Amino acid acquisition, cross-pathway control, and virulence in Aspergillus.

Supply of all amino acids required for translation is crucial for the synthesis of new proteins. Fungal amino acid biosynthesis has to be coordinated with amino acid uptake as well as protein degradation. A global regulator that connects amino acid biosynthesis and developmental programs is the transcription factor CpcA/Gcn4p. This transcriptional activator is conserved within the fungal kingdom and the cellular levels of this protein are carefully regulated. Deletion of the encoding cpcA gene in the opportunistic pathogen Aspergillus fumigatus results in impaired virulence in immuno-compromised mice, suggesting a role of the cross-pathway control system in fungal pathogenicity.