Enables GDP binding activity; GTP binding activity; and translation initiation factor activity. Contributes to guanyl-nucleotide exchange factor activity. Involved in several processes, including negative regulation of guanyl-nucleotide exchange factor activity; response to amino acid starvation; and translational initiation. Part of eukaryotic translation initiation factor 2 complex and eukaryotic translation initiation factor 2B complex. Human ortholog(s) of this gene implicated in leukoencephalopathy with vanishing white matter. Orthologous to human EIF2B1 (eukaryotic translation initiation factor 2B subunit alpha). [provided by Alliance of Genome Resources, Apr 2022]