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The vacuolar-sorting protein Snf7 is required for export of virulence determinants in members of the Cryptococcus

Rodrigo M da C Godinho1, Juliana Crestani2, Lívia Kmetzsch3

  • 11] Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, Brazil [2].

Scientific Reports
|September 3, 2014
PubMed

Insights

The endosomal sorting complex required for transport (ESCRT) protein Snf7 is crucial for fungal virulence. Deleting Snf7 in Cryptococcus species impairs polysaccharide secretion and melanin production, leading to a loss of virulence.

Area of Science:

  • Mycology
  • Cell Biology
  • Pathogenesis

Background:

  • Fungal virulence relies on extracellular factors, with many lacking traditional secretory signals.
  • Unconventional secretion pathways are increasingly recognized as vital for fungal pathogenesis.
  • The endosomal sorting complex required for transport (ESCRT) machinery is implicated in exporting molecules in eukaryotic pathogens.

Purpose of the Study:

  • To investigate the role of the ESCRT component Snf7 in the virulence of Cryptococcus neoformans and Cryptococcus gattii.
  • To determine if Snf7 is involved in the unconventional secretion of virulence factors like polysaccharides and melanin.
  • To assess the impact of Snf7 deletion on fungal morphology and pathogenicity.

Main Methods:

  • Generation of snf7Δ mutant strains in Cryptococcus neoformans and Cryptococcus gattii.
  • Analysis of polysaccharide secretion, capsule formation, and melanin production in wild-type and mutant strains.
  • Evaluation of virulence in an intranasal murine infection model.

Main Results:

  • Deletion of Snf7 significantly altered polysaccharide secretion, capsule formation, and pigmentation in both fungal species.
  • snf7Δ mutants exhibited a complete loss of virulence in the murine infection model.
  • These findings indicate Snf7 is essential for the traffic of polysaccharides and melanin.

Conclusions:

  • Snf7 plays a critical role in regulating fungal virulence by controlling the unconventional secretion of polysaccharides and melanin.
  • Unconventional secretion mechanisms are essential for Cryptococcus pathogenesis.
  • The study highlights the importance of obscure export mechanisms for non-protein molecules in eukaryotes.

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