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Robinson BP, Hawbaker S, Chiang A, Jordahl EM, Anaokar S, Nikiforov A, Bowman RW, Ziegler P, McAtee CK, Patton-Vogt J, O'Donnell AF. Alpha-arrestins Aly1/Art6 and Aly2/Art3 regulate trafficking of the glycerophosphoinositol transporter Git1 and impact phospholipid homeostasis. Biol Cell 2021; 114:3-31. [PMID: 34562280 DOI: 10.1111/boc.202100007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/23/2021] [Accepted: 07/15/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND INFORMATION Phosphatidylinositol (PI) is an essential phospholipid, critical to membrane bilayers. The complete deacylation of PI by B-type phospholipases produces intracellular and extracellular glycerophosphoinositol (GPI). Extracellular GPI is transported into the cell via Git1, a member of the Major Facilitator Superfamily of transporters at the yeast plasma membrane. Internalized GPI is degraded to produce inositol, phosphate and glycerol, thereby contributing to these pools. GIT1 gene expression is controlled by nutrient balance, with phosphate or inositol starvation increasing GIT1 expression to stimulate GPI uptake. However, less is known about control of Git1 protein levels or localization. RESULTS We find that the α-arrestins, an important class of protein trafficking adaptor, regulate Git1 localization and this is dependent upon their interaction with the ubiquitin ligase Rsp5. Specifically, α-arrestin Aly2 stimulates Git1 trafficking to the vacuole under basal conditions, but in response to GPI-treatment, either Aly1 or Aly2 promote Git1 vacuole trafficking. Cell surface retention of Git1, as occurs in aly1∆ aly2∆ cells, is linked to impaired growth in the presence of exogenous GPI and results in increased uptake of radiolabeled GPI, suggesting that accumulation of GPI somehow causes cellular toxicity. Regulation of α-arrestin Aly1 by the protein phosphatase calcineurin improves steady-state and substrate-induced trafficking of Git1, however, calcineurin plays a larger role in Git1 trafficking beyond regulation of α-arrestins. Interestingly, loss of Aly1 and Aly2 increased phosphatidylinositol-3-phosphate on the limiting membrane of the vacuole, and this was further exacerbated by GPI addition, suggesting that the effect is partially linked to Git1. Loss of Aly1 and Aly2 leads to increased incorporation of inositol label from [3 H]-inositol-labelled GPI into PI, confirming that internalized GPI influences PI balance and indicating a role for the a-arrestins in this regulation. CONCLUSIONS The α-arrestins Aly1 and Aly2 are novel regulators of Git1 trafficking with previously unanticipated roles in controlling phospholipid distribution and balance. SIGNIFICANCE To our knowledge, this is the first example of α-arrestin regulation of phosphatidyliniositol-3-phosphate levels. In future studies it will be exciting to determine if other α-arrestins similarly alter PI and PIPs to change the cellular landscape.
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Affiliation(s)
- Benjamin P Robinson
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Sarah Hawbaker
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Annette Chiang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Eric M Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sanket Anaokar
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Alexiy Nikiforov
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ray W Bowman
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Philip Ziegler
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ceara K McAtee
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Allyson F O'Donnell
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Gallagher JE, Ser SL, Ayers MC, Nassif C, Pupo A. The Polymorphic PolyQ Tail Protein of the Mediator Complex, Med15, Regulates the Variable Response to Diverse Stresses. Int J Mol Sci 2020; 21:ijms21051894. [PMID: 32164312 PMCID: PMC7094212 DOI: 10.3390/ijms21051894] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 01/01/2023] Open
Abstract
The Mediator is composed of multiple subunits conserved from yeast to humans and plays a central role in transcription. The tail components are not required for basal transcription but are required for responses to different stresses. While some stresses are familiar, such as heat, desiccation, and starvation, others are exotic, yet yeast can elicit a successful stress response. 4-Methylcyclohexane methanol (MCHM) is a hydrotrope that induces growth arrest in yeast. We found that a naturally occurring variation in the Med15 allele, a component of the Mediator tail, altered the stress response to many chemicals in addition to MCHM. Med15 contains two polyglutamine repeats (polyQ) of variable lengths that change the gene expression of diverse pathways. The Med15 protein existed in multiple isoforms and its stability was dependent on Ydj1, a protein chaperone. The protein level of Med15 with longer polyQ tracts was lower and turned over faster than the allele with shorter polyQ repeats. MCHM sensitivity via variation of Med15 was regulated by Snf1 in a Myc-tag-dependent manner. Tagging Med15 with Myc altered its function in response to stress. Genetic variation in transcriptional regulators magnified genetic differences in response to environmental changes. These polymorphic control genes were master variators.
