Figure 3.

Effect of S. pombe eIF2α Phosphorylation Pathway Mutations on Protein Synthesis and Cell Survival

(A) WT, eIF2α^S52A, and Δhri1 Δhri2 Δgcn2 strains of S. pombe were treated with 1 mM H₂O₂ for 15 min and [³⁵S]-methionine was added for the next 45 min. Total protein was isolated and separated by SDS-PAGE, and protein synthesis was detected by film autoradiography (top panel). The same lysates were analyzed by immunoblotting for eIF2α phosphorylation. Signals for Cdc2p are shown for reference.

(B) The same lysates as described in (A) were TCA precipitated, and [³⁵S]-methionine incorporation was quantified by scintillation counting.

(C) Sensitivity of WT, eIF2α^S52A, Δhri1 Δhri2 Δgcn2, and Δsty1 strains to H₂O₂ was assessed by spotting 5-fold serial dilutions on plates containing 1 mM H₂O₂.

See Figure S3.