scholarly journals Axl2 Integrates Polarity Establishment, Maintenance, and Environmental Stress Response in the Filamentous Fungus Ashbya gossypii

2011 ◽  
Vol 10 (12) ◽  
pp. 1679-1693 ◽  
Author(s):  
Jonathan F. Anker ◽  
Amy S. Gladfelter
Keyword(s):  
Stress Response ◽  
Environmental Stress ◽  
Filamentous Fungus ◽  
Ashbya Gossypii ◽  
Polarized Growth ◽  
Environmental Stress Response ◽  
Content Type ◽  
Polarity Establishment ◽  
Bud Site ◽  
Hyphal Tip

ABSTRACTIn budding yeast, new sites of polarity are chosen with each cell cycle and polarization is transient. In filamentous fungi, sites of polarity persist for extended periods of growth and new polarity sites can be established while existing sites are maintained. How the polarity establishment machinery functions in these distinct growth forms found in fungi is still not well understood. We have examined the function of Axl2, a transmembrane bud site selection protein discovered inSaccharomyces cerevisiae, in the filamentous fungusAshbya gossypii.A. gossypiidoes not divide by budding and instead exhibits persistent highly polarized growth, and multiple axes of polarity coexist in one cell.A. gossypiiaxl2Δ(Agaxl2Δ) cells have wavy hyphae, bulbous tips, and a high frequency of branch initiations that fail to elongate, indicative of a polarity maintenance defect. Mutant colonies also have significantly lower radial growth and hyphal tip elongation speeds than wild-type colonies, and Agaxl2Δhyphae have depolarized actin patches. Consistent with a function in polarity, AgAxl2 localizes to hyphal tips, branches, and septin rings. UnlikeS. cerevisiaeAxl2, AgAxl2 contains a Mid2 homology domain and may function to sense or respond to environmental stress. In support of this idea, hyphae lacking AgAxl2 also display hypersensitivity to heat, osmotic, and cell wall stresses. Axl2 serves to integrate polarity establishment, polarity maintenance, and environmental stress response for optimal polarized growth inA. gossypii.

scholarly journals Comparative Transcriptome Analysis Reveals Novel Roles of the Ras and Cyclic AMP Signaling Pathways in Environmental Stress Response and Antifungal Drug Sensitivity in Cryptococcus neoformans

2010 ◽  
Vol 9 (3) ◽  
pp. 360-378 ◽  
Author(s):  
Shinae Maeng ◽  
Young-Joon Ko ◽  
Gyu-Bum Kim ◽  
Kwang-Woo Jung ◽  
Anna Floyd ◽  
...  
Keyword(s):  
Stress Response ◽  
Cyclic Amp ◽  
Environmental Stress ◽  
Cryptococcus Neoformans ◽  
Signaling Pathway ◽  
Transcriptome Analysis ◽  
Antifungal Drug ◽  
Environmental Stress Response ◽  
Content Type ◽  
Camp Pathway

ABSTRACT The cyclic AMP (cAMP) pathway plays a central role in the growth, differentiation, and virulence of pathogenic fungi, including Cryptococcus neoformans. Three upstream signaling regulators of adenylyl cyclase (Cac1), Ras, Aca1, and Gpa1, have been demonstrated to control the cAMP pathway in C. neoformans, but their functional relationship remains elusive. We performed a genome-wide transcriptome analysis with a DNA microarray using the ras1Δ, gpa1Δ, cac1Δ, aca1Δ, and pka1Δ pka2Δ mutants. The aca1Δ, gpa1Δ, cac1Δ, and pka1Δ pka2Δ mutants displayed similar transcriptome patterns, whereas the ras1Δ mutant exhibited transcriptome patterns distinct from those of the wild type and the cAMP mutants. Interestingly, a number of environmental stress response genes are modulated differentially in the ras1Δ and cAMP mutants. In fact, the Ras signaling pathway was found to be involved in osmotic and genotoxic stress responses and the maintenance of cell wall integrity via the Cdc24-dependent signaling pathway. Notably, the Ras and cAMP mutants exhibited hypersensitivity to a polyene drug, amphotericin B, without showing effects on ergosterol biosynthesis, which suggested a novel method of antifungal combination therapy. Among the cAMP-dependent gene products that we characterized, two small heat shock proteins, Hsp12 and Hsp122, were found to be involved in the polyene antifungal drug susceptibility of C. neoformans.

Loss of alkaline ceramidase inhibits autophagy in Arabidopsis and plays an important role during environmental stress response

2018 ◽  
Vol 41 (4) ◽  
pp. 837-849 ◽  
Author(s):  
Ping Zheng ◽  
Jian-Xin Wu ◽  
Sunil Kumar Sahu ◽  
Hong-Yun Zeng ◽  
Li-Qun Huang ◽  
...  
Keyword(s):  
Stress Response ◽  
Environmental Stress ◽  
Environmental Stress Response

scholarly journals The environmental stress response causes ribosome loss in aneuploid yeast cells

2020 ◽  
Vol 117 (29) ◽  
pp. 17031-17040 ◽  
Author(s):  
Allegra Terhorst ◽  
Arzu Sandikci ◽  
Abigail Keller ◽  
Charles A. Whittaker ◽  
Maitreya J. Dunham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stress Response ◽  
Stationary Phase ◽  
Environmental Stress ◽  
Budding Yeast ◽  
Expression Patterns ◽  
Yeast Cells ◽  
Specific Gene ◽  
Environmental Stress Response ◽  
Cellular Stresses

Aneuploidy, a condition characterized by whole chromosome gains and losses, is often associated with significant cellular stress and decreased fitness. However, how cells respond to the aneuploid state has remained controversial. In aneuploid budding yeast, two opposing gene-expression patterns have been reported: the “environmental stress response” (ESR) and the “common aneuploidy gene-expression” (CAGE) signature, in which many ESR genes are oppositely regulated. Here, we investigate this controversy. We show that the CAGE signature is not an aneuploidy-specific gene-expression signature but the result of normalizing the gene-expression profile of actively proliferating aneuploid cells to that of euploid cells grown into stationary phase. Because growth into stationary phase is among the strongest inducers of the ESR, the ESR in aneuploid cells was masked when stationary phase euploid cells were used for normalization in transcriptomic studies. When exponentially growing euploid cells are used in gene-expression comparisons with aneuploid cells, the CAGE signature is no longer evident in aneuploid cells. Instead, aneuploid cells exhibit the ESR. We further show that the ESR causes selective ribosome loss in aneuploid cells, providing an explanation for the decreased cellular density of aneuploid cells. We conclude that aneuploid budding yeast cells mount the ESR, rather than the CAGE signature, in response to aneuploidy-induced cellular stresses, resulting in selective ribosome loss. We propose that the ESR serves two purposes in aneuploid cells: protecting cells from aneuploidy-induced cellular stresses and preventing excessive cellular enlargement during slowed cell cycles by down-regulating translation capacity.

The root of ABA action in environmental stress response

2013 ◽  
Vol 32 (7) ◽  
pp. 971-983 ◽  
Author(s):  
Jing Han Hong ◽  
Seng Wee Seah ◽  
Jian Xu
Keyword(s):  
Stress Response ◽  
Environmental Stress ◽  
Environmental Stress Response
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