1
|
Kleinberger T. Biology of the adenovirus E4orf4 protein: from virus infection to cancer cell death. FEBS Lett 2019; 594:1891-1917. [DOI: 10.1002/1873-3468.13704] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Tamar Kleinberger
- Department of Molecular Microbiology the Rappaport Faculty of Medicine Technion –Israel Institute of Technology Haifa Israel
| |
Collapse
|
2
|
Li Y, Hou J, Wang F, Sheng J. High-throughput assays of leloir-glycosyltransferase reactions: The applications of rYND1 in glycotechnology. J Biotechnol 2016; 227:10-18. [PMID: 27059478 DOI: 10.1016/j.jbiotec.2016.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 11/25/2022]
Abstract
Glycosyltransferases (GTs) play a critical role in the enzymatic and chemoenzymatic synthesis of oligosaccharides and glycoconjugates. However, the development of these synthetic approaches has been limited by a lack of sensitive screening methods for the isolation of novel natural GTs or their active variants. Herein, we describe the results of our investigation towards the soluble expression and potential application of the Saccharomyces cerevisiae apyrase YND1. By replacing the hydrophobic transmembrane domain of YND1 with three glycine-serine repeats, this protein was successfully expressed in a soluble form in Escherichia coli. This new protein was then used to develop a two-step nucleoside diphosphate (NDP)-based Leloir-GT high-throughput assay. Purified rYND1 was initially added to a GT reaction to hydrolyze NDP to nucleoside phosphate plus inorganic phosphate, which was determined using a phosphorus molybdenum blue chromogenic reaction. Purified rYND1 was shown to have a positive effect on saccharide synthesis by eliminating the potential by-product inhibition from NDP. Most of the mono-sugar donors used for Leloir-GTs are activated by uridine diphosphate and guanosine diphosphate, which can be catalyzed by rYND1. The rYND1 is amenable to screening methods and could be applied to a wide range of Leloir-GT-catalyzed reactions, therefore representing a remarkable step forward in glycotechnology.
Collapse
Affiliation(s)
- Yijun Li
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Jin Hou
- The State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, China
| | - Fengshan Wang
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China; National Glycoengineering Research Center, Shandong University, Jinan 250012, China.
| | - Juzheng Sheng
- Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China; National Glycoengineering Research Center, Shandong University, Jinan 250012, China.
| |
Collapse
|
3
|
Kleinberger T. Mechanisms of cancer cell killing by the adenovirus E4orf4 protein. Viruses 2015; 7:2334-57. [PMID: 25961489 PMCID: PMC4452909 DOI: 10.3390/v7052334] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 04/23/2015] [Accepted: 04/30/2015] [Indexed: 12/24/2022] Open
Abstract
During adenovirus (Ad) replication the Ad E4orf4 protein regulates progression from the early to the late phase of infection. However, when E4orf4 is expressed alone outside the context of the virus it induces a non-canonical mode of programmed cell death, which feeds into known cell death pathways such as apoptosis or necrosis, depending on the cell line tested. E4orf4-induced cell death has many interesting and unique features including a higher susceptibility of cancer cells to E4orf4-induced cell killing compared with normal cells, caspase-independence, a high degree of evolutionary conservation of the signaling pathways, a link to perturbations of the cell cycle, and involvement of two distinct cell death programs, in the nucleus and in the cytoplasm. Several E4orf4-interacting proteins including its major partners, protein phosphatase 2A (PP2A) and Src family kinases, contribute to induction of cell death. The various features of E4orf4-induced cell killing as well as studies to decipher the underlying mechanisms are described here. Many explanations for the cancer specificity of E4orf4-induced cell death have been proposed, but a full understanding of the reasons for the different susceptibility of cancer and normal cells to killing by E4orf4 will require a more detailed analysis of the complex E4orf4 signaling network. An improved understanding of the mechanisms involved in this unique mode of programmed cell death may aid in design of novel E4orf4-based cancer therapeutics.
Collapse
Affiliation(s)
- Tamar Kleinberger
- Department of Microbiology, Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron St., Bat Galim, Haifa 31096, Israel.
| |
Collapse
|
4
|
Massalski C, Bloch J, Zebisch M, Steinebrunner I. The biochemical properties of the Arabidopsis ecto-nucleoside triphosphate diphosphohydrolase AtAPY1 contradict a direct role in purinergic signaling. PLoS One 2015; 10:e0115832. [PMID: 25822168 PMCID: PMC4379058 DOI: 10.1371/journal.pone.0115832] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/02/2014] [Indexed: 11/18/2022] Open
Abstract
The Arabidopsis E-NTPDase (ecto-nucleoside triphosphate diphosphohydrolase) AtAPY1 was previously shown to be involved in growth and development, pollen germination and stress responses. It was proposed to perform these functions through regulation of extracellular ATP signals. However, a GFP-tagged version was localized exclusively in the Golgi and did not hydrolyze ATP. In this study, AtAPY1 without the bulky GFP-tag was biochemically characterized with regard to its suggested role in purinergic signaling. Both the full-length protein and a soluble form without the transmembrane domain near the N-terminus were produced in HEK293 cells. Of the twelve nucleotide substrates tested, only three--GDP, IDP and UDP--were hydrolyzed, confirming that ATP was not a substrate of AtAPY1. In addition, the effects of pH, divalent metal ions, known E-NTPDase inhibitors and calmodulin on AtAPY1 activity were analyzed. AtAPY1-GFP extracted from transgenic Arabidopsis seedlings was included in the analyses. All three AtAPY1 versions exhibited very similar biochemical properties. Activity was detectable in a broad pH range, and Ca(2+), Mg(2+) and Mn(2+) were the three most efficient cofactors. Of the inhibitors tested, vanadate was the most potent one. Surprisingly, sulfonamide-based inhibitors shown to inhibit other E-NTPDases and presumed to inhibit AtAPY1 as well were not effective. Calmodulin stimulated the activity of the GFP-tagless membranous and soluble AtAPY1 forms about five-fold, but did not alter their substrate specificities. The apparent Km values obtained with AtAPY1-GFP indicate that AtAPY1 is primarily a GDPase. A putative three-dimensional structural model of the ecto-domain is presented, explaining the potent inhibitory potential of vanadate and predicting the binding mode of GDP. The found substrate specificity classifies AtAPY1 as a nucleoside diphosphatase typical of N-terminally anchored Golgi E-NTPDases and negates a direct function in purinergic signaling.
Collapse
Affiliation(s)
- Carolin Massalski
- Department of Biology, Technische Universität Dresden, Dresden, Germany
| | - Jeannine Bloch
- Department of Biology, Technische Universität Dresden, Dresden, Germany
| | - Matthias Zebisch
- Division of Structural Biology, University of Oxford, Oxford, United Kingdom
| | | |
Collapse
|
5
|
NTPDASE4 gene products cooperate with the adenovirus E4orf4 protein through PP2A-dependent and -independent mechanisms and contribute to induction of cell death. J Virol 2014; 88:6318-28. [PMID: 24672025 DOI: 10.1128/jvi.00381-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED The adenovirus E4orf4 protein induces nonclassical apoptosis in mammalian cells through at least two complementing pathways regulated by the interactions of E4orf4 with protein phosphatase 2A (PP2A) and Src kinases. In Saccharomyces cerevisiae cells, which do not express Src, E4orf4 induces PP2A-dependent toxicity. The yeast Golgi apyrase Ynd1 was found to contribute to E4orf4-mediated toxicity and to interact with the PP2A-B55α regulatory subunit. In addition, a mammalian Ynd1 orthologue, the NTPDASE4 gene product Golgi UDPase, was shown to physically interact with E4orf4. Here we report that knockdown of NTPDASE4 suppressed E4orf4-induced cell death. Conversely, overexpression of the NTPDASE4 gene products Golgi UDPase and LALP70 enhanced E4orf4-induced cell killing. We found that similarly to results obtained in yeast, the apyrase activity of mammalian UDPase was not required for its contribution to E4orf4-induced toxicity. The interaction between E4orf4 and UDPase had two consequences: a PP2A-dependent one, resulting in increased UDPase levels, and a PP2A-independent outcome that led to dissociation of large UDPase-containing protein complexes. The present report extends our findings in yeast to E4orf4-mediated death of mammalian cells, and combined with previous results, it suggests that the E4orf4-NTPDase4 pathway, partly in association with PP2A, may provide an alternative mechanism for the E4orf4-Src pathway to contribute to the cytoplasmic death function of E4orf4. IMPORTANCE The adenovirus E4orf4 protein contributes to regulation of the progression of virus infection from the early to the late phase, and when expressed alone, it induces a unique caspase-independent programmed cell death which is more efficient in cancer cells than in normal cells. The interactions of E4orf4 with cellular proteins that mediate its functions, such as PP2A and Src kinases, are highly conserved in evolution. The results presented here reveal that the NTPDASE4 gene product Golgi UDPase, first discovered to contribute to E4orf4 toxicity in Saccharomyces cerevisiae, associates with E4orf4 and plays a role in induction of cell death in mammalian cells. Details of the functional interaction between E4orf4, PP2A, and the UDPase are described. Identification of the evolutionarily conserved mechanisms underlying E4orf4 activity will increase our understanding of the interactions between the virus and the host cell and will contribute to our grasp of the unique mode of E4orf4-induced cell death.
Collapse
|
6
|
Kleinberger T. Induction of cancer-specific cell death by the adenovirus E4orf4 protein. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 818:61-97. [PMID: 25001532 DOI: 10.1007/978-1-4471-6458-6_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The adenovirus E4orf4 protein is a multifunctional viral regulator that contributes to temporal regulation of the progression of viral infection. When expressed alone, outside the context of the virus, E4orf4 induces p53-independent cell-death in transformed cells. Oncogenic transformation of primary cells in tissue culture sensitizes them to cell killing by E4orf4, indicating that E4orf4 research may have implications for cancer therapy. It has also been reported that E4orf4 induces a caspase-independent, non-classical apoptotic pathway, which maintains crosstalk with classical caspase-dependent pathways. Furthermore, several E4orf4 activities in the nucleus and in the cytoplasm and various protein partners contribute to cell killing by this viral protein. In the following chapter I summarize the current knowledge of the unique mode of E4orf4-induced cell death and its underlying mechanisms. Although several explanations for the cancer-specificity of E4orf4-induced toxicity have been proposed, a better grasp of the mechanisms responsible for E4orf4-induced cell death is required to elucidate the differential sensitivity of normal and cancer cells to E4orf4.
Collapse
Affiliation(s)
- Tamar Kleinberger
- Department of Molecular Microbiology, The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 31096, Israel,
| |
Collapse
|
7
|
Paavilainen S, Guidotti G. Interactions between the transmembrane domains of CD39: identification of interacting residues by yeast selection. SCIENCEOPEN RESEARCH 2014; 2014. [PMID: 26258004 DOI: 10.14293/s2199-1006.1.sorlife.aeeerm.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rat CD39, a membrane-bound ectonucleoside triphosphate diphosphohydrolase that hydrolyzes extracellular nucleoside tri- and diphosphates, is anchored to the membrane by two transmembrane domains at the two ends of the molecule. The transmembrane domains are important for enzymatic activity, as mutants lacking one or both of these domains have a fraction of the enzymatic activity of the wild-type CD39. We investigated the interactions between the transmembrane domains by using a strain of yeast that requires surface expression of CD39 for growth. Random mutagenesis of selected amino acid residues in the N-terminal transmembrane domain revealed that the presence of charged amino acids at these positions prevents expression of functional protein. Rescue of the growth of these mutants by complementary mutations on selected residues of the C-terminal transmembrane domain indicates that there is contact between particular faces of the transmembrane domains.
Collapse
Affiliation(s)
- Sari Paavilainen
- Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA
| | - Guido Guidotti
- Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA
| |
Collapse
|
8
|
Chiu TY, Christiansen K, Moreno I, Lao J, Loqué D, Orellana A, Heazlewood JL, Clark G, Roux SJ. AtAPY1 and AtAPY2 function as Golgi-localized nucleoside diphosphatases in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2012; 53:1913-25. [PMID: 23034877 DOI: 10.1093/pcp/pcs131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Nucleoside triphosphate diphosphohydrolases (NTPDases; apyrases) (EC 3.6.1.5) hydrolyze di- and triphosphate nucleotides, but not monophosphate nucleotides. They are categorized as E-type ATPases, have a broad divalent cation (Mg(2+), Ca(2+)) requirement for activation and are insensitive to inhibitors of F-type, P-type and V-type ATPases. Among the seven NTPDases identified in Arabidopsis, only APYRASE 1 (AtAPY1) and APYRASE 2 (AtAPY2) have been previously characterized. In this work, either AtAPY1 or AtAPY2 tagged with C-terminal green fluorescent protein (GFP) driven by their respective native promoter can rescue the apy1 apy2 double knockout (apy1 apy2 dKO) successfully, and confocal microscopy reveals that these two Arabidopsis apyrases reside in the Golgi apparatus. In Saccharomyces cerevisiae, both AtAPY1 and AtAPY2 can complement the Golgi-localized GDA1 mutant, rescuing its aberrant protein glycosylation phenotype. In Arabidopsis, microsomes of the wild type show higher substrate preferences toward UDP compared with other NDP substrates. Loss-of-function Arabidopsis AtAPY1 mutants exhibit reduced microsomal UDPase activity, and this activity is even more significantly reduced in the loss-of-function AtAPY2 mutant and in the AtAPY1/AtAPY2 RNA interference (RNAi) technology repressor lines. Microsomes from wild-type plants also have detectable GDPase activity, which is significantly reduced in apy2 but not apy1 mutants. The GFP-tagged AtAPY1 or AtAPY2 constructs in the apy1 apy2 dKO plants can restore microsomal UDP/GDPase activity, confirming that they both also have functional competency. The cell walls of apy1, apy2 and the RNAi-silenced lines all have an increased composition of galactose, but the transport efficiency of UDP-galactose across microsomal membranes was not altered. Taken together, these results reveal that AtAPY1 and AtAPY2 are Golgi-localized nucleotide diphosphatases and are likely to have roles in regulating UDP/GDP concentrations in the Golgi lumen.
Collapse
Affiliation(s)
- Tsan-Yu Chiu
- Section of Molecular Cell and Developmental Biology, University of Texas, Austin, TX 78712, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Knowles AF. The GDA1_CD39 superfamily: NTPDases with diverse functions. Purinergic Signal 2011; 7:21-45. [PMID: 21484095 DOI: 10.1007/s11302-010-9214-7] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 12/21/2010] [Indexed: 01/05/2023] Open
Abstract
The first comprehensive review of the ubiquitous "ecto-ATPases" by Plesner was published in 1995. A year later, a lymphoid cell activation antigen, CD39, that had been cloned previously, was shown to be an ecto-ATPase. A family of proteins, related to CD39 and a yeast GDPase, all containing the canonical apyrase conserved regions in their polypeptides, soon started to expand. They are now recognized as members of the GDA1_CD39 protein family. Because proteins in this family hydrolyze nucleoside triphosphates and diphosphates, a unifying nomenclature, nucleoside triphosphate diphopshohydrolases (NTPDases), was established in 2000. Membrane-bound NTPDases are either located on the cell surface or membranes of intracellular organelles. Soluble NTPDases exist in the cytosol and may be secreted. In the last 15 years, molecular cloning and functional expression have facilitated biochemical characterization of NTPDases of many organisms, culminating in the recent structural determination of the ecto-domain of a mammalian cell surface NTPDase and a bacterial NTPDase. The first goal of this review is to summarize the biochemical, mutagenesis, and structural studies of the NTPDases. Because of their ability in hydrolyzing extracellular nucleotides, the mammalian cell surface NTPDases (the ecto-NTPDases) which regulate purinergic signaling have received the most attention. Less appreciated are the functions of intracellular NTPDases and NTPDases of other organisms, e.g., bacteria, parasites, Drosophila, plants, etc. The second goal of this review is to summarize recent findings which demonstrate the involvement of the NTPDases in multiple and diverse physiological processes: pathogen-host interaction, plant growth, eukaryote cell protein and lipid glycosylation, eye development, and oncogenesis.
Collapse
Affiliation(s)
- Aileen F Knowles
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182-1030, USA,
| |
Collapse
|
10
|
Mittelman K, Ziv K, Maoz T, Kleinberger T. The cytosolic tail of the Golgi apyrase Ynd1 mediates E4orf4-induced toxicity in Saccharomyces cerevisiae. PLoS One 2010; 5:e15539. [PMID: 21124936 PMCID: PMC2989921 DOI: 10.1371/journal.pone.0015539] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Accepted: 10/13/2010] [Indexed: 11/18/2022] Open
Abstract
The adenovirus E4 open reading frame 4 (E4orf4) protein contributes to regulation of the progression of virus infection. When expressed individually, E4orf4 was shown to induce non-classical transformed cell-specific apoptosis in mammalian cells. At least some of the mechanisms underlying E4orf4-induced toxicity are conserved from yeast to mammals, including the requirement for an interaction of E4orf4 with protein phosphatase 2A (PP2A). A genetic screen in yeast revealed that the Golgi apyrase Ynd1 associates with E4orf4 and contributes to E4orf4-induced toxicity, independently of Ynd1 apyrase activity. Ynd1 and PP2A were shown to contribute additively to E4orf4-induced toxicity in yeast, and to interact genetically and physically. A mammalian orthologue of Ynd1 was shown to bind E4orf4 in mammalian cells, confirming the evolutionary conservation of this interaction. Here, we use mutation analysis to identify the cytosolic tail of Ynd1 as the protein domain required for mediation of the E4orf4 toxic signal and for the interaction with E4orf4. We also show that E4orf4 associates with cellular membranes in yeast and is localized at their cytoplasmic face. However, E4orf4 is membrane-associated even in the absence of Ynd1, suggesting that additional membrane proteins may mediate E4orf4 localization. Based on our results and on a previous report describing a collection of Ynd1 protein partners, we propose that the Ynd1 cytoplasmic tail acts as a scaffold, interacting with a multi-protein complex, whose targeting by E4orf4 leads to cell death.
