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Myronidi I, Ring A, Wu F, Ljungdahl PO. ER-localized Shr3 is a selective co-translational folding chaperone necessary for amino acid permease biogenesis. J Cell Biol 2023; 222:e202208060. [PMID: 37477900 PMCID: PMC10359922 DOI: 10.1083/jcb.202208060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 04/16/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023] Open
Abstract
Proteins with multiple membrane-spanning segments (MS) co-translationally insert into the endoplasmic reticulum (ER) membrane of eukaryotic cells. Shr3, an ER membrane-localized chaperone in Saccharomyces cerevisiae, is required for the functional expression of a family of 18 amino acid permeases (AAP) comprised of 12 MS. We have used comprehensive scanning mutagenesis and deletion analysis of Shr3 combined with a modified split-ubiquitin approach to probe chaperone-substrate interactions in vivo. Shr3 selectively interacts with nested C-terminal AAP truncations in marked contrast to similar truncations of non-Shr3 substrate sugar transporters. Shr3-AAP interactions initiate with the first four MS of AAP and successively strengthen but weaken abruptly when all 12 MS are present. Shr3-AAP interactions are based on structural rather than sequence-specific interactions involving membrane and luminal domains of Shr3. The data align with Shr3 engaging nascent N-terminal chains of AAP, functioning as a scaffold to facilitate folding as translation completes.
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Affiliation(s)
- Ioanna Myronidi
- Department of Molecular Biosciences, The Wenner-Gren Institute, SciLifeLab, Stockholm University, Stockholm, Sweden
| | - Andreas Ring
- Department of Molecular Biosciences, The Wenner-Gren Institute, SciLifeLab, Stockholm University, Stockholm, Sweden
| | - Fei Wu
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, Stockholm, Sweden
| | - Per O. Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, SciLifeLab, Stockholm University, Stockholm, Sweden
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2
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Zekhnini A, Albacar M, Casamayor A, Ariño J. The ENA1 Na+-ATPase Gene Is Regulated by the SPS Sensing Pathway and the Stp1/Stp2 Transcription Factors. Int J Mol Sci 2023; 24:ijms24065548. [PMID: 36982620 PMCID: PMC10055992 DOI: 10.3390/ijms24065548] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/16/2023] Open
Abstract
The Saccharomyces cerevisiae ENA1 gene, encoding a Na+-ATPase, responds transcriptionally to the alkalinization of the medium by means of a network of signals that involves the Rim101, the Snf1 and PKA kinases, and the calcineurin/Crz1 pathways. We show here that the ENA1 promoter also contains a consensus sequence, located at nt −553/−544, for the Stp1/2 transcription factors, the downstream components of the amino acid sensing SPS pathway. Mutation of this sequence or deletion of either STP1 or STP2 decreases the activity of a reporter containing this region in response to alkalinization as well as to changes in the amino acid composition in the medium. Expression driven from the entire ENA1 promoter was affected with similar potency by the deletion of PTR3, SSY5, or simultaneous deletion of STP1 and STP2 when cells were exposed to alkaline pH or moderate salt stress. However, it was not altered by the deletion of SSY1, encoding the amino acid sensor. In fact, functional mapping of the ENA1 promoter reveals a region spanning from nt −742 to −577 that enhances transcription, specifically in the absence of Ssy1. We also found that the basal and alkaline pH-induced expression from the HXT2, TRX2, and, particularly, SIT1 promoters was notably decreased in an stp1 stp2 deletion mutant, whereas the PHO84 and PHO89 gene reporters were unaffected. Our findings add a further layer of complexity to the regulation of ENA1 and suggest that the SPS pathway might participate in the regulation of a subset of alkali-inducible genes.
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TORC1 Signaling in Fungi: From Yeasts to Filamentous Fungi. Microorganisms 2023; 11:microorganisms11010218. [PMID: 36677510 PMCID: PMC9864104 DOI: 10.3390/microorganisms11010218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Target of rapamycin complex 1 (TORC1) is an important regulator of various signaling pathways. It can control cell growth and development by integrating multiple signals from amino acids, glucose, phosphate, growth factors, pressure, oxidation, and so on. In recent years, it has been reported that TORC1 is of great significance in regulating cytotoxicity, morphology, protein synthesis and degradation, nutrient absorption, and metabolism. In this review, we mainly discuss the upstream and downstream signaling pathways of TORC1 to reveal its role in fungi.
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Goh CJH, Cui L, Wong JH, Lewis J, Goh M, Kong KW, Yang LK, Alfatah M, Kanagasundaram Y, Hoon S, Arumugam P. Diethyl phthalate (DEP) perturbs nitrogen metabolism in Saccharomyces cerevisiae. Sci Rep 2022; 12:10237. [PMID: 35715465 PMCID: PMC9205984 DOI: 10.1038/s41598-022-14284-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/16/2022] [Indexed: 11/10/2022] Open
Abstract
Phthalates are ubiquitously used as plasticizers in various consumer care products. Diethyl phthalate (DEP), one of the main phthalates, elicits developmental and reproductive toxicities but the underlying mechanisms are not fully understood. Chemogenomic profiling of DEP in S. cerevisiae revealed that two transcription factors Stp1 and Dal81 involved in the Ssy1-Ptr5-Ssy5 (SPS) amino acid-sensing pathway provide resistance to DEP. Growth inhibition of yeast cells by DEP was stronger in poor nitrogen medium in comparison to nitrogen-rich medium. Addition of amino acids to nitrogen-poor medium suppressed DEP toxicity. Catabolism of amino acids via the Ehrlich pathway is required for suppressing DEP toxicity. Targeted metabolite analyses showed that DEP treatment alters the amino acid profile of yeast cells. We propose that DEP inhibits the growth of yeast cells by affecting nitrogen metabolism and discuss the implications of our findings on DEP-mediated toxic effects in humans.
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Affiliation(s)
| | - Liang Cui
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore, 138602, Singapore
| | - Jin Huei Wong
- Bioinformatics Institute, 30 Biopolis Street, Singapore, 138671, Singapore
| | - Jacqueline Lewis
- Singapore Institute of Food and Biotechnology Innovation, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Megan Goh
- Singapore Institute of Food and Biotechnology Innovation, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Kiat Whye Kong
- Institute of Molecular and Cellular Biology, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Lay Kien Yang
- Singapore Institute of Food and Biotechnology Innovation, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Mohammad Alfatah
- Bioinformatics Institute, 30 Biopolis Street, Singapore, 138671, Singapore
| | - Yoganathan Kanagasundaram
- Singapore Institute of Food and Biotechnology Innovation, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Shawn Hoon
- Institute of Molecular and Cellular Biology, 61 Biopolis Drive, Singapore, 138673, Singapore
| | - Prakash Arumugam
- Singapore Institute of Food and Biotechnology Innovation, 61 Biopolis Drive, Singapore, 138673, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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5
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Burchacka E, Pięta P, Łupicka-Słowik A. Recent advances in fungal serine protease inhibitors. Biomed Pharmacother 2021; 146:112523. [PMID: 34902742 DOI: 10.1016/j.biopha.2021.112523] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 12/20/2022] Open
Abstract
Four types of antifungal drugs are available that include inhibitors of ergosterol synthesis, of fungal RNA biosynthesis, and of cell wall biosynthesis as well as physiochemical regulators of fungal membrane sterols. Increasing resistance to antifungal drugs can severely limit treatment options of fungal nail infections, vaginal candidiasis, ringworm, blastomycosis, histoplasmosis, and Candida infections of the mouth, throat, and esophagus, among other infections. Development of strategies focused on new fungicides can effectively help tackle troublesome fungal diseases. The virulence and optimal growth of fungi depend on various extracellular secreted factors, among which proteases, such as serine proteases, are of particular interest. A specific extracellular proteolytic system enables fungi to survive and penetrate the tissues. Given the role of fungal proteases in infection, any molecule capable of selectively and specifically inhibiting their activity can lead to the development of potential drugs. Owing to their specific mode of action, fungal protease inhibitors can avoid fungal resistance observed with currently available treatments. Although fungal secreted proteases have been extensively studied as potential virulence factors, our understanding of the substrate specificity of such proteases remains poor. In this review, we summarize the recent advances in the design and development of specific serine protease inhibitors and provide a brief history of the compounds that inhibit fungal serine protease activity.
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Affiliation(s)
- E Burchacka
- Faculty of Chemistry, Department of Organic and Medicinal Chemistry, Wrocław University of Science and Technology, 27 Wybrzeże Wyspiańskiego St, 50-370 Wrocław, Poland.
| | - P Pięta
- Department of Bionic and Medical Experimental Biology, Poznań University of Medical Sciences, Parkowa 2 St, 60-775 Poznań, Poland
| | - A Łupicka-Słowik
- Faculty of Chemistry, Department of Organic and Medicinal Chemistry, Wrocław University of Science and Technology, 27 Wybrzeże Wyspiańskiego St, 50-370 Wrocław, Poland
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6
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Capturing hidden regulation based on noise change of gene expression level from single cell RNA-seq in yeast. Sci Rep 2021; 11:22547. [PMID: 34799619 PMCID: PMC8604932 DOI: 10.1038/s41598-021-01558-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/29/2021] [Indexed: 11/08/2022] Open
Abstract
Recent progress in high throughput single cell RNA-seq (scRNA-seq) has activated the development of data-driven inferring methods of gene regulatory networks. Most network estimations assume that perturbations produce downstream effects. However, the effects of gene perturbations are sometimes compensated by a gene with redundant functionality (functional compensation). In order to avoid functional compensation, previous studies constructed double gene deletions, but its vast nature of gene combinations was not suitable for comprehensive network estimation. We hypothesized that functional compensation may emerge as a noise change without mean change (noise-only change) due to varying physical properties and strong compensation effects. Here, we show compensated interactions, which are not detected by mean change, are captured by noise-only change quantified from scRNA-seq. We investigated whether noise-only change genes caused by a single deletion of STP1 and STP2, which have strong functional compensation, are enriched in redundantly regulated genes. As a result, noise-only change genes are enriched in their redundantly regulated genes. Furthermore, novel downstream genes detected from noise change are enriched in "transport", which is related to known downstream genes. Herein, we suggest the noise difference comparison has the potential to be applied as a new strategy for network estimation that capture even compensated interaction.
