Rck1 and Rck2 MAPKAP kinases and the HOG pathway are required for oxidative
stress resistance
Elizabeth Bilsland, Claes Molin, Swarna Swaminathan, Anna Ramne‡,
and Per Sunnerhagen
Department of Cell and Molecular Biology, Lundberg Laboratory, Göteborg
University P.O. Box 462 SE-405 30 Göteborg, Sweden
‡ Present address: Arexis AB Arvid Wallgrens
backe, SE-413 46 Göteborg, Sweden
We demonstrate a role in oxidative and metal stress resistance for the MAPK-activated
protein kinases Rck1 and Rck2 in Saccharomyces cerevisiae. We show
that Hog1 is robustly phosphorylated in a Pbs2-dependent way during oxidative
stress, and that Rck2 also is phosphorylated under these circumstances. Hog1
concentrates in the nucleus in oxidative stress. Hog1 localisation is partially
dependent on Rck2, as rck2 cells have more nuclear Hog1 than wild-type
cells. We find several proteins with a role in oxidative stress resistance
using Rck1 or Rck2 as baits in a two-hybrid screen. We identify the transcription
factor Yap2 as a putative target for Rck1, and the Zn2+ transporter
Zrc1 as a target for Rck2. Yap2 is normally cytoplasmic, but rapidly migrates
to the nucleus upon exposure to oxidative stress agents. In a fraction of
untreated pbs2 cells, Yap2 is nuclear. Zrc1 co-immunoprecipitates
with Rck2, and ZRC1 is genetically downstream of RCK2. These
data connect activation of the Hog1 MAPK cascade with effectors having a
role in oxidative stress resistance.