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A family of Candida cell surface haem-binding proteins involved in haemin and haemoglobin-iron utilization

Ziva Weissman1, Daniel Kornitzer

  • 1Department of Molecular Microbiology, Technion - B. Rappaport Faculty of Medicine, and the Rappaport Institute for Research in the Medical Sciences, Haifa 31096, Israel.

Molecular Microbiology
|August 13, 2004
PubMed

Insights

Pathogenic fungi like Candida albicans use host iron for virulence. Researchers identified RBT5 and RBT51 proteins crucial for utilizing hemoglobin iron, a key step in fungal infection.

Area of Science:

  • Microbiology
  • Mycology
  • Molecular Biology

Background:

  • Iron acquisition is vital for pathogenic microorganisms' virulence.
  • Candida albicans is a significant fungal pathogen causing systemic infections.
  • The molecular mechanisms of iron utilization from host heme and hemoglobin in fungi remain largely unknown.

Purpose of the Study:

  • To identify and characterize the molecular basis of heme-iron utilization in pathogenic fungi.
  • To investigate the role of specific proteins in enabling Candida albicans to acquire iron from host sources.

Main Methods:

  • Gene isolation and functional analysis in Saccharomyces cerevisiae.
  • Homology studies and protein characterization (mannosylation, CFEM domain).
  • Gene deletion studies in Candida albicans to assess iron utilization capabilities.

Main Results:

  • RBT51 gene confers hemoglobin iron utilization ability to S. cerevisiae.
  • RBT5 and RBT51 are homologous, mannosylated, plasma membrane-anchored proteins with a CFEM domain.
  • RBT5 deletion significantly impairs C. albicans' ability to utilize heme and hemoglobin for iron.

Conclusions:

  • A conserved family of plasma membrane-anchored, heme-binding proteins, including Rbt5 and Rbt51, are involved in fungal heme-iron utilization.
  • RBT5 is induced by iron starvation and plays a critical role in C. albicans iron acquisition.
  • This iron acquisition pathway is conserved among pathogenic fungi, highlighting its importance in virulence.

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