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7
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Sangkaew A, Kojornna T, Tanahashi R, Takagi H, Yompakdee C. A novel yeast-based screening system for potential compounds that can alleviate human α-synuclein toxicity. J Appl Microbiol 2021; 132:1409-1421. [PMID: 34448525 PMCID: PMC9291589 DOI: 10.1111/jam.15256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 07/10/2021] [Accepted: 07/27/2021] [Indexed: 11/29/2022]
Abstract
Aims This study aimed to establish a yeast‐based screening system for potential compounds that can alleviate the toxicity of α‐synuclein (α‐syn), a neuropathological hallmark of Parkinson’s disease, either inhibition of α‐syn aggregation or promotion of ubiquitin‐mediated degradation of α‐syn. Methods and Results A powerful yeast‐based screening assay using the rsp5A401E‐mutant strain, which is hypersensitive to α‐syn aggregation, was established by two‐step gene replacement and further overexpressed the GFP‐fused α‐syn in the drug‐sensitive yeast strain with a galactose‐inducible multicopy plasmid. The rsp5A401E‐mutant strain treated with baicalein, a known α‐syn aggregation inhibitor, showed better α‐syn toxicity alleviation than the same background wild type strain as accessed by comparison on the reduction kinetics of viable dye resazurin fluorometrically (λex540/λem590 nm). The rsp5A401E‐mutant yeast‐based assay system showed high sensitivity as it could detect as low as 3.13 µmol l−1 baicalein, the concentration that lower than previously report detected by the in vitro assay. Conclusions Our yeast‐based system has been effective for screening potential compounds that can alleviate α‐syn toxicity with high sensitivity and specificity. Significance and Impact of the Study Yeast‐based assay system can be used to discover novel neuroprotective drug candidates which may be either efficiently suppress‐α‐syn aggregation or enhance ubiquitin‐dependent degradation.
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Affiliation(s)
- Anyaporn Sangkaew
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Thanaporn Kojornna
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Ryoya Tanahashi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Hiroshi Takagi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Chulee Yompakdee
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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8
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Dai J, Xia H, Yang C, Chen X. Sensing, Uptake and Catabolism of L-Phenylalanine During 2-Phenylethanol Biosynthesis via the Ehrlich Pathway in Saccharomyces cerevisiae. Front Microbiol 2021; 12:601963. [PMID: 33717002 PMCID: PMC7947893 DOI: 10.3389/fmicb.2021.601963] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/29/2021] [Indexed: 01/15/2023] Open
Abstract
2-Phenylethanol (2-PE) is an important flavouring ingredient with a persistent rose-like odour, and it has been widely utilized in food, perfume, beverages, and medicine. Due to the potential existence of toxic byproducts in 2-PE resulting from chemical synthesis, the demand for “natural” 2-PE through biotransformation is increasing. L-Phenylalanine (L-Phe) is used as the precursor for the biosynthesis of 2-PE through the Ehrlich pathway by Saccharomyces cerevisiae. The regulation of L-Phe metabolism in S. cerevisiae is complicated and elaborate. We reviewed current progress on the signal transduction pathways of L-Phe sensing, uptake of extracellular L-Phe and 2-PE synthesis from L-Phe through the Ehrlich pathway. Moreover, the anticipated bottlenecks and future research directions for S. cerevisiae biosynthesis of 2-PE are discussed.
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Affiliation(s)
- Jun Dai
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China.,ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Huili Xia
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China
| | - Chunlei Yang
- Tobacco Research Institute of Hubei Province, Wuhan, China
| | - Xiong Chen
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China
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9
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Nuclear Ubiquitin-Proteasome Pathways in Proteostasis Maintenance. Biomolecules 2021; 11:biom11010054. [PMID: 33406777 PMCID: PMC7824755 DOI: 10.3390/biom11010054] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/19/2022] Open
Abstract
Protein homeostasis, or proteostasis, is crucial for the functioning of a cell, as proteins that are mislocalized, present in excessive amounts, or aberrant due to misfolding or other type of damage can be harmful. Proteostasis includes attaining the correct protein structure, localization, and the formation of higher order complexes, and well as the appropriate protein concentrations. Consequences of proteostasis imbalance are evident in a range of neurodegenerative diseases characterized by protein misfolding and aggregation, such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. To protect the cell from the accumulation of aberrant proteins, a network of protein quality control (PQC) pathways identifies the substrates and direct them towards refolding or elimination via regulated protein degradation. The main pathway for degradation of misfolded proteins is the ubiquitin-proteasome system. PQC pathways have been first described in the cytoplasm and the endoplasmic reticulum, however, accumulating evidence indicates that the nucleus is an important PQC compartment for ubiquitination and proteasomal degradation of not only nuclear, but also cytoplasmic proteins. In this review, we summarize the nuclear ubiquitin-proteasome pathways involved in proteostasis maintenance in yeast, focusing on inner nuclear membrane-associated degradation (INMAD) and San1-mediated protein quality control.
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10
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Mechanisms for Induction of Microbial Extracellular Proteases in Response to Exterior Proteins. Appl Environ Microbiol 2020; 86:AEM.01036-20. [PMID: 32709731 DOI: 10.1128/aem.01036-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Proteins are a main organic nitrogen source for microorganisms. Many heterotrophic microorganisms secrete extracellular proteases (ex-proteases) to efficiently decompose proteins into oligopeptides and amino acids when exterior proteins are required for growth. These ex-proteases not only play important roles in microbial nutrient acquisition or host infection but also contribute greatly to the global recycling of carbon and nitrogen. Moreover, may microbial ex-proteases have important applications in industrial, medical, and biotechnological areas. Therefore, uncovering the mechanisms by which microorganisms initiate the expression of ex-protease genes in response to exterior proteins is of great significance. In this review, the progress made in understanding the induction mechanisms of microbial ex-proteases in response to exterior proteins is summarized, with a focus on the inducer molecules, membrane sensors, and downstream pathways. Problems to be solved for better understanding of the induction mechanisms of microbial ex-proteases are also discussed.
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11
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Jackson CA, Castro DM, Saldi GA, Bonneau R, Gresham D. Gene regulatory network reconstruction using single-cell RNA sequencing of barcoded genotypes in diverse environments. eLife 2020; 9:e51254. [PMID: 31985403 PMCID: PMC7004572 DOI: 10.7554/elife.51254] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
Understanding how gene expression programs are controlled requires identifying regulatory relationships between transcription factors and target genes. Gene regulatory networks are typically constructed from gene expression data acquired following genetic perturbation or environmental stimulus. Single-cell RNA sequencing (scRNAseq) captures the gene expression state of thousands of individual cells in a single experiment, offering advantages in combinatorial experimental design, large numbers of independent measurements, and accessing the interaction between the cell cycle and environmental responses that is hidden by population-level analysis of gene expression. To leverage these advantages, we developed a method for scRNAseq in budding yeast (Saccharomyces cerevisiae). We pooled diverse transcriptionally barcoded gene deletion mutants in 11 different environmental conditions and determined their expression state by sequencing 38,285 individual cells. We benchmarked a framework for learning gene regulatory networks from scRNAseq data that incorporates multitask learning and constructed a global gene regulatory network comprising 12,228 interactions.
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Affiliation(s)
- Christopher A Jackson
- Center For Genomics and Systems BiologyNew York UniversityNew YorkUnited States
- Department of BiologyNew York UniversityNew YorkUnited States
| | | | | | - Richard Bonneau
- Center For Genomics and Systems BiologyNew York UniversityNew YorkUnited States
- Department of BiologyNew York UniversityNew YorkUnited States
- Courant Institute of Mathematical Sciences, Computer Science DepartmentNew York UniversityNew YorkUnited States
- Center For Data ScienceNew York UniversityNew YorkUnited States
- Flatiron Institute, Center for Computational BiologySimons FoundationNew YorkUnited States
| | - David Gresham
- Center For Genomics and Systems BiologyNew York UniversityNew YorkUnited States
- Department of BiologyNew York UniversityNew YorkUnited States
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12
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Muñoz SA, Gulias JF, Valencia-Guillén J, Correa-García S, Bermúdez-Moretti M. Novel function of transcription factor Uga3 as an activator of branched-chain amino acid permease BAP2 gene expression. Microbiology (Reading) 2020; 166:85-92. [DOI: 10.1099/mic.0.000863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gene regulation in yeast occurs at the transcription level, i.e. the basal level of expression is very low and increased transcription requires gene-specific transcription factors allowing the recruitment of basal transcriptional machinery. Saccharomyces cerevisiae BAP2 gene encodes the permease responsible for most uptake of leucine, valine and isoleucine, amino acids that this yeast can use as nitrogen sources. Moreover, BAP2 expression is known to be induced by the presence of amino acids such as leucine. In this context, the results presented in this paper show that BAP2 is an inducible gene in the presence of nitrogen-non-preferred source proline but exhibits high constitutive non-inducible expression in nitrogen-preferred source ammonium. BAP2 expression is regulated by the SPS sensor system and transcription factors Leu3, Gcn4 and Dal81. This can be achieved or not through a direct binding to the promoter depending on the quality of the nitrogen source. We further demonstrate here that an interaction occurs in vivo between Uga3 ‒ the transcriptional activator responsible for γ-aminobutyric acid (GABA)-dependent induction of the GABA genes ‒ and the regulatory region of the BAP2 gene, which leads to an increase in BAP2 transcription.
