Activation of Slt2 MAP kinase by genotoxic stress. Exponentially growing cultures of the wild type W303-1a and SEY6211 strains were split and incubated for 60 min in the absence or presence of 200 mM hydroxyurea, 0.04% MMS, 5 and 10 μg/mL phleomycin, or were irradiated with different doses of UV radiation as indicated. Cultures of the GAL1:HO (JKM139) mutant strain grown on rafinose were split and incubated for 4 hours after the addition of glucose or galactose up to 2%. The level of Slt2 phosphorylated in the activation loop and total Slt2 protein in cell extracts was determined by western analysis. Analysis of chekpoint kinase Rad53 activation is shown as a control of the presence of genotoxic stress. Ponceau staining of the membranes are shown as loading control.