scholarly journals Membrane Fluidity and Temperature Sensing Are Coupled via Circuitry Comprised of Ole1, Rsp5, and Hsf1 in Candida albicans

2014 ◽  
Vol 13 (8) ◽  
pp. 1077-1084 ◽  
Author(s):  
Michelle D. Leach ◽  
Leah E. Cowen
Keyword(s):  
Candida Albicans ◽  
Fatty Acid ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Fatty Acid Synthase ◽  
Temperature Sensing ◽  
Yeast Cells ◽  
Thermal Transitions ◽  
Content Type ◽  
Shock Response

ABSTRACTTemperature is a ubiquitous environmental variable which can profoundly influence the physiology of living cells as it changes over time and space. When yeast cells are exposed to a sublethal heat shock, normal metabolic functions become repressed and the heat shock transcription factor Hsf1 is activated, inducing heat shock proteins (HSPs).Candida albicans, the most prevalent human fungal pathogen, is an opportunistic pathogen that has evolved as a relatively harmless commensal of healthy individuals. Even thoughC. albicansoccupies thermally buffered niches, it has retained the classic heat shock response, activating Hsf1 during slow thermal transitions such as the increases in temperature suffered by febrile patients. However, the mechanism of temperature sensing in fungal pathogens remains enigmatic. A few studies withSaccharomyces cerevisiaesuggest that thermal stress is transduced into a cellular signal at the level of the membrane. In this study, we manipulated the fluidity ofC. albicansmembrane to dissect mechanisms of temperature sensing. We determined that in response to elevated temperature, levels ofOLE1, encoding a fatty acid desaturase, decrease. Subsequently, loss ofOLE1triggers expression ofFAS2, encoding a fatty acid synthase. Furthermore, depletion ofOLE1prevents full activation of Hsf1, thereby reducingHSPexpression in response to heat shock. This reduction in Hsf1 activation is attributable to the E3 ubiquitin ligase Rsp5, which regulatesOLE1expression. To our knowledge, this is the first study to define a molecular link between fatty acid synthesis and the heat shock response in the fungal kingdom.

scholarly journals Thermotolerance and the Heat-shock Response in Candida albicans

Microbiology ◽  
1989 ◽  
Vol 135 (9) ◽  
pp. 2509-2518 ◽  
Author(s):  
M. L. Zeuthen ◽  
D. H. Howard
Keyword(s):  
Candida Albicans ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Shock Response

Heat shock proteins affect RNA processing during the heat shock response of Saccharomyces cerevisiae

1991 ◽  
Vol 11 (2) ◽  
pp. 1062-1068
Author(s):  
H J Yost ◽  
S Lindquist
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Response ◽  
Rna Splicing ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Shock Response ◽  
Shock Proteins

In the yeast Saccharomyces cerevisiae, the splicing of mRNA precursors is disrupted by a severe heat shock. Mild heat treatments prior to severe heat shock protect splicing from disruption, as was previously reported for Drosophila melanogaster. In contrast to D. melanogaster, protein synthesis during the pretreatment is not required to protect splicing in yeast cells. However, protein synthesis is required for the rapid recovery of splicing once it has been disrupted by a sudden severe heat shock. Mutations in two classes of yeast hsp genes affect the pattern of RNA splicing during the heat shock response. First, certain hsp70 mutants, which overproduce other heat shock proteins at normal temperatures, show constitutive protection of splicing at high temperatures and do not require pretreatment. Second, in hsp104 mutants, the recovery of RNA splicing after a severe heat shock is delayed compared with wild-type cells. These results indicate a greater degree of specialization in the protective functions of hsps than has previously been suspected. Some of the proteins (e.g., members of the hsp70 and hsp82 gene families) help to maintain normal cellular processes at higher temperatures. The particular function of hsp104, at least in splicing, is to facilitate recovery of the process once it has been disrupted.

scholarly journals Characterization of the Biosynthetic Genes for 10,11-Dehydrocurvularin, a Heat Shock Response-Modulating Anticancer Fungal Polyketide from Aspergillus terreus