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Affiliation(s)
- Sebastián A. Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Juan F. Gulias
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Jenniffer Valencia-Guillén
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Susana Correa-García
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Mariana Bermúdez-Moretti
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
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13
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Handara G, Kröger S. Alternative Splicing and the Intracellular Domain Mediate TM-agrin's Ability to Differentially Regulate the Density of Excitatory and Inhibitory Synapse-like Specializations in Developing CNS Neurons. Neuroscience 2019; 419:60-71. [PMID: 31672640 DOI: 10.1016/j.neuroscience.2019.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 01/26/2023]
Abstract
Agrin is a multi-domain protein best known for its essential function during formation of the neuromuscular junction. Alternative mRNA splicing at sites named y and z in the C-terminal part of agrin regulates its interaction with a receptor complex consisting of the agrin-binding low-density lipoprotein receptor-related protein 4 (Lrp4) and the muscle-specific kinase (MuSK). Isoforms with inserts at both splice sites bind to Lrp4, activate MuSK and are synaptogenic at the neuromuscular junction. Agrin is also expressed as a transmembrane protein in the central nervous system (CNS) but its function during interneuronal synapse formation is unclear. Recently we demonstrated that transfection of a full-length cDNA coding for transmembrane agrin (TM-agrin) in cultured embryonic cortical neurons induced an Lrp4-dependent but MuSK-independent increase in dendritic glutamatergic synapses and an Lrp4- and MuSK-independent reduction of inhibitory synapses. Here we show that presynaptic specializations were similarly affected by TM-agrin overexpression. In addition, we mapped the regions within TM-agrin responsible for TM-agrin's effects on dendritic aggregates of synapse-associated proteins. We show that the presence of a four amino acid insert at splice site y is essential for the increase in the density of puncta containing the postsynaptic density protein 95 kDa. This effect was independent of splice site z. The reduction of the gephyrin puncta density was independent of the entire extracellular part of TM-agrin but required a highly conserved serine residue in the intracellular domain of TM-agrin. These results provide further evidence for a function of TM-agrin during CNS synaptogenesis and demonstrate that different domains and alternative splicing of TM-agrin differentially affect excitatory and inhibitory synapse formation in cultured embryonic CNS neurons.
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Affiliation(s)
- Gerry Handara
- Department of Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Großhaderner Str. 9, D-82152 Planegg-Martinsried, Germany; Institute for Stem Cell Research, German Research Center for Environmental Health, Helmholtz Centre Munich, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany
| | - Stephan Kröger
- Department of Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Großhaderner Str. 9, D-82152 Planegg-Martinsried, Germany.
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14
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Mukai Y, Kamei Y, Liu X, Jiang S, Sugimoto Y, Mat Nanyan NSB, Watanabe D, Takagi H. Proline metabolism regulates replicative lifespan in the yeast Saccharomyces cerevisiae. MICROBIAL CELL 2019; 6:482-490. [PMID: 31646149 PMCID: PMC6780008 DOI: 10.15698/mic2019.10.694] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In many plants and microorganisms, intracellular proline has a protective role against various stresses, including heat-shock, oxidation and osmolarity. Environmental stresses induce cellular senescence in a variety of eukaryotes. Here we showed that intracellular proline regulates the replicative lifespan in the budding yeast Saccharomyces cerevisiae. Deletion of the proline oxidase gene PUT1 and expression of the γ-glutamate kinase mutant gene PRO1-I150T that is less sensitive to feedback inhibition accumulated proline and extended the replicative lifespan of yeast cells. Inversely, disruption of the proline biosynthetic genes PRO1, PRO2, and CAR2 decreased stationary proline level and shortened the lifespan of yeast cells. Quadruple disruption of the proline transporter genes unexpectedly did not change intracellular proline levels and replicative lifespan. Overexpression of the stress-responsive transcription activator gene MSN2 reduced intracellular proline levels by inducing the expression of PUT1, resulting in a short lifespan. Thus, the intracellular proline levels at stationary phase was positively correlated with the replicative lifespan. Furthermore, multivariate analysis of amino acids in yeast mutants deficient in proline metabolism showed characteristic metabolic profiles coincident with longevity: acidic and basic amino acids and branched-chain amino acids positively contributed to the replicative lifespan. These results allude to proline metabolism having a physiological role in maintaining the lifespan of yeast cells.
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Affiliation(s)
- Yukio Mukai
- Department of Frontier Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Yuka Kamei
- Department of Frontier Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Xu Liu
- Department of Frontier Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Shan Jiang
- Department of Frontier Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Yukiko Sugimoto
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Noreen Suliani Binti Mat Nanyan
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Daisuke Watanabe
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Hiroshi Takagi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
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15
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Martins A, Ring A, Omnus DJ, Heessen S, Pfirrmann T, Ljungdahl PO. Spatial and temporal regulation of the endoproteolytic activity of the SPS-sensor-controlled Ssy5 signaling protease. Mol Biol Cell 2019; 30:2709-2720. [PMID: 31461372 PMCID: PMC6761765 DOI: 10.1091/mbc.e19-02-0096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Saccharomyces cerevisiae Ssy5 signaling protease is a core component of the plasma membrane (PM)-localized SPS (Ssy1-Ptr3-Ssy5) sensor. In response to extracellular amino acids, the SPS-sensor orchestrates the proteasomal degradation of the inhibitory Ssy5 prodomain. The unfettered catalytic (Cat)-domain cleaves latent transcription factors Stp1 and Stp2, freeing them from negative N-terminal regulatory domains. By studying the spatial and temporal constraints affecting the unfettered Cat-domain, we found that it can cleave substrates not associated with the PM; the Cat-domain efficiently cleaves Stp1 even when fused to the carboxy terminus of the endoplasmic reticulum (ER) membrane protein Shr3. The amino acid-induced cleavage of this synthetic membrane-anchored substrate occurs in a Δtether strain lacking ER-PM junctions. We report that the bulk of the Cat-domain is soluble, exhibits a disperse intracellular distribution, and is subject to ubiquitylation. Cat-domain ubiquitylation is dependent on Ptr3 and the integral PM casein kinase I (Yck1/2). Time-course experiments reveal that the non- and ubiquitylated forms of the Cat-domain are stable in cells grown in the absence of inducing amino acids. By contrast, amino acid induction significantly accelerates Cat-domain degradation. These findings provide novel insights into the SPS-sensing pathway and suggest that Cat-domain degradation is a requisite for resetting SPS-sensor signaling.
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Affiliation(s)
- António Martins
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Andreas Ring
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Deike J Omnus
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Stijn Heessen
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Thorsten Pfirrmann
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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16
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Ring A, Martins A, Ljungdahl PO. Ssy1 functions at the plasma membrane as a receptor of extracellular amino acids independent of plasma membrane-endoplasmic reticulum junctions. Traffic 2019; 20:775-784. [PMID: 31336002 DOI: 10.1111/tra.12681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/17/2019] [Accepted: 07/18/2019] [Indexed: 01/23/2023]
Abstract
Evidence from multiple laboratories has implicated Ssy1, a nontransporting amino acid permease, as the receptor component of the yeast plasma membrane (PM)-localized SPS (Ssy1-Ptr3-Ssy5)-sensor. Upon binding external amino acids, Ssy1 is thought to initiate signaling events leading to the induction of amino acid permease gene expression. In striking contrast, Kralt et al (2015) (Traffic 16:135-147) have questioned the role of Ssy1 in amino acid sensing and reported that Ssy1 is a component of the endoplasmic reticulum (ER), where it reportedly participates in the formation of ER-PM junctions. Here, we have re-examined the intracellular location of Ssy1 and tested the role of ER-PM junctions in SPS sensor signaling. We show that the C-terminal of Ssy1 carries a functional ER-export motif required for proper localization of Ssy1 to the PM. Furthermore, ER-PM junctions are dispensable for PM-localization and function of Ssy1; Ssy1 localizes to the PM in a Δtether strain lacking ER-PM junctions (ist2Δ scs2Δ scs22Δ tcb1Δ tcb2Δ tcb3Δ), and this strain retains the ability to initiate signals induced by extracellular amino acids. The data demonstrate that Ssy1 functions as the primary amino acid receptor and that it carries out this function at the PM.
