Cellular ADP-ribosylation of elongation factor 2.

A cellular ADP-ribosyltransferase activity has been found in a variety of animals and tissues. The enzyme transfers ADP-ribose from NAD to elongation factor 2, inactivating the factor and thus inhibiting in vitro protein synthesis. Although, the mechanism of action of the cellular enzyme appears similar to diphtheria toxin and Pseudomonas exotoxin A, it differs from the toxins in that only a fraction of the EF-2 pool is modified.

Characterization of the endogenous ADP-ribosylation of wild-type and mutant elongation factor 2 in eukaryotic cells.

Anti-[ADP-ribosylated elongation factor 2 (EF-2)] antiserum has been used to immunoprecipitate the modified form of EF-2 from polyoma-virus-transformed baby hamster kidney (pyBHK) cells [Fendrick, J. L. & Iglewski, W.

Cellular mono(ADP-ribosyl) transferase inhibits protein synthesis.

A reticulocyte translation system was depleted of functional EF-2 by treatment with diphtheria toxin (DT) fragment A and NAD. After dialysis to remove NAD, the system was reconstituted using preparations of EF-2 derived from pyBHK cells. Untreated and reconstituted lysates permitted similar rates of translation.

Endogenous ADP-ribosylation of elongation factor 2 in polyoma virus-transformed baby hamster kidney cells.

Polyoma virus-transformed baby hamster kidney (pyBHK) cells were cultured in medium containing [32P]orthophosphate and 10% (vol/vol) fetal bovine serum. A 32P-labeled protein with an apparent molecular mass of 97 kDa was immunoprecipitated from cell lysates with antiserum to ADP-ribosylated elongation factor 2 (EF-2). The 32P labeling of the protein was enhanced by culturing cells in medium containing 2% serum instead of 10% serum.