2013 ◽  
Vol 79 (6) ◽  
pp. 2038-2047 ◽  
Author(s):  
Yuquan Xu ◽  
Patricia Espinosa-Artiles ◽  
Vivien Schubert ◽  
Ya-ming Xu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Aspergillus Terreus ◽  
Polyketide Synthase ◽  
Polyketide Synthases ◽  
Content Type ◽  
Shock Response ◽  
Starter Unit ◽  
Acid Lactone ◽  
Resorcylic Acid Lactones

ABSTRACT10,11-Dehydrocurvularin is a prevalent fungal phytotoxin with heat shock response and immune-modulatory activities. It features a dihydroxyphenylacetic acid lactone polyketide framework with structural similarities to resorcylic acid lactones like radicicol or zearalenone. A genomic locus was identified from the dehydrocurvularin producer strainAspergillus terreusAH-02-30-F7 to reveal genes encoding a pair of iterative polyketide synthases (A. terreusCURS1 [AtCURS1] and AtCURS2) that are predicted to collaborate in the biosynthesis of 10,11-dehydrocurvularin. Additional genes in this locus encode putative proteins that may be involved in the export of the compound from the cell and in the transcriptional regulation of the cluster. 10,11-Dehydrocurvularin biosynthesis was reconstituted inSaccharomyces cerevisiaeby heterologous expression of the polyketide synthases. Bioinformatic analysis of the highly reducing polyketide synthase AtCURS1 and the nonreducing polyketide synthase AtCURS2 highlights crucial biosynthetic programming differences compared to similar synthases involved in resorcylic acid lactone biosynthesis. These differences lead to the synthesis of a predicted tetraketide starter unit that forms part of the 12-membered lactone ring of dehydrocurvularin, as opposed to the penta- or hexaketide starters in the 14-membered rings of resorcylic acid lactones. TetraketideN-acetylcysteamine thioester analogues of the starter unit were shown to support the biosynthesis of dehydrocurvularin and its analogues, with yeast expressing AtCURS2 alone. Differential programming of the product template domain of the nonreducing polyketide synthase AtCURS2 results in an aldol condensation with a different regiospecificity than that of resorcylic acid lactones, yielding the dihydroxyphenylacetic acid scaffold characterized by an S-type cyclization pattern atypical for fungal polyketides.

scholarly journals Heat shock proteins affect RNA processing during the heat shock response of Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (2) ◽  
pp. 1062-1068 ◽  
Author(s):  
H J Yost ◽  
S Lindquist
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Response ◽  
Rna Splicing ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Shock Response ◽  
Shock Proteins

In the yeast Saccharomyces cerevisiae, the splicing of mRNA precursors is disrupted by a severe heat shock. Mild heat treatments prior to severe heat shock protect splicing from disruption, as was previously reported for Drosophila melanogaster. In contrast to D. melanogaster, protein synthesis during the pretreatment is not required to protect splicing in yeast cells. However, protein synthesis is required for the rapid recovery of splicing once it has been disrupted by a sudden severe heat shock. Mutations in two classes of yeast hsp genes affect the pattern of RNA splicing during the heat shock response. First, certain hsp70 mutants, which overproduce other heat shock proteins at normal temperatures, show constitutive protection of splicing at high temperatures and do not require pretreatment. Second, in hsp104 mutants, the recovery of RNA splicing after a severe heat shock is delayed compared with wild-type cells. These results indicate a greater degree of specialization in the protective functions of hsps than has previously been suspected. Some of the proteins (e.g., members of the hsp70 and hsp82 gene families) help to maintain normal cellular processes at higher temperatures. The particular function of hsp104, at least in splicing, is to facilitate recovery of the process once it has been disrupted.

scholarly journals Fatty acid profile of Escherichia coli during the heat-shock response

IUBMB Life ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 835-844 ◽  
Author(s):  
Ricardo Mejía ◽  
M. Carmen Gómez-Eichelmann ◽  
Marta Fernández
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Heat Shock ◽  
Fatty Acid Profile ◽  
Heat Shock Response ◽  
Shock Response
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