EUKARYOTIC INITIATION-FACTOR 2B (EIF2B)

Eukaryotic initiation factor 2B (eIF2B) is a guanine nucleotide-exchan ge factor which mediates the exchange of GDP (bound to initiation fact or eIF2) for GTP, thus regenerating the active [eIF2.GTP] complex that is required for peptide-chain initiation. The activity of eIF2B is a key control point for eukaryotic protein synthesis and is altered in r esponse to viral infection, hormones, nutrients, growth factors and ce rtain stresses. It may be regulated directly by its own phosphorylatio n, phosphorylation of its substrate, eIF2 and by allosteric effecters. Understanding its regulation will lead to a better knowledge of insul in action, regulation of the immune system and of insulin production i n the pancreas. (C) 1997 Elsevier Science Ltd.