Role of the ESCRT Pathway in Laccase Trafficking and Virulence of Cryptococcus neoformans

• Published in: Infection and immunity Vol. 88; no. 7
• Main Authors: Park, Yoon-Dong, Chen, Shu Hui, Camacho, Emma, Casadevall, Arturo, Williamson, Peter R.
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 22.06.2020
• Subjects: Actins - metabolism; Animals; Biological Transport; Cryptococcosis - microbiology; Cryptococcus neoformans - genetics; Cryptococcus neoformans - growth & development; Cryptococcus neoformans - pathogenicity; Disease Models, Animal; Endosomal Sorting Complexes Required for Transport - metabolism; Extracellular Vesicles - metabolism; Fungal Proteins - genetics; Fungal Proteins - metabolism; Hydrogen-Ion Concentration; Laccase - metabolism; Meningitis, Cryptococcal - microbiology; Mice; Molecular Pathogenesis; Mutation; Protein Transport; Salt Tolerance; Signal Transduction; Vacuoles - metabolism; Virulence; Virulence Factors - genetics; Cryptococcus neoformans; ESCRT; multivesicular bodies (MVB); attenuates virulence; laccase trafficking; VPS27
• ISSN: 0019-9567; 1098-5522; 1098-5522
• DOI: 10.1128/IAI.00954-19

The endosomal sorting complex required for transport (ESCRT) plays a crucial role in the transportation and degradation of proteins. We determined that Vps27, a key protein of the ESCRT-0 complex, is required for the transport of the virulence factor laccase to the cell wall in Cryptococcus neoformans . Laccase activity was perturbed, as was melanin production, in vps27 Δ strains. In the absence of VPS27 , there was an accumulation of multivesicular bodies with vacuolar fragmentation and mistargeting of the vacuolar carboxypeptidase CPY/Prc1, resulting in an extracellular localization. The endosomal sorting complex required for transport (ESCRT) plays a crucial role in the transportation and degradation of proteins. We determined that Vps27, a key protein of the ESCRT-0 complex, is required for the transport of the virulence factor laccase to the cell wall in Cryptococcus neoformans . Laccase activity was perturbed, as was melanin production, in vps27 Δ strains. In the absence of VPS27 , there was an accumulation of multivesicular bodies with vacuolar fragmentation and mistargeting of the vacuolar carboxypeptidase CPY/Prc1, resulting in an extracellular localization. In addition, deletion of VPS27 resulted in a defect in laccase targeting of a Lac1-green fluorescent protein (GFP) fusion to the cell wall with trapping within intracellular puncta; this deletion was accompanied by reduced virulence in a mouse model. However, the actin cytoskeleton remained intact, suggesting that the trafficking defect is not due to defects in actin-related localization. Extracellular vesicle maturation was also defective in the vps27 Δ mutant, which had a larger vesicle size as measured by dynamic light scattering. Our data identify cryptococcal VPS27 as a required gene for laccase trafficking and attenuates virulence of C. neoformans in a mouse intravenous (i.v.) meningitis model.