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Cited by 74Heat shock proteins researchAntifungal resistance and susceptibilityFungal and yeast genetics research

Identification of a Key Lysine Residue in Heat Shock Protein 90 Required for Azole and Echinocandin Resistance in Aspergillus fumigatus

Open access
Lamoth, Frédéric, Juvvadi, Praveen R., Soderblom, Erik J., Moseley, M. Arthur, Asfaw, Yohannes G., Steinbach, William J.·2014·Antimicrobial Agents and Chemotherapy
DOI 10.1128/aac.02286-13PMC PMC4023766
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Abstract

Heat shock protein 90 (Hsp90) is an essential chaperone involved in the fungal stress response that can be harnessed as a novel antifungal target for the treatment of invasive aspergillosis. We previously showed that genetic repression of Hsp90 reduced Aspergillus fumigatus virulence and potentiated the effect of the echinocandin caspofungin. In this study, we sought to identify sites of posttranslational modifications (phosphorylation or acetylation) that are important for Hsp90 function in A. fumigatus . Phosphopeptide enrichment and tandem mass spectrometry revealed phosphorylation of three residues in Hsp90 (S49, S288, and T681), but their mutation did not compromise Hsp90 function. Acetylation of lysine residues of Hsp90 was recovered after treatment with deacetylase inhibitors, and acetylation-mimetic mutations (K27A and K271A) resulted in reduced virulence in a murine model of invasive aspergillosis, supporting their role in Hsp90 function. A single deletion of lysine K27 or an acetylation-mimetic mutation (K27A) resulted in increased susceptibility to voriconazole and caspofungin. This effect was attenuated following a deacetylation-mimetic mutation (K27R), suggesting that this site is crucial and should be deacetylated for proper Hsp90 function in antifungal resistance pathways. In contrast to previous reports in Candida albicans , the lysine deacetylase inhibitor trichostatin A (TSA) was active alone against A. fumigatus and potentiated the effect of caspofungin against both the wild type and an echinocandin-resistant strain. Our results indicate that the Hsp90 K27 residue is required for azole and echinocandin resistance in A. fumigatus and that deacetylase inhibition may represent an adjunctive anti- Aspergillus strategy.

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Written from the paper’s full text.

TL;DR

In *Aspergillus fumigatus*, Hsp90 lysine 27 (K27) is required for resistance to voriconazole and caspofungin, while acetylation-mimetic mutation at K27 increases antifungal susceptibility and reduces virulence. The lysine deacetylase inhibitor trichostatin A is active against *A. fumigatus* and synergizes with caspofungin against an echinocandin-resistant strain.

Key findings

  • LC-MS/MS identified Hsp90 phosphorylation at S49, S288, and T681, but alanine mutations at these sites did not compromise Hsp90 function or antifungal susceptibility.
  • Acetylation of Hsp90 K271 was detected after trichostatin A (TSA) treatment; the double acetylation-mimetic mutant K27A-K271A showed a 44% reduction in radial growth versus wild type (P < 0.0001) and reduced conidiation (0.09 ± 0.02 vs 1.32 ± 0.22 million conidia/mm²; P < 0.001).
  • In a murine inhalational invasive aspergillosis model, 45% of mice infected with K27A-K271A were alive at day 14 versus 20% infected with akuBKU80 (P = 0.02).
  • Single K27A or K27 deletion increased susceptibility to voriconazole and caspofungin; K27R (deacetylation mimic) attenuated this effect. TSA was active against wild-type AF293 (MEC 0.5 μg/ml; MIC50 1 μg/ml; MIC90 4 μg/ml), was additive with caspofungin (FICI 1), and was synergistic with caspofungin against echinocandin-resistant strain EMFR-S678P (FICI < 0.5 for MIC50).

Methods

  • Hsp90-EGFP was purified from *A. fumigatus*, digested, enriched for phosphopeptides with TiO2, and analyzed by LC-ESI-MS/MS; acetylation was assessed after TSA treatment.
  • Mutant strains with phosphorylation-site or lysine substitutions/deletion were generated by fusion PCR in *A. fumigatus* akuBKU80 and tested for growth, stress responses, Western expression, and antifungal susceptibility by CLSI broth dilution and checkerboard FICI.
  • Virulence was assessed in 40 male CD1 mice immunosuppressed with cyclophosphamide and triamcinolone acetonide and exposed to aerosolized conidia of K27A-K271A or akuBKU80; survival was compared by Kaplan-Meier log-rank test.

Limitations

  • The paper states that phosphorylation is substoichiometric and dynamic, so some sites may be undetected or stress-specific, and complete determination of a protein’s phosphorylation profile remains challenging.
  • The paper states that in vivo circumstances of Hsp90 K27 acetylation are unknown, the role of K27 in humans is unknown, and TSA’s short half-life limits its in vivo use.
  • Evident from the text: virulence testing was performed only for the K27A-K271A double mutant, not for the single K27A, K27R, or K27Δ strains; TSA antifungal/combination testing was in vitro only.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1128/aac.02286-13

Cites

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Claims the paper makes

0 of 78 cited sources checked · 0 supported · 0 flagged

  • Findingown data
    § RESULTS

    No positive interaction was found between TSA and voriconazole against A. fumigatus wild-type AF293 (FICI, 2; indifference).

