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PLoS Pathog. 2012;8(11):e1002956. doi: 10.1371/journal.ppat.1002956. Epub 2012 Nov 1.

Post-transcriptional regulation of the Sef1 transcription factor controls the virulence of Candida albicans in its mammalian host.

Author information

1
Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, California, United States of America.

Abstract

The yeast Candida albicans transitions between distinct lifestyles as a normal component of the human gastrointestinal microbiome and the most common agent of disseminated fungal disease. We previously identified Sef1 as a novel Cys(6)Zn(2) DNA binding protein that plays an essential role in C. albicans virulence by activating the transcription of iron uptake genes in iron-poor environments such as the host bloodstream and internal organs. Conversely, in the iron-replete gastrointestinal tract, persistence as a commensal requires the transcriptional repressor Sfu1, which represses SEF1 and genes for iron uptake. Here, we describe an unexpected, transcription-independent role for Sfu1 in the direct inhibition of Sef1 function through protein complex formation and localization in the cytoplasm, where Sef1 is destabilized. Under iron-limiting conditions, Sef1 forms an alternative complex with the putative kinase, Ssn3, resulting in its phosphorylation, nuclear localization, and transcriptional activity. Analysis of sfu1 and ssn3 mutants in a mammalian model of disseminated candidiasis indicates that these post-transcriptional regulatory mechanisms serve as a means for precise titration of C. albicans virulence.

PMID:
23133381
PMCID:
PMC3486892
DOI:
10.1371/journal.ppat.1002956
[Indexed for MEDLINE]
Free PMC Article

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