FIG. 1.

Slt2 phosphorylation indicated CWI pathway activation in cells lacking Isw2. Protein extracts were prepared from the wild-type strain and strains deleted for the ISW2 gene cultivated overnight in YPD medium. Phosphorylated Slt2 (Phospho-Slt2) was detected by the anti-phospho-p44/42 MAPK antibody (top panels). After stripping, we used the specific anti-Mpk1 antibody to quantify the amount of Slt2 protein (bottom panels). (A) The isw2Δ MATa (isw2Δa), isw2Δ MATα (isw2Δα), and isw2Δ ste4Δ MATα (isw2Δste4Δα) strains (strains CRY3, CRY4, and CRY146) displayed increased Slt2 phosphorylation in comparison with that of the wild-type strain (BY4741). (B) In contrast to deletions of the CHS1 and CTS1 genes (isw2Δchs1Δa and isw2Δcts1Δa; strains CRY900 and CRY902), deletion of the DSE1 gene (isw2Δdse1Δa; strain CRY671) lowered the level of Slt2 phosphorylation in the isw2Δ background.