FIGURE 4.

Sty1 is activated during the 3AT-induced starvation response. A, haploid S. pombe strains KAY641 (row 1), KAY647 (row 2), KAY640 (row 3), KAY645 (row 4), KAY456 (row 5), KAY508 (row 6), KAY464 (row 7), KAY484 (row 8), KAY584 (row 9), KAY569 (row 10), and KAY606 (row 11) carrying the indicated mutations were spotted onto EMM-C medium with (+) or without (-) 10 mm 3AT as described in legend to Fig. 1A. B, KAY655 (sty1-His₆HA int6⁺) and KAY658 (sty1–6hisHA int6Δ) were treated with 30 mm 3AT or 1 mm H₂O₂ for the indicated times and used to prepare WCE. Western blots of the WCE were probed using anti-phospho-p38 antibodies. The blot was then stripped and probed with anti-HA antibodies to detect total levels of Sty1 protein. The graphs at the bottom indicate the time course of Sty1 activation in wild-type (int6⁺) and int6Δ cells. The relative reactivities against anti-phospho p38 antibodies compared with the value at time 0 were measured by NIH Image and plotted against time. Bars indicate standard deviations (n = 6 for int6⁺; n = 3 for int6Δ).