Figure 3. Hog1 proteins lacking the C-terminal tail are capable of partially rescuing pbs2Δ cells of osmostress.

A. Phosphorylation levels of wild type Hog1 (Hog1^WT) and of the truncated Hog1 proteins, Hog1^A366, Hog1^S356 and Hog1^F343 were tested when expressed in hog1Δ cells, before (−) and 10 minutes after (+) exposure to 1 M NaCl. B. hog1Δ cells harboring an empty vector (negative control), or vectors expressing Hog1^WT, or the truncated Hog1 proteins Hog1^A366, Hog1^S356 or Hog1^F343 were plated in five dilutions on plates containing YPD supplemented with 1 M NaCl. All strains were also plated on medium with no NaCl and all grew equally well on these plates (not shown). C. hog1Δpbs2Δ cells harboring same vectors as in panel B were plated in five dilutions on plates containing YPD supplemented with 0.8 M NaCl. Growth of cells expressing an intrinsically active Hog1 variant (Hog1^D170A) served as a positive control. All strains were also plated on medium with no NaCl and all grew equally well on these plates (not shown). D. Phosphorylation levels of the indicated Hog1 proteins were tested as in panel A, but when expressed in hog1Δpbs2Δ cells. Phosphorylation level of Hog1^WT, expressed in hog1Δ strain is presented for comparison (right lanes).