FIG. 2.

Hyperosmotic stress response in S. cerevisiae and S. pombe. Response to hyperosmolarity is mediated by the HOG pathway in S. cerevisiae (left) and by the Sty pathway in S. pombe (right). Ptp2 is a phosphatase involved in down regulation of Hog1. Pyp2 is a phosphatase involved in down regulation of Sty1. Arrows indicate activation; lines with bars indicate inhibition. The dashed rectangle around Ypd1 indicates that the protein is present but not phosphorylated (see Fig. 5). See the text for details.