    “No positive interaction was found with voriconazole (FICI, 2; indifference).”
    Quote in the paperNot a substantial claim
  • Findingown data
    § RESULTS

    The combination of TSA with caspofungin was additive against A. fumigatus wild-type AF293 (FICI, 1).

    “In checkerboard dilution, the combination of TSA with caspofungin was additive (FICI, 1).”
    Quote in the paperNot a substantial claim
  • Findingown data
    § RESULTS

    The K27A-K271A mutant stably expressed the mutated Hsp90 protein despite functional alterations.

    “Western analysis confirmed that the mutated Hsp90 protein was stably expressed in this strain despite these important functional alterations (Fig. 2C).”
    Quote in the paperSubstantial claim
  • Findingown data
    § RESULTS

    The K27A-K271A double mutation reduced sporulation, with conidial count 0.09 ± 0.02 million conidia/mm2 versus 1.32 ± 0.22 million conidia/mm2 in wild type (P < 0.001).

    “Sporulation was also reduced, as shown by the white colony appearance (Fig. 2A), which was confirmed by the conidial count (0.09 ± 0.02 million conidia/mm2 versus 1.32 ± 0.22 million conidia/mm2 in the wild type; P < 0.001).”
    Quote in the paperNot a substantial claim
  • Findingown data
    § RESULTS

    The echinocandin-resistant A. fumigatus strain EMFR-S678P displayed a higher TSA MEC (4 μg/ml).

    “The echinocandin-resistant strain (EMFR-S678P) displayed a higher MEC (4 μg/ml).”
    Quote in the paperNot a substantial claim
  • May combine two claims. 21
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 37

  • May combine two claims.

    Findingown data
    § RESULTS

    The K27Δ strain displayed the same antifungal susceptibility profile as the K27A strain and could not adapt to heat stress.

    “We then generated another strain in which K27 was deleted (K27Δ), and this strain displayed the same antifungal susceptibility profile as the K27A strain and could not adapt to heat stress.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    The K27A mutation was sufficient to impact Hsp90 function, shown by hypersensitivity to geldanamycin, and to induce substantial increase of sensitivity to caspofungin and voriconazole without compromising heat stress responses.

    “However, the K27A mutation was sufficient to impact Hsp90 function, as shown by the hypersensitivity to geldanamycin, and to induce a substantial increase of sensitivity to caspofungin and voriconazole without compromising other Hsp90-mediated stress responses such as to heat stress.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    The single K271A mutation did not impact adaptive responses to geldanamycin, heat stress, voriconazole, or caspofungin.

    “The single K271A mutation did not result in any impact on the adaptive responses to these stress conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    TSA achieved ≥50% growth inhibition (MIC50) at 1 μg/ml and ≥90% (MIC90) at 4 μg/ml against A. fumigatus wild-type AF293.

    “Growth inhibition levels of ≥50% (MIC50) and ≥90% (MIC90) were achieved at concentrations of 1 and 4 μg/ml, respectively (see Fig. S2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    Azole-resistant A. fumigatus clinical isolates (F16134, F14946, F16216, F12776) were resistant to TSA (MEC ≥8 μg/ml), and TSA did not reduce their azole resistance.

    “Azole-resistant strains (F16134, F14946, F16216, and F12776) were also resistant to TSA (MEC of ≥8 μg/ml), and there was no reduction of azole resistance in the presence of TSA.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    The K27R mutation resulted in a slight increase of susceptibility to geldanamycin and voriconazole but did not cause hypersensitivity to caspofungin and retained the caspofungin paradoxical response.

    “Despite a slight increase of susceptibility to geldanamycin and voriconazole, the K27R strain was not hypersensitive to caspofungin and was still capable of a paradoxical response (Fig. 4).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    The K27A-K271A strain exhibited hypersensitivity to voriconazole and caspofungin, including loss of the caspofungin paradoxical effect.

    “Hypersensitivity to the antifungal drugs voriconazole and caspofungin, including loss of the caspofungin paradoxical effect (i.e., increase of growth at high concentrations), were also observed (Fig. 4)”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingnone given
    § RESULTS

    The response to heat stress was conserved under TSA treatment.

    “The response to heat stress was conserved.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § DISCUSSION

    The double K27A-K271A mutation significantly reduced A. fumigatus growth and virulence.

    “and the double K27A-K271A mutation significantly reduced A. fumigatus growth and virulence.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § INTRODUCTION

    Fungal Hsp90 promotes resistance to azole and echinocandin drugs, as demonstrated in Candida albicans.

