PKA and MAPK phosphorylation of Prf1 allows promoter discrimination in Ustilago maydis.
Mating in Ustilago maydis requires cross-talk between cAMP and mitogen-activated protein kinase (MAPK) signalling. During this process, pheromone response factor 1 (Prf1) activates transcription of a and b mating type genes by binding to pheromone response elements (PREs) located in regulatory regions of these genes. Here, we show that PREs are also necessary and sufficient to mediate cAMP-induced gene expression. Prf1 interacts with cAMP-dependent protein kinase A (PKA) Adr1 as well as MAPK Kpp2 in vivo, and its central phosphorylation sites that are functionally important are modified by the respective kinases in vitro. PKA sites in Prf1 are essential for induced expression of a and b mating type genes. In contrast, MAPK sites are not required for pheromone-induced expression of a genes but are crucial for pheromone-responsive b gene expression. This illustrates how a single transcription factor can integrate signals from two pathways and how its phosphorylation status can determine different transcriptional responses.
Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
Florian
F
Kaffarnik
Philip
P
Müller
Marc
M
Leibundgut
Regine
R
Kahmann
Michael
M
Feldbrügge
D001665:Binding Sites; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D006609:High Mobility Group Proteins / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D010675:Pheromones / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014588:Ustilago / Q000235:genetics* / Q000378:metabolism*
D005656:Fungal Proteins; D006609:High Mobility Group Proteins; D010675:Pheromones; D010940:Plant Proteins; D014157:Transcription Factors; C121065:pheromone response factor 1, Ustilago maydis; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases