Cloning and characterization of 4EHP, a novel mammalian eIF4E-related cap-binding protein

J Biol Chem. 1998 May 22;273(21):13104-9. doi: 10.1074/jbc.273.21.13104.


All eukaryotic mRNAs (except organellar) are capped at their 5' end. The cap structure (m7GpppN, where N is any nucleotide) is extremely important for the processing and translation of mRNA. Several cap-binding proteins that facilitate these processes have been characterized. Here we describe a novel human cytoplasmic protein that is 30% identical and 60% similar to the human translation initiation factor 4E (eIF4E). We demonstrate that this protein, named 4E Homologous Protein (4EHP), binds specifically to capped RNA in an ATP- and divalent ion-independent manner. The three-dimensional structure of 4EHP, as predicted by homology modeling, closely resembles that of eIF4E and site-directed mutagenesis analysis of 4EHP strongly suggests that it shares with eIF4E a common mechanism for cap binding. A putative function for 4EHP is discussed.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cloning, Molecular
  • DNA, Complementary
  • Eukaryotic Initiation Factor-4E
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Peptide Initiation Factors / metabolism*
  • RNA Cap-Binding Proteins
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Subcellular Fractions / metabolism


  • DNA, Complementary
  • EIF4E2 protein, human
  • Eukaryotic Initiation Factor-4E
  • Peptide Initiation Factors
  • RNA Cap-Binding Proteins
  • RNA-Binding Proteins

Associated data

  • GENBANK/AF047695