Enables translation initiation factor binding activity. Contributes to guanyl-nucleotide exchange factor activity. Involved in several processes, including hippocampus development; response to glucose; and response to lithium ion. Part of eukaryotic translation initiation factor 2B complex. Human ortholog(s) of this gene implicated in leukoencephalopathy with vanishing white matter. Orthologous to human EIF2B5 (eukaryotic translation initiation factor 2B subunit epsilon). [provided by Alliance of Genome Resources, Apr 2022]