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

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 Laccase activity was perturbed, as was melanin production, in Δ strains. In the absence of , 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 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 Δ mutant, which had a larger vesicle size as measured by dynamic light scattering. Our data identify cryptococcal as a required gene for laccase trafficking and attenuates virulence of in a mouse intravenous (i.v.) meningitis model.