Phosphorylation of elongation factor 2 during Ca(2+)-mediated secretion from rat parotid acini

Biochem J. 1992 Mar 15;282 ( Pt 3)(Pt 3):877-82. doi: 10.1042/bj2820877.


In this paper we report the rapid phosphorylation of a cytosolic 100 kDa protein during stimulation of secretion from dispersed aggregates of parotid acinar cells with Ca(2+)-mobilizing secretagogues (carbachol, Substance P, ATP and the Ca2+ ionophore A23187). Phosphorylation was inhibited by removal of extracellular Ca2+ but was not observed during stimulation with phorbol esters, suggesting that this protein is not a substrate for protein kinase C. Two-dimensional PAGE and immunoprecipitation with a specific antiserum indicated that this protein is elongation factor 2, whose Ca2+ calmodulin-dependent phosphorylation has been shown to inhibit protein synthesis [Nairn & Palfrey (1987) J. Biol. Chem. 262, 17299-17303]. These results suggest that phosphorylation of elongation factor 2 is the molecular mechanism for the inhibition of protein synthesis which has been previously observed in rat parotid cells during stimulation with Ca(2+)-mobilizing secretagogues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Autoradiography
  • Calcimycin / pharmacology
  • Calcium / metabolism
  • Calcium / physiology*
  • Carbachol / pharmacology
  • Kinetics
  • Male
  • Parotid Gland / drug effects
  • Parotid Gland / metabolism*
  • Peptide Elongation Factor 2
  • Peptide Elongation Factors / metabolism*
  • Phosphorylation
  • Rats
  • Rats, Inbred Strains
  • Stimulation, Chemical
  • Substance P / pharmacology


  • Peptide Elongation Factor 2
  • Peptide Elongation Factors
  • Substance P
  • Calcimycin
  • Adenosine Triphosphate
  • Carbachol
  • Calcium