The Candida albicans MEKK Ste11 has both structural and enzymatic functions in opaque cells under pheromone stimulation
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PROVIDER: PRJNA663875 | ENA |
REPOSITORIES: ENA
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Project description:In this study, we investigated the relationships among the pheromone components to identify how the MAPK proteins are coordinated through a scaffold that lacks a key domain. An attempt to bypass other components by artificially driving either Cst5 or Ste11 to the plasma membrane suggested that the interactions among the proteins are more complex than the linear cascade characterized in S. cerevisiae. Moreover, the findings suggest the MAPK proteins Hst7 and Ste11 regulate the translocation of Cst5 within the cytoplasm. Indeed, it appears that Ste11 interacts with Cst5 to generate a complex node to tether the downstream kinases where Ste11 can both act enzymatically on Hst7 as well as make the MAPK Cek1 available for phosphorylation and activation by Hst7.
2020-12-01 | GSE158062 | GEO
Project description:Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 206 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former.
2013-02-22 | GSE44449 | GEO
Project description:Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 206 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former. 4 condition experiment: white and opaque cells in planktonic and pheromone-induced biofilm conditions with and without alpha pheromone. WT strain (P37005), the tec1 mutant strain and the cph1 mutant strain
2013-02-22 | E-GEOD-44449 | biostudies-arrayexpress
Project description:Modes of sexual reproduction in eukaryotic organisms are highly diversified. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally and morphologically differentiated white and opaque cells show a coordinating behavior in the process of mating. Although white cells are mating-incompetent, they are induced to produce sexual pheromones when treated with opposite pheromones or interacted with opaque cells of an opposite mating type. In a co-culture system, pheromones released by white cells induce opaque cells to form mating projections and thus facilitate both opposite- and same-sex mating of opaque cells. Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in sexual mating of opaque cells. White and opaque cells communicate via a paracrine pheromone signaling and thus create an environment conducive to sexual mating. This coordination behavior of the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans. total RNA profiles of white cell treated with pheromone
2014-10-23 | E-GEOD-56039 | biostudies-arrayexpress
Project description:Modes of sexual reproduction in eukaryotic organisms are highly diversified. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally and morphologically differentiated white and opaque cells show a coordinating behavior in the process of mating. Although white cells are mating-incompetent, they are induced to produce sexual pheromones when treated with opposite pheromones or interacted with opaque cells of an opposite mating type. In a co-culture system, pheromones released by white cells induce opaque cells to form mating projections and thus facilitate both opposite- and same-sex mating of opaque cells. Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in sexual mating of opaque cells. White and opaque cells communicate via a paracrine pheromone signaling and thus create an environment conducive to sexual mating. This coordination behavior of the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.
2014-10-23 | GSE56039 | GEO
Project description:As a successful commensal and pathogen of humans, Candida albicans encounters a wide range of environmental changes. Among them, ambient pH is an important factor, which changes frequently and affects many biological processes in this species. The ability to adapt to pH changes is tightly linked with pathogenesis and morphogenesis. In this study, we report that pH has a profound effect on white-opaque switching and sexual mating in C. albicans. Acidic pHs promote white-to-opaque switching but repress sexual mating of opaque cells. The cAMP signaling and Rim101-mediated pH sensing pathways are involved in the regulation of pH-regulated white-opaque switching. Interestingly, white and opaque cells of the cyr1/cyr1 mutant, which is defective in producing cAMP, show distinct growth defects under acidic and alkaline conditions. Phr2 could play a major role in acidic pHs-induced opaque cell formation. We further discover that acidic pH conditions repress sexual mating due to the failure of activation of the Ste2-mediated a-pheromone response pathway. The effects of pH changes on phenotypic switching and sexual mating could be a balance behavior between host adaptation and sexual reproduction.
