Deletion of the NOT4 gene impairs hyphal development and pathogenicity in Candida albicans

Microbiology ◽  
2004 ◽  
Vol 150 (1) ◽  
pp. 229-240 ◽  
Author(s):  
Karl E. Krueger ◽  
Anup K. Ghosh ◽  
Bastiaan P. Krom ◽  
Ronald L. Cihlar
2002 ◽  
Vol 46 (11) ◽  
pp. 3617-3620 ◽  
Author(s):  
Carol A. Baker ◽  
Kevin Desrosiers ◽  
Joseph W. Dolan

ABSTRACT Propranolol was used to investigate the role of phosphatidic acid (PA) and diacylglycerol in the dimorphic transition in Candida albicans. Propranolol was able to inhibit the appearance of germ tubes without decreasing growth rate. Data suggest that inhibition of morphogenesis may be due to binding by propranolol of PA derived from PLD1 hydrolysis of phosphatidylcholine.


2011 ◽  
Vol 10 (8) ◽  
pp. 1034-1042 ◽  
Author(s):  
Rebecca A. Hall ◽  
Kara J. Turner ◽  
James Chaloupka ◽  
Fabien Cottier ◽  
Luisa De Sordi ◽  
...  

ABSTRACTLiving as a commensal,Candida albicansmust adapt and respond to environmental cues generated by the mammalian host and by microbes comprising the natural flora. These signals have opposing effects onC. albicans, with host cues promoting the yeast-to-hyphal transition and bacteria-derived quorum-sensing molecules inhibiting hyphal development. Hyphal development is regulated through modulation of the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway, and it has been postulated that quorum-sensing molecules can affect filamentation by inhibiting the cAMP pathway. Here, we show that both farnesol and 3-oxo-C12-homoserine lactone, a quorum-sensing molecule secreted byPseudomonas aeruginosa, block hyphal development by affecting cAMP signaling; they both directly inhibited the activity of theCandidaadenylyl cyclase, Cyr1p. In contrast, the 12-carbon alcohol dodecanol appeared to modulate hyphal development and the cAMP signaling pathway without directly affecting the activity of Cyr1p. Instead, we show that dodecanol exerted its effects through a mechanism involving theC. albicanshyphal repressor, Sfl1p. Deletion ofSFL1did not affect the response to farnesol but did interfere with the response to dodecanol. Therefore, quorum sensing inC. albicansis mediated via multiple mechanisms of action. Interestingly, our experiments raise the possibility that theBurkholderia cenocepaciadiffusible signal factor, BDSF, also mediates its effects via Sfl1p, suggesting that dodecanol's mode of action, but not farnesol or 3-oxo-C12-homoserine lactone, may be used by other quorum-sensing molecules.


2007 ◽  
Vol 13 (3) ◽  
pp. 421-432 ◽  
Author(s):  
Indrajit Sinha ◽  
Yan-Ming Wang ◽  
Robin Philp ◽  
Chang-Run Li ◽  
Wai Ho Yap ◽  
...  

2007 ◽  
Vol 6 (11) ◽  
pp. 2112-2121 ◽  
Author(s):  
Yandong Li ◽  
Chang Su ◽  
Xuming Mao ◽  
Fang Cao ◽  
Jiangye Chen

ABSTRACT The ability to switch between different morphological forms is an important feature of Candida albicans and is relevant to its pathogenesis. Many conserved positive and negative transcription factors are involved in morphogenetic regulation of the two dimorphic fungi Candida albicans and Saccharomyces cerevisiae. In S. cerevisiae, the transcriptional repressor Sfl1 and the activator Flo8 function antagonistically in invasive and filamentous growth. We have previously reported that Candida albicans Flo8 is a transcription factor essential for hyphal development and virulence in C. albicans. To determine whether a similar negative factor exists in C. albicans, we identified Candida albicans Sfl1 as a functional homolog of the S. cerevisiae sfl1 mutant. Sfl1 is a negative regulator of hyphal development in C. albicans. Deletion of C. albicans SFL1 enhanced filamentous growth and hypha-specific gene expression in several media and at several growth temperatures. Overexpression of the SFL1 led to a significant reduction of filament formation. Both deletion and overexpression of the SFL1 attenuated virulence of C. albicans in a mouse model. Deleting FLO8 in an sfl1/sfl1 mutant completely blocked hyphal development in various growth conditions examined, suggesting that C. albicans Sfl1 may act as a negative regulator of filamentous growth by antagonizing Flo8 functions. We suggest that, similar to the case for S. cerevisiae, a combination of dual control by activation and repression of Flo8 and Sfl1 may contribute to the fine regulatory network in C. albicans morphogenesis responding to different environmental cues.


2011 ◽  
Vol 22 (14) ◽  
pp. 2458-2469 ◽  
Author(s):  
Pilar Gutiérrez-Escribano ◽  
Alberto González-Novo ◽  
M. Belén Suárez ◽  
Chang-Run Li ◽  
Yue Wang ◽  
...  

Nuclear Dbf2-related (NDR) protein kinases are essential components of regulatory pathways involved in cell morphogenesis, cell cycle control, and viability in eukaryotic cells. For their activity and function, these kinases require interaction with Mob proteins. However, little is known about how the Mob proteins are regulated. In Candida albicans, the cyclin-dependent kinase (CDK) Cdc28 and the NDR kinase Cbk1 are required for hyphal growth. Here we demonstrate that Mob2, the Cbk1 activator, undergoes a Cdc28-dependent differential phosphorylation on hyphal induction. Mutations in the four CDK consensus sites in Mob2 to Ala significantly impaired hyphal development. The mutant cells produced short hyphae with enlarged tips that displayed an illicit activation of cell separation. We also show that Cdc28 phosphorylation of Mob2 is essential for the maintenance of polarisome components at hyphal tips but not at bud tips during yeast growth. Thus we have found a novel signaling pathway by which Cdc28 controls Cbk1 through the regulatory phosphorylation of Mob2, which is crucial for normal hyphal development.


2000 ◽  
Vol 68 (4) ◽  
pp. 1997-2002 ◽  
Author(s):  
Noboru Tsuchimori ◽  
Laura L. Sharkey ◽  
William A. Fonzi ◽  
Samuel W. French ◽  
John E. Edwards ◽  
...  

ABSTRACT The Candida albicans gene HWP1 encodes a surface protein that is required for normal hyphal development in vitro. We used mutants lacking one or both alleles of HWP1to investigate the role of this gene in virulence. Mice infected intravenously with the homozygous hwp1 null mutant, CAL3, survived a median of >14 days, whereas mice infected with a control strain containing two functional alleles of HWP1 survived only 3.5 days. After 1 day of infection, all strains produced similar levels of infection in the kidneys, spleen, and blood. However, after 2 and 3 days, there was a significant decrease in the number of organisms in the kidneys of the mice infected with CAL3. This finding suggests that the hwp1 homozygous null mutant is normal in its ability to initiate infection but deficient in its capacity to maintain infection. CAL3 also germinated minimally in the kidneys. The ability of the heterozygous null mutant to germinate and cause mortality in mice was intermediate to CAL3, suggesting a gene dosage effect. To investigate potential mechanisms for the diminished virulence of CAL3, we examined its interactions with endothelial cells and neutrophils in vitro. CAL3 caused less endothelial cell injury than the heterozygoushwp1 mutant. We conclude that the HWP1 gene product is important for both in vivo hyphal development and pathogenicity of C. albicans. Also, the ability to form filaments may be critical for candidal virulence by enabling the fungus to induce cellular injury and maintain a deep-seated infection.


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