Stress-activated protein kinase pathways in Saccharomyces. The HOG1 MAPK pathway is controlled by two separate osmosensors, SLN1 and SHO1. Sln1 is activated in low osmolarity, thus repressing Ssk1 by phosphorylating it. Ssk1 is in charge of activating Ssk2/22 which in turn activates Pbs2 and in turn activates Hog1. SHO1 is activated during high osmolarity, resulting in Ste11 being activated, which in turn activates Pbs2 and activates Hog1. Ptp2 and Ptp3 negatively regulates Hog1.

Stress-Activated Signalling Pathways: Low Osmolarity References