The Saccharomyces cerevisiae atypical protein kinase Bud32p is a member of the nuclear endopeptidase‐like, kinase, chromatin‐associated/kinase, endopeptidase‐like and other protein of small size (EKC/KEOPS) complex, known to be involved in the control of transcription and telomere homeostasis. Complex subunits (Pcc1p, Pcc2p, Cgi121p, Kae1p) represent, however, a small subset of the proteins able to interact with Bud32p, suggesting that this protein may be endowed with additional roles unrelated to its participation in the EKC/KEOPS complex. In this context, we investigated the relationships between Bud32p and the nuclear glutaredoxin Grx4p, showing that it is actually a physiological substrate of the kinase and that Bud32p contributes to the full functionality of Grx4p in vivo. We also show that this regulatory system is influenced by the phosphorylation of Bud32p at Ser258, which is specifically mediated by the Sch9p kinase [yeast homolog of mammalian protein kinase B (Akt/PKB)]. Notably, Ser258 phosphorylation of Bud32p does not alter the catalytic activity of the protein kinase per se, but positively regulates its ability to interact with Grx4p and thus to phosphorylate it. Interestingly, this novel signaling pathway represents a function of Bud32p that is independent from its role in the EKC/KEOPS complex, as the known functions of the complex in the regulation of transcription and telomere homeostasis are unaffected when the cascade is impaired. A similar relationship has already been observed in humans between Akt/PKB and p53‐related protein kinase (Bud32p homolog), and could indicate that this pathway is conserved throughout evolution.

Sequence analysis of an 11 628 bp DNA segment from the right arm of Saccharomyces cerevisiae chromosome VII revealed the presence of the 5′ end of the RAD2 gene, the MES1 gene and six open reading frames (ORFs) each longer than 300 bp. Four of these ORFs are expressed genes, as indicated by transcript analysis. One of them, YGR261c, which specifies a putative β‐adaptine, corresponds to gene YKS5, which has recently been identified as a suppressor of loss of casein kinase 1 function. The remaining three ORFs are new genes; of these, YGR260w encodes a protein showing similarity to the S. cerevisiae allantoate permease and YGR262c specifies a putative protein kinase. The sequence has been deposited in the EMBL data library under Accession Number Y07777. ©1997 John Wiley & Sons, Ltd.

Sulphur dioxide (SO₂) is mostly used as an antioxidant additive in winemaking, but excessive levels may be harmful to both wine quality and consumers health. During fermentation, yeast Saccharomyces cerevisiae contributes significantly to final SO₂ levels, and low-producing strains become especially interesting for the wine industry. Recent evidence implicating the impairment of sulphate transport in the SO₂ decrease prompted us to further investigate the sulphate/sulphite metabolic connection in multiple winery yeast strains. Here, we inactivated by CRISPR/Cas9 the high-affinity sulphate permeases (Sul1p and Sul2p) in four strains normally used in winemaking, selected by their different abilities to produce SO₂. Mutant strains were then used to perform fermentation assays in different types of natural must, and the final levels of SO₂ and other secondary metabolites, crucial for wine organoleptic properties, were further determined for all fermentation products. Overall, data demonstrated the double ΔSUL1/ΔSUL2 inactivation in winery strains significantly decreases the levels of SO₂ produced by mutant cells, without however altering both yeast fermentative properties and the ability to release relevant metabolites. Since similar effects were observed in diverse must types for strains with different features, the data strongly support that sulphate assimilation is the determining factor in SO₂ production during oenological fermentations.

The Transactivating response (TAR) element DNA-binding of 43 kDa (TDP-43) is mainly implicated in the regulation of gene expression, playing multiple roles in RNA metabolism. Pathologically, it is implicated in amyotrophic lateral sclerosis and in a class of neurodegenerative diseases broadly going under the name of frontotemporal lobar degeneration (FTLD). A common hallmark of most forms of such diseases is the presence of TDP-43 insoluble inclusions in the cell cytosol. The molecular mechanisms of TDP-43-related cell toxicity are still unclear, and the contribution to cell damage from either loss of normal TDP-43 function or acquired toxic properties of protein aggregates is yet to be established. Here, we investigate the effects on cell viability of FTLD-related TDP-43 mutations in both yeast and mammalian cell models. Moreover, we focus on nucleolin (NCL) gene, recently identified as a genetic suppressor of TDP-43 toxicity, through a thorough structure/function characterization aimed at understanding the role of NCL domains in rescuing TDP-43-induced cytotoxicity. Using functional and biochemical assays, our data demonstrate that the N-terminus of NCL is necessary, but not sufficient, to exert its antagonizing effects on TDP-43, and further support the relevance of the DNA/RNA binding central region of the protein. Concurrently, data suggest the importance of the NCL nuclear localization for TDP-43 trafficking, possibly related to both TDP-43 physiology and toxicity.

Saccharomyces cerevisiae plays a fundamental role in winemaking, not only driving alcoholic fermentation but also producing secondary metabolites that contribute to the organoleptic properties of wine. To ensure consistent quality and process efficiency, wineries commonly employ selected starter strains. Accordingly, the ability to control strain purity and traceability is of critical importance. Currently, the inter-delta PCR method is widely used for the strain-specific genotyping of S. cerevisiae. However, its resolution diminishes when analyzing genetically similar strains, such as those isolated from related grape types or during genotyping of large yeast collections. To address this limitation, we developed a novel strategy that integrates computational and experimental approaches to identify highly specific allelic variants (single nucleotide polymorphisms, SNPs) within the S. cerevisiae genome. Comparative genomic analysis of twenty-eight different strains led to the identification of multiple strain-specific SNPs. From these, nine SNPs spanning five strains were selected and validated through targeted PCR assays. These assays confirmed the feasibility of using SNPs as reliable genetic markers for strain discrimination and traceability. Overall, our findings demonstrate that this SNP-based approach, implemented via multiplex allele-specific (AS) PCR assays, offers a rapid, cost-effective, and highly discriminatory alternative to current genotyping methods, particularly for differentiating closely related strains.