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Chia SZ, Lai YW, Yagoub D, Lev S, Hamey JJ, Pang CNI, Desmarini D, Chen Z, Djordjevic JT, Erce MA, Hart-Smith G, Wilkins MR. Knockout of the Hmt1p Arginine Methyltransferase in Saccharomyces cerevisiae Leads to the Dysregulation of Phosphate-associated Genes and Processes. Mol Cell Proteomics 2018; 17:2462-2479. [PMID: 30206180 PMCID: PMC6283299 DOI: 10.1074/mcp.ra117.000214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/14/2018] [Indexed: 11/06/2022] Open
Abstract
Hmt1p is the predominant arginine methyltransferase in Saccharomyces cerevisiae Its substrate proteins are involved in transcription, transcriptional regulation, nucleocytoplasmic transport and RNA splicing. Hmt1p-catalyzed methylation can also modulate protein-protein interactions. Hmt1p is conserved from unicellular eukaryotes through to mammals where its ortholog, PRMT1, is lethal upon knockout. In yeast, however, the effect of knockout on the transcriptome and proteome has not been described. Transcriptome analysis revealed downregulation of phosphate-responsive genes in hmt1Δ, including acid phosphatases PHO5, PHO11, and PHO12, phosphate transporters PHO84 and PHO89 and the vacuolar transporter chaperone VTC3 Analysis of the hmt1Δ proteome revealed decreased abundance of phosphate-associated proteins including phosphate transporter Pho84p, vacuolar alkaline phosphatase Pho8p, acid phosphatase Pho3p and subunits of the vacuolar transporter chaperone complex Vtc1p, Vtc3p and Vtc4p. Consistent with this, phosphate homeostasis was dysregulated in hmt1Δ cells, showing decreased extracellular phosphatase levels and decreased total Pi in phosphate-depleted medium. In vitro, we showed that transcription factor Pho4p can be methylated at Arg-241, which could explain phosphate dysregulation in hmt1Δ if interplay exists with phosphorylation at Ser-242 or Ser-243, or if Arg-241 methylation affects the capacity of Pho4p to homodimerize or interact with Pho2p. However, the Arg-241 methylation site was not validated in vivo and the localization of a Pho4p-GFP fusion in hmt1Δ was not different from wild type. To our knowledge, this is the first study to reveal an association between Hmt1p and phosphate homeostasis and one which suggests a regulatory link between S-adenosyl methionine and intracellular phosphate.
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Affiliation(s)
- Samantha Z Chia
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Yu-Wen Lai
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Daniel Yagoub
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Joshua J Hamey
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Chi Nam Ignatius Pang
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Zhiliang Chen
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute and Sydney Medical School, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
| | - Melissa A Erce
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Gene Hart-Smith
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marc R Wilkins
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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4
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Pautasso C, Reca S, Chatfield-Reed K, Chua G, Galello F, Portela P, Zaremberg V, Rossi S. Identification of novel transcriptional regulators of PKA subunits inSaccharomyces cerevisiaeby quantitative promoter–reporter screening. FEMS Yeast Res 2016; 16:fow046. [DOI: 10.1093/femsyr/fow046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2016] [Indexed: 01/22/2023] Open
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5
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Schifferdecker AJ, Siurkus J, Andersen MR, Joerck-Ramberg D, Ling Z, Zhou N, Blevins JE, Sibirny AA, Piškur J, Ishchuk OP. Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast. Appl Microbiol Biotechnol 2016; 100:3219-31. [PMID: 26743658 PMCID: PMC4786601 DOI: 10.1007/s00253-015-7266-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/13/2015] [Accepted: 12/19/2015] [Indexed: 01/05/2023]
Abstract
Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions, respectively. The overexpression of ADH3 in D. bruxellensis also reduced the inhibition of fermentation by anaerobiosis, the “Custer effect”. Thus, the fermentative capacity of D. bruxellensis could be further improved by metabolic engineering.
