Dissecting the transcriptional activation function of the cell wall integrity MAP kinase

Abstract

The cell wall integrity signalling MAP kinase of Saccharomyces cerevisiae, Slt2p/ Mpk1p, is activated in response to cell wall stress. Slt2 and its mammalian orthologue ERK5 are unusual among MAP kinases, in that they possess the ability to activate transcription of a GAL1-lacZ reporter when fused to the DNA-binding domain of the Gal4 transcription factor. In this study, we demonstrate that transcriptional activation of a Gal4-Slt2p fusion is responsive to cell wall stress and requires phosphorylation of Slt2p. We identify two neighbouring but separable transcription activation domains within the C-terminal half of Slt2p. Additionally, we present data suggesting that intramolecular interactions controlled by phosphorylation of Slt2p regulate the function of these domains, which are masked by the N-terminal catalytic domain under inactive conditions. Finally, we demonstrate that Slt2p self-associates, probably through a glutamine-rich region within the C-terminal half of the protein.

Flocculation of Saccharomyces cerevisiae is dependent on activation of Slt2 and Rlm1 regulated by the cell wall integrity pathway

“…Further, we found that most of the flocculating sen1 mutants ( sen1‐1 , sen1 ∆N and sen1‐K128E ) display cell wall defects (Fig. D) which attribute to a deficiency in cell wall construction (Kim et al , ). As predicted, same pattern of sensitivity toward cell wall damaging agents was observed in the flocculating nrd1‐102 , nab3‐11 and rnt1Δ cells (Fig.…”

Distinct Docking Mechanisms Mediate Interactions between the Msg5 Phosphatase and Mating or Cell Integrity Mitogen-activated Protein Kinases (MAPKs) in Saccharomyces cerevisiae

“…Because Slt2 has been shown to dimerize (39), we wanted to rule out the possibility that the effect of Msg5 on Slt2(1–373) phosphorylation was facilitated by binding to endogenous full-length Slt2 protein. To this end, recombinant GST-Msg5 and both full-length Slt2 and Slt2(1–373) tagged in the N terminus with a poly-His epitope were produced in E. coli and tested for in vitro interaction by a pull-down assays.…”

Differences in activation of MAP kinases and variability in the polyglutamine tract of Slt2 in clinical and non‐clinical isolates of Saccharomyces cerevisiae

“…Such diversification could be relatively rapid on an evolutionary time scale, due to the high mutation rates of microsatellites, which is congruent with the overrepresentation of transcription factors containing trinucleotide repeats among fast‐evolving hemiascomycete‐specific genes (Malpertuy et al 2003). Slt2 is a protein kinase but it has also been shown to possess a transcriptional activation domain within the glutamine‐rich region previous to the poli‐Q tract (Kim et al , 2007). Recently, Sampaio et al (2009) has described a polymorphic microsatellite encoding a poly‐Q stretch within the Candida albicans RLM1 gene, which encodes a transcription factor from the MADS box family whose orthologue in S. cerevisiae mediates CWI pathway‐dependent gene expression.…”