Similar Datasets
Project description:Protein mutational landscapes are sculpted by the impacts of the resulting amino acid substitutions on the protein’s stability and folding or aggregation kinetics. These properties can, in turn, be modulated by the composition and activities of the cellular proteostasis network. Heat shock factor 1 (HSF1) is the master regulator of the cytosolic and nuclear proteostasis networks, dynamically tuning the expression of cytosolic and nuclear chaperones and quality control factors to meet demand. Chronic increases in HSF1 levels and activity are prominent hallmarks of cancer cells. One plausible explanation for this observation is that the consequent upregulation of proteostasis factors could biophysically facilitate the acquisition of oncogenic mutations. Here, we experimentally evaluate the impacts of chronic HSF1 activation on the mutational landscape accessible to the quintessential oncoprotein p53. Specifically, we apply quantitative deep mutational scanning of p53 to assess how HSF1 activation shapes the mutational pathways by which p53 can escape cytotoxic pressure conferred by the small molecule nutlin-3, which is a potent antagonist of the p53 negative regulator MDM2. We find that HSF1 activation broadly increases the fitness of dominant-negative substitutions within p53. This effect of HSF1 activation was particularly notable for non-conservative, biophysically unfavorable amino acid substitutions within buried regions of the p53 DNA-binding domain. These results indicate that chronic HSF1 activation shapes the oncogenic mutational landscape, preferentially supporting the acquisition of cancer-associated substitutions that are biophysically destabilizing. Along with providing the first experimental and quantitative insights into how HSF1 influences oncoprotein mutational spectra, these findings also implicate HSF1 inhibition as a strategy to alter the accessible mutational landscape of p53.
2025-12-30 | GSE304317 | GEO
Project description:Protein mutational landscapes are sculpted by the impacts of the resulting amino acid substitu-tions on the protein’s stability and folding or aggregation kinetics. These properties can, in turn, be modu-lated by the composition and activities of the cellular proteostasis network. Heat shock factor 1 (HSF1) is the master regulator of the cytosolic and nuclear proteostasis networks, dynamically tuning the expres-sion of cytosolic and nuclear chaperones and quality control factors to meet demand. Chronic increases in HSF1 levels and activity are prominent hallmarks of cancer cells. One plausible explanation for this ob-servation is that the consequent upregulation of proteostasis factors could facilitate the acquisition of on-cogenic mutations. Here, we experimentally evaluate the impacts of chronic HSF1 activation on the muta-tional landscape accessible to the quintessential oncoprotein p53. Specifically, we apply quantitative deep mutational scanning to assess how HSF1 activation shapes the mutational pathways by which p53 can escape cytotoxic pressure conferred by the small molecule nutlin-3, which is a potent antagonist of the p53 negative regulator mouse double minute 2 homolog (MDM2). We find that activation of HSF1 broadly and significantly increases the fitness of dominant-negative substitutions within p53. This effect of HSF1 activation was particularly notable for non-conservative, otherwise biophysically unfavorable non-polar to polar or charged amino acid substitutions within buried regions of the p53 DNA-binding domain. These results indicate that chronic HSF1 activation profoundly shapes the oncogenic mutational land-scape, preferentially supporting the acquisition of cancer-associated substitutions that are biophysically destabilizing. Along with providing the first experimental and quantitative insights into how HSF1 influ-ences oncoprotein mutational spectra, these findings also implicate HSF1 inhibition as a strategy to re-duce the accessibility of mutations that drive chemotherapeutic resistance and metastasis.