    “Fungal Hsp90 promotes resistance to azole and echinocandin drugs, which has been well demonstrated in the pathogenic yeast Candida albicans (6, 10, 11).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [6] Cowen LE, Singh SD, Kohler JR, Collins C, Zaas AK, Schell WA, Aziz H, Mylonakis E, Perfect JR, Whitesell L, Lindquist S. 2009. Harnessing Hsp90 function as a powerful, broadly effective therapeutic strategy for fungal infectious disease. Proc. Natl. Acad. Sci. U. S. A. 106:2818–2823. 10.1073/pnas.0813394106 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [10] Cowen LE, Lindquist S. 2005. Hsp90 potentiates the rapid evolution of new traits: drug resistance in diverse fungi. Science 309:2185–2189. 10.1126/science.1118370 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [11] Singh SD, Robbins N, Zaas AK, Schell WA, Perfect JR, Cowen LE. 2009. Hsp90 governs echinocandin resistance in the pathogenic yeast Candida albicans via calcineurin. PLoS Pathog. 5:e1000532. 10.1371/journal.ppat.1000532 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § INTRODUCTION

    Activation of Hsp90 and interactions with its client proteins and cochaperones are mediated by posttranslational modifications.

    “Activation of Hsp90 and interactions with its client proteins and cochaperones are mediated by posttranslational modifications, such as phosphorylation, acetylation, oxidation, S-nitrosylation, and ubiquitination (13).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § INTRODUCTION

    Calcineurin inhibitors (FK506 and cyclosporine) and Hsp90 inhibitors (geldanamycin, 17-AAG, and 17-DMAG) are active against A. fumigatus and potentiate the effect of caspofungin.

    “Calcineurin inhibitors (FK506 and cyclosporine) and Hsp90 inhibitors (geldanamycin, 17-allylamino-17-demethoxygeldanamycin [17-AAG], and 17-demethylaminoethylamino-17-demethoxygeldanamycin [17-DMAG]) are active against A. fumigatus and potentiate the effect of caspofungin (6–8)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [6] Cowen LE, Singh SD, Kohler JR, Collins C, Zaas AK, Schell WA, Aziz H, Mylonakis E, Perfect JR, Whitesell L, Lindquist S. 2009. Harnessing Hsp90 function as a powerful, broadly effective therapeutic strategy for fungal infectious disease. Proc. Natl. Acad. Sci. U. S. A. 106:2818–2823. 10.1073/pnas.0813394106 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [7] Lamoth F, Juvvadi PR, Fortwendel JR, Steinbach WJ. 2012. Heat shock protein 90 is required for conidiation and cell wall integrity in Aspergillus fumigatus. Eukaryot. Cell 11:1324–1332. 10.1128/EC.00032-12 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    • cites [8] Lamoth F, Juvvadi PR, Gehrke C, Steinbach WJ. 2013. In vitro activity of calcineurin and heat shock protein 90 Inhibitors against Aspergillus fumigatus azole- and echinocandin-resistant strains. Antimicrob. Agents Chemother. 57:1035–1039. 10.1128/AAC.01857-12 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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  • Classified as probably not a substantial claim.

    Premisecitation
    § INTRODUCTION

    The Hsp90-calcineurin axis is a crucial element governing stress adaptation processes in fungi.

    “The heat shock protein 90 (Hsp90)-calcineurin axis is a crucial element governing stress adaptation processes in fungi (5).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5] Cowen LE. 2008. The evolution of fungal drug resistance: modulating the trajectory from genotype to phenotype. Nat. Rev. Microbiol. 6:187–198. 10.1038/nrmicro1835 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § INTRODUCTION

    Compromising Hsp90-mediated stress responses by genetic modifications of the hsp90 promoter potentiates the effect of caspofungin and abolishes the paradoxical effect of this drug.

    “Compromising Hsp90-mediated stress responses by genetic modifications of the hsp90 promoter also potentiated the effect of caspofungin and abolished the paradoxical effect of this drug (7, 12).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [7] Lamoth F, Juvvadi PR, Fortwendel JR, Steinbach WJ. 2012. Heat shock protein 90 is required for conidiation and cell wall integrity in Aspergillus fumigatus. Eukaryot. Cell 11:1324–1332. 10.1128/EC.00032-12 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    • cites [12] Lamoth F, Juvvadi PR, Gehrke C, Asfaw YG, Steinbach WJ. 4 October 2013. Transcriptional activation of heat shock protein 90 (Hsp90) mediated via a proximal promoter region as trigger of caspofungin resistance in Aspergillus fumigatus. J. Infect. Dis. 10.1093/infdis/jit530 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    Premisecitation
    § INTRODUCTION

    The K27 residue was found to be acetylated in yeasts.