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Affiliation(s)
| | - Juozas Siurkus
- Department of Systems Biology, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Mikael Rørdam Andersen
- Department of Systems Biology, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Dorte Joerck-Ramberg
- Department of Systems Biology, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Zhihao Ling
- Department of Biology, Lund University, Sölvegatan 35, Lund, SE-223 62, Sweden
| | - Nerve Zhou
- Department of Biology, Lund University, Sölvegatan 35, Lund, SE-223 62, Sweden
| | - James E Blevins
- Consulting statistician, Pinnmöllevägen 48, SE-24755, Dalby, Sweden
| | - Andriy A Sibirny
- Institute of Cell Biology, NAS of Ukraine, Drahomanov Street 14/16, Lviv, 79005, Ukraine.,Department of Biotechnology and Microbiology, University of Rzeszow, Zelwerowizca 4, Rzeszow, 35-601, Poland
| | - Jure Piškur
- Department of Biology, Lund University, Sölvegatan 35, Lund, SE-223 62, Sweden
| | - Olena P Ishchuk
- Department of Biology, Lund University, Sölvegatan 35, Lund, SE-223 62, Sweden.
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6
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Abstract
In budding yeast, Saccharomyces cerevisiae, the phosphate signalling and response pathway, known as PHO pathway, monitors phosphate cytoplasmic levels by controlling genes involved in scavenging, uptake and utilization of phosphate. Recent attempts to understand the phosphate starvation response in other ascomycetes have suggested the existence of both common and novel components of the budding yeast PHO pathway in these ascomycetes. In this review, we discuss the components of PHO pathway, their roles in maintaining phosphate homeostasis in yeast and their conservation across ascomycetes. The role of high-affinity transporter, Pho84, in sensing and signalling of phosphate has also been discussed.
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Affiliation(s)
- Parul Tomar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India
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7
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Phosphate homeostasis in the yeast Saccharomyces cerevisiae, the key role of the SPX domain-containing proteins. FEBS Lett 2012; 586:289-95. [PMID: 22285489 DOI: 10.1016/j.febslet.2012.01.036] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/11/2012] [Accepted: 01/16/2012] [Indexed: 12/27/2022]
Abstract
In the yeast Saccharomyces cerevisiae, a working model for nutrient homeostasis in eukaryotes, inorganic phosphate (Pi) homeostasis is regulated by the PHO pathway, a set of phosphate starvation induced genes, acting to optimize Pi uptake and utilization. Among these, a subset of proteins containing the SPX domain has been shown to be key regulators of Pi homeostasis. In this review, we summarize the recent progresses in elucidating the mechanisms controlling Pi homeostasis in yeast, focusing on the key roles of the SPX domain-containing proteins in these processes, as well as describing the future challenges and opportunities in this fast-moving field.
