(A) Kd measurements from eIF2-TC formation assays shown in Figure 4—source data 1. Experiments were performed as in Figure 2A.±20 nM eIF2B ±20 nM eIF5, eIF5-NTD or eIF5-CTD. (B). As panel A except ±5 nM or 20 nM of full eIF2B complex, eIF2Bγε subcomplexes or eIF2B epsilon alone. (C). Left, Serial dilution growth assay of gcn2∆ yeast cells bearing multi-copy plasmids overexpressing the indicated combination of tRNAi (IMT4) and eIF2Bε (GCD6), eIF2Bγ (GCD1), eIF5 (TIF5) or eIF2Bεγ (GCD6 + GCD1) grown on minimal and 3AT medium. Right, Western blot of strains used confirming overexpression of indicated proteins. (D). Model showing eIF2Bε antagonism of TC/eIF5 and TC. **p<0.01, ***p<0.001, NS non-significant (p≥0.05), two-tailed T-test.