Collapse
Affiliation(s)
- Karin Mittelman
- Department of Molecular Microbiology, Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel
| | - Keren Ziv
- Department of Molecular Microbiology, Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel
| | - Tsofnat Maoz
- Department of Molecular Microbiology, Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel
| | - Tamar Kleinberger
- Department of Molecular Microbiology, Faculty of Medicine, Technion – Israel Institute of Technology, Haifa, Israel
- * E-mail:
| |
Collapse
|
11
|
Juanes MA, Martínez-Garay CA, Igual JC, Bañó MC. Targeting and membrane insertion into the endoplasmic reticulum membrane of Saccharomyces cerevisiae essential protein Rot1. FEMS Yeast Res 2010; 10:639-47. [PMID: 20608986 DOI: 10.1111/j.1567-1364.2010.00653.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Rot1 is an essential yeast protein that has been related to cell wall biosynthesis, actin cytoskeleton dynamics and protein folding. Rot1 is an N-glycosylated protein anchored to the nuclear envelope-endoplasmic reticulum (ER) membrane by a transmembrane domain at its C-terminal end. Rot1 is translocated to the ER by a post-translational mechanism. Here, we investigate the protein domain required to target and translocate Rot1 to the ER membrane. We found that several deletions of the N-terminal region of Rot1 prevented neither membrane targeting nor the insertion of this protein. Interestingly, we obtained the same results when different truncated forms in the C-terminal transmembrane domain were analyzed, suggesting the presence of an internal topogenic element that is capable of translocating Rot1 to the ER. To identify this sequence, we generated a combination of N- and C-terminal deletion mutants of Rot1 and we investigated their insertion into the membrane. The results show that two regions, amino acids 26-60 and 200-228, are involved in the post-translational translocation of Rot1 across the ER membrane.
Collapse
Affiliation(s)
- María Angeles Juanes
- Departament de Bioquímica i Biologia Molecular, Universitat de València, València, Spain
| | | | | | | |
Collapse
|
12
|
Kiffer-Moreira T, Fernandes Sampaio ME, Alviano DS, Axelband F, Cesar GV, Cosentino-Gomes D, Rodrigues ML, Nimrichter L, Vieyra A, Alviano CS, Meyer-Fernandes JR. Biochemical characterization of an ecto-ATP diphosphohydrolase activity in Candida parapsilosis and its possible role in adenosine acquisition and pathogenesis. FEMS Yeast Res 2010; 10:735-46. [PMID: 20584084 DOI: 10.1111/j.1567-1364.2010.00641.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
In this work, we describe the ability of intact cells of Candida parapsilosis to hydrolyze extracellular ATP. ATP hydrolysis was stimulated by MgCl(2) in a dose-dependent manner. The ecto-ATPase activity was increased in the presence of 5 mM MgCl(2), with values of V(max) and apparent K(m) for Mg-ATP(2-) increasing to 33.80 +/- 1.2 nmol Pi h(-1) 10(-8) cells and 0.6 +/- 0.06 mM, respectively. Inhibitors of phosphatases, mitochondrial Mg(2+)-ATPases and Na(+)-ATPases had no effect on the C. parapsilosis Mg(2+)-stimulated ATPase activity, but extracellular impermeant compounds, 4,4'-diisothiocyanatostilbene-2,2'disulfonic acid and suramin, reduced enzyme activity in yeast living cells by 83.1% and 81.9%, respectively. ARL 67156 (6-N,N'-diethyl-d-beta-gamma-dibromomethylene ATP), a nucleotide analogue, also inhibited the ecto-ATPase activity in a dose-dependent manner. ATP was the best substrate for the yeast Mg(2+)-stimulated ecto-enzyme, but ADP, ITP, CTP, GTP and UTP were also hydrolyzed. A direct relationship between ecto-ATPase activity and adhesion to host cells was observed. In these assays, inhibition of enzyme activity resulted in decreased levels of yeast adhesion to epithelial cells. Based also on the differential expression of ecto-ATPase activities in the different isolates of C. parapsilosis, the possible role of this enzyme in fungal biology is discussed.
Collapse
Affiliation(s)
- Tina Kiffer-Moreira
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Uccelletti D, Pascoli A, Farina F, Alberti A, Mancini P, Hirschberg CB, Palleschi C. APY-1, a novel Caenorhabditis elegans apyrase involved in unfolded protein response signalling and stress responses. Mol Biol Cell 2008; 19:1337-45. [PMID: 18216284 DOI: 10.1091/mbc.e07-06-0547] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Protein glycosylation modulates a wide variety of intracellular events and dysfunction of the glycosylation pathway has been reported in a variety of human pathologies. Endo-apyrases have been suggested to have critical roles in protein glycosylation and sugar metabolism. However, deciphering the physiological relevance of Endo-apyrases activity has actually proved difficult, owing to their complexity and the functional redundancy within the family. We report here that a UDP/GDPase, homologous to the human apyrase Scan-1, is present in the membranes of Caenorhabditis elegans, encoded by the ORF F08C6.6 and hereinafter-named APY-1. We showed that ER stress induced by tunicamycin or high temperature resulted in increased transcription of apy-1. This increase was not observed in C. elegans mutants defective in ire-1 or atf-6, demonstrating the requirement of both ER stress sensors for up-regulation of apy-1. Depletion of APY-1 resulted in constitutively activated unfolded protein response. Defects in the pharynx and impaired organization of thin fibers in muscle cells were observed in adult worms depleted of APY-1. Some of the apy-1(RNAi) phenotypes are suggestive of premature aging, because these animals also showed accumulation of lipofuscin and reduced lifespan that was not dependent on the functioning of DAF-2, the receptor of the insulin/IGF-1 signaling pathway.
