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

Infect Immun. 2020 Jun 22;88(7):e00954-19. doi: 10.1128/IAI.00954-19. Print 2020 Jun 22.

Abstract

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 vps27Δ 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 vps27Δ 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.

Keywords: Cryptococcus neoformans; ESCRT; VPS27; attenuates virulence; laccase trafficking; multivesicular bodies (MVB).

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • 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
  • Mutation
  • Protein Transport
  • Salt Tolerance
  • Signal Transduction*
  • Vacuoles / metabolism
  • Virulence
  • Virulence Factors / genetics

Substances

  • Actins
  • Endosomal Sorting Complexes Required for Transport
  • Fungal Proteins
  • Virulence Factors
  • Laccase