2015-12-30 | GSE67101 | GEO
Project description:Fission yeast cells belong to one of two specialized cell types, M or P. Specific environmental conditions trigger sexual differentiation, which leads to an internal program starting with pheromone signalling between M and P cells, followed by mating, meiosis and sporulation. The initial steps of this process are controlled by Ste11p, a master transcriptional regulator that activates the expression of cell type-specific genes (only expressed in either M or P cells) as well as genes expressed in both M and P cells. <br><br> Pheromone signalling is activated by Ste11p-dependent transcription, and in turn enhances some of this transcription in a positive feedback. To obtain a genome-wide view of Ste11p target genes, their cell-type specificity, and their dependence on pheromone, we used DNA microarrays along with different genetic and environmental manipulations of fission yeast cells.We directly compared the transcriptome of homothallic wild-type cells (h90 fus1) with that of ste11 delta mutants under conditions that induce sexual differentiation. To allow for indirect effects of the ste11 delta mutation, we took advantage of the fact that ectopic expression of ste11 can drive cells into sexual differentiation and therefore is expected to cause the expression of Ste11p targets. We thus defined Ste11p targets as those genes whose expression was significantly reduced in a ste11 delta mutant and significantly increased when ste11 is overexpressed in vegetative cells.<br> <br> This study looked at the effect of deletion or overexpression of ste11, and changes in gene expression after nitrogen starvation of h plus, h minus, h90fus1 and h90ste11 cells.
2006-09-22 | E-TABM-139 | biostudies-arrayexpress
Project description:Transcriptional profiling of C. tropicalis a cells (CAY1503) in opaque state and overexpressing Wor1 in biofilms hybridized against a universal mixed reference sample of a cells in white and opaque states grown in Spider liquid.
2013-05-01 | GSE43267 | GEO
Project description:In Candida albicans, the a1-alpha2 complex represses white-opaque switching as well as mating. A ChIP-chip strategy was, therefore, used to screen for genes with a1-alpha2 binding sites and expression patterns consistent with a master switch gene (MSG). Of 51 genes identified with an a1-alpha2 binding site, one gene, TOS9, also referred to as EAP2, exhibited an expression pattern consistent with a MSG. TOS9 is expressed in opaque, not white a/a and alpha/alpha cells and Tos9p localizes to the opaque cell nucleus. Deletion of TOS9 blocks cells in the white phase, and misexpression in the white phase of the parent tos9+/tos9+ strain results in mass conversion to opaque. Expression of TOS9 under control of a MET promoter rescues the TOS9 null mutant tos9-/tos9- phenotype. Temperature-induced mass conversion of opaque to white in the parent strain results in the immediate cessation of TOS9 transcription, and loss of Tos9p prior to the point of commitment to white (the switch event), which occurs at the time of the second cell doubling. Misexpression of TOS9, as well as inhibition of the second round of DNA replication inhibits the temperature-induced switch from opaque to white. Based on these observations, a model is developed for the regulation and role of TOS9 in switching. Keywords: ChIP chip
2006-09-19 | GSE5493 | GEO
Project description:Reduced prolamin (zein) accumulation and defective ER-body formation occurs in maize opaque endosperm mutants opaque2 (o2), floury2 (fl2), defective endosperm*B30 (DeB30), and mucronate (Mc) whereas other opaque mutants such as opaque1 (o1) and floury1 (fl1) are normal in these regards. This suggests that other factors contribute to kernel texture. We used a LC-MS/MS proteomics approach to compare non-zein proteins of nearly isogenic opaque mutants. In total, 2762 proteins were identified that were enriched for biological processes such as protein transport and folding, amino acid biosynthesis, and proteolysis. Amino acid analysis of top proteins revealed qualitative changes in lysine abundance contributing to the overall lysine increase. Principal component analysis and pathway enrichment suggested that the mutants partition into three groups: Mc, DeB30, fl2 and o2; o1; and fl1. Indicator species analysis revealed mutant-specific proteins, and highlighted ER secretory pathway components that are enriched in selected groups of mutants, albeit with no common proteins across all mutants. Most significantly changed proteins were related to stress or defense and zein partitioning into the soluble fraction for Mc, DeB30, o1 and fl1 specifically. We suggest that ER stress is a universal trigger of opacity regardless of qualitative or quantitative changes in zein accumulation.
2016-01-05 | PXD002379 | Pride