<i>N</i>-acetylglucosamine (GlcNAc) Triggers a Rapid, Temperature-Responsive Morphogenetic Program in Thermally Dimorphic Fungi Sarah A. Gilmore Shamoon Naseem James B. Konopka Anita Sil 10.1371/journal.pgen.1003799 https://plos.figshare.com/articles/dataset/_N_acetylglucosamine_GlcNAc_Triggers_a_Rapid_Temperature_Responsive_Morphogenetic_Program_in_Thermally_Dimorphic_Fungi/803442 <div><p>The monosaccharide <i>N</i>-acetylglucosamine (GlcNAc) is a major component of microbial cell walls and is ubiquitous in the environment. GlcNAc stimulates developmental pathways in the fungal pathogen <i>Candida albicans</i>, which is a commensal organism that colonizes the mammalian gut and causes disease in the setting of host immunodeficiency. Here we investigate GlcNAc signaling in thermally dimorphic human fungal pathogens, a group of fungi that are highly evolutionarily diverged from <i>C. albicans</i> and cause disease even in healthy individuals. These soil organisms grow as polarized, multicellular hyphal filaments that transition into a unicellular, pathogenic yeast form when inhaled by a human host. Temperature is the primary environmental cue that promotes reversible cellular differentiation into either yeast or filaments; however, a shift to a lower temperature <i>in vitro</i> induces filamentous growth in an inefficient and asynchronous manner. We found GlcNAc to be a potent and specific inducer of the yeast-to-filament transition in two thermally dimorphic fungi, <i>Histoplasma capsulatum</i> and <i>Blastomyces dermatitidis</i>. In addition to increasing the rate of filamentous growth, micromolar concentrations of GlcNAc induced a robust morphological transition of <i>H. capsulatum</i> after temperature shift that was independent of GlcNAc catabolism, indicating that fungal cells sense GlcNAc to promote filamentation. Whole-genome expression profiling to identify candidate genes involved in establishing the filamentous growth program uncovered two genes encoding GlcNAc transporters, <i>NGT1</i> and <i>NGT2</i>, that were necessary for <i>H. capsulatum</i> cells to robustly filament in response to GlcNAc. Unexpectedly, <i>NGT1</i> and <i>NGT2</i> were important for efficient <i>H. capsulatum</i> yeast-to-filament conversion in standard glucose medium, suggesting that Ngt1 and Ngt2 monitor endogenous levels of GlcNAc to control multicellular filamentous growth in response to temperature. Overall, our work indicates that GlcNAc functions as a highly conserved cue of morphogenesis in fungi, which further enhances the significance of this ubiquitous sugar in cellular signaling in eukaryotes.</p></div> 2013-09-19 02:03:47 triggers temperature-responsive morphogenetic thermally dimorphic fungi