2025-12-30 | GSE280707 | GEO
Project description:Protein mutational landscapes are sculpted by the impacts of the resulting amino acid substitutions on the protein's stability and folding or aggregation kinetics. These properties can, in turn, be modulated by the composition and activities of the cellular proteostasis network. Heat shock factor 1 (HSF1) is the master regulator of the cytosolic and nuclear proteostasis networks, dynamically tuning the expression of cytosolic and nuclear chaperones and quality control factors to meet demand. Chronic increases in HSF1 levels and activity are prominent hallmarks of cancer cells. One plausible explanation for this observation is that the consequent upregulation of proteostasis factors could biophysically facilitate the acquisition of oncogenic mutations. Here, we experimentally evaluate the impacts of chronic HSF1 activation on the mutational landscape accessible to the quintessential oncoprotein p53. Specifically, we apply quantitative deep mutational scanning of p53 to assess how HSF1 activation shapes the mutational pathways by which p53 can escape cytotoxic pressure conferred by the small molecule nutlin-3, which is a potent antagonist of the p53 negative regulator MDM2. We find that activation of HSF1 broadly increases the fitness of dominant-negative substitutions within p53. This effect of HSF1 activation was particularly notable for non-conservative, biophysically unfavorable amino acid substitutions within buried regions of the p53 DNA-binding domain. These results indicate that chronic HSF1 activation profoundly shapes the oncogenic mutational landscape, preferentially supporting the acquisition of cancer-associated substitutions that are biophysically destabilizing. Along with providing the first experimental and quantitative insights into how HSF1 influences oncoprotein mutational spectra, these findings also implicate HSF1 inhibition as a strategy to reduce the accessibility of mutations that drive chemotherapeutic resistance and metastasis.
| S-EPMC11565964 | biostudies-literature
Project description:Dominant-negative TP53 mutations potentiated by the HSF1-regulated proteostasis network
| PRJNA1300364 | ENA
Project description:Dominant-negative TP53 mutations potentiated by the HSF1-regulated proteostasis network [1]
| PRJNA1180069 | ENA
Project description:Dominant-negative TP53 mutations potentiated by the HSF1-regulated proteostasis network [2]
| PRJNA1300371 | ENA
Project description:The role of stress-induced increases in SUMO2/3 conjugation during the heat shock response (HSR) has remained enigmatic. We investigated SUMO signal transduction at the proteomic and functional level during the HSR in cells depleted of proteostasis network components via chronic heat shock factor 1 inhibition. In the recovery phase post heat shock, high SUMO2/3 conjugation was prolonged in cells lacking sufficient chaperones. Similar results were obtained upon inhibiting HSP90, indicating that increased chaperone activity during the HSR is critical for recovery to normal SUMO2/3 levels post-heat shock. Proteasome inhibition likewise prolonged SUMO2/3 conjugation, indicating that stress-induced SUMO2/3 targets are subsequently degraded by the ubiquitin-proteasome system. Functionally, we suggest that SUMOylation can enhance the solubility of target proteins upon heat shock, a phenomenon that we experimentally observed in vitro. Collectively, our results implicate SUMO2/3 as a rapid response factor that coordinates proteome degradation and assists the maintenance of proteostasis upon proteotoxic stress.
| S-EPMC6316133 | biostudies-literature
Project description:TP53, which encodes the tumor suppressor p53, is the most frequently mutated gene in human cancer. The selective pressures shaping its mutational spectrum, dominated by missense mutations, are enigmatic, and neomorphic gain-of-function (GOF) activities have been implicated. We used CRISPR-Cas9 to generate isogenic human leukemia cell lines of the most common TP53 missense mutations. Functional, DNA-binding, and transcriptional analyses revealed loss of function but no GOF effects. Comprehensive mutational scanning of p53 single-amino acid variants demonstrated that missense variants in the DNA-binding domain exert a dominant-negative effect (DNE). In mice, the DNE of p53 missense variants confers a selective advantage to hematopoietic cells on DNA damage. Analysis of clinical outcomes in patients with acute myeloid leukemia showed no evidence of GOF for TP53 missense mutations. Thus, a DNE is the primary unit of selection for TP53 missense mutations in myeloid malignancies.
| S-EPMC7327437 | biostudies-literature
Project description:Expression of a dominant negative HSF1 mutant (HSF379) was induced in HEK293 cells and the effect of the transcriptome of non-stressed cells was monitored
2012-03-01 | E-MEXP-3561 | biostudies-arrayexpress
Project description:Identifying triple negative breast cancer (TNBC) patients expected to have poor outcomes provides an opportunity to enhance clinical management. We applied an Evolutionary Action Score to functionally characterize TP53 mutations (EAp53) in 96 TNBC patients and observed that EAp53 stratification may identify TP53 mutations associated with worse outcomes. These findings merit further exploration in larger TNBC cohorts and in patients treated with neoadjuvant chemotherapy regimens.
| S-EPMC9463132 | biostudies-literature