    “The K27 residue was also found to be acetylated in yeasts (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

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    Premisecitation
    § INTRODUCTION

    Multiple phosphorylation sites have been identified as regulatory elements of Hsp90 function in human and yeast.

    “Multiple phosphorylation sites have been identified as regulatory elements of Hsp90 function in human and yeast (13–15).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [14] Mollapour M, Tsutsumi S, Kim YS, Trepel J, Neckers L. 2011. Casein kinase 2 phosphorylation of Hsp90 threonine 22 modulates chaperone function and drug sensitivity. Oncotarget 2:407–417 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    • cites [15] Soroka J, Wandinger SK, Mausbacher N, Schreiber T, Richter K, Daub H, Buchner J. 2012. Conformational switching of the molecular chaperone Hsp90 via regulated phosphorylation. Mol. Cell 45:517–528. 10.1016/j.molcel.2011.12.031 [DOI] [PubMed] [Google Scholar] source

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    Premisecitation
    § INTRODUCTION

    Acetylation of the K294 residue in human Hsp90 and its corresponding residue K270 in Saccharomyces cerevisiae is important for Hsp90 function.

    “Acetylation of the K294 residue in human Hsp90 and its corresponding residue K270 in Saccharomyces cerevisiae is important for Hsp90 function (16, 21).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [16] Scroggins BT, Robzyk K, Wang D, Marcu MG, Tsutsumi S, Beebe K, Cotter RJ, Felts S, Toft D, Karnitz L, Rosen N, Neckers L. 2007. An acetylation site in the middle domain of Hsp90 regulates chaperone function. Mol. Cell 25:151–159. 10.1016/j.molcel.2006.12.008 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

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    Premisecitation
    § MATERIALS AND METHODS

    The laboratory strain EMFR-S678P is pan-echinocandin-resistant.

    “the pan-echinocandin-resistant laboratory strain EMFR-S678P (a gift from David Perlin) (32)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] Rocha EM, Garcia-Effron G, Park S, Perlin DS. 2007. A Ser678Pro substitution in Fks1p confers resistance to echinocandin drugs in Aspergillus fumigatus. Antimicrob. Agents Chemother. 51:4174–4176. 10.1128/AAC.00917-07 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

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    Study design and conductcitation
    § MATERIALS AND METHODS

    Antifungal susceptibility testing was performed in liquid RPMI 1640 medium according to the Clinical and Laboratory Standards Institute (CLSI) procedure.

    “Antifungal susceptibility testing was performed in liquid RPMI 1640 medium according to the Clinical and Laboratory Standards Institute (CLSI) procedure (33).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] Clinical and Laboratory Standards Institute. 2008. Reference method for broth dilution antifungal susceptibility testing of filamentous fungi, 2nd ed. CLSI document M38-A2 Clinical and Laboratory Standards Institute, Wayne, PA [Google Scholar]

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    Premisecitation
    § DISCUSSION

    Four serine residues (S379, S485, S602, and S604) in S. cerevisiae Hsp90 play some role in Hsp90 function.

    “Four serine residues were found to play some role in Hsp90 function (S379, S485, S602, and S604).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Soroka J, Wandinger SK, Mausbacher N, Schreiber T, Richter K, Daub H, Buchner J. 2012. Conformational switching of the molecular chaperone Hsp90 via regulated phosphorylation. Mol. Cell 45:517–528. 10.1016/j.molcel.2011.12.031 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Mutation of K270 to arginine or glutamine in S. cerevisiae Hsp90 resulted in increased susceptibility to geldanamycin, indicative of altered Hsp90 function.

    “Mutation of K270 to arginine or glutamine in S. cerevisiae Hsp90 resulted in increased susceptibility to geldanamycin, indicative of altered Hsp90 function, which was enhanced by additional K27 mutation (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § RESULTS

    Phosphorylation of S49 was previously reported in human Hsp90 (corresponding human site S63).

    “While phosphorylation of S49 was previously reported in human Hsp90 (corresponding human site S63) (13)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    A similar mass spectrometric analysis in S. cerevisiae identified 10 phosphorylation sites in Hsp90.

    “A similar mass spectrometric analysis in the yeast S. cerevisiae identified 10 phosphorylation sites in Hsp90 (15).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Soroka J, Wandinger SK, Mausbacher N, Schreiber T, Richter K, Daub H, Buchner J. 2012. Conformational switching of the molecular chaperone Hsp90 via regulated phosphorylation. Mol. Cell 45:517–528. 10.1016/j.molcel.2011.12.031 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § MATERIALS AND METHODS

    The clinical isolates F16134, F14946, F16216, and F12776 are multiazole-resistant and harbor various mutations of the cyp51a gene.