Collapse
Affiliation(s)
- D Uccelletti
- Department of Developmental and Cell Biology, University of Rome "La Sapienza," 00185 Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
14
|
Collopy-Junior I, Kneipp LF, da Silva FC, Rodrigues ML, Alviano CS, Meyer-Fernandes JR. Characterization of an ecto-ATPase activity in Fonsecaea pedrosoi. Arch Microbiol 2006; 185:355-62. [PMID: 16528535 DOI: 10.1007/s00203-006-0100-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 02/16/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022]
Abstract
In this work, we characterized an ecto-ATPase activity in intact mycelial forms of Fonsecaea pedrosoi, the primary causative agent of chromoblastomycosis. In the presence of 1 mM EDTA, fungal cells hydrolyzed adenosine-5'-triphosphate (ATP) at a rate of 84.6 +/- 11.3 nmol Pi h(-1) mg(-1) mycelial dry weight. The ecto-ATPase activity was increased at about five times (498.3 +/- 27.6 nmol Pi h(-1) mg(-1)) in the presence of 5 mM MgCl2, with values of Vmax and apparent Km for Mg-ATP(2-) corresponding to 541.9 +/- 48.6 nmol Pi h(-1) mg(-1) cellular dry weight and 1.9 +/- 0.2 mM, respectively. The Mg2+-stimulated ecto-ATPase activity was insensitive to inhibitors of intracellular ATPases such as vanadate (P-ATPases), bafilomycin A1(V-ATPases), and oligomycin (F-ATPases). Inhibitors of acid phosphatases (molybdate, vanadate, and fluoride) or alkaline phosphatases (levamizole) had no effect on the ecto-ATPase activity. The surface of the Mg2+ -stimulated ATPase in F. pedrosoi was confirmed by assays in which 4,4'-diisothiocyanostylbene-2,2'-disulfonic acid (DIDS), a membrane impermeant inhibitor, and suramin, an inhibitor of ecto-ATPase and antagonist of P2 purinoreceptors. Based on the differential expression of ecto-ATPases in the different morphological stages of F. pedrosoi, the putative role of this enzyme in fungal biology is discussed.
Collapse
Affiliation(s)
- Italo Collopy-Junior
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, CCS, Bloco H, Cidade Universitária, Ilha do Fundão, 21541-590, Rio de Janeiro, Brazil
| | | | | | | | | | | |
Collapse
|
15
|
Maoz T, Koren R, Ben-Ari I, Kleinberger T. YND1 interacts with CDC55 and is a novel mediator of E4orf4-induced toxicity. J Biol Chem 2005; 280:41270-7. [PMID: 16227198 DOI: 10.1074/jbc.m507281200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adenovirus E4orf4 (early region 4 open reading frame 4) protein induces protein phosphatase 2A-dependent non-classical apoptosis in mammalian cells and irreversible growth arrest in Saccharomyces cerevisiae. Oncogenic transformation sensitizes cells to E4orf4-induced cell death. To uncover additional components of the E4orf4 network required for induction of its unique mode of apoptosis, we used yeast genetics to select gene deletions conferring resistance to E4orf4. Deletion of YND1, encoding a yeast Golgi apyrase, conferred partial resistance to E4orf4. However, Ynd1p apyrase activity was not required for E4orf4-induced toxicity. Ynd1p and Cdc55p, the yeast protein phosphatase 2A-B subunit, contributed additively to E4orf4-induced toxicity. Furthermore, concomitant overexpression of one and deletion of the other was detrimental to yeast growth, demonstrating a functional interaction between the two proteins. YND1 and CDC55 also interacted genetically with CDC20 and CDH1/HCT1, encoding activating subunits of the anaphase-promoting complex/cyclosome. In addition to their functional interaction, Ynd1p and Cdc55p interacted physically, and this interaction was disrupted by E4orf4, which remained associated with both proteins. The results suggested that Ynd1p and Cdc55p share a common downstream target whose balanced modulation by the two E4orf4 partners is crucial to viability. Disruption of this balance by E4orf4 may lead to cell death. NTPDase-4/Lalp70/UDPase, the closest mammalian homologue of Ynd1p, associated with E4orf4 in mammalian cells, suggesting that the results in yeast are relevant to the mammalian system.
Collapse
Affiliation(s)
- Tsofnat Maoz
- The Gonda Center of Molecular Microbiology and The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Bat Galim, Haifa, 31096, Israel
| | | | | | | |
Collapse
|
16
|
Zhong X, Malhotra R, Guidotti G. A eukaryotic carboxyl-terminal signal sequence translocating large hydrophilic domains across membranes. FEBS Lett 2005; 579:5643-50. [PMID: 16214140 DOI: 10.1016/j.febslet.2005.09.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 09/11/2005] [Indexed: 11/17/2022]
Abstract
Yeast Golgi ecto-ATPase Ynd1p is an unusual type III membrane protein with the longest translocated N-terminus reported. Sequential deletion analysis reveals that translocation of this 500-residue-long hydrophilic domain across the membranes requires the C-terminal transmembrane domain of Ynd1p and its flanking regions. Additional studies indicate that the topogenic sequence of Ynd1p overrides the effect of a reverse signal-anchor sequence present at the N-terminus of Ynd1p, while it is not affected by a classic signal sequence at the N-terminus. When placed at the C-terminal end, the sequence can translocate large extracellular domains of two membrane proteins across the membranes. The data demonstrate the existence of a true eukaryotic C-terminal signal sequence.
Collapse
Affiliation(s)
- Xiaotian Zhong
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | | | | |
Collapse
|
17
|
D'Alessio C, Caramelo JJ, Parodi AJ. Absence of nucleoside diphosphatase activities in the yeast secretory pathway does not abolish nucleotide sugar-dependent protein glycosylation. J Biol Chem 2005; 280:40417-27. [PMID: 16172132 DOI: 10.1074/jbc.m503149200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It is accepted that glycosyltransferase-generated nucleoside diphosphates are converted to monophosphates in the secretory pathway by nucleoside diphosphatases (NDPases) to provide substrates for antiport transport systems by which entrance of nucleotide sugars from the cytosol into the lumen is coupled to exit of nucleoside monophosphates. Working with Saccharomyces cerevisiae mutants affected in anterograde and/or retrograde endoplasmic reticulum (ER)-Golgi vesicular traffic and/or defective in one or both secretory pathway (Golgi) NDPases, we show that UDP-Glc: glycoprotein glucosyltransferase-mediated glucosylation is not dependent on the presence of NDPases or on ER-Golgi vesicular traffic and that GDP-Man-dependent N- and O-mannosylations are reduced but not abolished in the absence of NDPases in the secretory pathway. Further, the absence of the main Man-1-P transferase (a Golgi GMP-generating enzyme) does not modify the limited mannosylation observed in the absence of NDPases. Based on these results and on available additional information, we suggest that in the absence of NDPases, the already characterized nucleotide sugar transporters allow entrance of nucleotide sugars into the luminal compartments and that resulting nucleoside diphosphates exit to the cytosol by a still unknown mechanism. Further, an unexpected side result suggests that formation of Ser/Thr-Man(2) may occur in the ER and not exclusively in the Golgi.
