FIG. 2.
Cell-permeable phosphatase inhibitors increase eIF-2α phosphorylation. (A) eIF-2α phosphorylation was increased by treatment of HEK293T cells for 30 min with increasing concentrations of OA. FLAG-GADD34 expression attenuated the eIF-2α phosphorylation elicited by all concentrations of OA. (B) Treatment of HEK293T cells for 30 min with increasing concentrations of CA also promoted eIF-2α phosphorylation. However, FLAG-GADD34 expression failed to reverse eIF-2α phosphorylation induced by the presence of CA at concentrations above 100 nM. (C) Representative dose-response curves for OA (circles)- and CA (squares)-induced eIF-2α phosphorylation in the presence (open shapes) and absence (filled shapes) of GADD34 expression are shown. eIF-2α phosphorylation, monitored by laser densitometry analysis of anti-phosphoserine-51-eIF-2α antibody immunoblots, is expressed as a percentage of maximum response.