Melanin and pyomelanin in Aspergillus fumigatus: from its genetics to host interaction

• Published in: International microbiology Vol. 23; no. 1; pp. 55 - 63
• Main Authors: Perez-Cuesta, U., Aparicio-Fernandez, L., Guruceaga, X., Martin-Souto, L., Abad-Diaz-de-Cerio, A., Antoran, A., Buldain, I., Hernando, F. L., Ramirez-Garcia, A., Rementeria, A.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-01-2020; Spanish Society for Microbiology
• Subjects: Applied Microbiology; Aspergillosis; Aspergillus fumigatus; Biodegradation; Biomedical and Life Sciences; Clusters; Endosomes; Eukaryotic Microbiology; Fungi; Genes; Genetics; Germination; Immune system; Life Sciences; Medical Microbiology; Melanin; Metabolic pathways; Microbial Ecology; Microbiology; Phenylalanine; Pigments; Review; Tyrosine; Virulence; Virulence factors; Yard waste; Metabolism; Virulence; Melanin; Pyomelanin; Aspergillus fumigatus
• ISSN: 1139-6709; 1618-1905
• DOI: 10.1007/s10123-019-00078-0

Aspergillus fumigatus
is a worldwide-distributed saprophytic fungus and the major cause of invasive aspergillosis. This fungus can produce two types of melanin—dihydroxynaphthalene melanin (DHN-melanin) and pyomelanin. These pigments are considered important resistance mechanisms to stress, as well as virulence factors. The aim of this review is to present the current knowledge of the genetic basis and metabolic pathways of melanin production, their activation, function, and interaction with the host immune system. The DHN-melanin pathway is encoded in a cluster that includes six genes (
abr1
,
abr2
,
ayg1
,
arp1
,
arp2
, and
pksP
/
alb1
genes) whose encoded proteins seem to be the origin of the pigment in endosomes. These vesicles are secreted and the pigment is subsequently located in the wall of the conidium beneath the rodlet layer. Unlike DHN-melanin, pyomelanin does not have its own biosynthetic pathway but is related to the activation of the
l
-tyrosine/
l
-phenylalanine degradation pathway that includes a cluster of six genes (
hppD
,
hmgX
,
hmgA
,
fahA
,
maiA
, and
hmgR
). Its production is due to the polymerization of homogentisic acid and is linked to conidial germination. Despite the knowledge gained in recent years, further studies will be necessary to confirm the pathways that produce these pigments and their role in the virulence mechanisms of
A
.
fumigatus
.