Catalyzes the exchange of eukaryotic initiation factor 2-bound GDP for GTP. Complex of five different subunits; alpha, beta, gamma, delta and epsilon. Interacts with RGS2. Phosphorylated at Ser-544 by DYRK2; this is required for subsequent phosphorylation by GSK3B (By similarity). Phosphorylated on serine and threonine residues by GSK3B; phosphorylation inhibits its function. Polyubiquitinated, probably by NEDD4. The disease is caused by variants affecting the gene represented in this entry. Belongs to the eIF-2B gamma/epsilon subunits family. Leiden Open Variation Database (LOVD)