Molecular Insights into Pathogenesis and Infection with Aspergillus Fumigatus.

The virulence of fungi is dependent on multiple factors, including the immune status of patients and biological features of fungi. In particular, the virulence of Aspergillus fumigatus is due to the complex interaction among various molecules involved in thermotolerance (such as ribosomal biogenesis proteins, α-mannosyltransferase and heat shock proteins), pigment production (DHN-melanin), immune evasion (like melanin and hydrophobin) and nutrient uptake (such as siderophores and zinc transporters). Other molecules also play important roles in the virulence of A. fumigatus, including cell wall components and those which maintain its integrity (for instance β-1-3 glucan, α-1-3 glucan, chitin, galactomannan and mannoproteins) and adhesion (such as hydrophobins), as well as various hydrolytic enzymes (such as serine and aspartic protease, phospholipases, metalloproteinase and dipeptidyl peptidases). Signalling molecules (including G-protein, cAMP, Ras protein and calcineurin) also increase the virulence through altering the metabolic response to stress conditions and toxins (such as gliotoxin, fumitremorgins, fumagatin and helvolic acid).