scholarly journals RELATION OF PROTEIN SYNTHESIS TO THE DIVISION CYCLE IN MAMMALIAN CELL CULTURES

1963 ◽  
Vol 19 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Edwin W. Taylor
Keyword(s):  
Mathematical Model ◽  
Protein Synthesis ◽  
Mitotic Index ◽  
Relative Rate ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Mammalian Cell Cultures ◽  
Inhibition Process ◽  
Rate Limiting ◽  
Logarithmic Growth

Protein synthesis in suspension cultures of human cells in logarithmic growth was inhibited with puromycin or chloramphenicol, and the growth rate and mitotic index were measured as a function of time. The mitotic index remained constant for about 1 hour after addition of inhibitor; this indicates that any protein synthesis necessary for mitosis is completed before the beginning of prophase. For rates of protein synthesis equal to or greater than 0.3 that of untreated cells, the index decreased over a 5- to-7-hour period and then remained constant. The final value of the index relative to that of the uninhibited control was approximately equal to the relative rate of protein synthesis. The period from the end of DNA synthesis to mitosis (G2) was increased by partial inhibition of protein synthesis. A mathematical model of the inhibition process has been formulated which predicts the shape of the mitotic index curves and the increase in the G2 period. An interpretation of the model is that the rate-limiting step is the synthesis of an enzyme which catalyzes the formation of a compound necessary to initiate mitosis.

scholarly journals The rate-limiting step of protein synthesis in vivo and in vitro and the distribution of growing peptides between the puromycinlabile and puromycin-non-labile sites on polyribosomes

1971 ◽  
Vol 122 (3) ◽  
pp. 267-276 ◽  
Author(s):  
D. C. N. Earl ◽  
Susan T. Hindley
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Donor Site ◽  
Peptide Bond ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Donor And Acceptor ◽  
Rate Limiting

1. At 3 min after an intravenous injection of radioactive amino acids into the rat, the bulk of radioactivity associated with liver polyribosomes can be interpreted as growing peptides. 2. In an attempt to identify the rate-limiting step of protein synthesis in vivo and in vitro, use was made of the action of puromycin at 0°C, in releasing growing peptides only from the donor site, to study the distribution of growing peptides between the donor and acceptor sites. 3. Evidence is presented that all growing peptides in a population of liver polyribosomes labelled in vivo are similarly distributed between the donor and acceptor sites, and that the proportion released by puromycin is not an artifact of methodology. 4. The proportion released by puromycin is about 50% for both liver and muscle polyribosomes labelled in vivo, suggesting that neither the availability nor binding of aminoacyl-tRNA nor peptide bond synthesis nor translocation can limit the rate of protein synthesis in vivo. Attempts to alter this by starvation, hypophysectomy, growth hormone, alloxan, insulin and partial hepatectomy were unsuccessful. 5. Growing peptides on liver polyribosomes labelled in a cell-free system in vitro or by incubating hemidiaphragms in vitro were largely in the donor site, suggesting that either the availability or binding of aminoacyl-tRNA, or peptide bond synthesis, must be rate limiting in vitro and that the rate-limiting step differs from that in vivo. 6. Neither in vivo nor in the hemidiaphragm system in vitro was a correlation found between the proportion of growing peptides in the donor site and changes in the rate of incorporation of radioactivity into protein. This could indicate that the intracellular concentration of amino acids or aminoacyl-tRNA limits the rate of protein synthesis and that the increased incorporation results from a rise to a higher but still suboptimum concentration.

Regulation of Protein Synthesis by eIF4E in the Brain

2020 ◽  
Author(s):  
Kleanthi Chalkiadaki ◽  
Stella Kouloulia ◽  
Clive R. Bramham ◽  
Christos G. Gkogkas
Keyword(s):  
Protein Synthesis ◽  
Brain Function ◽  
Regulation Of Gene Expression ◽  
Mrna Translation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Eukaryotic Mrnas ◽  
Rate Limiting ◽  
The Brain ◽  
Key Pathways

Regulation of gene expression at the level of mRNA translation is crucial for all the functions our brains carry out. eIF4E binds to the 5′-end of eukaryotic mRNAs and dictates the rate-limiting step of cap-dependent initiation. This chapter reviews the key pathways regulating eIF4E function, but also the less studied and novel mechanisms of eIF4E modulation, linked to synaptic plasticity, learning and memory, and nervous system disorders. Understanding how regulation of protein synthesis by eIF4E affects different aspects of brain function is yet elusive.

Translation initiation in the crenarchaeon Sulfolobus solfataricus: eukaryotic features but bacterial route

2013 ◽  
Vol 41 (1) ◽  
pp. 350-355 ◽  
Author(s):  
Anna La Teana ◽  
Dario Benelli ◽  
Paola Londei ◽  
Udo Bläsi
Keyword(s):  
Protein Synthesis ◽  
Translation Initiation ◽  
Current Knowledge ◽  
Sulfolobus Solfataricus ◽  
Initiation Complex ◽  
Initiation Factors ◽  
Sequence Of Events ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

The formation of the translation initiation complex represents the rate-limiting step in protein synthesis. Translation initiation in the crenarchaeon Sulfolobus solfataricus depends on several translation IFs (initiation factors), some of which have eukaryal but no bacterial counterparts. In the present paper, we review the current knowledge of the structure, function and evolution of the IFs in S. solfataricus in the context of eukaryotic and bacterial orthologues. Despite similarities between eukaryotic and S. solfataricus IFs, the sequence of events in translation initiation in S. solfataricus follows the bacterial mode.

scholarly journals The eIF4E-binding proteins are modifiers of cytoplasmic eIF4E relocalization during the heat shock response

2009 ◽  
Vol 296 (5) ◽  
pp. C1207-C1217 ◽  
Author(s):  
R. Sukarieh ◽  
N. Sonenberg ◽  
J. Pelletier
Keyword(s):  
Protein Synthesis ◽  
Binding Proteins ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor ◽  
Eukaryotic Initiation Factor 4E ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Repressor Proteins ◽  
Shock Response ◽  
Rate Limiting

Stress granules (SGs) arise as a consequence of cellular stress, contain stalled translation preinitiation complexes, and are associated with cell survival during environmental insults. SGs are dynamic entities with proteins relocating into and out of them during stress. Among the repertoire of proteins present in SGs is eukaryotic initiation factor 4E (eIF4E), a translation factor required for cap-dependent translation and that regulates a rate-limiting step for protein synthesis. Herein, we demonstrate that localization of eIF4E to SGs is dependent on the presence of a family of repressor proteins, eIF4E-binding proteins (4E-BPs). Our results demonstrate that 4E-BPs regulate the SG localization of eIF4E.

Targeting the rate limiting step of protein synthesis may provide an alternative approach to overcome the chemoresistance of malignant mesothelioma

2014 ◽  
Vol 229 ◽  
pp. S226
Author(s):  
Stefano Grosso ◽  
Gifty M. George ◽  
Tatyana Chernova ◽  
Xiao Ming Sun ◽  
Fiona A. Murphy ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Malignant Mesothelioma ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Alternative Approach ◽  
Rate Limiting

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting
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