Collapse
Affiliation(s)
- Cecilia D'Alessio
- Laboratory of Glycobiology, Fundación Instituto Leloir, Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | | | | |
Collapse
|
18
|
Uccelletti D, O'Callaghan C, Berninsone P, Zemtseva I, Abeijon C, Hirschberg CB. ire-1-dependent Transcriptional Up-regulation of a Lumenal Uridine Diphosphatase from Caenorhabditis elegans. J Biol Chem 2004; 279:27390-8. [PMID: 15102851 DOI: 10.1074/jbc.m402624200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Lumenal ecto-nucleoside tri- and di-phosphohydrolases (ENTPDases) of the secretory pathway of eukaryotes hydrolyze nucleoside diphosphates resulting from glycosyltransferase-mediated reactions, yielding nucleoside monophosphates. The latter are weaker inhibitors of glycosyltransferases than the former and are also antiporters for the transport of nucleotide sugars from the cytosol to the endoplasmic reticulum (ER) and Golgi apparatus (GA) lumen. Here we describe the presence of two cation-dependent nucleotide phosphohydrolase activities in membranes of Caenorhabditis elegans: one, UDA-1, is a UDP/GDPase encoded by the gene uda-1, whereas the other is an apyrase encoded by the gene ntp-1. UDA-1 shares significant amino acid sequence similarity to yeast GA Gda1p and mammalian UDP/GDPases and has a lumenal active site in vesicles displaying an intermediate density between those of the ER and GA when expressed in S. cerevisiae. NTP-1 expressed in COS-7 cells appeared to localize to the GA. The transcript of uda-1 but not those of two other C. elegans ENTPDase mRNAs (ntp-1 and mig-23) was induced up to 3.5-fold by high temperature, tunicamycin, and ethanol. The same effectors triggered the unfolded protein response as shown by the induction of expression of green fluorescent protein under the control of the BiP chaperone promoter and the UDP-glucose:glycoprotein glucosyltransferase. Up-regulation of uda-1 did not occur in ire-1-deficient mutants, demonstrating the role of this ER stress sensor in this event. We hypothesize that up-regulation of uda-1 favors hydrolysis of the glucosyltransferase inhibitory product UDP to UMP, and that the latter product then exits the lumen of the ER or pre-GA compartment in a coupled exchange with the entry of UDP-glucose, thereby further relieving ER stress by favoring protein re-glycosylation.
Collapse
Affiliation(s)
- Daniela Uccelletti
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts 02118, USA
| | | | | | | | | | | |
Collapse
|
19
|
Mans BJ, Neitz AWH. Adaptation of ticks to a blood-feeding environment: evolution from a functional perspective. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2004; 34:1-17. [PMID: 14723893 DOI: 10.1016/j.ibmb.2003.09.002] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ticks had to adapt to an existing and complex vertebrate hemostatic system from being free-living scavengers. A large array of anti-hemostatic mechanisms evolved during this process and includes blood coagulation as well as platelet aggregation inhibitors. Several questions regarding tick evolution exist. What was the nature of the ancestral tick? When did ticks evolve blood-feeding capabilities? How did these capabilities evolve? Did host specificity influence the adaptation of ticks to a blood-feeding environment? What are the implications of tick evolution for future research into tick biology and vaccine development? We investigate these questions in the light of recent research into protein superfamilies from tick saliva. Our conclusions are that the main tick families adapted independently to a blood-feeding environment. This is supported by major differences observed in all processes involved with blood-feeding for hard and soft ticks. Gene duplication events played a major role in the evolution of novel protein functions involved in tick-host interactions. This occurred during the late Cretaceous and was stimulated by the radiation of birds and placental mammals, which provided numerous new niches for ticks to adapt to a new lifestyle. Independent adaptation of the main tick families to a blood-feeding environment has several implications for future tick research in terms of tick genome projects and vaccine development.
Collapse
Affiliation(s)
- Ben J Mans
- Department of Biochemistry, University of Pretoria, Pretoria 0002, South Africa.
| | | |
Collapse
|
20
|
Zhong X, Malhotra R, Guidotti G. ATP uptake in the Golgi and extracellular release require Mcd4 protein and the vacuolar H+-ATPase. J Biol Chem 2003; 278:33436-44. [PMID: 12807869 DOI: 10.1074/jbc.m305785200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Extracellular nucleotides signal via a large group of purinergic receptors. Although much is known about these receptors, the mechanism of nucleotide transport out of the cytoplasm is unknown. We developed a functional screen for ATP release to the extracellular space and identified Mcd4p, a 919-amino acid membrane protein with 14 putative transmembrane domains, as a participant in glucose-dependent ATP release from Saccharomyces cerevisiae. This release occurred through the vesicular trafficking pathway initiated by ATP uptake into the Golgi compartment. Both the compartmental uptake and the extracellular release of ATP were regulated by the activity of the vacuolar H+-ATPase. It is likely that the Mcd4p pathway is generally involved in non-mitochondrial ATP movement across membranes, it is essential for Golgi and endoplasmic reticulum function, and its occurrence led to the appearance of P2 purinergic receptors.
Collapse
Affiliation(s)
- Xiaotian Zhong
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|
21
|
D'Alessio C, Trombetta ES, Parodi AJ. Nucleoside diphosphatase and glycosyltransferase activities can localize to different subcellular compartments in Schizosaccharomyces pombe. J Biol Chem 2003; 278:22379-87. [PMID: 12686557 DOI: 10.1074/jbc.m300892200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nucleoside diphosphates generated by glycosyltransferases in the fungal, plant, and mammalian cell secretory pathways are converted into monophosphates to relieve inhibition of the transferring enzymes and provide substrates for antiport transport systems by which the entrance of nucleotide sugars from the cytosol into the secretory pathway lumen is coupled to the exit of nucleoside monophosphates. Analysis of the yeast Schizosaccharomyces pombe genome revealed that it encodes two enzymes with potential nucleoside diphosphatase activity, Spgda1p and Spynd1p. Characterization of the overexpressed enzymes showed that Spgda1p is a GDPase/UDPase, whereas Spynd1p is an apyrase because it hydrolyzed both nucleoside tri and diphosphates. Subcellular fractionation showed that both activities localize to the Golgi. Individual disruption of their encoding genes did not affect cell viability, but disruption of both genes was synthetically lethal. Disruption of Spgda1+ did not affect Golgi N- or O-glycosylation, whereas disruption of Spynd1+ affected Golgi N-mannosylation but not O-mannosylation. Although no nucleoside diphosphatase activity was detected in the endoplasmic reticulum (ER), N-glycosylation mediated by the UDP-Glc:glycoprotein glucosyltransferase (GT) was not severely impaired in mutants because first, no ER accumulation of misfolded glycoproteins occurred as revealed by the absence of induction of BiP mRNA, and second, in vivo GT-dependent glucosylation monitored by incorporation of labeled Glc into folding glycoproteins showed a partial (35-50%) decrease in Spgda1 but was not affected in Spynd1 mutants. Results show that, contrary to what has been assumed to date for eukaryotic cells, in S. pombe nucleoside diphosphatase and glycosyltransferase activities can localize to different subcellular compartments. It is tentatively suggested that ER-Golgi vesicle transport might be involved in nucleoside diphosphate hydrolysis.
