FIG. 5.

Schematic illustration of Hog1-mediated posttranslational and transcriptional hyperosmotic stress response pathway. At low stress levels, activated Hog1 posttranslationally alters the activities of a suite of enzymes involved in glycerol metabolism (Pfk2, Tdh, Gpd1, Fps1, etc.), resulting in increased production and decreased exportation of intracellular glycerol. At high stress levels, Hog1 activates transcription factor Hot1, which transcriptionally regulates the expression of the enzymes above, resulting in alterations in their abundance, which helps increase intracellular glycerol concentration on a longer time scale. Denotations of line colors: blue, posttranslational control; red, transcriptional control; green, common pathway shared by both posttranslational and transcriptional control. Denotations of colored arrow heads: pointed, activation; blunted, inhibition; dotted, activation or inhibition depending on target.