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Affiliation(s)
- Andreas Ring
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - António Martins
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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17
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Mat Nanyan NSB, Watanabe D, Sugimoto Y, Takagi H. Involvement of the stress-responsive transcription factor gene MSN2 in the control of amino acid uptake in Saccharomyces cerevisiae. FEMS Yeast Res 2019; 19:5536248. [DOI: 10.1093/femsyr/foz052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 07/17/2019] [Indexed: 11/14/2022] Open
Abstract
ABSTRACT
The transcriptional factor Msn2 plays a pivotal role in response to environmental stresses by activating the transcription of stress-responsive genes in Saccharomyces cerevisiae. Our previous studies demonstrate that intracellular proline acts as a key protectant against various stresses. It is unknown, however, whether Msn2 is involved in proline homeostasis in S. cerevisiae cells. We here found that MSN2-overexpressing (MSN2-OE) cells showed higher sensitivity to a toxic analogue of proline, l-azetidine-2-carboxylic acid (AZC), as well as to the other amino acid toxic analogues, than wild-type cells. Overexpression of MSN2 increased the intracellular content of AZC, suggesting that Msn2 positively regulates the uptake of proline. Among the known proline permease genes, GNP1 was shown to play a predominant role in the AZC toxicity. Based on quantitative real-time PCR and western blot analyses, the overexpression of MSN2 did not induce any increases in the transcript levels of GNP1 or the other proline permease genes, while the amount of the Gnp1 protein was markedly increased in MSN2-OE cells. Microscopic observation suggested that the endocytic degradation of Gnp1 was impaired in MSN2-OE cells. Thus, this study sheds light on a novel link between the Msn2-mediated global stress response and the amino acid homeostasis in S. cerevisiae.
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Affiliation(s)
- Noreen Suliani binti Mat Nanyan
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Daisuke Watanabe
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Yukiko Sugimoto
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Hiroshi Takagi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
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18
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Zhang P, Chen Q, Fu G, Xia L, Hu X. Regulation and metabolic engineering strategies for permeases of Saccharomyces cerevisiae. World J Microbiol Biotechnol 2019; 35:112. [PMID: 31286266 DOI: 10.1007/s11274-019-2684-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 06/26/2019] [Indexed: 12/19/2022]
Abstract
Microorganisms have evolved permeases to incorporate various essential nutrients and exclude harmful products, which assists in adaptation to different environmental conditions for survival. As permeases are directly involved in the utilization of and regulatory response to nutrient sources, metabolic engineering of microbial permeases can predictably influence nutrient metabolism and regulation. In this mini-review, we have summarized the mechanisms underlying the general regulation of permeases, and the current advancements and future prospects of metabolic engineering strategies targeting the permeases in Saccharomyces cerevisiae. The different types of permeases and their regulatory mechanisms have been discussed. Furthermore, methods for metabolic engineering of permeases have been highlighted. Understanding the mechanisms via which permeases are meticulously regulated and engineered will not only facilitate research on regulation of global nutrition and yeast metabolic engineering, but can also provide important insights for future studies on the synthesis of valuable products and elimination of harmful substances in S. cerevisiae.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Qian Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Guiming Fu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China
| | - Linglin Xia
- Department of Software, Nanchang University, Nanchang, 330047, China
| | - Xing Hu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China. .,School of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang, 330047, Jiangxi, China.
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19
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Patrolling the nucleus: inner nuclear membrane-associated degradation. Curr Genet 2019; 65:1099-1106. [PMID: 31020383 PMCID: PMC6744382 DOI: 10.1007/s00294-019-00971-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 12/13/2022]
Abstract
Protein quality control and transport are important for the integrity of organelles such as the endoplasmic reticulum, but it is largely unknown how protein homeostasis is regulated at the nuclear envelope (NE) despite the connection between NE protein function and human disease. Elucidating mechanisms that regulate the NE proteome is key to understanding nuclear processes such as gene expression, DNA replication and repair as NE components, particularly proteins at the inner nuclear membrane (INM), are involved in the maintenance of nuclear structure, nuclear positioning and chromosome organization. Nuclear pore complexes control the entry and exit of proteins in and out of the nucleus, restricting movement across the nuclear membrane based on protein size, or the size of the extraluminal-facing domain of a transmembrane protein, providing one level of INM proteome regulation. Research in budding yeast has identified a protein quality control system that targets mislocalized and misfolded proteins at the INM. Here, we review what is known about INM-associated degradation, including recent evidence suggesting that it not only targets mislocalized or misfolded proteins, but also contributes to homeostasis of resident INM proteins.
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20
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Martins A, Pfirrmann T, Heessen S, Sundqvist G, Bulone V, Andréasson C, Ljungdahl PO. Ssy5 is a signaling serine protease that exhibits atypical biogenesis and marked S1 specificity. J Biol Chem 2018; 293:8362-8378. [PMID: 29661936 DOI: 10.1074/jbc.ra118.002457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/06/2018] [Indexed: 11/06/2022] Open
Abstract
Ssy5 is a signaling endoprotease that plays a key role in regulating central metabolism, cellular aging, and morphological transitions important for growth and survival of yeast (Saccharomyces cerevisiae) cells. In response to extracellular amino acids, Ssy5 proteolytically activates the transcription factors Stp1 and Stp2, leading to enhanced Ssy1-Ptr3-Ssy5 (SPS) sensor-regulated gene expression. Ssy5 comprises a catalytic (Cat) domain and an extensive regulatory prodomain. Ssy5 is refractory to both broad-spectrum and serine protease-specific inhibitors, confounding its classification as a protease, and no information about Ssy5's cleavage-site preferences and its mechanism of substrate selection is available. Here, using mutational and inhibition experiments, we investigated the biogenesis and catalytic properties of Ssy5 and conclusively show that it is a serine protease. Atypical for the majority of serine proteases, Ssy5's prodomain was obligatorily required in cis during biogenesis for the maturation of the proteolytic activity of the Cat domain. Autolysis and Stp1 and Stp2 cleavage occurred between a cysteine (at the P1 site) and a serine or alanine (at the P'1 site) and required residues with short side chains at the P1 site. Substitutions in the Cat domain affecting substrate specificity revealed that residues Phe-634, His-661, and Gly-671 in the S1-binding pocket of this domain are important for Ssy5 catalytic function. This study confirms that the signaling protease Ssy5 is a serine protease and provides a detailed understanding of the biogenesis and intrinsic properties of this key enzyme in yeast.
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Affiliation(s)
- António Martins
- From the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University SE-106 91 Stockholm, Sweden
| | - Thorsten Pfirrmann
- From the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University SE-106 91 Stockholm, Sweden
| | - Stijn Heessen
- From the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University SE-106 91 Stockholm, Sweden
| | - Gustav Sundqvist
- the Division of Glycoscience, AlbaNova University Centre, Royal Institute of Technology (KTH), SE-106 91 Stockholm, Sweden, and
| | - Vincent Bulone
- the Division of Glycoscience, AlbaNova University Centre, Royal Institute of Technology (KTH), SE-106 91 Stockholm, Sweden, and.,the ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Urrbra 5064, South Australia, Australia
| | - Claes Andréasson
- From the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University SE-106 91 Stockholm, Sweden
| | - Per O Ljungdahl
- From the Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University SE-106 91 Stockholm, Sweden,
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21
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Regulation of Sensing, Transportation, and Catabolism of Nitrogen Sources in Saccharomyces cerevisiae. Microbiol Mol Biol Rev 2018; 82:82/1/e00040-17. [PMID: 29436478 DOI: 10.1128/mmbr.00040-17] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Nitrogen is one of the most important essential nutrient sources for biogenic activities. Regulation of nitrogen metabolism in microorganisms is complicated and elaborate. For this review, the yeast Saccharomyces cerevisiae was chosen to demonstrate the regulatory mechanism of nitrogen metabolism because of its relative clear genetic background. Current opinions on the regulation processes of nitrogen metabolism in S. cerevisiae, including nitrogen sensing, transport, and catabolism, are systematically reviewed. Two major upstream signaling pathways, the Ssy1-Ptr3-Ssy5 sensor system and the target of rapamycin pathway, which are responsible for sensing extracellular and intracellular nitrogen, respectively, are discussed. The ubiquitination of nitrogen transporters, which is the most general and efficient means for controlling nitrogen transport, is also summarized. The following metabolic step, nitrogen catabolism, is demonstrated at two levels: the transcriptional regulation process related to GATA transcriptional factors and the translational regulation process related to the general amino acid control pathway. The interplay between nitrogen regulation and carbon regulation is also discussed. As a model system, understanding the meticulous process by which nitrogen metabolism is regulated in S. cerevisiae not only could facilitate research on global regulation mechanisms and yeast metabolic engineering but also could provide important insights and inspiration for future studies of other common microorganisms and higher eukaryotic cells.
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22
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Huang CW, Walker ME, Fedrizzi B, Gardner RC, Jiranek V. Yeast genes involved in regulating cysteine uptake affect production of hydrogen sulfide from cysteine during fermentation. FEMS Yeast Res 2017; 17:3934655. [PMID: 28810701 DOI: 10.1093/femsyr/fox046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/04/2017] [Indexed: 11/13/2022] Open
Abstract
An early burst of hydrogen sulfide (H2S) produced by Saccharomyces cerevisiae during fermentation could increase varietal thiols and therefore enhance desirable tropical aromas in varieties such as Sauvignon Blanc. Here we attempted to identify genes affecting H2S formation from cysteine by screening yeast deletion libraries via a colony colour assay on media resembling grape juice. Both Δlst4 and Δlst7 formed lighter coloured colonies and produced significantly less H2S than the wild type on high concentrations of cysteine, likely because they are unable to take up cysteine efficiently. We then examined the nine known cysteine permeases and found that deletion of AGP1, GNP1 and MUP1 led to reduced production of H2S from cysteine. We further showed that deleting genes involved in the SPS-sensing pathway such as STP1 and DAL81 also reduced H2S from cysteine. Together, this study indirectly confirms that Agp1p, Gnp1p and Mup1p are the major cysteine permeases and that they are regulated by the SPS-sensing and target of rapamycin pathways under the grape juice-like, cysteine-supplemented, fermentation conditions. The findings highlight that cysteine transportation could be a limiting factor for yeast to generate H2S from cysteine, and therefore selecting wine yeasts without defects in cysteine uptake could maximise thiol production potential.