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8
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Life in the midst of scarcity: adaptations to nutrient availability in Saccharomyces cerevisiae. Curr Genet 2010; 56:1-32. [PMID: 20054690 DOI: 10.1007/s00294-009-0287-1] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 12/18/2009] [Accepted: 12/19/2009] [Indexed: 12/27/2022]
Abstract
Cells of all living organisms contain complex signal transduction networks to ensure that a wide range of physiological properties are properly adapted to the environmental conditions. The fundamental concepts and individual building blocks of these signalling networks are generally well-conserved from yeast to man; yet, the central role that growth factors and hormones play in the regulation of signalling cascades in higher eukaryotes is executed by nutrients in yeast. Several nutrient-controlled pathways, which regulate cell growth and proliferation, metabolism and stress resistance, have been defined in yeast. These pathways are integrated into a signalling network, which ensures that yeast cells enter a quiescent, resting phase (G0) to survive periods of nutrient scarceness and that they rapidly resume growth and cell proliferation when nutrient conditions become favourable again. A series of well-conserved nutrient-sensory protein kinases perform key roles in this signalling network: i.e. Snf1, PKA, Tor1 and Tor2, Sch9 and Pho85-Pho80. In this review, we provide a comprehensive overview on the current understanding of the signalling processes mediated via these kinases with a particular focus on how these individual pathways converge to signalling networks that ultimately ensure the dynamic translation of extracellular nutrient signals into appropriate physiological responses.
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9
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Chen M, Lopes JM. Multiple basic helix-loop-helix proteins regulate expression of the ENO1 gene of Saccharomyces cerevisiae. EUKARYOTIC CELL 2007; 6:786-96. [PMID: 17351075 PMCID: PMC1899243 DOI: 10.1128/ec.00383-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The basic helix-loop-helix (bHLH) eukaryotic transcription factors have the ability to form multiple dimer combinations. This property, together with limited DNA-binding specificity for the E box (CANNTG), makes them ideally suited for combinatorial control of gene expression. We tested the ability of all nine Saccharomyces cerevisiae bHLH proteins to regulate the enolase-encoding gene ENO1. ENO1 was known to be activated by the bHLH protein Sgc1p. Here we show that expression of an ENO1-lacZ reporter was also regulated by the other eight bHLH proteins, namely, Ino2p, Ino4p, Cbf1p, Rtg1p, Rtg3p, Pho4p, Hms1p, and Ygr290wp. ENO1-lacZ expression was also repressed by growth in inositol-choline-containing medium. Epistatic analysis and chromatin immunoprecipitation experiments showed that regulation by Sgc1p, Ino2p, Ino4p, and Cbf1p and repression by inositol-choline required three distal E boxes, E1, E2, and E3. The pattern of bHLH binding to the three E boxes and experiments with two dominant-negative mutant alleles of INO4 and INO2 support the model that bHLH dimer selection affects ENO1-lacZ expression. These results support the general model that bHLH proteins can coordinate different biological pathways via multiple mechanisms.
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Affiliation(s)
- Meng Chen
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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10
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Abstract
We wish to understand the role of electrostatics in DNA stiffness and bending. The DNA charge collapse model suggests that mutual electrostatic repulsions between neighboring phosphates significantly contribute to DNA stiffness. According to this model, placement of fixed charges near the negatively charged DNA surface should induce bending through asymmetric reduction or enhancement of these inter-phosphate repulsive forces. We have reported previously that charged variants of the elongated basic-leucine zipper (bZIP) domain of Gcn4p bend DNA in a manner consistent with this charge collapse model. To extend this result to a more globular protein, we present an investigation of the dimeric basic-helix–loop–helix (bHLH) domain of Pho4p. The 62 amino acid bHLH domain has been modified to position charged amino acid residues near one face of the DNA double helix. As observed for bZIP charge variants, DNA bending toward appended cations (away from the protein:DNA interface) is observed. However, unlike bZIP proteins, DNA is not bent away from bHLH anionic charges. This finding can be explained by the structure of the more globular bHLH domain which, in contrast to bZIP proteins, makes extensive DNA contacts along the binding face.