    “four multiazole-resistant clinical isolates harboring various mutations of the cyp51a gene (strains F16134, F14946, F16216, and F12776; gifts from David Denning) (3)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Howard SJ, Cerar D, Anderson MJ, Albarrag A, Fisher MC, Pasqualotto AC, Laverdiere M, Arendrup MC, Perlin DS, Denning DW. 2009. Frequency and evolution of Azole resistance in Aspergillus fumigatus associated with treatment failure. Emerg. Infect. Dis. 15:1068–1076. 10.3201/eid1507.090043 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Internal acetylation of lysine residues has recently emerged as an important posttranslational modification of Hsp90.

    “Internal acetylation of lysine residues has recently emerged as an important posttranslational modification of Hsp90 (13, 16, 21).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [16] Scroggins BT, Robzyk K, Wang D, Marcu MG, Tsutsumi S, Beebe K, Cotter RJ, Felts S, Toft D, Karnitz L, Rosen N, Neckers L. 2007. An acetylation site in the middle domain of Hsp90 regulates chaperone function. Mol. Cell 25:151–159. 10.1016/j.molcel.2006.12.008 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § RESULTS

    TSA induces acetylation of Hsp90 in eukaryotes.

    “To further investigate the potential of acetylation to inhibit Hsp90 function, we used trichostatin A (TSA), which was shown to induce acetylation of Hsp90 in eukaryotes (17–20).”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [17] Bali P, Pranpat M, Bradner J, Balasis M, Fiskus W, Guo F, Rocha K, Kumaraswamy S, Boyapalle S, Atadja P, Seto E, Bhalla K. 2005. Inhibition of histone deacetylase 6 acetylates and disrupts the chaperone function of heat shock protein 90: a novel basis for antileukemia activity of histone deacetylase inhibitors. J. Biol. Chem. 280:26729–26734. 10.1074/jbc.C500186200 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

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      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § RESULTS

    TSA and other related KDAC inhibitors were previously found to have minimal antifungal activity against C. albicans but to enhance the effect of azole compounds and to reduce resistance of azole-resistant strains.

    “TSA and other related lysine deacetylase (KDAC) inhibitors were previously found to have minimal antifungal activity against C. albicans but to enhance the effect of azole compounds and to reduce resistance of azole-resistant strains (21, 35, 36).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [35] Pfaller MA, Messer SA, Georgopapadakou N, Martell LA, Besterman JM, Diekema DJ. 2009. Activity of MGCD290, a Hos2 histone deacetylase inhibitor, in combination with azole antifungals against opportunistic fungal pathogens. J. Clin. Microbiol. 47:3797–3804. 10.1128/JCM.00618-09 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [36] Smith WL, Edlind TD. 2002. Histone deacetylase inhibitors enhance Candida albicans sensitivity to azoles and related antifungals: correlation with reduction in CDR and ERG upregulation. Antimicrob. Agents Chemother. 46:3532–3539. 10.1128/AAC.46.11.3532-3539.2002 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § RESULTS

    The N-terminal serine residue S2 is a constitutively acetylated site in eukaryotic proteins with a role in degradation signaling.

    “except for the N-terminal serine residue (S2), which represents a constitutively acetylated site in eukaryotic proteins that has a role in degradation signaling (34).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Hwang CS, Shemorry A, Varshavsky A. 2010. N-terminal acetylation of cellular proteins creates specific degradation signals. Science 327:973–977. 10.1126/science.1183147 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Posttranslational modifications such as phosphorylation and acetylation play important roles in Hsp90 activation and in regulation of its interactions.

    “As a chaperone, Hsp90 interacts with a large network of client proteins, and posttranslational modifications, such as phosphorylation and acetylation, are known to play important roles in its activation and in the regulation of these interactions (13).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Hsp90 interacts with a large network of client proteins.

    “As a chaperone, Hsp90 interacts with a large network of client proteins, and posttranslational modifications, such as phosphorylation and acetylation, are known to play important roles in its activation and in the regulation of these interactions (13).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Mollapour M, Neckers L. 2012. Post-translational modifications of Hsp90 and their contributions to chaperone regulation. Biochim. Biophys. Acta 1823:648–655. 10.1016/j.bbamcr.2011.07.018 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationown data
    § DISCUSSION

    Important differences may exist in the phosphorylation profile and mechanisms of activation of Hsp90 between yeasts and molds.

    “which suggests that important differences may exist in the phosphorylation profile and mechanisms of activation of Hsp90 between yeasts and molds.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    A complete determination of the phosphorylation profile of a given protein remains a challenge despite advanced phospho-enrichment MS techniques.

    “Thus, despite the high confidence of localization and sensitivity of such advanced phospho-enrichment MS techniques, a complete determination of the phosphorylation profile of a given protein still remains a challenge (37).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] Eyrich B, Sickmann A, Zahedi RP. 2011. Catch me if you can: mass spectrometry-based phosphoproteomics and quantification strategies. Proteomics 11:554–570. 10.1002/pmic.201000489 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Single mutation of K27 to arginine or glutamine in S. cerevisiae did not impact geldanamycin or azole susceptibility.