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Affiliation(s)
- Chien-Wei Huang
- Department of Wine and Food Science, University of Adelaide, Adelaide, SA 5064, Australia
| | - Michelle E Walker
- Department of Wine and Food Science, University of Adelaide, Adelaide, SA 5064, Australia
| | - Bruno Fedrizzi
- Wine Science Programme, School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Richard C Gardner
- Wine Science Programme, School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Vladimir Jiranek
- Department of Wine and Food Science, University of Adelaide, Adelaide, SA 5064, Australia
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23
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Abstract
To respond to the changing environment, cells must be able to sense external conditions. This is important for many processes including growth, mating, the expression of virulence factors, and several other regulatory effects. Nutrient sensing at the plasma membrane is mediated by different classes of membrane proteins that activate downstream signaling pathways: nontransporting receptors, transceptors, classical and nonclassical G-protein-coupled receptors, and the newly defined extracellular mucin receptors. Nontransporting receptors have the same structure as transport proteins, but have lost the capacity to transport while gaining a receptor function. Transceptors are transporters that also function as a receptor, because they can rapidly activate downstream signaling pathways. In this review, we focus on these four types of fungal membrane proteins. We mainly discuss the sensing mechanisms relating to sugars, ammonium, and amino acids. Mechanisms for other nutrients, such as phosphate and sulfate, are discussed briefly. Because the model yeast Saccharomyces cerevisiae has been the most studied, especially regarding these nutrient-sensing systems, each subsection will commence with what is known in this species.
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24
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González A, Hall MN. Nutrient sensing and TOR signaling in yeast and mammals. EMBO J 2017; 36:397-408. [PMID: 28096180 DOI: 10.15252/embj.201696010] [Citation(s) in RCA: 485] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 01/13/2023] Open
Abstract
Coordinating cell growth with nutrient availability is critical for cell survival. The evolutionarily conserved TOR (target of rapamycin) controls cell growth in response to nutrients, in particular amino acids. As a central controller of cell growth, mTOR (mammalian TOR) is implicated in several disorders, including cancer, obesity, and diabetes. Here, we review how nutrient availability is sensed and transduced to TOR in budding yeast and mammals. A better understanding of how nutrient availability is transduced to TOR may allow novel strategies in the treatment for mTOR-related diseases.
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25
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Pantazopoulou M, Boban M, Foisner R, Ljungdahl PO. Cdc48 and Ubx1 participate in a pathway associated with the inner nuclear membrane that governs Asi1 degradation. J Cell Sci 2016; 129:3770-3780. [PMID: 27566164 DOI: 10.1242/jcs.189332] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 08/18/2016] [Indexed: 01/04/2023] Open
Abstract
The nuclear envelope is a barrier comprising outer and inner membranes that separate the cytoplasm from the nucleoplasm. The two membranes have different physical characteristics and protein compositions. The processes governing the stability of inner nuclear membrane (INM) proteins are not well characterized. In Saccharomyces cerevisiae, the INM Asi1-Asi3 complex, principally composed of integral membrane proteins Asi1 and Asi3, is an E3 ubiquitin ligase. In addition to its well-documented function in endoplasmic reticulum (ER)-associated degradation, the Doa10 E3 ubiquitin ligase complex partially localizes to the INM. The Asi1-Asi3 and Doa10 complexes define independent INM-associated degradation (INMAD) pathways that target discrete sets of nuclear substrates for proteasomal degradation. Here, we report that Asi1 is rapidly turned over (t1/2≤30 min). Its turnover depends on ubiquitin-mediated degradation by nucleus-localized proteasomes, exhibiting a clear requirement for the E2 ubiquitin-conjugating enzyme Ubc7, Cue1 and the AAA ATPase Cdc48 and co-factor Ubx1. Asi1 turnover occurs largely independently of the Asi1-Asi3 or Doa10 complexes, indicating that it is subject to quality control at the INM in a manner distinct from that of the characterized INMAD pathways.
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Affiliation(s)
- Marina Pantazopoulou
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm SE-106 91, Sweden
| | - Mirta Boban
- University of Zagreb, School of Medicine, Croatian Institute for Brain Research, Šalata 12, Zagreb 10000, Croatia
| | - Roland Foisner
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna A-1030, Austria
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm SE-106 91, Sweden
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26
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Goldman-Pinkovich A, Balno C, Strasser R, Zeituni-Molad M, Bendelak K, Rentsch D, Ephros M, Wiese M, Jardim A, Myler PJ, Zilberstein D. An Arginine Deprivation Response Pathway Is Induced in Leishmania during Macrophage Invasion. PLoS Pathog 2016; 12:e1005494. [PMID: 27043018 PMCID: PMC4846328 DOI: 10.1371/journal.ppat.1005494] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/15/2016] [Indexed: 11/18/2022] Open
Abstract
Amino acid sensing is an intracellular function that supports nutrient homeostasis, largely through controlled release of amino acids from lysosomal pools. The intracellular pathogen Leishmania resides and proliferates within human macrophage phagolysosomes. Here we describe a new pathway in Leishmania that specifically senses the extracellular levels of arginine, an amino acid that is essential for the parasite. During infection, the macrophage arginine pool is depleted due to its use to produce metabolites (NO and polyamines) that constitute part of the host defense response and its suppression, respectively. We found that parasites respond to this shortage of arginine by up-regulating expression and activity of the Leishmania arginine transporter (LdAAP3), as well as several other transporters. Our analysis indicates the parasite monitors arginine levels in the environment rather than the intracellular pools. Phosphoproteomics and genetic analysis indicates that the arginine-deprivation response is mediated through a mitogen-activated protein kinase-2-dependent signaling cascade. Protozoa of the genus Leishmania are the causative agents of leishmaniasis in humans. These parasites cycle between promastigotes in the sand fly mid-gut and amastigotes in phagolysosome of mammalian macrophages. During infection, host cells up-regulate nitric oxide while/or parasites induce expression of host arginase, both of which use arginine as a substrate. These elevated activities deplete macrophage arginine pools, a situation that invading Leishmania must overcome since it is an essential amino acid. Leishmania donovani imports exogenous arginine via a mono-specific amino acid transporter (AAP3) and utilizes it primarily through the polyamine pathway to provide precursors for trypanothione biosynthesis as well as hypusination of eukaryotic translation Initiation Factor 5A. Here we report the discovery of a pathway whereby Leishmania sense the lack of environmental arginine and respond with rapid up-regulation in the expression and activity of AAP3, as well as several other transporters. Significantly, this arginine deprivation response is also activated in parasites during macrophage infection. Phosphoproteomic analyses of L. donovani promastigotes have implicated a mitogen-activated protein kinase 2 (MPK2)-mediated signaling cascade in this response, and L. mexicana mutants lacking MPK2 are unable to respond to arginine deprivation. The arginine-sensing pathway might play an important role in Leishmania virulence and hence serve as target for drug development.
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Affiliation(s)
| | - Caitlin Balno
- Faculty of Biology, Technion—Israel Institute of Technology, Haifa, Haifa, Israel
| | - Rona Strasser
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | - Michal Zeituni-Molad
- Carmel Medical Center and Faculty of Medicine, Technion,—Israel institute of Technology, Haifa, Israel
| | - Keren Bendelak
- The Smoler Proteomic Center, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Moshe Ephros
- Carmel Medical Center and Faculty of Medicine, Technion,—Israel institute of Technology, Haifa, Israel
| | - Martin Wiese
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Armando Jardim
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | - Peter J. Myler
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington, United States of America
- Departments of Global Health and Biomedical Informatics & Medical Education, University of Washington, Seattle, Washington, United States of America
| | - Dan Zilberstein
- Faculty of Biology, Technion—Israel Institute of Technology, Haifa, Haifa, Israel
- * E-mail:
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27
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Function and Regulation of Fungal Amino Acid Transporters: Insights from Predicted Structure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:69-106. [PMID: 26721271 DOI: 10.1007/978-3-319-25304-6_4] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amino acids constitute a major nutritional source for probably all fungi. Studies of model species such as the yeast Saccharomyces cerevisiae and the filamentous fungus Aspergillus nidulans have shown that they possess multiple amino acid transporters. These proteins belong to a limited number of superfamilies, now defined according to protein fold in addition to sequence criteria, and differ in subcellular location, substrate specificity range, and regulation. Structural models of several of these transporters have recently been built, and the detailed molecular mechanisms of amino acid recognition and translocation are now being unveiled. Furthermore, the particular conformations adopted by some of these transporters in response to amino acid binding appear crucial to promoting their ubiquitin-dependent endocytosis and/or to triggering signaling responses. We here summarize current knowledge, derived mainly from studies on S. cerevisiae and A. nidulans, about the transport activities, regulation, and sensing role of fungal amino acid transporters, in relation to predicted structure.
