The cta3(+) gene that encodes a cation-transporting P-type ATPase is induced by salt stress under control of the Wis1-Sty1 MAPKK-MAPK cascade in fission yeast

In Schizosaccharomyces pombe, the Wis1-Sty1 MAP (mitogen-activated protein) kinase signaling cascade is known to play a major role in cellular adaptat ion to adverse external stimuli, including osmotic stress, oxidative stress , nutrient deprivation, DNA-damaging agents, and heat stress, Nonetheless, it is not known whether or not this particular MAPK cascade is also involve d in response to the most common stress, salinity, In this study, we provid e evidence that the Wis1-Sty1 MAP cascade is implicated in salt stress resp onse through regulating expression of a salinity-inducible gene, The downst ream target gene thus identified is the cta3(+) gene, which encodes a catio n-transporting P-type ATPase, The salt stress-responsive nature of cta3(+) expression was characterized extensively, It was found that not only the St y1 MAP kinase but also the Atf1 transcription factor is crucial for the ind ucible expression of cta3(+). As far as we know, this is the first instance that the stress-activated Wis1-Sty1 MAPK cascade plays a role in salt stre ss response in S. pombe. (C) 1999 Federation of European Biochemical Societ ies.