Collapse
Affiliation(s)
- Cecilia D'Alessio
- Institute for Biotechnological Research, University of San Martin, CC30, 1650 San Martin, Argentina
| | | | | |
Collapse
|
22
|
Nourizad N, Ehn M, Gharizadeh B, Hober S, Nyrén P. Methylotrophic yeast Pichia pastoris as a host for production of ATP-diphosphohydrolase (apyrase) from potato tubers (Solanum tuberosum). Protein Expr Purif 2003; 27:229-37. [PMID: 12597881 DOI: 10.1016/s1046-5928(02)00605-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
ATP-diphosphohydrolase (apyrase) catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside tri- and di-phosphates in the presence of divalent cations. This enzyme has broad substrate specificity for nucleotides, which makes it an ideal enzyme for different biotechnical applications, such as DNA sequencing and platelet-aggregation inhibition. The only commercially available apyrase is isolated from potato tubers. To avoid batch-to-batch variations in activity and quality, we decided to produce a recombinant enzyme. The methylotrophic yeast Pichia pastoris was chosen as an eukaryotic expression host. The coding sequence of potato apyrase, without the signal peptide, was cloned into the YpDC541 vector to create a fusion with the alpha-mating secretion signal of Saccharomyces cerevisiae. The gene was placed under the control of the methanol-inducible alcohol oxidase promoter. The YpDC541-apyrase construct was integrated into P. pastoris strain SMD1168. Methanol induction resulted in secretion of apyrase to a level of 1mg/L. The biologically active recombinant apyrase was purified by hydrophobic interaction and ion exchange chromatography. According to SDS-PAGE and Western blot analysis, the purified enzyme showed to be hyperglycosylated. By enzymatic removal of N-glycans, a single band corresponding to a molecular mass of 48kDa was detected. The recombinant apyrase was found to function well when it was used in combination with the Pyrosequencing technology.
Collapse
Affiliation(s)
- Nader Nourizad
- Department of Biotechnology, AlbaNova University center, SCFAB, Royal Institute of Technology, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden.
| | | | | | | | | |
Collapse
|
23
|
Failer BU, Braun N, Zimmermann H. Cloning, expression, and functional characterization of a Ca(2+)-dependent endoplasmic reticulum nucleoside diphosphatase. J Biol Chem 2002; 277:36978-86. [PMID: 12167635 DOI: 10.1074/jbc.m201656200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have isolated and characterized the cDNA encoding a Ca(2+)-dependent nucleoside diphosphatase (EC ) related to two secreted ATP- and ADP-hydrolyzing apyrases of the bloodsucking insects, Cimex lectularius and Phlebotomus papatasi. The rat brain-derived cDNA has an open reading frame of 1209 bp encoding a protein of 403 amino acids and a calculated molecular mass of 45.7 kDa. The mRNA was expressed in all tissues investigated, revealing two major transcripts with varying preponderance. The immunohistochemical analysis of the Myc-His-tagged enzyme expressed in Chinese hamster ovary cells revealed its association with the endoplasmic reticulum and also with pre-Golgi intermediates. Ca(2+)-dependent nucleoside diphosphatase is a membrane protein with its catalytic site facing the organelle lumen. It hydrolyzes nucleoside 5'-diphosphates in the order UDP >GDP = IDP >>>CDP but not ADP. Nucleoside 5'-triphosphates were hydrolyzed to a minor extent, and no hydrolysis of nucleoside 5'-monophosphates was observed. The enzyme was strongly activated by Ca(2+), insensitive to Mg(2+), and had a K(m) for UDP of 216 microm. Ca(2+)-dependent nucleoside diphosphatase may support glycosylation reactions related to quality control in the endoplasmic reticulum.
Collapse
Affiliation(s)
- Bernd U Failer
- Arbeitskreis Neurochemie, Biozentrum der J. W. Goethe-Universitaet, Marie-Curie-Strasse 9, D-60439 Frankfurt am Main, Germany
| | | | | |
Collapse
|
24
|
Nishikawa A, Mendez B, Jigami Y, Dean N. Identification of a Candida glabrata homologue of the S. cerevisiae VRG4 gene, encoding the Golgi GDP-mannose transporter. Yeast 2002; 19:691-8. [PMID: 12185838 DOI: 10.1002/yea.854] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mannoproteins on the cell wall of yeast and fungi help regulate cell shape, porosity, and cell-cell interactions, including those required for attachment to host cells by fungal pathogens. The mannose-containing oligosaccharides on proteins and lipids are extended in the Golgi by glycosyltransferases that use GDP-mannose as the sugar substrate. A membrane-bound transporter that, in Saccharomyces cerevisiae, is encoded by the VRG4 gene catalyses delivery of GDP-mannose into the lumen of the Golgi. We report here the cloning of the homologous VRG4 gene from the pathogenic yeast, Candida glabrata, by functional complementation of an S. cerevisiae vrg4 mutant. The sequence of the CgVrg4 protein displays significant homology to GDP-mannose transporters from other yeast, fungi, protozoa, and plants. CgVRG4 fully complements the glycosylation defect and other cell wall associated vrg4 mutant phenotypes. Like ScVRG4, CgVRG4 is essential for the viability of C. glabrata. These results suggest that, as in S. cerevisiae, CgVrg4p accounts for all of the GDP-mannose transport activity in the Golgi lumen.