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Nakatsukasa K, Okumura F, Kamura T. Proteolytic regulation of metabolic enzymes by E3 ubiquitin ligase complexes: lessons from yeast. Crit Rev Biochem Mol Biol 2015; 50:489-502. [PMID: 26362128 DOI: 10.3109/10409238.2015.1081869] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Eukaryotic organisms use diverse mechanisms to control metabolic rates in response to changes in the internal and/or external environment. Fine metabolic control is a highly responsive, energy-saving process that is mediated by allosteric inhibition/activation and/or reversible modification of preexisting metabolic enzymes. In contrast, coarse metabolic control is a relatively long-term and expensive process that involves modulating the level of metabolic enzymes. Coarse metabolic control can be achieved through the degradation of metabolic enzymes by the ubiquitin-proteasome system (UPS), in which substrates are specifically ubiquitinated by an E3 ubiquitin ligase and targeted for proteasomal degradation. Here, we review select multi-protein E3 ligase complexes that directly regulate metabolic enzymes in Saccharomyces cerevisiae. The first part of the review focuses on the endoplasmic reticulum (ER) membrane-associated Hrd1 and Doa10 E3 ligase complexes. In addition to their primary roles in the ER-associated degradation pathway that eliminates misfolded proteins, recent quantitative proteomic analyses identified native substrates of Hrd1 and Doa10 in the sterol synthesis pathway. The second part focuses on the SCF (Skp1-Cul1-F-box protein) complex, an abundant prototypical multi-protein E3 ligase complex. While the best-known roles of the SCF complex are in the regulation of the cell cycle and transcription, accumulating evidence indicates that the SCF complex also modulates carbon metabolism pathways. The increasing number of metabolic enzymes whose stability is directly regulated by the UPS underscores the importance of the proteolytic regulation of metabolic processes for the acclimation of cells to environmental changes.
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Affiliation(s)
- Kunio Nakatsukasa
- a Division of Biological Sciences , Graduate School of Science, Nagoya University , Nagoya , Aichi , Japan
| | - Fumihiko Okumura
- a Division of Biological Sciences , Graduate School of Science, Nagoya University , Nagoya , Aichi , Japan
| | - Takumi Kamura
- a Division of Biological Sciences , Graduate School of Science, Nagoya University , Nagoya , Aichi , Japan
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29
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Boban M, Ljungdahl PO, Foisner R. Atypical ubiquitylation in yeast targets lysine-less Asi2 for proteasomal degradation. J Biol Chem 2014; 290:2489-95. [PMID: 25492870 PMCID: PMC4303697 DOI: 10.1074/jbc.m114.600593] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins are typically targeted for proteasomal degradation by the attachment of a polyubiquitin chain to ϵ-amino groups of lysine residues. Non-lysine ubiquitylation of proteasomal substrates has been considered an atypical and rare event limited to complex eukaryotes. Here we report that a fully functional lysine-less mutant of an inner nuclear membrane protein in yeast, Asi2, is polyubiquitylated and targeted for proteasomal degradation. Efficient degradation of lysine-free Asi2 requires E3-ligase Doa10 and E2 enzymes Ubc6 and Ubc7, components of the endoplasmic reticulum-associated degradation pathway. Together, our data suggest that non-lysine ubiquitylation may be more prevalent than currently considered.
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Affiliation(s)
- Mirta Boban
- From the Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, A-1030 Vienna, Austria and
| | - Per O Ljungdahl
- the Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University SE-S-10691 Stockholm, Sweden
| | - Roland Foisner
- From the Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, A-1030 Vienna, Austria and
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30
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Omnus DJ, Ljungdahl PO. Latency of transcription factor Stp1 depends on a modular regulatory motif that functions as cytoplasmic retention determinant and nuclear degron. Mol Biol Cell 2014; 25:3823-33. [PMID: 25253722 PMCID: PMC4230787 DOI: 10.1091/mbc.e14-06-1140] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The latent properties of Stp1—the effector transcription factor of the SPS signaling pathway in yeast—depend on the RI motif in the N-terminal regulatory domain and three inner nuclear membrane proteins, Asi1, Asi2, and Asi3. RI functions in a modular and transferable manner as a cytoplasmic retention determinant and an Asi-dependent degron. The Ssy1-Ptr3-Ssy5 (SPS)–sensing pathway enables yeast to respond to extracellular amino acids. Stp1, the effector transcription factor, is synthesized as a latent cytoplasmic precursor with an N-terminal regulatory domain that restricts its nuclear accumulation. The negative regulatory mechanisms impinging on the N-terminal domain are poorly understood. However, Stp1 latency depends on three inner nuclear membrane proteins, Asi1, Asi2, and Asi3. We report that the N-terminal domain of Stp1 contains a small motif, designated RI, that fully accounts for latency. RI is modular, mediates interactions with the plasma membrane, and can retain histone Htb2 in the cytoplasm. A novel class of STP1 mutations affecting RI were isolated that are less efficiently retained in the cytoplasm but remain under tight negative control by the Asi proteins. Intriguingly, these mutant proteins exhibit enhanced stability in strains lacking ASI1. Our results indicate that RI mediates latency by two distinct activities: it functions as a cytoplasmic retention determinant and an Asi-dependent degron. These findings provide novel insights into the SPS-sensing pathway and demonstrate for the first time that the inner nuclear membrane Asi proteins function in a degradation pathway in the nucleus.
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Affiliation(s)
- Deike J Omnus
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
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31
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Abstract
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host-fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany
| | - Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany Center for Sepsis Control and Care, Universitätsklinikum Jena, 07747 Jena, Germany
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32
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Boban M, Pantazopoulou M, Schick A, Ljungdahl PO, Foisner R. A nuclear ubiquitin-proteasome pathway targets the inner nuclear membrane protein Asi2 for degradation. J Cell Sci 2014; 127:3603-13. [PMID: 24928896 DOI: 10.1242/jcs.153163] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The nuclear envelope consists of inner and outer nuclear membranes. Whereas the outer membrane is an extension of the endoplasmic reticulum, the inner nuclear membrane (INM) represents a unique membranous environment containing specific proteins. The mechanisms of integral INM protein degradation are unknown. Here, we investigated the turnover of Asi2, an integral INM protein in Saccharomyces cerevisiae. We report that Asi2 is degraded by the proteasome independently of the vacuole and that it exhibited a half-life of ∼45 min. Asi2 exhibits enhanced stability in mutants lacking the E2 ubiquitin conjugating enzymes Ubc6 or Ubc7, or the E3 ubiquitin ligase Doa10. Consistent with these data, Asi2 is post-translationally modified by poly-ubiquitylation in a Ubc7- and Doa10-dependent manner. Importantly Asi2 degradation is significantly reduced in a sts1-2 mutant that fails to accumulate proteasomes in the nucleus, indicating that Asi2 is degraded in the nucleus. Our results reveal a molecular pathway that affects the stability of integral proteins of the inner nuclear membrane and indicate that Asi2 is subject to protein quality control in the nucleus.
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Affiliation(s)
- Mirta Boban
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
| | - Marina Pantazopoulou
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Anna Schick
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Per O Ljungdahl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Roland Foisner
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
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33
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Genetic Interaction between theero1-1andleu2Mutations inSaccharomyces cerevisiae. Biosci Biotechnol Biochem 2014; 71:2934-42. [DOI: 10.1271/bbb.70323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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34
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Liu G, Marras A, Nielsen J. The future of genome-scale modeling of yeast through integration of a transcriptional regulatory network. QUANTITATIVE BIOLOGY 2014. [DOI: 10.1007/s40484-014-0027-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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35
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Ramachandra S, Linde J, Brock M, Guthke R, Hube B, Brunke S. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans. PLoS One 2014; 9:e92734. [PMID: 24651113 PMCID: PMC3961412 DOI: 10.1371/journal.pone.0092734] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/24/2014] [Indexed: 12/22/2022] Open
Abstract
Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA), representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA). In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.
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Affiliation(s)
- Shruthi Ramachandra
- Department of Microbial Biochemistry and Physiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Jörg Linde
- Department of Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Matthias Brock
- Department of Microbial Biochemistry and Physiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Reinhard Guthke
- Department of Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
- * E-mail:
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36
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Uesugi S, Watanabe D, Kitajima M, Watanabe R, Kawamura Y, Ohnishi M, Takagi H, Kimura KI. Calcineurin inhibitors suppress the high-temperature stress sensitivity of the yeast ubiquitin ligase Rsp5 mutant: a new method of screening for calcineurin inhibitors. FEMS Yeast Res 2014; 14:567-74. [DOI: 10.1111/1567-1364.12143] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Shota Uesugi
- The United Graduate School of Agricultural Sciences; Iwate University; Morioka Iwate Japan
| | - Daisuke Watanabe
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma Nara Japan
| | - Moe Kitajima
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma Nara Japan
| | - Ryo Watanabe
- Graduate School of Agriculture; Iwate University; Morioka Iwate Japan
| | - Yumi Kawamura
- Graduate School of Agriculture; Iwate University; Morioka Iwate Japan
| | - Motoko Ohnishi
- Department of Biological Chemistry; College of Bioscience and Biotechnology; Chubu University; Kasugai Aichi Japan
| | - Hiroshi Takagi
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma Nara Japan
| | - Ken-ichi Kimura
- The United Graduate School of Agricultural Sciences; Iwate University; Morioka Iwate Japan
- Graduate School of Agriculture; Iwate University; Morioka Iwate Japan
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37
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Conrad M, Schothorst J, Kankipati HN, Van Zeebroeck G, Rubio-Texeira M, Thevelein JM. Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae. FEMS Microbiol Rev 2014; 38:254-99. [PMID: 24483210 PMCID: PMC4238866 DOI: 10.1111/1574-6976.12065] [Citation(s) in RCA: 419] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/23/2013] [Accepted: 01/22/2014] [Indexed: 02/04/2023] Open
Abstract
The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth.
