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Abstract
Moonlighting proteins are multifunctional proteins that participate in unrelated biological processes and that are not the result of gene fusion. A certain number of these proteins have been characterized in yeasts, and the easy genetic manipulation of these microorganisms has been useful for a thorough analysis of some cases of moonlighting. As the awareness of the moonlighting phenomenon has increased, a growing number of these proteins are being uncovered. In this review, we present a crop of newly identified moonlighting proteins from yeasts and discuss the experimental evidence that qualifies them to be classified as such. The variety of moonlighting functions encompassed by the proteins considered extends from control of transcription to DNA repair or binding to plasminogen. We also discuss several questions pertaining to the moonlighting condition in general. The cases presented show that yeasts are important organisms to be used as tools to understand different aspects of moonlighting proteins.
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Ottaviano D, Montanari A, De Angelis L, Santomartino R, Visca A, Brambilla L, Rinaldi T, Bello C, Reverberi M, Bianchi MM. Unsaturated fatty acids-dependent linkage between respiration and fermentation revealed by deletion of hypoxic regulatory KlMGA2 gene in the facultative anaerobe-respiratory yeast Kluyveromyces lactis. FEMS Yeast Res 2015; 15:fov028. [PMID: 26019145 DOI: 10.1093/femsyr/fov028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2015] [Indexed: 01/03/2023] Open
Abstract
In the yeast Kluyveromyces lactis, the inactivation of structural or regulatory glycolytic and fermentative genes generates obligate respiratory mutants which can be characterized by sensitivity to the mitochondrial drug antimycin A on glucose medium (Rag(-) phenotype). Rag(-) mutations can occasionally be generated by the inactivation of genes not evidently related to glycolysis or fermentation. One such gene is the hypoxic regulatory gene KlMGA2. In this work, we report a study of the many defects, in addition to the Rag(-) phenotype, generated by KlMGA2 deletion. We analyzed the fermentative and respiratory metabolism, mitochondrial functioning and morphology in the Klmga2Δ strain. We also examined alterations in the regulation of the expression of lipid biosynthetic genes, in particular fatty acids, ergosterol and cardiolipin, under hypoxic and cold stress and the phenotypic suppression by unsaturated fatty acids of the deleted strain. Results indicate that, despite the fact that the deleted mutant strain had a typical glycolytic/fermentative phenotype and KlMGA2 is a hypoxic regulatory gene, the deletion of this gene generated defects linked to mitochondrial functions suggesting new roles of this protein in the general regulation and cellular fitness of K. lactis. Supplementation of unsaturated fatty acids suppressed or modified these defects suggesting that KlMga2 modulates membrane functioning or membrane-associated functions, both cytoplasmic and mitochondrial.
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Affiliation(s)
- Daniela Ottaviano
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Arianna Montanari
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Lorenzo De Angelis
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Rosa Santomartino
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Andrea Visca
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Luca Brambilla
- Department of Biotechnology and Biosciences, Bicocca University of Milan, p.zza Della Scienza 2, 20126 Milan, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy Pasteur Institut Cenci-Bolognetti Foundation, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Cristiano Bello
- Departement of Environmental Biology, Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Massimo Reverberi
- Departement of Environmental Biology, Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Michele M Bianchi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy
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Flores CL, Gancedo C. The gene YALI0E20207g from Yarrowia lipolytica encodes an N-acetylglucosamine kinase implicated in the regulated expression of the genes from the N-acetylglucosamine assimilatory pathway. PLoS One 2015; 10:e0122135. [PMID: 25816199 PMCID: PMC4376941 DOI: 10.1371/journal.pone.0122135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 12/31/2022] Open
Abstract
The non-conventional yeast Yarrowia lipolytica possesses an ORF, YALI0E20207g, which encodes a protein with an amino acid sequence similar to hexokinases from different organisms. We have cloned that gene and determined several enzymatic properties of its encoded protein showing that it is an N-acetylglucosamine (NAGA) kinase. This conclusion was supported by the lack of growth in NAGA of a strain carrying a YALI0E20207g deletion. We named this gene YlNAG5. Expression of YlNAG5 as well as that of the genes encoding the enzymes of the NAGA catabolic pathway-identified by a BLAST search-was induced by this sugar. Deletion of YlNAG5 rendered that expression independent of the presence of NAGA in the medium and reintroduction of the gene restored the inducibility, indicating that YlNag5 participates in the transcriptional regulation of the NAGA assimilatory pathway genes. Expression of YlNAG5 was increased during sporulation and homozygous Ylnag5/Ylnag5 diploid strains sporulated very poorly as compared with a wild type isogenic control strain pointing to a participation of the protein in the process. Overexpression of YlNAG5 allowed growth in glucose of an Ylhxk1glk1 double mutant and produced, in a wild type background, aberrant morphologies in different media. Expression of the gene in a Saccharomyces cerevisiae hxk1 hxk2 glk1 triple mutant restored ability to grow in glucose.
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Affiliation(s)
- Carmen-Lisset Flores
- Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC-UAM, Madrid, Spain
- * E-mail:
| | - Carlos Gancedo
- Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC-UAM, Madrid, Spain
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