scholarly journals Induction of carnitine acetyltransferase by clofibrate in rat liver

1981 ◽  
Vol 194 (1) ◽  
pp. 249-255 ◽  
Author(s):  
B Mittal ◽  
C K R Kurup
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Rat Liver ◽  
Time Lag ◽  
Mitochondrial Protein ◽  
Carnitine Acetyltransferase ◽  
Enzyme Protein ◽  
General Protein Synthesis ◽  
Liver And Kidney ◽  
General Protein

Administration of the anti-hypercholesterolaemic drug clofibrate to the rat increases the activity of carnitine acetyltransferase (acetyl-CoA-carnitine O-acetyltransferase, EC 2.3.1.7) in liver and kidney. The drug-mediated increase in enzyme activity in hepatic mitochondria shows a time lag during which the activity increases in the microsomal and peroxisomal fractions. The enzyme induced in the particulate fractions is identical with one normally present in mitochondria. The increase in enzyme activity is prevented by inhibitors of RNA and general protein synthesis. Mitochondrial protein-synthetic machinery does not appear to be involved in the process. Immunoprecipitation shows increased concentration of the enzyme protein in hepatic mitochondria isolated from drug-treated animals. In these animals, the rate of synthesis of the enzyme is increased 7-fold.

scholarly journals Effect of 1,3-diaminopropane on ornithine decarboxylase enzyme protein in thioacetamide-treated rat liver

1983 ◽  
Vol 216 (3) ◽  
pp. 701-707 ◽  
Author(s):  
J E Seely ◽  
A E Pegg
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Enzyme Protein ◽  
Rapid Loss ◽  
Immunoreactive Protein ◽  
Full Effect

A radioimmunoassay for ornithine decarboxylase was used to study the regulation of this enzyme in rat liver. The antiserum used reacts with ornithine decarboxylase from mouse, human or rat cells. Rat liver ornithine decarboxylase enzyme activity and enzyme protein (as determined by radioimmunoassay) were measured in thioacetamide-treated rats at various times after administration of 1,3-diaminopropane. Enzyme activity declined rapidly after 1,3-diaminopropane treatment as did the amount of enzyme protein, although the disappearance of enzyme activity slightly preceded the loss of immunoreactive protein. The loss of enzyme protein after cycloheximide treatment also occurred rapidly, but was significantly slower than that seen with 1,3-diaminopropane. When 1,3-diaminopropane and cycloheximide were injected simultaneously, the rate of disappearance of enzyme activity and enzyme protein was the same as that seen with cycloheximide alone. These results show that the rapid loss in enzyme activity after 1,3-diaminopropane treatment is primarily due to a loss in enzyme protein and that protein synthesis is needed in order for 1,3-diaminopropane to exert its full effect. A macromolecular inhibitor of ornithine decarboxylase that has been termed antizyme is induced in response to 1,3-diaminopropane, but our results indicate that the loss of enzyme activity is not due to the accumulation of inactive ornithine decarboxylase-antizyme complexes. It is possible that the antizyme enhances the degradation of the enzyme protein. Control experiments demonstrated that the antiserum used would have detected any inactive antizyme-ornithine decarboxylase complexes present in liver since addition of antizyme to ornithine decarboxylase in vitro did not affect the amount of ornithine decarboxylase detected in our radioimmunoassay. Anti-(ornithine decarboxylase) antibodies may be useful in the purification of antizyme since the antizyme-ornithine decarboxylase complex can be immunoprecipitated, and antizyme released from the precipitate with 0.3 M-NaCl.

scholarly journals Bmp Induces Osteoblast Differentiation through both Smad4 and mTORC1 Signaling

2016 ◽  
Vol 37 (4) ◽  
Author(s):  
Courtney M. Karner ◽  
Seung-Yon Lee ◽  
Fanxin Long
Keyword(s):  
Protein Synthesis ◽  
Intracellular Signaling ◽  
Osteoblast Differentiation ◽  
De Novo ◽  
Bmp Signaling ◽  
Endoplasmic Reticulum Stress Response ◽  
Versus Protein ◽  
Mtorc1 Signaling ◽  
General Protein Synthesis ◽  
General Protein

ABSTRACT The bone morphogenetic protein (Bmp) family of secreted molecules has been extensively studied in the context of osteoblast differentiation. However, the intracellular signaling cascades that mediate the osteoblastogenic function of Bmp have not been fully elucidated. By profiling mRNA expression in the bone marrow mesenchymal progenitor cell line ST2, we discover that BMP2 induces not only genes commonly associated with ossification and mineralization but also genes important for general protein synthesis. We define the two groups of genes as mineralization related versus protein anabolism signatures of osteoblasts. Although it induces the expression of several Wnt genes, BMP2 activates the osteogenic program largely independently of de novo Wnt secretion. Remarkably, although Smad4 is necessary for the activation of the mineralization-related genes, it is dispensable for BMP2 to induce the protein anabolism signature, which instead critically depends on the transcription factor Atf4. Upstream of Atf4, BMP2 activates mTORC1 to stimulate protein synthesis, resulting in an endoplasmic reticulum stress response mediated by Perk. Thus, Bmp signaling induces osteoblast differentiation through both Smad4- and mTORC1-dependent mechanisms.