    “The K27 residue was found to be acetylated in a lysine deacetylase knockdown strain of S. cerevisiae, but its single mutation to either arginine or glutamine did not result in any impact on geldanamycin or azole susceptibility (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data
    § MATERIALS AND METHODS

    Homologous recombination and integration of the mutations were verified by sequencing.

    “Homologous recombination and integration of the mutations were verified by sequencing.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation
    § RESULTS

    The K27 residue was found to be acetylated after genetic knockdown of lysine deacetylases in S. cerevisiae.

    “Because the K27 residue, located in a highly conserved region, was found to be acetylated after genetic knockdown of lysine deacetylases in S. cerevisiae (21)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Acetylation mimic of K271 was sufficient to destabilize Hsp90 function in human and yeast.

    “Mutation mimicking acetylation of this site, which was sufficient to destabilize Hsp90 function in human and yeast (16, 21), had no major impact in A. fumigatus.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [16] Scroggins BT, Robzyk K, Wang D, Marcu MG, Tsutsumi S, Beebe K, Cotter RJ, Felts S, Toft D, Karnitz L, Rosen N, Neckers L. 2007. An acetylation site in the middle domain of Hsp90 regulates chaperone function. Mol. Cell 25:151–159. 10.1016/j.molcel.2006.12.008 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation
    § MATERIALS AND METHODS

    The probability of correct phosphorylation site localization was assessed by the Ascore algorithm.

    “The probability of correct phosphorylation site localization was assessed by the Ascore algorithm (24).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Beausoleil SA, Villen J, Gerber SA, Rush J, Gygi SP. 2006. A probability-based approach for high-throughput protein phosphorylation analysis and site localization. Nat. Biotechnol. 24:1285–1292. 10.1038/nbt1240 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    The K27 residue was found to be acetylated in a lysine deacetylase knockdown strain of S. cerevisiae.

    “The K27 residue was found to be acetylated in a lysine deacetylase knockdown strain of S. cerevisiae, but its single mutation to either arginine or glutamine did not result in any impact on geldanamycin or azole susceptibility (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    In yeasts, TSA and other KDAC inhibitors demonstrated very modest antifungal activity, despite their potentiating effect on azoles.

    “In yeasts, TSA and other KDAC inhibitors demonstrated very modest antifungal activity, despite their potentiating effect on azoles (21, 35, 36).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [35] Pfaller MA, Messer SA, Georgopapadakou N, Martell LA, Besterman JM, Diekema DJ. 2009. Activity of MGCD290, a Hos2 histone deacetylase inhibitor, in combination with azole antifungals against opportunistic fungal pathogens. J. Clin. Microbiol. 47:3797–3804. 10.1128/JCM.00618-09 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [36] Smith WL, Edlind TD. 2002. Histone deacetylase inhibitors enhance Candida albicans sensitivity to azoles and related antifungals: correlation with reduction in CDR and ERG upregulation. Antimicrob. Agents Chemother. 46:3532–3539. 10.1128/AAC.46.11.3532-3539.2002 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    The short half-life of TSA does not make it a good candidate for in vivo use.

    “The short half-life of TSA does not make it a good candidate for in vivo use (42), but more stable and more specific KDAC inhibitors have been developed and are contemplated for application in anticancer therapy (43, 44).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Sanderson L, Taylor GW, Aboagye EO, Alao JP, Latigo JR, Coombes RC, Vigushin DM. 2004. Plasma pharmacokinetics and metabolism of the histone deacetylase inhibitor trichostatin a after intraperitoneal administration to mice. Drug Metab. Dispos. 32:1132–1138. 10.1124/dmd.104.000638 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Deletion of both rpd3 and hda1 in yeasts resulted in decreased azole resistance similar to the effect of pharmacologic inhibition by TSA.

    “Yeasts with deletion of the ortholog gene (rpd3) were still viable, and deletion of both rpd3 and hda1 resulted in decreased azole resistance similar to the effect of pharmacologic inhibition by TSA (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Analyses of the KDAC activity pattern in fungi revealed important differences among yeasts and molds.

    “Analyses of the KDAC activity pattern in fungi revealed important differences among yeasts and molds (39, 40), which could explain these discrepancies.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [39] Tribus M, Galehr J, Trojer P, Brosch G, Loidl P, Marx F, Haas H, Graessle S. 2005. HdaA, a major class 2 histone deacetylase of Aspergillus nidulans, affects growth under conditions of oxidative stress. Eukaryot. Cell 4:1736–1745. 10.1128/EC.4.10.1736-1745.2005 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [40] Trojer P, Brandtner EM, Brosch G, Loidl P, Galehr J, Linzmaier R, Haas H, Mair K, Tribus M, Graessle S. 2003. Histone deacetylases in fungi: novel members, new facts. Nucleic Acids Res. 31:3971–3981. 10.1093/nar/gkg473 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data
    § DISCUSSION

    Either K27 or K271 should be unacetylated to counteract heat stress.

