Genetic Involvement of a cAMP-Dependent Protein Kinase in a G Protein Signaling Pathway Regulating Morphological and Chemical Transitions in Aspergillus nidulans

摘要: In the filamentous fungus Aspergillus nidulans, a heterotrimeric G protein alpha-subunit and an RGS domain protein, encoded by fadA flbA, respectively, regulate production of carcinogenic metabolite sterigmatocystin (ST) asexual spores (i.e., conidia). We investigated genetic involvement cAMP-dependent kinase catalytic subunit (PkaA), potential downstream target FadA activity, in ST conidiation. Relative to wild type, sporulation was decreased pkaA overexpression strain but not totally absent, as occurs DeltaflbA or fadA(G42R) (fadA-dominant active) strains. Deletion resulted hyper-conidiating with limited radial growth. This phenotype epistatic mutation flbA fadA; double mutants DeltapkaA; recovered their growth severely restricted. PkaA also negatively regulated AflR, biosynthesis-specific transcription factor, both transcriptionally post-transcriptionally. restored background background. These data provide evidence that FlbA/FadA signaling pathway regulating morphological development is partially mediated through PkaA.