The two-component sensor kinase TcsC and its role in stress resistance of the human-pathogenic mold Aspergillus fumigatus.
Two-component signaling systems are widespread in bacteria, but also found in fungi. In this study, we have characterized TcsC, the only Group III two-component sensor kinase of Aspergillus fumigatus. TcsC is required for growth under hyperosmotic stress, but dispensable for normal growth, sporulation and conidial viability. A characteristic feature of the ΔtcsC mutant is its resistance to certain fungicides, like fludioxonil. Both hyperosmotic stress and treatment with fludioxonil result in a TcsC-dependent phosphorylation of SakA, the final MAP kinase in the high osmolarity glycerol (HOG) pathway, confirming a role for TcsC in this signaling pathway. In wild type cells fludioxonil induces a TcsC-dependent swelling and a complete, but reversible block of growth and cytokinesis. Several types of stress, such as hypoxia, exposure to farnesol or elevated concentrations of certain divalent cations, trigger a differentiation in A. fumigatus toward a "fluffy" growth phenotype resulting in white, dome-shaped colonies. The ΔtcsC mutant is clearly more susceptible to these morphogenetic changes suggesting that TcsC normally antagonizes this process. Although TcsC plays a role in the adaptation of A. fumigatus to hypoxia, it seems to be dispensable for virulence.
Max-von-Pettenkofer-Institut, Ludwig-Maximilians-University, Munich, Germany.
Allison
A
McCormick
Ilse D
ID
Jacobsen
Marzena
M
Broniszewska
Julia
J
Beck
Jürgen
J
Heesemann
Frank
F
Ebel
D000818:Animals; D001228:Aspergillosis / Q000382:microbiology / Q000473:pathology; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D000242:Cyclic AMP / Q000494:pharmacology; D004149:Dioxoles / Q000494:pharmacology; D025141:Drug Resistance, Fungal / Q000187:drug effects / Q000528:radiation effects; D005656:Fungal Proteins / Q000378:metabolism*; D005659:Fungicides, Industrial / Q000494:pharmacology; D000071677:Histidine Kinase; D006801:Humans; D016867:Immunocompromised Host; D008027:Light; D051379:Mice; D008826:Microbial Sensitivity Tests; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D011494:Protein Kinases / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D013312:Stress, Physiological / Q000187:drug effects / Q000528:radiation effects; D014774:Virulence / Q000187:drug effects / Q000528:radiation effects
D004149:Dioxoles; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D011758:Pyrroles; D000242:Cyclic AMP; D011494:Protein Kinases; D000071677:Histidine Kinase; C108339:fludioxonil