"To evaluate whether either GCN-2 or PEK-1 kinases are required for H2S-dependent phosphorylation of eIF2α, we introduced
gcn-2(
ok886) or
pek-1(
ok275) deletion alleles into
sqrd-1(
tm3378) mutant animals. When exposed to H2S, we observed robust phosphorylation of eIF2α in both
pek-1;
sqrd-1 and
gcn-2;
sqrd-1 double mutant animals (Fig. 3, A and B). This result suggests that either these kinases act redundantly to phosphorylate eIF2α in H2S, or that neither of these eIF2α kinases are involved in this response to H2S. To distinguish these possibilities, we generated
pek-1;
gcn-2;
sqrd-1 triple mutant animals. H2S-dependent phosphorylation of eIF2α was abrogated in these animals (Fig. 3, A and B). We conclude that both PEK-1 and GCN-2 phosphorylate eIF2α when
sqrd-1 animals are exposed to H2S."