FIGURE 8.

Model depicting proposed transcriptional regulation and translational control of ATF4 expression and the ISR. The y axis represents the levels of mRNA translation in stressed cells compared with non-stressed, whereas the x axis represents changes in transcript levels of a given gene in stressed cells relative to non-stressed. The diagonal line represents the levels of transcription and translation that are proposed to yield no change in ATF4 protein levels. The black gradient depicts the levels of transcriptional regulation and translational control that would enhance ATF4 protein levels and induce its target ISR genes. The solid circles represent the outcome of the transcriptional regulation and translational control of ATF4 in response to UV irradiation (UV) or ER stress elicited by TG treatment.