Collapse
Affiliation(s)
- Akiko Nishikawa
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, State University of New York, Stony Brook, NY 11794-5215, USA
| | | | | | | |
Collapse
|
25
|
Herrero AB, Uccelletti D, Hirschberg CB, Dominguez A, Abeijon C. The Golgi GDPase of the fungal pathogen Candida albicans affects morphogenesis, glycosylation, and cell wall properties. EUKARYOTIC CELL 2002; 1:420-31. [PMID: 12455990 PMCID: PMC118022 DOI: 10.1128/ec.1.3.420-431.2002] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cell wall mannoproteins are largely responsible for the adhesive properties and immunomodulation ability of the fungal pathogen Candida albicans. The outer chain extension of yeast mannoproteins occurs in the lumen of the Golgi apparatus. GDP-mannose must first be transported from the cytosol into the Golgi lumen, where mannose is transferred to mannans. GDP is hydrolyzed by a GDPase, encoded by GDA1, to GMP, which then exits the Golgi lumen in a coupled, equimolar exchange with cytosolic GDP-mannose. We isolated and disrupted the C. albicans homologue of the Saccharomyces cerevisiae GDA1 gene in order to investigate its role in protein mannosylation and pathogenesis. CaGda1p shares four apyrase conserved regions with other nucleoside diphosphatases. Membranes prepared from the C. albicans disrupted gda1/gda1 strain had a 90% decrease in the ability to hydrolyze GDP compared to wild type. The gda1/gda1 mutants showed a severe defect in O-mannosylation and reduced cell wall phosphate content. Other cell wall-related phenotypes are present, such as elevated chitin levels and increased susceptibility to attack by beta-1,3-glucanases. Our results show that the C. albicans organism contains beta-mannose at their nonreducing end, differing from S. cerevisiae, which has only alpha-linked mannose residues in its O-glycans. Mutants lacking both alleles of GDA1 grow at the same rate as the wild type but are partially blocked in hyphal formation in Lee solid medium and during induction in liquid by changes in temperature and pH. However, the mutants still form normal hyphae in the presence of serum and N-acetylglucosamine and do not change their adherence to HeLa cells. Taken together, our data are in agreement with the hypothesis that several pathways regulate the yeast-hypha transition. Gda1/gda1 cells offer a model for discriminating among them.
Collapse
Affiliation(s)
- Ana B Herrero
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts 02118, USA
| | | | | | | | | |
Collapse
|
26
|
Zhong X, Malhotra R, Woodruff R, Guidotti G. Mammalian plasma membrane ecto-nucleoside triphosphate diphosphohydrolase 1, CD39, is not active intracellularly. The N-glycosylation state of CD39 correlates with surface activity and localization. J Biol Chem 2001; 276:41518-25. [PMID: 11546800 DOI: 10.1074/jbc.m104415200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
CD39 is a member of the membrane-bound ecto-nucleoside triphosphate diphosphohydrolase family. The active site for native CD39 is located on the outer surface of the cellular plasma membrane; however, it is not yet known at what stage this enzyme becomes active along the secretory pathway to the plasma membrane. In this study, sucrose density fractionations performed on CD39-transfected COS-7 cell membranes suggest that CD39 activity resides primarily in the plasma membrane. Furthermore, we have created recombinant, soluble versions of CD39, one that is secreted and others that are retained in the endoplasmic reticulum, to demonstrate that CD39 is not active until it reaches the plasma membrane both in yeast and COS-7 cells. Moreover, the secreted active soluble CD39 in COS-7 cells is found to receive a higher degree of N-glycan addition than the inactive form retained intracellularly. When COS-7 cells were treated with tunicamycin to prevent N-glycosylation, soluble CD39 was not detected in the extracellular medium and remained inactive intracellularly. Surface biotinylation analysis also revealed that surface-expressed wild type CD39 receives a higher degree of N-glycosylation than intracellular forms and that inhibition of N-glycosylation prevents its plasma membrane localization. In addition, both intact and digitonin-permeablized COS-7 cells transfected with CD39 possess similar ecto-ATPase activities, further supporting the conclusion that only surface-expressed CD39 is enzymatically active. All of these data suggest that intracellular CD39 is inactive and that only a fully glycosylated CD39 has apyrase activity and is localized at the cell surface.
Collapse
Affiliation(s)
- X Zhong
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | |
Collapse
|
27
|
Zimmermann H. Ectonucleotidases: Some recent developments and a note on nomenclature. Drug Dev Res 2001. [DOI: 10.1002/ddr.1097] [Citation(s) in RCA: 325] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
28
|
Zhong X, Malhotra R, Guidotti G. Regulation of yeast ectoapyrase ynd1p activity by activator subunit Vma13p of vacuolar H+-ATPase. J Biol Chem 2000; 275:35592-9. [PMID: 10954728 DOI: 10.1074/jbc.m006932200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
CD39-like ectoapyrases are involved in protein and lipid glycosylation in the Golgi lumen of Saccharomyces cerevisiae. By using a two-hybrid screen, we found that an activator subunit (Vma13p) of yeast vacuolar H(+)-ATPase (V-ATPase) binds to the cytoplasmic domain of Ynd1p, a yeast ectoapyrase. Interaction of Ynd1p with Vma13p was demonstrated by direct binding and co-immunoprecipitation. Surprisingly, the membrane-bound ADPase activity of Ynd1p in a vma13Delta mutant was drastically increased compared with that of Ynd1p in VMA13 cells. A similar increase in the apyrase activity of Ynd1p was found in a vma1Delta mutant, in which the catalytic subunit A of V-ATPase is missing, and the membrane peripheral subunits including Vma13p are dissociated from the membranes. However, the E286Q mutant of VMA1, which assembles inactive V-ATPase complex including Vma13p in the membrane, retained wild type levels of Ynd1p activity, demonstrating that the presence of Vma13p rather than the function of V-ATPase in the membrane represses Ynd1p activity. These results suggest that association of Vma13p with the cytoplasmic domain of Ynd1p regulates its apyrase activity in the Golgi lumen.
Collapse
Affiliation(s)
- X Zhong
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|