ADP-ribosylatable content of elongation factor-2 changes during cell cycle of normal and cancerous human cells.
The amount of protein elongation factor EF-2 that can be inactivated by diphtheria toxin-mediated ADP-ribosylation, a measure of its active content, decreases by 45% and 66% in G1-arrested normal human fibroblasts and in HeLa cells respectively. On restimulation of cells with fresh serum, the amounts of ADP-ribosylatable EF-2 begin to increase within 4 h. Whereas the level of active EF-2 returns to normal (exponential phase of growth) in 20 h in the case of fibroblasts, only 47% recovery was observed for HeLa cells during this period. The apparent long half-lives of EF-2 mRNA and protein indicate possibilities of posttranslational ADP-ribosylation and de-ADP-ribosylation as the regulators of the amounts of active EF-2 during human cell cycle.
Riis
B
B
Department of Chemistry, Aarhus University, Denmark.
Rattan
S I
SI
Cavallius
J
J
Clark
B F
BF
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D002453:Cell Cycle; D002460:Cell Line; D002474:Cell-Free System; D002478:Cells, Cultured; D004167:Diphtheria Toxin / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D012867:Skin / Q000166:cytology; D014407:Tumor Cells, Cultured / Q000166:cytology* / Q000187:drug effects
D004167:Diphtheria Toxin; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D000246:Adenosine Diphosphate Ribose