Phosphoproteomics of Aspergillus fumigatus exposed to the antifungal drug caspofungin, Supplementary files

Aspergillus fumigatus is an opportunistic and allergenic pathogenic fungus,
responsible for fungal infections in humans. A.
fumigatus infections are usually treated with polyenes, azoles, or
echinocandins. Echinocandins, such as caspofungin, can inhibit the biosynthesis
of the β-1,3-glucan polysaccharide, affecting the cell wall integrity and
leading to fungal death. In some A.
fumigatus strains, caspofungin treatment at high concentrations
induces an increase of fungal growth, a phenomenon called Caspofungin
Paradoxical Effect (CPE). Here, we analyze the proteome and phosphoproteome of A. fumigatus wild-type and
the mitogen-activated protein kinases mpkA
and sakA null
mutant strains during CPE (2 µg/ml caspofungin for 1 hour). The wild-type
proteome shows 75 proteins and 814 phosphopeptides (corresponding to 520
proteins) altered in abundance in response to caspofungin treatment. The ΔmpkA (ΔmpkA caspofungin/wild-type
caspofungin) and ΔsakA
(ΔsakA caspofungin/wild-type
caspofungin) display 626 proteins and 1236 phosphopeptides (corresponding to
703 proteins) and 101 proteins and 1217 phosphopeptides (corresponding to 645
proteins), respectively, altered in abundance. Functional characterization of the
phosphopeptides from the wild-type exposed to caspofungin show enrichment for
transcription factors, protein kinases, and cytoskeleton proteins. Proteomic
analysis for the ΔmpkA and
ΔsakA mutants
indicates that the control of proteins involved in metabolism, such as in
secondary metabolites production, was highly represented in both mutants.
Functional categorization of phosphopeptides from both mutants is very similar,
and show a high number of proteins with decreased phosphorylation of proteins
involved in transcriptional control, DNA/RNA binding, cell cycle control, and
DNA processing. This study reveals novel transcription factors involved in
caspofungin tolerance.