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Affiliation(s)
- Robert J. McDonald
- Medical Scientist Training Program, Mayo Clinic College of MedicineRochester, MN 55905, USA
| | - Jason D. Kahn
- Medical Scientist Training Program, Mayo Clinic College of MedicineRochester, MN 55905, USA
| | - L. James Maher
- Department of Chemistry and Biochemistry, University of MarylandCollege Park, MD 20742-2021, USA
- To whom correspondence should be addressed. Tel: +1 507 284 9041; Fax: +1 507 284 2053;
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11
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Gardocki ME, Bakewell M, Kamath D, Robinson K, Borovicka K, Lopes JM. Genomic analysis of PIS1 gene expression. EUKARYOTIC CELL 2005; 4:604-14. [PMID: 15755922 PMCID: PMC1087795 DOI: 10.1128/ec.4.3.604-614.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Saccharomyces cerevisiae PIS1 gene is essential and required for the final step in the de novo synthesis of phosphatidylinositol. Transcription of the PIS1 gene is uncoupled from the factors that regulate other yeast phospholipid biosynthetic genes. Most of the phospholipid biosynthetic genes are regulated in response to inositol and choline via a regulatory circuit that includes the Ino2p:Ino4p activator complex and the Opi1p repressor. PIS1 is regulated in response to carbon source and anaerobic growth conditions. Both of these regulatory responses are modest, which is not entirely surprising since PIS1 is essential. However, even modest regulation of PIS1 expression has been shown to affect phosphatidylinositol metabolism and to affect cell cycle progression. This prompted the present study, which employed a genomic screen, database mining, and more traditional promoter analysis to identify genes that affect PIS1 expression. A screen of the viable yeast deletion set identified 120 genes that affect expression of a PIS1-lacZ reporter. The gene set included several peroxisomal genes, silencing genes, and transcription factors. Factors suggested by database mining, such as Pho2 and Yfl044c, were also found to affect PIS1-lacZ expression. A PIS1 promoter deletion study identified an upstream regulatory sequence element that was required for carbon source regulation located downstream of three previously defined upstream activation sequence elements. Collectively, these studies demonstrate how a collection of genomic and traditional strategies can be implemented to identify a set of genes that affect the regulation of an essential gene.
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Affiliation(s)
- Mary E Gardocki
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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12
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Gardocki ME, Jani N, Lopes JM. Phosphatidylinositol biosynthesis: biochemistry and regulation. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1735:89-100. [PMID: 15967713 DOI: 10.1016/j.bbalip.2005.05.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 05/14/2005] [Accepted: 05/19/2005] [Indexed: 12/22/2022]
Abstract
Phosphatidylinositol (PI) is a ubiquitous membrane lipid in eukaryotes. It is becoming increasingly obvious that PI and its metabolites play a myriad of very diverse roles in eukaryotic cells. The Saccharomyces cerevisiae PIS1 gene is essential and encodes PI synthase, which is required for the synthesis of PI. Recently, PIS1 expression was found to be regulated in response to carbon source and oxygen availability. It is particularly significant that the promoter elements required for these responses are conserved evolutionarily throughout the Saccharomyces genus. In addition, several genome-wide strategies coupled with more traditional screens suggest that several other factors regulate PIS1 expression. The impact of regulating PIS1 expression on PI synthesis will be discussed along with the possible role(s) that this may have on diseases such as cancer.
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Affiliation(s)
- Mary E Gardocki
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit MI 48202, USA
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13
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Persson BL, Lagerstedt JO, Pratt JR, Pattison-Granberg J, Lundh K, Shokrollahzadeh S, Lundh F. Regulation of phosphate acquisition in Saccharomyces cerevisiae. Curr Genet 2003; 43:225-44. [PMID: 12740714 DOI: 10.1007/s00294-003-0400-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2003] [Revised: 04/05/2003] [Accepted: 04/08/2003] [Indexed: 01/08/2023]
Abstract
Membrane transport systems active in cellular inorganic phosphate (P(i)) acquisition play a key role in maintaining cellular P(i) homeostasis, independent of whether the cell is a unicellular microorganism or is contained in the tissue of a higher eukaryotic organism. Since unicellular eukaryotes such as yeast interact directly with the nutritious environment, regulation of P(i) transport is maintained solely by transduction of nutrient signals across the plasma membrane. The individual yeast cell thus recognizes nutrients that can act as both signals and sustenance. The present review provides an overview of P(i) acquisition via the plasma membrane P(i) transporters of Saccharomyces cerevisiae and the regulation of internal P(i) stores under the prevailing P(i) status.
