When budding yeast is confronted with high salt concentrations, a complex signaling network helps it to adapt and so ultimately survive. It was discovered that the protein phosphatase PP2A-Cdc55 is involved in modulating the timing and duration of the necessary cellular responses. “Our question was where in the network the function of this enzyme was required” explains Wolfgang Reiter, first author of the paper. “What we found is that the loss of the phosphatase perturbs the behavior and function of the main stress specific transcription factor at multiple levels without using it as a substrate. This again shows that the primary suspect is not necessarily the correct one if investigated thoroughly enough”.
No breakthrough for years
First experiments to establish the role of PP2A-Cdc55 in stress response were performed more than ten years ago, when the project was taken over from the group of Helmut Ruis, one of the founding fathers of the Campus Vienna Biocenter. The experiments came to a halt when necessary methods were not available. “It really bugged me at that time, that we didn’t finish the work”, he says. “A couple of years later new technologies had emerged and also mass spectrometry had developed further, sowe could continue the project were we left it off.” In the end this project was a collaborative effort of many people including the Schüller and Brocard lab as well as the mass spec facility of the University of Vienna and also the group of Karl Mechtler at the IMP.. “I am really happy that we finished the study in the end, as a lot of work by many people went into it.”
Reiter W, Klopf E, De Wever V, Anrather D, Petryshyn A, Roetzer A, Niederacher G, Roitinger E, Dohnal I, Görner W, Mechtler K, Brocard C, Schüller C & Ammerer G (2012). The yeast PP2A-Cdc55 phosphatase regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4 chromatin recruitment. Mol Cell Biol, epub ahead of print.