Abstract
The activity of eukaryotic elongation factor 2 is regulated by phosphorylation catalysed by a highly specific Ca2+/calmodulin-dependent protein kinase. Phosphorylated EF2 binds to ribosomes with decreased affinity. The present evidence indicates that EF2 prebound to ribosomes is protected from phosphorylation, just as earlier evidence indicated that ribosome-bound EF2 is protected from ADP-ribosylation catalysed by diphtheria toxin. Ribosome-inactivating proteins ricin and gelonin, by interfering with the EF2-ribosome interaction, allow full phosphorylation of EF2.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Calcium-Calmodulin-Dependent Protein Kinases
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In Vitro Techniques
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Peptide Elongation Factor 2
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Peptide Elongation Factors / metabolism*
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Phosphorylation
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Plant Proteins / pharmacology
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Protein Kinases / metabolism*
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Protein Synthesis Inhibitors / pharmacology
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Rabbits
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Reticulocytes / metabolism
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Ribosome Inactivating Proteins, Type 1
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Ribosomes / drug effects
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Ribosomes / metabolism
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Ricin / metabolism
Substances
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Peptide Elongation Factor 2
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Peptide Elongation Factors
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Plant Proteins
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Protein Synthesis Inhibitors
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Ribosome Inactivating Proteins, Type 1
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GEL protein, Gelonium multiflorum
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Ricin
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Protein Kinases
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Calcium-Calmodulin-Dependent Protein Kinases