The transcription factor Rap1p is required for tolerance to cell-wall perturbing agents and for cell-wall maintenance in Saccharomyces cerevisiae

Yeast repressor activator protein (Rap1p) is involved in genomic stability and transcriptional regulation. We explored the function of Rap1p in yeast physiology using Rap1p truncation mutants. Our results revealed that the N-terminal truncation of Rap1p (Rap1 Delta N) leads to hypersensitivity towards elevated temperature and cell-wall perturbing agents. Cell wall analysis showed an increase in the chitin and glucan content in Rap1 Delta N cells as compared with wild type cells. Accordingly, mutant cells had a twofold thicker cell wall, as observed by electron microscopy. Furthermore, Rap1 Delta N cells had increased levels of phosphorylated Slt2p, a MAP kinase of the cell wall integrity pathway. Mutant cells also had elevated levels of cell wall integrity response transcripts. Taken together, our findings suggest a connection between Rap1p and cell wall homeostasis. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.