Yeast Saccharomyces cerevisiae adiponectin receptor homolog Izh2 is involved in the regulation of zinc, phospholipid and pH homeostasis

[EN] The functional link between zinc homeostasis and membrane-related processes, including lipid metabolism regulation, extends from yeast to humans, and has a likely role in the pathogenesis of diabetes. The yeast Izh2 protein has been previously implicated in zinc ion homeostasis and in the regulation of lipid and phosphate metabolism, but its precise molecular function is not known. We performed a chemogenomics experiment to determine the genes conferring resistance or sensitivity to different environmental zinc concentrations. We then determined at normal, depleted and excess zinc concentrations, the genetic interactions of IZH2 at the genome-wide level and measured changes in the transcriptome caused by deletion of IZH2. We found evidence for an important cellular function of the Rim101 pathway in zinc homeostasis in neutral or acidic environments, and observed that phosphatidylinositol is a source of inositol when zinc availability is limited. Comparison of our experimental profiles with published gene expression and genetic interaction profiles revealed pleiotropic functions for Izh2. We propose that Izh2 acts as an integrator of intra- and extracellular signals in providing adequate cellular responses to maintain homeostasis under different external conditions, including but not limited to alterations in zinc concentrations. Guardar / Salir Siguiente >This work was supported by grant P1-0207 from the Slovenian Research Agency. M.M.U. was supported by the Young Investigator fellowship scheme from the Slovenian Research Agency. Work done in the group of L.Y. was funded by grant BFU2011-30197-C03-03 from the Spanish Ministry of Science and Innovation (Madrid, Spain). C.P. was supported by a pre-doctoral fellowship from the Spanish Research Council.Mattiazzi Usaj, M.; Prelec, M.; Brioznic, M.; Primo Planta, C.; Curk, T.; Scancar, J.; Yenush, L.... (2015). Yeast Saccharomyces cerevisiae adiponectin receptor homolog Izh2 is involved in the regulation of zinc, phospholipid and pH homeostasis. Metallomics. 7(9):1338-1351. https://doi.org/10.1039/c5mt00095e133813517

Systematic genetics and single‐cell imaging reveal widespread morphological pleiotropy and cell‐to‐cell variability

Abstract Our ability to understand the genotype‐to‐phenotype relationship is hindered by the lack of detailed understanding of phenotypes at a single‐cell level. To systematically assess cell‐to‐cell phenotypic variability, we combined automated yeast genetics, high‐content screening and neural network‐based image analysis of single cells, focussing on genes that influence the architecture of four subcellular compartments of the endocytic pathway as a model system. Our unbiased assessment of the morphology of these compartments—endocytic patch, actin patch, late endosome and vacuole—identified 17 distinct mutant phenotypes associated with ~1,600 genes (~30% of all yeast genes). Approximately half of these mutants exhibited multiple phenotypes, highlighting the extent of morphological pleiotropy. Quantitative analysis also revealed that incomplete penetrance was prevalent, with the majority of mutants exhibiting substantial variability in phenotype at the single‐cell level. Our single‐cell analysis enabled exploration of factors that contribute to incomplete penetrance and cellular heterogeneity, including replicative age, organelle inheritance and response to stress

Mammalian-Membrane-Two-Hybrid (MaMTH): a novel split-ubiquitin assay for investigation of signaling pathways in human cells

Cell signaling, one of the key processes involved in human health and disease, is coordinated by numerous membrane protein-protein interactions (PPIs) that change in response to stimuli. Currently, there is a lack of assays that can detect these changes in stimuli- and disease-related contexts. Here, we present a novel split-ubiquitin-method for the detection of integral membrane PPIs in human cells, termed Mammalian-Membrane-Two-Hybrid (MaMTH). We highlight the strength of this technology by showing that it detects stimuli (hormone/agonist)- and phosphorylationdependent PPIs. Importantly, it can detect changes in PPIs conferred by mutations such as those in oncogenic ErbB-receptor variants or by treatment with drugs like the tyrosine-kinase inhibitor erlotinib. Using MaMTH as a screening assay, we identified CRKII as an interactor of oncogenic EGFRL858R, promoting persistent activation of aberrant signaling. In conclusion, our study illustrates that MaMTH is a powerful tool for investigating dynamic interactomes of human integral membrane proteins.The work was supported by grants from the Ontario Genomics Institute (303547), Canadian Institutes of Health Research (Catalyst - NHG99091; ppp-125785), Canadian Foundation for Innovation (IOF-LOF), Natural Sciences and Engineering Research Council of Canada (RGPIN 372393-12), Canadian Cystic Fibrosis Foundation (300348), Canadian Cancer Society (2010-700406), Novartis, UNiversity Health Network (GL2-01-018), FWF-Erwin Schrödinger Fellowship progra

Data from: Systematic analysis of complex genetic interactions

To systematically explore complex genetic interactions, we constructed ~200,000 yeast triple mutants and scored negative trigenic interactions. We selected double-mutant query genes across a broad spectrum of biological processes, spanning a range of quantitative features of the global digenic interaction network and tested for a genetic interaction with a third mutation. Trigenic interactions often occurred among functionally related genes, and essential genes were hubs on the trigenic network. Despite their functional enrichment, trigenic interactions tended to link genes in distant bioprocesses and displayed a weaker magnitude than digenic interactions. We estimate that the global trigenic interaction network is ~100 times as large as the global digenic network, highlighting the potential for complex genetic interactions to affect the biology of inheritance, including the genotype-to-phenotype relationship

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AdditionalDataS5

This file contains the complete list of yeast strains present on the diagnostic array, which was used for genetic interaction screens in this study

AdditionalDataS6

This file contains the trigenic interactions list of MDY2-MTC1 and digenic interaction list of MDY2 and MTC1 corresponding to Fig. 3. The ‘Tetrad Analysis’ tab contains confirmations results obtained from tetrad analysis: SS is synthetic sick, SL is synthetic lethal. The ‘Genetic interactions’ tab contains columns that are annotated with ‘CellMap’ since they contain genetic interactions from (7) downloaded from theCellMap.org (26) as well as scores derived in this study