WB (peptide competition) analysis of recombinant eIF2B epsilon treated with lambda phosphatase (Lane 1) or GSK-3beta (Lane 2-5) using GTX24775 EIF2B epsilon (phospho Ser539) antibody prior incubated with the non-phosphopeptide corresponding to the phosphopeptide immunogen (Lane 3), a generic phosphoserine-containing peptide (Lane 4), or the phosphopeptide immunogen (Lane 5). The data show that only the immunogen phosphopeptide blocks the signal, demonstrating the specificity of the antibody.