Action of Inhibitors of Protein Biosynthesis

Vázquez, David; Zaera, E.; Dölz, Humberto; Jiménez, Antonio Moreno

doi:10.1007/978-1-4684-4124-6_13

Cited by 14 publications

(15 citation statements)

References 59 publications

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“…The rate of protein synthesis is inhibited by a variety of chemical agents (28). We verified that protein synthesis ( J. Mr, 30,000 to 55,000) and are shown in the left set of panels.…”

supporting

confidence: 56%

Initiation factor protein modifications and inhibition of protein synthesis.

Duncan¹

1987

Mol. Cell. Biol.

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The protein covalent modification state of eucaryotic initiation factors eIF-2 and eIF-4B in HeLa cells was examined after they were exposed to a variety of conditions or treatments that regulate protein synthesis. A few factors (e.g., variant pH and sodium fluoride) altered the phosphorylation state of the initiation factor proteins, but the majority (hypertonic medium, ethanol, dimethyl sulfoxide, sodium selenite, sodium azide, and colchicine) had no effect on either protein. While initiation factor phosphorylation may regulate protein synthesis in response to many physiological situations, other pathways can regulate protein synthesis under nonphysiological circumstances.The rate of protein synthesis in mammalian cells can be regulated by a variety of physiological (4,8,12,15) and nonphysiological (28) treatments. Inhibition principally occurs at the initiation phase (16,22), wherein Met-tRNA, ribosomal subunits, and mRNA associate to form the translationally active ribosome. Each of the initiation steps requires or is promoted by one or more protein cofactors, called eucaryotic initiation factors, which transiently associate with the translational machinery during the initiation process (20,22).These protein factors are, a priori, likely candidates to serve as regulatory molecules. Substantial evidence indicates that phosphorylation of 20 to 30% of the eIF-2a molecules leads to a protein synthesis inhibition of greater than 75% in rabbit reticulocytes (11, 16) and probably in other eucaryotic cells as well (6,8,27). We and others have shown that covalent modification or cleavage of initiation factor proteins correlates with an inhibition of protein synthesis in a variety of instances including hemin deprivation (11), nutrient deprivation (8), heat shock (3, 6, 9), and poliovirus infection (10). Although it now seems clear that initiation factors play a role in translational control in some situations, it remains to be determined how frequently modulations of initiation rate are mediated by eIF-2a phosphorylation and how many of the factors can serve as controlling elements.Using rapid, sensitive qualitative and quantitative techniques for examining covalent modification of the initiation factor proteins (5), we have shown that eIF-2a, eIF-2p, eIF-4B, and eIF-4Fp28 (CBP-I) are covalently altered when translation is inhibited in HeLa cells by either heat shock (6, 8a) or serum depletion (8). Both treatments induced parallel initiation factor changes, suggesting the existence of a common response pathway that could be linked to many dissimilar stimuli. We initiated the present study to extend our survey of initiation factor status during translational inhibitions.The initiation process is inhibited by increasing the tonicity of the growth medium (24). Excess NaCl (125 mM) inhibits by >95% the incorporation of amino acids into protein by HeLa cells (data not shown). In these and subsequent experiments, cytoplasmic lysates prepared from inhibited cells were analyzed by isoelectric focusing/sodium * Corresponding ...

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“…The rate of protein synthesis is inhibited by a variety of chemical agents (28). We verified that protein synthesis ( J. Mr, 30,000 to 55,000) and are shown in the left set of panels.…”

supporting

confidence: 56%

Initiation factor protein modifications and inhibition of protein synthesis.

Duncan¹

1987

Mol. Cell. Biol.

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“…Erythromycin and related macrolide antibiotics have been shown to inhibit 50S subunit function in translation, and their mechanism of action has been investigated well (Vazquez, 1979; Corcoran, 1984; Mazzei et al ., 1993). Much less is known about antibiotic effects on 50S subunit assembly.…”

Section: Discussionmentioning

confidence: 99%

Erythromycin inhibition of 50S ribosomal subunit formation in Escherichia coli cells

Usary

Champney²

2001

Molecular Microbiology

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SummaryThe effects of erythromycin on the formation of ribosomal subunits were examined in wild-type Escherichia coli cells and in an RNase E mutant strain. Pulse±chase labelling kinetics revealed a reduced rate of 50S subunit formation in both strains compared with 30S synthesis, which was unaffected by the antibiotic. Growth of cells in the presence of [ 14 C]-erythromycin showed drug binding to 50S particles and to a 50S subunit precursor sedimenting at about 30S in sucrose gradients. Antibiotic binding to the precursor correlated with the decline in 50S formation in both strains. Erythromycin binding to the precursor showed the same 1:1 stoichiometry as binding to the 50S particle. Gel electrophoresis of rRNA from antibiotic-treated organisms revealed the presence of both 23S and 5S rRNAs in the 30S region of sucrose gradients. Hybridization with a 23S rRNAspecific probe confirmed the presence of this species of rRNA in the precursor. Eighteen 50S ribosomal proteins were associated with the precursor particle. A model is presented to account for erythromycin inhibition of 50S formation.

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“…However, the mechanism of chloramphenicol‐dependent SRC formation is unclear. The main binding site of chloramphenicol has been mapped in the PTC where binding of the antibiotic inhibits peptide bond formation, apparently irrespective of the nascent peptide sequence (Vazquez, 1979). Some hypotheses pertaining to the induction mechanism invoked direct interaction of the MVKTD nascent peptide, encoded in the catA86 leader ORF, with 23S rRNA in the PTC (Gu et al ., 1994a,b).…”

Section: Programmed Ribosome Stalling May Control Expression Of Genesmentioning

confidence: 99%

Programmed drug‐dependent ribosome stalling

Ramu

Mankin

Vázquez‐Laslop

2009

Molecular Microbiology

150

157

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SummaryThe ribosome has the intrinsic capacity to monitor the sequence and structure of the nascent peptide. This fundamental property of the ribosome is often exploited in regulation of gene expression, in particular, for activation of expression of genes conferring resistance to ribosome-targeting antibiotics. Induction of expression of these genes is controlled by the programmed stalling of the ribosome at a regulatory open reading frame located upstream of the resistance cistron. Formation of the stalled translation complex depends on the presence of an antibiotic in the ribosome exit tunnel and the sequence of the nascent peptide. In this review, we summarize our current understanding of the molecular mechanisms of drug-and nascent peptide-dependent ribosome stalling.

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Action of Inhibitors of Protein Biosynthesis

Cited by 14 publications

References 59 publications

Initiation factor protein modifications and inhibition of protein synthesis.

Initiation factor protein modifications and inhibition of protein synthesis.

Erythromycin inhibition of 50S ribosomal subunit formation in Escherichia coli cells

Programmed drug‐dependent ribosome stalling

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