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Affiliation(s)
- Michaela Conrad
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Joep Schothorst
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Harish Nag Kankipati
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Griet Van Zeebroeck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Marta Rubio-Texeira
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
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38
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Acetic acid inhibits nutrient uptake in Saccharomyces cerevisiae: auxotrophy confounds the use of yeast deletion libraries for strain improvement. Appl Microbiol Biotechnol 2013; 97:7405-16. [DOI: 10.1007/s00253-013-5071-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 06/04/2013] [Accepted: 06/17/2013] [Indexed: 02/05/2023]
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39
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Pfirrmann T, Lokapally A, Andréasson C, Ljungdahl P, Hollemann T. SOMA: a single oligonucleotide mutagenesis and cloning approach. PLoS One 2013; 8:e64870. [PMID: 23750217 PMCID: PMC3672168 DOI: 10.1371/journal.pone.0064870] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/13/2013] [Indexed: 11/30/2022] Open
Abstract
Modern biology research requires simple techniques for efficient and restriction site-independent modification of genetic material. Classical cloning and mutagenesis strategies are limited by their dependency on restriction sites and the use of complementary primer pairs. Here, we describe the Single Oligonucleotide Mutagenesis and Cloning Approach (SOMA) that is independent of restriction sites and only requires a single mutagenic oligonucleotide to modify a plasmid. We demonstrate the broad application spectrum of SOMA with three examples. First, we present a novel plasmid that in a standardized and rapid fashion can be used as a template for SOMA to generate GFP-reporters. We successfully use such a reporter to assess the in vivo knock-down quality of morpholinos in Xenopus laevis embryos. In a second example, we show how to use a SOMA-based protocol for restriction-site independent cloning to generate chimeric proteins by domain swapping between the two human hRMD5a and hRMD5b isoforms. Last, we show that SOMA simplifies the generation of randomized single-site mutagenized gene libraries. As an example we random-mutagenize a single codon affecting the catalytic activity of the yeast Ssy5 endoprotease and identify a spectrum of tolerated and non-tolerated substitutions. Thus, SOMA represents a highly efficient alternative to classical cloning and mutagenesis strategies.
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Affiliation(s)
- Thorsten Pfirrmann
- Department of Molecular Medicine, Institute for Physiological Chemistry, Martin-Luther University Halle-Wittenberg, Halle, Germany.
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40
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Sasaki T, Takagi H. Phosphorylation of a conserved Thr357 in yeast Nedd4-like ubiquitin ligase Rsp5 is involved in down-regulation of the general amino acid permease Gap1. Genes Cells 2013; 18:459-75. [DOI: 10.1111/gtc.12049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 02/18/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Toshiya Sasaki
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; 8916-5 Takayama; Ikoma; Nara; 630-0192; Japan
| | - Hiroshi Takagi
- Graduate School of Biological Sciences; Nara Institute of Science and Technology; 8916-5 Takayama; Ikoma; Nara; 630-0192; Japan
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41
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Omnus DJ, Ljungdahl PO. Rts1-protein phosphatase 2A antagonizes Ptr3-mediated activation of the signaling protease Ssy5 by casein kinase I. Mol Biol Cell 2013; 24:1480-92. [PMID: 23447701 PMCID: PMC3639058 DOI: 10.1091/mbc.e13-01-0019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Ssy1-Ptr3-Ssy5 sensor of external amino acids couples Ssy1 receptor–initiated signals to casein kinase–dependent activation of the protease Ssy5. Here Ssy5 activity is shown to be tuned by interactions with Rts1-protein phosphatase 2A and the specific adapter protein Ptr3, which activates Ssy5 by mediating its proximity to casein kinase. Ligand-induced conformational changes of plasma membrane receptors initiate signals that enable cells to respond to discrete extracellular cues. In response to extracellular amino acids, the yeast Ssy1-Ptr3-Ssy5 sensor triggers the endoproteolytic processing of transcription factors Stp1 and Stp2 to induce amino acid uptake. Activation of the processing protease Ssy5 depends on the signal-induced phosphorylation of its prodomain by casein kinase I (Yck1/2). Phosphorylation is required for subsequent Skp1/Cullin/Grr1 E3 ubiquitin ligase–dependent polyubiquitylation and proteasomal degradation of the inhibitory prodomain. Here we show that Rts1, a regulatory subunit of the general protein phosphatase 2A, and Ptr3 have opposing roles in controlling Ssy5 prodomain phosphorylation. Rts1 constitutively directs protein phosphatase 2A activity toward the prodomain, effectively setting a signaling threshold required to mute Ssy5 activation in the absence of amino acid induction. Ptr3 functions as an adaptor that transduces conformational signals initiated by the Ssy1 receptor to dynamically induce prodomain phosphorylation by mediating the proximity of the Ssy5 prodomain and Yck1/2. Our results demonstrate how pathway-specific and general signaling components function synergistically to convert an extracellular stimulus into a highly specific, tuned, and switch-like transcriptional response that is critical for cells to adapt to changes in nutrient availability.
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Affiliation(s)
- Deike J Omnus
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
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42
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Regulation of amino acid, nucleotide, and phosphate metabolism in Saccharomyces cerevisiae. Genetics 2012; 190:885-929. [PMID: 22419079 DOI: 10.1534/genetics.111.133306] [Citation(s) in RCA: 338] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear.
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43
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Davis MM, Alvarez FJ, Ryman K, Holm ÅA, Ljungdahl PO, Engström Y. Wild-type Drosophila melanogaster as a model host to analyze nitrogen source dependent virulence of Candida albicans. PLoS One 2011; 6:e27434. [PMID: 22110651 PMCID: PMC3215725 DOI: 10.1371/journal.pone.0027434] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 10/17/2011] [Indexed: 12/21/2022] Open
Abstract
The fungal pathogen Candida albicans is a common cause of opportunistic infections in humans. We report that wild-type Drosophila melanogaster (OrR) flies are susceptible to virulent C. albicans infections and have established experimental conditions that enable OrR flies to serve as model hosts for studying C. albicans virulence. After injection into the thorax, wild-type C. albicans cells disseminate and invade tissues throughout the fly, leading to lethality. Similar to results obtained monitoring systemic infections in mice, well-characterized cph1Δ efg1Δ and csh3Δ fungal mutants exhibit attenuated virulence in flies. Using the OrR fly host model, we assessed the virulence of C. albicans strains individually lacking functional components of the SPS sensing pathway. In response to extracellular amino acids, the plasma membrane localized SPS-sensor (Ssy1, Ptr3, and Ssy5) activates two transcription factors (Stp1 and Stp2) to differentially control two distinct modes of nitrogen acquisition (host protein catabolism and amino acid uptake, respectively). Our results indicate that a functional SPS-sensor and Stp1 controlled genes required for host protein catabolism and utilization, including the major secreted aspartyl protease SAP2, are required to establish virulent infections. By contrast, Stp2, which activates genes required for amino acid uptake, is dispensable for virulence. These results indicate that nutrient availability within infected hosts directly influences C. albicans virulence.
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Affiliation(s)
- Monica M. Davis
- Department of Molecular Biology and Functional Genomics, Stockholm University, Stockholm, Sweden
| | | | - Kicki Ryman
- Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Åsa A. Holm
- Department of Molecular Biology and Functional Genomics, Stockholm University, Stockholm, Sweden
| | - Per O. Ljungdahl
- Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- * E-mail: (YE); (POL)
| | - Ylva Engström
- Department of Molecular Biology and Functional Genomics, Stockholm University, Stockholm, Sweden
- * E-mail: (YE); (POL)
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44
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Common features and differences in the expression of the three genes forming the UGA regulon in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2011; 410:885-9. [PMID: 21708130 DOI: 10.1016/j.bbrc.2011.06.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 06/13/2011] [Indexed: 11/23/2022]
Abstract
The three genes that form the UGA regulon in Saccharomyces cerevisiae are responsible for the transport and degradation of γ-aminobutyric acid (GABA) in this organism. Despite the differences in the sequence of their promoters, these genes similarly respond to GABA stimuli. The expression of UGA1, UGA2 and UGA4 depends on GABA induction and nitrogen catabolite repression (NCR). The induction of these genes requires the action of at least two positive proteins, the specific Uga3 and the pleiotropic Uga35/Dal81 transcription factors. Here we show that all the members of the UGA regulon, as was already demonstrated for UGA4, are negatively regulated by extracellular amino acids through the SPS amino acid sensor. We also show that this negative effect is caused by a low availability of Uga35/Dal81 transcription factor and that Leu3 transcription factor negatively regulates UGA4 and UGA1 expression but it does not affect UGA2 expression.
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Defining the specificity of cotranslationally acting chaperones by systematic analysis of mRNAs associated with ribosome-nascent chain complexes. PLoS Biol 2011; 9:e1001100. [PMID: 21765803 PMCID: PMC3134442 DOI: 10.1371/journal.pbio.1001100] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 05/27/2011] [Indexed: 01/06/2023] Open
Abstract
Polypeptides exiting the ribosome must fold and assemble in the crowded environment of the cell. Chaperones and other protein homeostasis factors interact with newly translated polypeptides to facilitate their folding and correct localization. Despite the extensive efforts, little is known about the specificity of the chaperones and other factors that bind nascent polypeptides. To address this question we present an approach that systematically identifies cotranslational chaperone substrates through the mRNAs associated with ribosome-nascent chain-chaperone complexes. We here focused on two Saccharomyces cerevisiae chaperones: the Signal Recognition Particle (SRP), which acts cotranslationally to target proteins to the ER, and the Nascent chain Associated Complex (NAC), whose function has been elusive. Our results provide new insights into SRP selectivity and reveal that NAC is a general cotranslational chaperone. We found surprising differential substrate specificity for the three subunits of NAC, which appear to recognize distinct features within nascent chains. Our results also revealed a partial overlap between the sets of nascent polypeptides that interact with NAC and SRP, respectively, and showed that NAC modulates SRP specificity and fidelity in vivo. These findings give us new insight into the dynamic interplay of chaperones acting on nascent chains. The strategy we used should be generally applicable to mapping the specificity, interplay, and dynamics of the cotranslational protein homeostasis network.