    “For instance, we noted that either K27 or K271 should be unacetylated to counteract heat stress.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data
    § DISCUSSION

    The authors' data suggest a similar Hsp90-mediated pathway but also mechanisms of action of TSA that may be independent of Hsp90.

    “Our data suggest a similar Hsp90-mediated pathway but also mechanisms of action of TSA that may be independent of Hsp90.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § DISCUSSION

    Deletion of hdaA led to a major defect of KDAC activity and hypersensitivity to oxidative stress in A. nidulans.

    “Deletion of hdaA led to a major defect of KDAC activity and hypersensitivity to oxidative stress (39).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Tribus M, Galehr J, Trojer P, Brosch G, Loidl P, Marx F, Haas H, Graessle S. 2005. HdaA, a major class 2 histone deacetylase of Aspergillus nidulans, affects growth under conditions of oxidative stress. Eukaryot. Cell 4:1736–1745. 10.1128/EC.4.10.1736-1745.2005 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Knockdown of certain lysine deacetylases (KDACs) in S. cerevisiae achieved an effect on azole resistance.

    “The key role of K27 in antifungal resistance is unique to A. fumigatus as mutation of K27 and/or K271 in S. cerevisiae to either acetylation- or deacetylation-mimicking residues did not have any impact on azole resistance although this effect was achieved following knockdown of certain lysine deacetylases (KDACs) (21).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Robbins N, Leach MD, Cowen LE. 2012. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2:878–888. 10.1016/j.celrep.2012.08.035 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    Deletion of rpdA (a class 1 KDAC) was lethal in A. nidulans.

    “Interestingly, deletion of rpdA (a class 1 KDAC), whose contribution to KDAC activity is less important, was lethal in A. nidulans, and its repression resulted in growth and conidiation defects that were comparable to the phenotypic consequences of Hsp90 repression in our previous works (7, 12, 41).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [7] Lamoth F, Juvvadi PR, Fortwendel JR, Steinbach WJ. 2012. Heat shock protein 90 is required for conidiation and cell wall integrity in Aspergillus fumigatus. Eukaryot. Cell 11:1324–1332. 10.1128/EC.00032-12 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [12] Lamoth F, Juvvadi PR, Gehrke C, Asfaw YG, Steinbach WJ. 4 October 2013. Transcriptional activation of heat shock protein 90 (Hsp90) mediated via a proximal promoter region as trigger of caspofungin resistance in Aspergillus fumigatus. J. Infect. Dis. 10.1093/infdis/jit530 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [41] Tribus M, Bauer I, Galehr J, Rieser G, Trojer P, Brosch G, Loidl P, Haas H, Graessle S. 2010. A novel motif in fungal class 1 histone deacetylases is essential for growth and development of Aspergillus. Mol. Biol. Cell 21:345–353. 10.1091/mbc.E09-08-0750 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § DISCUSSION

    Taken together, these data may explain discrepancies in TSA activity against A. fumigatus and C. albicans and support the existence of distinct activity patterns of KDACs in governing acetylation/deacetylation processes and antifungal resistance between yeasts and molds.

    “Taken together, these data may explain the discrepancies in TSA activity against A. fumigatus and C. albicans and further support the existence of distinct activity patterns of KDACs in governing acetylation/deacetylation processes and antifungal resistance between yeasts and molds.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § DISCUSSION

    In Aspergillus nidulans, RpdA (class 1) and HdaA (class 2) are major contributors to total KDAC activity.

    “In Aspergillus nidulans, RpdA (class 1) and HdaA (class 2) were shown to be the major contributors to the total KDAC activity (40).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Trojer P, Brandtner EM, Brosch G, Loidl P, Galehr J, Linzmaier R, Haas H, Mair K, Tribus M, Graessle S. 2003. Histone deacetylases in fungi: novel members, new facts. Nucleic Acids Res. 31:3971–3981. 10.1093/nar/gkg473 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § DISCUSSION

    More stable and more specific KDAC inhibitors have been developed and are contemplated for application in anticancer therapy.

    “The short half-life of TSA does not make it a good candidate for in vivo use (42), but more stable and more specific KDAC inhibitors have been developed and are contemplated for application in anticancer therapy (43, 44).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [43] Elaut G, Laus G, Alexandre E, Richert L, Bachellier P, Tourwe D, Rogiers V, Vanhaecke T. 2007. A metabolic screening study of trichostatin A (TSA) and TSA-like histone deacetylase inhibitors in rat and human primary hepatocyte cultures. J. Pharmacol. Exp. Ther. 321:400–408. 10.1124/jpet.106.116202 [DOI] [PubMed] [Google Scholar] source

      Not checked in the free run.

