Interaction of Cryptococcus neoformans Rim101 and Protein Kinase A Regulates Capsule

PLoS Pathogens

Connie B. Nichols¹  Teresa R. O'Meara¹  Michael S. Price¹  Christie Hay¹  J. Andrew Alspaugh¹  Diana Norton¹  Meredith F. Clements¹ 

[1] Departments of Medicine and Molecular Genetics/Microbiology, Duke University School of Medicine, Durham, North Carolina, United States of America

关键词: Cryptococcus neoformans;    Mutant strains;    Transcription factors;    Gene regulation;    Fungal pathogens;    Transcriptional control;    Polysaccharides;    Phenotypes;   

DOI  :  10.1371/journal.ppat.1000776

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Cryptococcus neoformans is a prevalent human fungal pathogen that must survive within various tissues in order to establish a human infection. We have identified the C. neoformans Rim101 transcription factor, a highly conserved pH-response regulator in many fungal species. The rim101Δ mutant strain displays growth defects similar to other fungal species in the presence of alkaline pH, increased salt concentrations, and iron limitation. However, the rim101Δ strain is also characterized by a striking defect in capsule, an important virulence-associated phenotype. This capsular defect is likely due to alterations in polysaccharide attachment to the cell surface, not in polysaccharide biosynthesis. In contrast to many other C. neoformans capsule-defective strains, the rim101Δ mutant is hypervirulent in animal models of cryptococcosis. Whereas Rim101 activation in other fungal species occurs through the conserved Rim pathway, we demonstrate that C. neoformans Rim101 is also activated by the cAMP/PKA pathway. We report here that C. neoformans uses PKA and the Rim pathway to regulate the localization, activation, and processing of the Rim101 transcription factor. We also demonstrate specific host-relevant activating conditions for Rim101 cleavage, showing that C. neoformans has co-opted conserved signaling pathways to respond to the specific niche within the infected host. These results establish a novel mechanism for Rim101 activation and the integration of two conserved signaling cascades in response to host environmental conditions.

【 授权许可】

CC BY