The p53 tumor suppressor is frequently inactivated in human cancers, often through mutations in its core-domain. Here, we developed a yeast reporter system in S. cerevisiae to investigate whether the p53 core-domain can function as a prion-forming domain. By using a chimeric protein (CD-FDp) combining the p53 Core Domain and the Functional Domain of the yeast prion protein Ure2p, we demonstrate that inactive CD-FDp forms heritable, self-propagating aggregates. These aggregates exhibit canonical prion properties, including dominance, non-Mendelian segregation, and cytoduction-mediated transmission. CD-FDp prionization is independent of canonical chaperones (Hsp104, Hsp70, Hsp90), distinguishing it from classical yeast prions. Prionized CD-FDp enhances the formation of amyloid-like foci in full-length p53-EYFP, as evidenced by Thioflavin T staining, and can transmit its prion state to full-length p53 via cytoplasmic transfer. This indicates that CD-FDp propagons can induce structural conversion of p53, supporting an autocatalytic aggregation model. Using a Luria-Delbrück fluctuation assay, we quantified the prionization propensity of wild-type and cancer-associated p53 core-domain mutants. While most mutants (e.g., R273H, R282W) showed inactivation frequencies similar to wild-type, the R175H mutant exhibited an ∼18-fold increase in prionization frequency, which correlates with its known aggregation propensity in human cancers. This yeast system thus provides a quantitative platform to assess the prion-like behavior of p53 mutants and screen for inhibitors of p53 inactivation. Our findings establish p53 core-domain as a novel, structurally distinct prion-forming domain and offer a powerful experimental framework for studying p53 inactivation mechanisms, with potential implications for cancer therapeutics.
Protein misfolding and aberrant protein aggregation are central features of neurodegenerative disorders, including amyotrophic lateral sclerosis, where the RNA-binding protein TDP-43 accumulates in abnormal intracellular assemblies. Although yeast models have identified multiple modifiers of TDP-43 toxicity, the cellular factors that determine how aggregation-prone proteins are organized remain incompletely understood. Here, we investigated whether the ribosome- and mRNP-associated proteins Scp160 and Bfr1 influence TDP-43 proteotoxicity and aggregate formation. We report that deletion of SCP160 or BFR1 improves growth during TDP43-GFP induction without reducing steady-state reporter abundance and decreases formation of prominent TDP43-GFP foci. Deletion of BFR1 produced an intermediate TDP-43 phenotype, with a weaker effect than SCP160 deletion on severe foci formation and toxicity. Importantly, the effect of SCP160 or BFR1 deletion on visible protein aggregation was not specific to TDP-43: severe Htt103Q-GFP aggregation was strongly reduced, and formation of VHL-GFP foci was suppressed, including under conditions of proteasome inhibition. Despite these shared effects, the two mutants were not phenotypically identical. Deletion of SCP160 produced a distinct spatial phenotype in which residual TDP43-GFP foci showed markedly increased association with Sec63-positive ER structures and reduced distance to these regions, whereas bfr1Δ cells did not show the same Sec63-associated shift. Together, these findings uncouple TDP43-GFP abundance from toxicity and prominent foci formation and identify Scp160 and Bfr1 as factors that influence the intracellular partitioning of aggregation-prone and misfolded proteins, with an additional role for Scp160 in the spatial organization of TDP43 relative to the ER.