    • cites [44] Kaliszczak M, Trousil S, Aberg O, Perumal M, Nguyen QD, Aboagye EO. 2013. A novel small molecule hydroxamate preferentially inhibits HDAC6 activity and tumour growth. Br. J. Cancer 108:342–350. 10.1038/bjc.2012.576 [DOI] [PMC free article] [PubMed] [Google Scholar] source

      Not checked in the free run.

50 of 50

  • The paper relies on this without support.

    Phosphorylation of A. fumigatus Hsp90 had not been previously investigated.

    “Phosphorylation of A. fumigatus Hsp90, however, has not been previously investigated.”

  • The paper relies on this without support.

    The S288 and T681 residues of A. fumigatus Hsp90 have never been described as phosphorylated.

    “the S288 and T681 residues have never been described as phosphorylated.”

  • The paper relies on this without support.

    Hsp90 is a highly conserved protein in eukaryotes.

    “Because Hsp90 is a highly conserved protein in eukaryotes”

  • The paper relies on this without support.

    The K27 residue is located in a highly conserved region.

    “Because the K27 residue, located in a highly conserved region, was found to be acetylated after genetic knockdown of lysine deacetylases in S. cerevisiae (21)”

  • The paper relies on this without support.

    Phosphorylation is a substoichiometric and dynamic process, so some phosphorylation sites may be undetected or become phosphorylated only under specific stress conditions.

    “because phosphorylation is a substoichiometric and dynamic process (i.e., a variable ratio of a given protein being phosphorylated at a given time point), it is possible that some sites may be undetected or become phosphorylated only under specific stress conditions.”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Lysine 27 residue of Hsp90 plays a vital role in acetylation-dependent regulation for azole and echinocandin resistance in A. fumigatus.

    “Acetylation-dependent regulation of Hsp90 is also crucial for azole and echinocandin resistance in A. fumigatus, with the lysine 27 residue playing a vital role in this process92.”

    From Molecular mechanisms governing antifungal drug resistance (2023) · cites this paper as [92]

  • Acetylation-dependent regulation of Hsp90 is crucial for azole and echinocandin resistance in A. fumigatus.

    “Acetylation-dependent regulation of Hsp90 is also crucial for azole and echinocandin resistance in A. fumigatus, with the lysine 27 residue playing a vital role in this process92.”

    From Molecular mechanisms governing antifungal drug resistance (2023) · cites this paper as [92]

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. MarrKSchlammHRottinghausSTJagannathaSBowEJWingardJRPappasPHebrechtRWalshTJMaertensJ. 2012. A randomised, double-bind study of combination antifungal therapy with voriconazole and anidulafungin versus voriconazole monotherapy for primary treatment of invasive aspergillosis, abstr LB2812. Absourcestr. 22nd Eur. Congr. Clin. Microbiol. Infect. Dis., London, United Kingdom, 31 March to 3 April 2012.

Cited by

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Related

Authors
Lamoth, F., Juvvadi, P. R., Soderblom, E. J., Moseley, M. A., Asfaw, Y. G., & Steinbach, W. J.
Affiliations
  • Centre Hospitalier Universitaire Vaudois (CH)
  • Duke Medical Center (US)
  • Duke University (US)
ORCID
Venue
Antimicrobial Agents and Chemotherapy
Publisher
American Society for Microbiology
Published
2014-04
Volume
58
Issue
4
Pages
1889-1896
ISSN
  • 0066-4804 (ISSN-L)
  • 1098-6596
DOI
10.1128/aac.02286-13
PMC
PMC4023766
OpenAlex
W1992114525
Semantic Scholar
59f06c1c304b364e525d5647c91c8be197978331
Cited by
74
References
44
Citations by year
2026: 4 · 2025: 3 · 2024: 2 · 2023: 4 · 2022: 7 · 2021: 6 · 2020: 9 · 2019: 11 · 2018: 3 · 2017: 6 · 2016: 7 · 2015: 9 · 2014: 3
FWCI
3.41
Type
journal article
Language
en
Open access
Licence
journals.asm.org/non-commercial-tdm-license (tdm)
Locations
  • Antimicrobial Agents and Chemotherapy (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • IRIS (submittedVersion)
  • SERVAL (Université de Lausanne) (submittedVersion)
Funders
  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (142746)
  • National Institutes of Health
  • National Institute of Allergy and Infectious Diseases (R21AI097541)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Heat shock proteins research
  • Health Sciences › Medicine › Infectious Diseases › Antifungal resistance and susceptibility
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Fungal and yeast genetics research
Keywords
HSP90, Aspergillus fumigatus, lysine acetylation, lysine deacetylation, trichostatin A, azole resistance, voriconazole, echinocandin resistance, caspofungin, antifungal resistance, invasive aspergillosis, fungal virulence, antifungal drug targets
MeSH terms
Caspofungin, Antifungal Agents, Aspergillus fumigatus, Azoles, Lysine, HSP90 Heat-Shock Proteins, Drug Resistance, Fungal, Echinocandins, Lipopeptides

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Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

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