The Cryptococcus neoformans capsule: a sword and a shield

Clin Microbiol Rev. 2012 Jul;25(3):387-408. doi: 10.1128/CMR.00001-12.

Abstract

The human fungal pathogen Cryptococcus neoformans is characterized by its ability to induce a distinct polysaccharide capsule in response to a number of host-specific environmental stimuli. The induction of capsule is a complex biological process encompassing regulation at multiple steps, including the biosynthesis, transport, and maintenance of the polysaccharide at the cell surface. By precisely regulating the composition of its cell surface and secreted polysaccharides, C. neoformans has developed intricate ways to establish chronic infection and dormancy in the human host. The plasticity of the capsule structure in response to various host conditions also underscores the complex relationship between host and parasite. Much of this precise regulation of capsule is achieved through the transcriptional responses of multiple conserved signaling pathways that have been coopted to regulate this C. neoformans-specific virulence-associated phenotype. This review focuses on specific host stimuli that trigger the activation of the signal transduction cascades and on the downstream transcriptional responses that are required for robust encapsulation around the cell.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptation, Physiological
  • Cell Wall / chemistry*
  • Cell Wall / physiology
  • Chitin / chemistry
  • Chromatin Assembly and Disassembly
  • Cryptococcosis / microbiology
  • Cryptococcus neoformans / chemistry
  • Cryptococcus neoformans / genetics
  • Cryptococcus neoformans / physiology*
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Gene Expression Regulation, Fungal
  • Genes, Fungal
  • Host-Parasite Interactions*
  • Humans
  • Polysaccharides / chemistry
  • Signal Transduction
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription, Genetic

Substances

  • Fungal Proteins
  • Polysaccharides
  • Transcription Factors
  • Chitin