DOCSLIB.ORG

Signal Transduction in the Control of Phosphate-Regulated Genes of Escherichia Coli

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Signal Transduction in the Control of Phosphate-Regulated Genes of Escherichia Coli Kidney International, Vol. 49 (1996), pp. 964—967 Signal transduction in the control of phosphate-regulated genes of Escherichia coli BARRY L. WANNER Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA Bacteria such as Escherichia co/i regulate the synthesis of aunique proteins with signatures of a sensor kinase (transmitter) large number of proteins in response to extracellular inorganicdomain and 170 with signatures of a receiver domain have been phosphate (P) levels by activating transcription of co-regulatedidentified on the basis of sequence similarities at the protein level genes. More than 80 proteins are synthesized in increased(as determined from searching DNA databases for homologous amounts in response to P. limitation in the gram-negative bacte-proteins). Analogous signaling systems exist in eucaryotic cells rium E. co/i [1—3]. Many of these proteins are the products of a set including Saccharomyces cerevisiae [6—8], Arabidopsis thaliana [9], of co-regulated genes known as the phosphate (Pho) regulon.and Neurospora crassa [10]. In yeast, a two-component system Altogether 38 Pho regulon genes have now been characterized (by(SLN1 and SSK1) can provide signaling input to a MAP kinase cloning, sequencing, mutational analysis, and/or examination ofcascade that is responsive to small molecules [7, 11]. MAP kinase their gene products) in E. co/i, or the closely related bacteriacascades are extremely important in signaling; they are key Enterobacter aerogenes and Sa/monella typhimurium [4]. Thesecomponents of convergent signal transduction pathways in mam- genes are arranged in eight (or more) transcriptional units, andmalian cells [12, 13]. Although histidine phosphorylation has also their gene products probably all have a role in the assimilation ofbeen recently found in human cells [14], the phosphorylation alternative phosphorus (P) sources from the environment. Theirchemistry of that system is distinctively different from two- transcription requires an upstream activation site (called a Phocomponent regulatory systems. Box) and a DNA-binding protein (called PhoB) that acts as a transcriptional activator only when it is phosphorylated (Fig. 1). P, control is a paradigm of a signal transduction pathway in The level of expression of Pho regulon genes is regulated by the which occupancy of a cell surface receptor(s) regulates gene amount of phospho-PhoB. expression in the cytoplasm P control of the Pho regulon involves a "two-component P1 control of the Pho regulon involves two processes: inhibition when environmental P1 is in excess (greater than a few jIM) and regulatory system" activation under conditions of P1 limitation (Fig. 2). It is con- The activation of Pho regulon genes such as phoA (encodingtrolled by the extracellular P1 level. The phosphate-specific trans- bacterial alkaline phosphatase, Bap) under conditions of P1 limi-porter (the Pst system) plays a crucial role in the process of tation requires two proteins: PhoR and PhoB. These proteins areinhibition; yet, transportperse is not involved. The expression of members of the large family of two-component regulatory systemsgenes of the Pho regulon is inhibited when environmental P1 (the in bacteria. These systems are important in a variety of adaptivepreferred P source) is in excess (greater than Ca. 4 jsM). This responses and signal transduction pathways [5]. All of them areinhibition requires an inhibitor form of PhoR (called PhoR'), a likely to share a common biochemical signaling mechanism inprotein called PhoU, and all components of the Pst system. By which a sensor kinase (usually membrane-associated, like PhoR)analogy to other two-component regulatory systems, PhoR is is autophosphorylated on a conserved histidine residue in re-thought to act as the P1 sensor. Whether PhoR detects P. directly sponse to an environmental stimulus (the extracellular P1 level in(perhaps via a regulatory site on PhoR) or indirectly via an the case of the Pho regulon) and then transfers the phosphoiylinteraction with PhoU (or the Pst transporter) is unknown. The group to a conserved aspartate residue on its partner responseexpression of Pho regulon genes is activated 100-fold or more regulator (commonly a transcriptional activator, like PhoB). during growth after exhaustion of environmental P. This activa- As many as 50 pairs of these sensor and regulator proteins cantion requires the activator form of PhoR (called Ph0RA) and exist in a single bacterium. Twenty-five potential signaling kinasesPhoB. and 37 response regulator (receiver domain) proteins have been Therefore, P1 control involves the interconversion of PhoR' identified on the basis of the E. co/i genome sequence, which isand PhoR'. This interconversion is likely to involve protein- now more than 50% known. A few examples of two-componentprotein interactions between PhoR, PhoU, and Pst components regulatory systems shown to act by a common phosphorylationand conformational changes brought about in response to the mechanism are listed in Table 1. Altogether, more than 110extracellular P level. Accordingly, PhoRR predominates when p. is in excess and Ph0RA predominates under conditions of P limitation. Formation of PhoR' can result due to association of © 1996 by the International Society of Nephrology PhoR with PhoU and the Pst system upon full P occupancy of the 964 Wanner: P1 regulation of Escherichia coli genes 965 Gene product/function Gene organization 01phoA (psiA)-psi? Bap, Unknown cii phoBR Regulator, P1 sensor 01phoE—. Polyanion porin ni phoH(psih') ATP-binding protein cIphnCDEFGHlJKLMNOP(psiD Carbon phosphorus lyase pathway 001pstSCAB-phoU P1 uptake and P1 inhibition 001ugpBAECQ(psiB,>C) Uptake sn-glycerol-3-phosphate Fig. 1. Organization of sequenced genes of the Pho Unknown regulon. (Adapted from Figure 5 in [31 Used with permission from the American Society for Phosphonatase pathway pnXWil1phnR>o,phnST13V Microbiology.) Table 1. Examples of two-component regulatory systems The cytoplasmic domains of PhoR include an unusually large Sensor kinase "linker domain" of about 150 residues following its membrane Regulatory system Response regulator(s) domain and a C-terminal kinase domain beginning near residue Chemotaxis CheA CheY, CheB 159 that is highly conserved among family members. Further, Nitrogen control NtrB (NR11) NtrC (NR1) in-frame deletions of its linker domain (160 to 167, M23 to 167, Osmoregulation EnvZ OmpR P1 control PhoR PhoB M10 to 157, and M60 to 174) lead to low level activation, Catabolite control CreC (PhoM) CreB suggesting that it has a regulatory role [161. The linker domain can Aerobic respiratory control ArcB AreA interact with PhoU. A truncated form of PhoR lacking its N-terminal 83 amino acids is radiolabeled with y-[32P]-ATP in vitro on His-213 [18] and phospho-'PhoR rapidly transfers the phosphoryl group to PhoB. It is reasonable to suppose that PhoR Pst system, or binding of P. to a hypothetical regulatory site onfacilitates the dephosphorylation of phospho-PhoB, yet no such PhoR. In the latter case, P. saturation of the Pst system canactivity has been demonstrated. Numerous phoR missense facilitate P1 binding to the regulatory site. A conformationalchanges have been characterized, including partially dominant change leading to formation of Ph0RA can result due to release ofones (suggestive of oligomerization) and ones causing constitutive PhoR from the inhibition complex, low P1 occupancy of the Pstsignaling. All of these alter residues of its cytoplasmic domain(s) system, or low P. occupancy of a PhoR regulatory site. [3J. PhoR is a cytoplasmic membrane protein that acts as a The Pho regulon is subject to additional controls that can be sensor kinase forms of "cross regulation" PhoR is a cytoplasmic integral membrane protein of 431 amino PhoR is required for inhibition when P is in excess. In its acids in length. It appears to be composed of three domains: anabsence, two other signaling pathways—involving CreC (formerly N-terminal "membrane-binding domain" and two cytoplasmiccalled PhoM) or acetyl phosphate—lead to high level activation of domains. Its N-terminal domain of about 50 amino acids has twoPhoB in response to carbon sources [19—21]. Therefore, the Pho predicted a-helical transmembrane segments capable of forming aregulon appears to be subject to multiple controls, each of which helical hairpin with a few amino acids exposed to the periplasm. Inaffect the phosphorylation of PhoB or dephosphorylation of agreement, its N-terminal segment is capable of translocating aphospho-PhoB. Its control by P, involves detection of the extra- reporter protein to the cell surface; in-frame fusions of TnphoAcellular P1 level and is coupled to the first step in P metabolism, [15, 16] to residues 29, 37, and 40, but not to 54 or beyond,P, uptake. Its additional controls are P1 independent and can be produce PhoR'-'PhoA fusion proteins with Bap activity, indicatingforms of cross regulation. This is because Pho regulon control by localization of these hybrid proteins to the periplasm. Full-lengthCreC and acetyl phosphate (which are independent of each other) PhoR is localized to the cytoplasmic membrane, while a truncatedinvolves regulatory couplings between P1, carbon, and energy protein (denoted 'PhoR) lacking this domain is cytoplasmic.metabolism. Both are coupled to subsequent steps in P1 metabo- These 'PhoRs lead to low level activation ("constitutive signal-lism, the entry of P1 into ATP, the primary phosphoryl donor in ing") of PhoB in vivo
Load more

