Dissecting the transcriptional activation function of the cell wall integrity MAP kinase.
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.
Kim
Ki-Young
KY
Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
Cosano
Inmaculada C
IC
Levin
David E
DE
Molina
María
M
Martín
Humberto
H
D000595:Amino Acid Sequence; D002473:Cell Wall / Q000502:physiology*; D004268:DNA-Binding Proteins; D015966:Gene Expression Regulation, Fungal; D018869:Heat-Shock Response; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C052130:GAL4 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae