Guanggan Hu, Erik Bakkeren, Mélissa Caza, Linda Horianopoulos, Eddy Sánchez-León, Melanie Sorensen, Wonhee Jung, James W. Kronstad
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引用次数: 2
Abstract
The pathogenic fungus Cryptococcus neoformans must overcome iron limitation to cause disease in mammalian hosts. Previously, we reported a screen for insertion mutants with poor growth on haem as the sole iron source. In this study, we characterised one such mutant and found that the defective gene encoded a Vam6/Vps39/TRAP1 domain-containing protein required for robust growth on haem, an important iron source in host tissue. We designated this protein Vps3 based on reciprocal best matches with the corresponding protein in Saccharomyces cerevisiae. C. neoformans encodes a second Vam6/Vps39/TRAP1 domain-containing protein designated Vam6/Vlp1, and we found that this protein is also required for robust growth on haem as well as on inorganic iron sources. This protein is predicted to be a component of the homotypic fusion and vacuole protein sorting complex involved in endocytosis. Further characterisation of the vam6Δ and vps3Δ mutants revealed perturbed trafficking of iron acquisition functions (e.g., the high affinity iron permease Cft1) and impaired processing of the transcription factor Rim101, a regulator of haem and iron acquisition. The vps3Δ and vam6Δ mutants also had pleiotropic phenotypes including loss of virulence in a mouse model of cryptococcosis, reduced virulence factor elaboration and increased susceptibility to stress, indicating pleiotropic roles for Vps3 and Vam6 beyond haem use in C. neoformans.
Take Aways
Two Vam6/Vps39/TRAP1-domain proteins, Vps3 and Vam6, support the growth of Cryptococcus neoformans on haem.
Loss of Vps3 and Vam6 influences the trafficking and expression of iron uptake proteins.
Loss of Vps3 or Vam6 eliminates the ability of C. neoformans to cause disease in a mouse model of cryptococcosis.
期刊介绍:
Cellular Microbiology aims to publish outstanding contributions to the understanding of interactions between microbes, prokaryotes and eukaryotes, and their host in the context of pathogenic or mutualistic relationships, including co-infections and microbiota. We welcome studies on single cells, animals and plants, and encourage the use of model hosts and organoid cultures. Submission on cell and molecular biological aspects of microbes, such as their intracellular organization or the establishment and maintenance of their architecture in relation to virulence and pathogenicity are also encouraged. Contributions must provide mechanistic insights supported by quantitative data obtained through imaging, cellular, biochemical, structural or genetic approaches.