Vesicle-associated melanization in Cryptococcus neoformans
Year: 2009
Type: article
Abstract: Recently, several pathogenic fungi were shown to produce extracellular vesicles that contain various components associated with virulence. In the human pathogenic fungus Cryptococcus neoformans, these components included laccase, an enzyme that catalyses melanin synthesis. Spherical melanin granules have been observed in the cell wall of C. neoformans. Given that melanin granules have dimensions that are comparable to those of extracellular vesicles, and that metazoan organisms produce melanin in vesicular structures known as melanosomes, we investigated the role of vesicles in cryptococcal melanization. Extracellular vesicles melanized when incubated with the melanin precursor L-3,4-dihydroxyphenylalanine (L-DOPA). The kinetics of substrate incorporation into cells and vesicles was analysed using radiolabelled L-DOPA. The results indicated that substrate incorporation was different for cells and isolated vesicles. Acid-generated melanin ghosts stained with lipophilic dyes, implying the presence of associated lipid. A model for C. neoformans melanization is proposed that accounts for these observations and provides a mechanism for the assembly of melanin into relatively uniform spherical particles stacked in an orderly arrangement in the cell wall.
Source: Microbiology
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
Awards: G1558937058, G177305599, G1790967239, G2436179761, Synergy of Host Defense Mechanisms in the Lung, G2773611754, G4559384, G4617214234, G624453842, Protective antibodies for Cryptococcal Infections, Biology of Fungal Melanin, G9000079094, G9000096188, G9000324242, Molecular Characterization of C. neoformans Antibodies
OpenAlex ID: W2165094718