Regulation of protein synthesis by heme-regulated eIF-2 alpha kinase

Trends Biochem Sci. 1995 Mar;20(3):105-8. doi: 10.1016/s0968-0004(00)88975-6.

Abstract

Protein synthesis is regulated by the phosphorylation of the alpha-subunit of eukaryotic initiation factor 2 (eIF-2 alpha) in a variety of cells. At present, there are two distinct mammalian eIF-2 alpha kinases that have been cloned, the double-stranded-RNA-dependent eIF-2 alpha kinase (PKR) and the heme-regulated eIF-2 alpha kinase (HRI). HRI is activated under conditions of heme deficiency in immature erythroid cells, and its activity is inhibited by heme. The high levels of HRI in reticulocytes indicate that its major physiological role is the regulation of protein synthesis, particularly of hemoglobin, according to the concentration of heme in these cells.

Publication types

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

MeSH terms

  • Animals
  • Heat-Shock Proteins / metabolism
  • Heme / metabolism*
  • Humans
  • Protein Biosynthesis*
  • Protein Conformation
  • Protein Serine-Threonine Kinases / chemistry
  • Protein Serine-Threonine Kinases / metabolism*
  • eIF-2 Kinase

Substances

  • Heat-Shock Proteins
  • Heme
  • Protein Serine-Threonine Kinases
  • eIF-2 Kinase