Effect of Cordycepin on Ribosome Formation and Enzyme Induction in Rat Liver

1972 ◽  
Vol 50 (9) ◽  
pp. 1010-1015 ◽  
Author(s):  
Arthur J. Rizzo ◽  
Camille Kelly ◽  
Thomas E. Webb
Keyword(s):  
Rat Liver ◽  
Messenger Rna ◽  
Nucleocytoplasmic Transport ◽  
Current Theory ◽  
Polyadenylic Acid ◽  
General Protein Synthesis ◽  
Tyrosine Transaminase ◽  
General Protein ◽  
Nuclear Processing ◽  
Ribosomal Precursor

Cordycepin (3′-deoxyadenosine), at a dose of 10 mg/kg, inhibits the accumulation of ribosomes in rat liver cytoplasm within 2.5 h of administration. This effect is not due to an inhibition of RNA synthesis per se but rather to the premature termination of the transcription of the 45 S ribosomal precursor in the presence of the analogue. The nucleoside analogue also inhibits the corticosteroid-mediated induction of tyrosine transaminase and general protein synthesis. The latter results are consistent with the current theory that cordycepin inhibits the formation of polyadenylic acid which is involved in the nuclear processing and/or nucleocytoplasmic transport of messenger RNA.

scholarly journals Proline responding1 Plays a Critical Role in Regulating General Protein Synthesis and the Cell Cycle in Maize

2014 ◽  
Vol 26 (6) ◽  
pp. 2582-2600 ◽  
Author(s):  
Gang Wang ◽  
Jushan Zhang ◽  
Guifeng Wang ◽  
Xiangyu Fan ◽  
Xin Sun ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Critical Role ◽  
General Protein Synthesis ◽  
General Protein

scholarly journals Multiple components of eIF4F are required for protein synthesis-dependent hippocampal long-term potentiation

2013 ◽  
Vol 109 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Charles A. Hoeffer ◽  
Emanuela Santini ◽  
Tao Ma ◽  
Elizabeth C. Arnold ◽  
Ashley M. Whelan ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Synaptic Plasticity ◽  
Translation Initiation ◽  
Translational Control ◽  
Late Phase ◽  
Long Term Potentiation ◽  
Term Potentiation ◽  
General Protein Synthesis ◽  
General Protein

Persistent forms of synaptic plasticity are widely thought to require the synthesis of new proteins. This feature of long-lasting forms of plasticity largely has been demonstrated using inhibitors of general protein synthesis, such as either anisomycin or emetine. However, these drugs, which inhibit elongation, cannot address detailed questions about the regulation of translation initiation, where the majority of translational control occurs. Moreover, general protein synthesis inhibitors cannot distinguish between cap-dependent and cap-independent modes of translation initiation. In the present study, we took advantage of two novel compounds, 4EGI-1 and hippuristanol, each of which targets a different component of the eukaryotic initiation factor (eIF)4F initiation complex, and investigated their effects on long-term potentiation (LTP) at CA3-CA1 synapses in the hippocampus. We found that 4EGI-1 and hippuristanol both attenuated long-lasting late-phase LTP induced by two different stimulation paradigms. We also found that 4EGI-1 and hippuristanol each were capable of blocking the expression of newly synthesized proteins immediately after the induction of late-phase LTP. These new pharmacological tools allow for a more precise dissection of the role played by translational control pathways in synaptic plasticity and demonstrate the importance of multiple aspects of eIF4F in processes underlying hippocampal LTP, laying the foundation for future studies investigating the role of eIF4F in hippocampus-dependent memory processes.

Effects of cycloheximide on thermotolerance expression, heat shock protein synthesis, and heat shock protein mRNA accumulation in rat fibroblasts

1986 ◽  
Vol 6 (4) ◽  
pp. 1088-1094
Author(s):  
R B Widelitz ◽  
B E Magun ◽  
E W Gerner
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Mrna Levels ◽  
Hsp 70 ◽  
Mrna Accumulation ◽  
General Protein Synthesis ◽  
Rat Fibroblasts ◽  
General Protein ◽  
Rat Embryonic Fibroblasts

A single hyperthermic exposure can render cells transiently resistant to subsequent high temperature stresses. Treatment of rat embryonic fibroblasts with cycloheximide for 6 h after a 20-min interval at 45 degrees C inhibits protein synthesis, including heat shock protein (hsp) synthesis, and results in an accumulation of hsp 70 mRNA, but has no effect on subsequent survival responses to 45 degrees C hyperthermia. hsp 70 mRNA levels decreased within 1 h after removal of cycloheximide but then appeared to stabilize during the next 2 h (3 h after drug removal and 9 h after heat shock). hsp 70 mRNA accumulation could be further increased by a second heat shock at 45 degrees C for 20 min 6 h after the first hyperthermic exposure in cycloheximide-treated cells. Both normal protein and hsp synthesis appeared increased during the 6-h interval after hyperthermia in cultures which received two exposures to 45 degrees C for 20 min compared with those which received only one treatment. No increased hsp synthesis was observed in cultures treated with cycloheximide, even though hsp 70 mRNA levels appeared elevated. These data indicate that, although heat shock induces the accumulation of hsp 70 mRNA in both normal and thermotolerant cells, neither general protein synthesis nor hsp synthesis is required during the interval between two hyperthermic stresses for Rat-1 cells to express either thermotolerance (survival resistance) or resistance to heat shock-induced inhibition of protein synthesis.

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