Proteasomes are primarily located within the nuclei of proliferating cells; however, their localization changes dynamically in response to environmental conditions. Saccharomyces cerevisiae forms proteasome storage granules (PSGs) in the cytoplasm upon glucose depletion, mitochondrial stress, transition to quiescence, or acetic acid stress, with intracellular acidification acting as a key trigger. Despite possessing similar dissociation constants, sorbic acid and acetic acid are noted to exert different physiological effects on yeast cells. In this study, we demonstrate that sorbic acid induces the fastest PSG formation ever reported (within 30 min) at lower concentrations than acetic acid, accompanied by the inhibition of proteasomal proteolysis. Conversely, our analysis of the required factors revealed that, similar to acetic acid, the proteasome subunits Sem1 and Rpn13 are essential for sorbic acid-induced PSG formation. In contrast, the shuttle factors Dsk2 and Rad23, along with the E3 ubiquitin ligase Hul5—which are required for PSG formation under mitochondrial stress or quiescence—are dispensable for sorbic acid-induced PSG formation. These findings not only identify a novel condition for rapid PSG formation but also provide new insights into the physiological effects of sorbic acid on the proteasome, highlighting both its similarities to and differences from acetic acid.
Cancer is a complex disease driven by genetic, metabolic, and environmental alterations, whose investigation is often constrained by the limited tractability of mammalian systems. The budding yeast Saccharomyces cerevisiae has emerged as a powerful eukaryotic model to study conserved cellular processes relevant to tumor biology in a simplified and scalable context and as a versatile platform for translational and biotechnological applications. Through genetic manipulation and heterologous expression, yeast allows systematic analysis of human cancer genes and variants, providing quantitative insights into their functional impact. In parallel, yeast reproduces fundamental features of cancer cell metabolism and stress adaptation, offering a controlled system to investigate cellular responses to environmental constraints. The conservation of major DNA repair and autophagy pathways further supports the use of yeast to study genome stability and survival mechanisms in cancer. Beyond its role in basic research, S. cerevisiae represents a scalable platform for anticancer drug discovery, enabling systematic identification of drug targets, resistance mechanisms, and genotype-specific vulnerabilities through high-throughput and engineered strain-based approaches. Continued development of yeast platforms, together with synthetic biology, functional genomics, and advanced genomic technologies, is expected to accelerate therapeutic innovation and improve our understanding of cancer biology. This review discusses recent advances in yeast-based cancer research, highlighting the contribution of engineered yeast platforms to the investigation of oncogenic signaling, metabolic rewiring, stress adaptation, DNA repair, and autophagy, reinforcing the role of yeast at the interface between cancer research and biotechnology.
Pseudomonas aeruginosa is an opportunistic nosocomial pathogen ranked by the World Health Organization (WHO) as a high priority for research and the development of new antimicrobial therapies. To characterize carbapenem-resistant P. aeruginosa (CRPA) isolated from patients at the Hospital de Urgencia Asistencia Pública (HUAP), Chile in 2022, and to evaluate clonal diversity, resistance mechanisms, virulence factors, and clinical associations. We analyzed 126 clinical CRPA isolates using PFGE, PCR screening of resistance and virulence genes, and whole-genome sequencing of 18 representative strains. Sequence types (STs), resistomes, and virulomes were identified, and their associations with severity, length of hospital stay, cost, and patient outcomes were evaluated. Seventy-four percent of isolates originated from critical care units, predominantly from respiratory and tissue samples. PFGE revealed 25 pulsotypes, with L and Y being the predominant types. Overall, 67% of isolates were XDR and 1% PDR. Carbapenemase genes were absent in 115 isolates, while blaVIM and blaKPC were detected in 8 and 3 isolates, respectively. The exoS +/exoU + genotype was identified in 6 isolates; whole-genome sequencing revealed eight distinct STs, including previously described high-risk clones ST654, ST395, and ST274. A resistome analysis revealed diverse aminoglycoside and β -lactam resistance determinants, while a virulome analysis confirmed the presence of exoS +/exoU + in two sequenced isolates. Carbapenem resistance was significantly associated with prolonged hospitalization (median 84 vs. 39 days), greater clinical severity, and substantially higher healthcare resource utilization, reflected by increased DRG (Diagnosis-Related Group) weights, compared with carbapenem-susceptible controls. Our findings highlight the circulation of high-risk P. aeruginosa clones in Chile and underscore the importance of molecular epidemiology in guiding infection control, optimizing antimicrobial therapy, and mitigating the clinical and economic burden of CRPA.
