽

J Clulow

Keyword(s):

Protein Synthesis ◽

Protein Secretion ◽

Tammar Wallaby ◽

Secreted Proteins ◽

Blood Proteins ◽

Macropus Eugenii ◽

Cauda Epididymidis

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.

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The Reverse Side of a Coin: “Factor-Free” Ribosomal Protein Synthesis In Vitro is a Consequence of the In Vivo Proofreading Mechanism

Biomolecules ◽

10.3390/biom9100588 ◽

2019 ◽

Vol 9 (10) ◽

pp. 588

Author(s):

Finkelstein

Keyword(s):

Quality Control ◽

Protein Synthesis ◽

Amino Acid ◽

Amino Acid Sequence ◽

Ribosomal Protein ◽

Elongation Factor ◽

Ribosomal Protein Synthesis

This paper elucidates a close connection between two well-known facts that until now have seemed independent: (i) the quality control (“proofreading”) of the emerging amino acid sequence, occurring during the normal, elongation-factor-dependent ribosomal biosynthesis, which is performed by removing those Aa-tRNAs (aminoacyl tRNAs) whose anticodons are not complementary to the exhibited mRNA codons, and (ii) the in vitro discovered existence of the factor-free ribosomal synthesis of polypeptides. It is shown that a biological role of proofreading is played by a process that is exactly opposite to the step of factor-free binding of Aa-tRNA to the ribosome-exposed mRNA: a factor-free removal of that Aa-tRNA whose anticodon is not complementary to the ribosome-exhibited mRNA codon.

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Studies on the Regulatory Role of trans-Cinnamic Acid on the Activity of the Phenylalanine Ammonia-Lyase (PAL) in Suspension Cultures of Daucus carota L.

Zeitschrift für Naturforschung C ◽

10.1515/znc-1983-5-613 ◽

1983 ◽

Vol 38 (5-6) ◽

pp. 408-412 ◽

Cited By ~ 6

Author(s):

W. Noé ◽

H. U. Seitz

Keyword(s):

Protein Synthesis ◽

Cinnamic Acid ◽

Phenylalanine Ammonia Lyase ◽

Competitive Inhibitor ◽

Regulatory Role ◽

Coumaric Acid ◽

Daucus Carota L

In vivo and in vitro experiments were performed in order to study the regulatory role of trans- cinnamic acid and its hydroxylated derivatives (p-coumaric acid, caffeic acid) on the deamination of phenylalanine catalyzed by PAL (EC 4.3.1.5). Trans-cinnamic acid inhibits growth and reduces the content of soluble proteins of anthocyanin-containing carrot cells grown in suspension. There is strong evidence from the polysomal patterns and from the effect of trans-cinnamic acid on protein synthesis in vitro that protein synthesis is inhibited. The kinetic data of PAL clearly demonstrate that trans-cinnamic acid inhibits the enzyme by a noncompetitive mechanism. On the contrary, ʟ-α-aminooxy-β-phenylpropionic acid (ʟ-AOPP), a competitive inhibitor of PAL, does not affect protein metabolism.

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