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Omnus DJ, Pfirrmann T, Andréasson C, Ljungdahl PO. A phosphodegron controls nutrient-induced proteasomal activation of the signaling protease Ssy5. Mol Biol Cell 2011; 22:2754-65. [PMID: 21653827 PMCID: PMC3145550 DOI: 10.1091/mbc.e11-04-0282] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The Ssy1-Ptr3-Ssy5 (SPS) sensor of extracellular amino acids coordinates the sequential activity of general signaling factors and the 26S proteasome in a novel proteolytic activation cascade to activate the intracellular signaling protease Ssy5, which endoproteolytically activates two latent transcription factors. Regulated proteolysis serves as a mechanism to control cellular processes. The SPS (Ssy1-Ptr3-Ssy5) sensor in yeast responds to extracellular amino acids by endoproteolytically activating transcription factors Stp1 and Stp2 (Stp1/2). The processing endoprotease Ssy5 is regulated via proteasomal degradation of its noncovalently associated N-terminal prodomain. We find that degradation of the prodomain requires a conserved phosphodegron comprising phosphoacceptor sites and ubiquitin-accepting lysine residues. Upon amino acid induction, the phosphodegron is modified in a series of linked events by a set of general regulatory factors involved in diverse signaling pathways. First, an amino acid–induced conformational change triggers phosphodegron phosphorylation by the constitutively active plasma membrane–localized casein kinase I (Yck1/2). Next the prodomain becomes a substrate for polyubiquitylation by the Skp1/Cullin/Grr1 E3 ubiquitin ligase complex (SCFGrr1). Finally, the modified prodomain is concomitantly degraded by the 26S proteasome. These integrated events are requisite for unfettering the Ssy5 endoprotease, and thus Stp1/2 processing. The Ssy5 phosphoacceptor motif resembles the Yck1/2- and Grr1-dependent degrons of regulators in the Snf3/Rgt2 glucose-sensing pathway. Our work defines a novel proteolytic activation cascade that regulates an intracellular signaling protease and illustrates how general signaling components are recruited to distinct pathways that achieve conditional and specific signaling outputs.
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Affiliation(s)
- Deike J Omnus
- Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
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Abdel-Sater F, Jean C, Merhi A, Vissers S, André B. Amino acid signaling in yeast: activation of Ssy5 protease is associated with its phosphorylation-induced ubiquitylation. J Biol Chem 2011; 286:12006-15. [PMID: 21310956 DOI: 10.1074/jbc.m110.200592] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast Ssy5 protein is a serine-type endoprotease autoprocessed into a catalytic domain and a large inhibitory prodomain. When external amino acids are detected by the plasma membrane Ssy1 sensor, Ssy5 is activated and catalyzes endoproteolytic processing of the Stp1 and Stp2 transcription factors. These Stp proteins then migrate into the nucleus and activate transcription of several amino acid permease genes. Previous studies showed that Ssy5 activation involves the SCFGrr1 ubiquitin ligase complex, but the molecular mechanisms of this activation remain unclear. We here report that the prodomain of Ssy5 is phosphorylated in a casein kinase I-dependent manner in response to amino acid detection. We describe a mutant form of Ssy5 whose prodomain is not phosphorylated and show that it is nonfunctional. Amino acid detection also induces ubiquitylation of the Ssy5 prodomain. This prodomain ubiquitylation requires its prior phosphorylation and the SCFGrr1 complex. When this ubiquitylation is defective, Ssy5 accumulates as a phosphorylated form but remains inactive. A constitutive Ssy5 form in which the prodomain fails to inhibit the catalytic domain does not need to be phosphorylated or ubiquitylated to be active. Finally, we provide evidence that ubiquitylation of the inhibitory prodomain rather than its subsequent degradation is the key step in the Ssy5 activation mechanism. We propose that the Ssy5 protease is activated by phosphorylation-induced ubiquitylation, the effect of which is relief from inhibition by its prodomain.
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Affiliation(s)
- Fadi Abdel-Sater
- Laboratoire de Physiologie Moléculaire de la Cellule CP300, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 11 Rue des Pr. Jeener et Brachet, 6041 Gosselies, Belgium
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Tumusiime S, Zhang C, Overstreet MS, Liu Z. Differential regulation of transcription factors Stp1 and Stp2 in the Ssy1-Ptr3-Ssy5 amino acid sensing pathway. J Biol Chem 2010; 286:4620-31. [PMID: 21127045 DOI: 10.1074/jbc.m110.195313] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stp1 and Stp2 are two homologous transcription factors activated in response to extracellular amino acid stimuli. Here we show that both ubiquitin-dependent degradation of Stp1 and Stp2 and their intracellular localization are differentially regulated. We have found that the E2 ubiquitin-conjugating enzyme Cdc34 is required for degradation of both full-length and processed Stp1, but not Stp2. We have also found that Grr1, the F-box component of the SCF(Grr1) E3 ubiquitin ligase, is the primary factor in degradation of full-length Stp1, whereas both Grr1 and Cdc4 are required for degradation of processed Stp1. Our localization studies showed that full-length Stp1 is localized both in the cytoplasm and at the cell periphery, whereas full-length Stp2 is localized only diffusely in the cytoplasm. We identified two nuclear localization signals of Stp1 and found that the N-terminal domain of Stp1 is required for localization of full-length Stp1 to the cell periphery. We also found that Stp2 is the primary factor involved in basal activation of target gene expression. Our results indicate that the functions of two seemingly redundant transcription factors can be separated by differential degradation and distinct cellular localization.
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Affiliation(s)
- Sylvester Tumusiime
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana 70148, USA
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The prodomain of Ssy5 protease controls receptor-activated proteolysis of transcription factor Stp1. Mol Cell Biol 2010; 30:3299-309. [PMID: 20421414 DOI: 10.1128/mcb.00323-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extracellular amino acids induce the yeast SPS sensor to endoproteolytically cleave transcription factors Stp1 and Stp2 in a process termed receptor-activated proteolysis (RAP). Ssy5, the activating endoprotease, is synthesized with a large N-terminal prodomain and a C-terminal chymotrypsin-like catalytic (Cat) domain. During biogenesis, Ssy5 cleaves itself and the prodomain and Cat domain remain associated, forming an inactive primed protease. Here we show that the prodomain is a potent inhibitor of Cat domain activity and that its inactivation is a requisite for RAP. Accordingly, amino acid-induced signals trigger proteasome-dependent degradation of the prodomain. A mutation that stabilizes the prodomain prevents Stp1 processing, whereas destabilizing mutations lead to constitutive RAP-independent Stp1 processing. We fused a conditional degron to the prodomain to synthetically reprogram the amino acid-responsive SPS signaling pathway, placing it under temperature control. Our results define a regulatory mechanism that is novel for eukaryotic proteases functioning within cells.
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Pasula S, Chakraborty S, Choi JH, Kim JH. Role of casein kinase 1 in the glucose sensor-mediated signaling pathway in yeast. BMC Cell Biol 2010; 11:17. [PMID: 20205947 PMCID: PMC2846877 DOI: 10.1186/1471-2121-11-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 03/07/2010] [Indexed: 02/06/2023] Open
Abstract
Background In yeast, glucose-dependent degradation of the Mth1 protein, a corepressor of the glucose transporter gene (HXT) repressor Rgt1, is a crucial event enabling expression of several HXT. This event occurs through a signaling pathway that involves the Rgt2 and Snf3 glucose sensors and yeast casein kinase 1 and 2 (Yck1/2). In this study, we examined whether the glucose sensors directly couple with Yck1/2 to convert glucose binding into an intracellular signal that leads to the degradation of Mth1. Results High levels of glucose induce degradation of Mth1 through the Rgt2/Snf3 glucose signaling pathway. Fluorescence microscopy analysis indicates that, under glucose-limited conditions, GFP-Mth1 is localized in the nucleus and does not shuttle between the nucleus and cytoplasm. If glucose-induced degradation is prevented due to disruption of the Rgt2/Snf3 pathway, GFP-Mth1 accumulates in the nucleus. When engineered to be localized to the cytoplasm, GFP-Mth1 is degraded regardless of the presence of glucose or the glucose sensors. In addition, removal of Grr1 from the nucleus prevents degradation of GFP-Mth1. These results suggest that glucose-induced, glucose sensor-dependent Mth1 degradation occurs in the nucleus. We also show that, like Yck2, Yck1 is localized to the plasma membrane via C-terminal palmitoylation mediated by the palmitoyl transferase Akr1. However, glucose-dependent degradation of Mth1 is not impaired in the absence of Akr1, suggesting that a direct interaction between the glucose sensors and Yck1/2 is not required for Mth1 degradation. Conclusion Glucose-induced, glucose sensor-regulated degradation of Mth1 occurs in the nucleus and does not require direct interaction of the glucose sensors with Yck1/2.
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Affiliation(s)
- Satish Pasula
- The Mississippi Functional Genomics Network, Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
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