EIF2B1 is one of five subunits of eukaryotic translation initiation factor 2B (EIF2B), a GTP exchange factor for eukaryotic initiation factor 2 and an essential regulator for protein synthesis. Phosphorylation of eIF2 inhibits GEF activity of EIF2B, an inhibition that requires the eIF2B1 subunit. Defects in eIF2B1 are a cause of leukoencephalopathy with vanishing white matter (VWM), a brain disease that is characterized by head trauma and motor deterioration