Eukaryotic Translation Initiation Factor 2B2 (EIF2B2)

Eukaryotic initiation factor-2B (EIF2B) is a GTP exchange protein essential for protein synthesis. It consists of alpha (EIF2B1), beta (EIF2B2), gamma (EIF2B3), delta (EIF2B4), and epsilon (EIF2B5) subunits. EIF2B activates its EIF2 substrate by exchanging EIF2-bound GDP for GTP.Fogli et al. (2004) measured the guanine nucleotide exchange factor (GEF) activity of EIF2B in transformed lymphocytes from 30 patients with leukoencephalopathies with homozygous or compound heterozygous mutations in EIF2B2, EIF2B3, EIF2B4, and EIF2B5 compared to 10 unaffected heterozygotes and 22 controls with no EIF2B mutation. A significant decrease of 20 to 70% in GEF activity was observed in all mutated cells, and the extent of the decrease correlated with age at onset of disease.