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Affiliation(s)
- Bengt L Persson
- Department of Chemistry and Biomedical Science, Kalmar University, P.O. Box 905, 39182, Kalmar, Sweden.
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14
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Jeffery DA, Springer M, King DS, O'Shea EK. Multi-site phosphorylation of Pho4 by the cyclin-CDK Pho80-Pho85 is semi-processive with site preference. J Mol Biol 2001; 306:997-1010. [PMID: 11237614 DOI: 10.1006/jmbi.2000.4417] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As part of a nutrient-responsive signaling pathway, the budding yeast cyclin-CDK complex Pho80-Pho85 phosphorylates the transcription factor Pho4 on five sites and inactivates it. Here, we describe the kinetic reaction between Pho80-Pho85 and Pho4. Through experimentation and computer modeling we have determined that Pho80-Pho85 phosphorylates Pho4 in a semi-processive fashion that results from a balance between kcat and k(off). In addition, we show that Pho80-Pho85 phosphorylates certain sites preferentially. Phosphorylation of the site with the highest preference inhibits the transcriptional activity of Pho4 when it is in the nucleus, while phosphorylation of the lowest-preference sites is required for export of Pho4 from the nucleus. This method of phosphorylation may allow Pho80-Pho85 to quickly inactivate Pho4 in the nucleus and efficiently phosphorylate Pho4 to completion.
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Affiliation(s)
- D A Jeffery
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA
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15
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Bourne Y, Watson MH, Arvai AS, Bernstein SL, Reed SI, Tainer JA. Crystal structure and mutational analysis of the Saccharomyces cerevisiae cell cycle regulatory protein Cks1: implications for domain swapping, anion binding and protein interactions. Structure 2000; 8:841-50. [PMID: 10997903 DOI: 10.1016/s0969-2126(00)00175-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND The Saccharomyces cerevisiae protein Cks1 (cyclin-dependent kinase subunit 1) is essential for cell-cycle progression. The biological function of Cks1 can be modulated by a switch between two distinct molecular assemblies: the single domain fold, which results from the closing of a beta-hinge motif, and the intersubunit beta-strand interchanged dimer, which arises from the opening of the beta-hinge motif. The crystal structure of a cyclin-dependent kinase (Cdk) in complex with the human Cks homolog CksHs1 single-domain fold revealed the importance of conserved hydrophobic residues and charged residues within the beta-hinge motif. RESULTS The 3.0 A resolution Cks1 structure reveals the strict structural conservation of the Cks alpha/beta-core fold and the beta-hinge motif. The beta hinge identified in the Cks1 structure includes a novel pivot and exposes a cluster of conserved tyrosine residues that are involved in Cdk binding but are sequestered in the beta-interchanged Cks homolog suc1 dimer structure. This Cks1 structure confirms the conservation of the Cks anion-binding site, which interacts with sidechain residues from the C-terminal alpha helix of another subunit in the crystal. CONCLUSIONS The Cks1 structure exemplifies the conservation of the beta-interchanged dimer and the anion-binding site in evolutionarily distant yeast and human Cks homologs. Mutational analyses including in vivo rescue of CKS1 disruption support the dual functional roles of the beta-hinge residue Glu94, which participates in Cdk binding, and of the anion-binding pocket that is located 22 A away and on an opposite face to Glu94. The Cks1 structure suggests a biological role for the beta-interchanged dimer and the anion-binding site in targeting Cdks to specific phosphoproteins during cell-cycle progression.
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Affiliation(s)
- Y Bourne
- Centre National de la Recherche Scientifique, Marseille, France.
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16
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Persson BL, Petersson J, Fristedt U, Weinander R, Berhe A, Pattison J. Phosphate permeases of Saccharomyces cerevisiae: structure, function and regulation. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1422:255-72. [PMID: 10548719 DOI: 10.1016/s0304-4157(99)00010-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- B L Persson
- Department of Engineering, Växjö University, S-351 95, Växjö, Sweden.
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