Activation of heat shock transcription factor in yeast is not influenced by the levels of expression of heat shock proteins

Hjorth-Sørensen, Bjørn; Hoffmann, Eva R.; Lissin, Nikolai; Sewell, Andrew K.; Jakobsen, Bent K.

doi:10.1046/j.1365-2958.2001.02279.x

Cited by 34 publications

(21 citation statements)

References 54 publications

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“…It is generally accepted that Hsp90 interaction suppresses Hsf1 activity (Zou et al, 1998), and compromised Hsp90 chaperone function, due to mutation or pharmacologic inhibition, leads to induction of Hsf1 activity in yeast even in the absence of heat shock (Hjorth-Sorensen et al, 2001). SMT3-MYC overexpression caused a heat shock response in wild-type yeast but not in yeast expressing yHsp90-K178R (Figure 5E).…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Hsp90 N Domain SUMOylation Recruits Aha1 and ATP-Competitive Inhibitors

et al. 2014

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Summary The stability and activity of numerous signaling proteins in both normal and cancer cells depends on the dimeric molecular chaperone Heat Shock Protein 90 (Hsp90). Hsp90 function is coupled to ATP binding and hydrolysis, and requires a series of conformational changes that are regulated by co-chaperones and numerous posttranslational modifications (PTMs). SUMOylation is one of the least understood Hsp90 PTMs. Here we show that asymmetric SUMOylation of a conserved lysine residue in the N-domain of both yeast (K178) and human (K191) Hsp90 facilitates both recruitment of the ATPase activating co-chaperone Aha1 and, unexpectedly, the binding of Hsp90 inhibitors, suggesting that these drugs associate preferentially with Hsp90 proteins that are actively engaged in the chaperone cycle. Importantly, cellular transformation is accompanied by elevated steady-state N-domain SUMOylation and increased Hsp90 SUMOylation sensitizes yeast and mammalian cells to Hsp90 inhibitors, providing a mechanism to explain the sensitivity of cancer cells to these drugs.

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Section: Resultsmentioning

confidence: 99%

Asymmetric Hsp90 N Domain SUMOylation Recruits Aha1 and ATP-Competitive Inhibitors

et al. 2014

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“…Thus, the hsp30, hsp70, and hsp90 genes are preferentially expressed in the palA + strain incubated at an optimal temperature for fungal growth at acidic pH. Eukaryotic heat shock and stress-related (Sfl1) transcription factors regulate the constitutive and stress-inducible transcription of several genes (Galeote et al 2007;Hjorth-Sorensen et al 2001;Truman et al 2007), including the hsp genes, and thereby play a central role in the regulation of numerous cellular reprogramming events (Sakurai and Takemori 2007;Squina et al 2010). Therefore, interactions between the PacC/Pal conserved signaling cascade and these transcription factors, which include their competition for target genes, are highly complex.…”

Section: Resultsmentioning

confidence: 99%

Transcription of the Hsp30, Hsp70, and Hsp90 heat shock protein genes is modulated by the PalA protein in response to acid pH-sensing in the fungus Aspergillus nidulans

Freitas

Silva

Leal

et al. 2011

Cell Stress and Chaperones

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Heat shock proteins are molecular chaperones linked to a myriad of physiological functions in both prokaryotes and eukaryotes. In this study, we show that the Aspergillus nidulans hsp30 (ANID_03555.1), hsp70 (ANID_05129.1), and hsp90 (ANID_08269.1) genes are preferentially expressed in an acidic milieu, whose expression is dependent on the palA + background under optimal temperature for fungal growth. Heat shock induction of these three hsp genes showed different patterns in response to extracellular pH changes in the palA + background. However, their accumulation upon heating for 2 h was almost unaffected by ambient pH changes in the palA − background. The PalA protein is a member of a conserved signaling cascade that is involved in the pH-mediated regulation of gene expression. Moreover, we identified several genes whose expression at pH 5.0 is also dependent on the palA + background. These results reveal novel aspects of the heat-and pH-sensing networks of A. nidulans.

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“…Chaperone levels are tightly regulated (Stone and Craig 1990;Hjorth-Sorensen et al 2001) and basal chaperone expression levels might dictate whether a given chaperone can be overexpressed. Thus, endogenous concentrations of Ssa1p and Hsp82p were determined in the presence or absence of Mid2p or Pkc1p overexpression in both the wild-type and ydj1D strains.…”

Section: Identification Of Suppressors Of T(k53r)-ydj1 and Ydj1d Yeastmentioning

confidence: 99%

The Hsp40 Molecular Chaperone Ydj1p, Along With the Protein Kinase C Pathway, Affects Cell-Wall Integrity in the YeastSaccharomyces cerevisiae

et al. 2007

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Molecular chaperones, such as Hsp40, regulate cellular processes by aiding in the folding, localization, and activation of multi-protein machines. To identify new targets of chaperone action, we performed a multi-copy suppressor screen for genes that improved the slow-growth defect of yeast lacking the YDJ1 chromosomal locus and expressing a defective Hsp40 chimera. Among the genes identified were MID2, which regulates cell-wall integrity, and PKC1, which encodes protein kinase C and is linked to cell-wall biogenesis. We found that ydj1D yeast exhibit phenotypes consistent with cell-wall defects and that these phenotypes were improved by Mid2p or Pkc1p overexpression or by overexpression of activated downstream components in the PKC pathway. Yeast containing a thermosensitive allele in the gene encoding Hsp90 also exhibited cell-wall defects, and Mid2p or Pkc1p overexpression improved the growth of these cells at elevated temperatures. To determine the physiological basis for suppression of the ydj1D growth defect, wild-type and ydj1D yeast were examined by electron microscopy and we found that Mid2p overexpression thickened the mutant's cell wall. Together, these data provide the first direct link between cytoplasmic chaperone function and cell-wall integrity and suggest that chaperones orchestrate the complex biogenesis of this structure.

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Activation of heat shock transcription factor in yeast is not influenced by the levels of expression of heat shock proteins

Cited by 34 publications

References 54 publications

Asymmetric Hsp90 N Domain SUMOylation Recruits Aha1 and ATP-Competitive Inhibitors

Asymmetric Hsp90 N Domain SUMOylation Recruits Aha1 and ATP-Competitive Inhibitors

Transcription of the Hsp30, Hsp70, and Hsp90 heat shock protein genes is modulated by the PalA protein in response to acid pH-sensing in the fungus Aspergillus nidulans

The Hsp40 Molecular Chaperone Ydj1p, Along With the Protein Kinase C Pathway, Affects Cell-Wall Integrity in the YeastSaccharomyces cerevisiae

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