The Aspergillus fumigatus SchASCH9 kinase modulates SakAHOG1 MAP kinase activity and it is essential for virulence

What is it about?

The serine-threonine kinase TOR, the Target of Rapamycin, is an important regulator of nutrient, energy, and stress signaling in eukaryotes. Sch9, a Ser/Thr kinase of AGC family (the cAMP-dependent PKA, cGMP- dependent protein kinase G and phospholipid-dependent protein kinase C family), is a substrate of TOR. Here, we characterized the fungal opportunistic pathogen Aspergillus fumigatus Sch9 homologue (SchA). The schA null mutant was sensitive to rapamycin, high concentrations of calcium, hyperosmotic stress, and SchA was involved in iron metabolism. Transcriptomics and proteomics identified direct and indirect targets of SchA post-exposure to hyperosmotic stress. The schA null mutant showed increased phosphorylation of SakA, the A. fumigatus Hog1 homologue. Finally, ΔschA was avirulent in a low dose murine infection model. Our results suggest that a complex network of interactions amongst the A. fumigatus TOR, SakA and SchA pathways.

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