Phosphorylation of the p220 subunit of eIF-4F by cAMP dependent protein kinase and protein kinase C in vitro

Biochem Biophys Res Commun. 1988 Jun 30;153(3):925-32. doi: 10.1016/s0006-291x(88)81316-0.

Abstract

Changes in the extent of phosphorylation of the 25 kDa subunit of eIF-4F occur during several major biological events including mitosis and heat shock in mammalian cells and shortly after fertilization of sea urchin (Lytechinus pictus) eggs. In vitro phosphorylation studies using highly purified protein kinases demonstrated that the 220 kDa subunit of eIF-4F was phosphorylated by cAMP dependent protein kinase, protein kinase C and probably to a lesser extent by cGMP dependent protein kinase. In addition, eIF-4A was readily phosphorylated by cAMP and cGMP dependent protein kinases whereas p48 of eIF-4F was not. The effect of these phosphorylation events on eIF-4F function, its assembly or disassembly, susceptibility to viral initiated proteolysis or the ability of p25 to be phosphorylated at serine-53 remain to be investigated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Cyclic GMP / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Eukaryotic Initiation Factor-4F
  • Guanosine Triphosphate / metabolism
  • Kinetics
  • Molecular Weight
  • Peptide Initiation Factors / metabolism*
  • Phosphorylation
  • Protein Kinase C / metabolism*
  • Protein Kinases / metabolism*
  • Rabbits

Substances

  • Eukaryotic Initiation Factor-4F
  • Peptide Initiation Factors
  • Guanosine Triphosphate
  • Adenosine Triphosphate
  • Protein Kinases
  • Protein Kinase C
  • Cyclic GMP