Recommended publications
  • Regulation of Components of the Pseudomonas Aeruginosa Phosphate-Starvation-Inducible Regulon in Escherichia Coii
    Molecular Microbiology (1988) 2(3), 347-352 Regulation of components of the Pseudomonas aeruginosa phosphate-starvation-inducible regulon in Escherichia coii R. J. Siehnel, E. A. Worobec and R. E. W. Hancock* of the structural elements of the Pho regulon since, in such Department ot Microbioiogy, University ot British mutants, another regulatory gene product, PhoM, will tran- Columbia, Vancouver, British Columbia, Canada scriptionally activate PhoB. The PhoM activator is not con- V6T1W5. trolled by changes in phosphate levels and is repressed when PhoR is functional. Summary Conditions of low environmental phosphate stimulate the co-induction, in E. coli, of an outer membrane porin Plasmids pPBP and pRS-XP containing the cloned (PhoE), a periplasmic phosphate-binding protein (PhoS), genes for the Pseudomonas aeruginosa phosphate- and a periplasmic alkaline phosphatase (PhoA). JUephoB starvation-inducible periplasmic phosphate-binding gene product appears to activate the transcription of each protein and outer membrane porin P {oprP), respec- of these genes by interacting with specific regulation tively, were introduced into various Escherichia coti sequences located in analogous regions upstream from Pho-regulon regulatory mutants. Using Western the structural genes. These sequences are highly hom- immunoblots and specific antisera, the production of ologous and have been termed the 'Pho box' (Shinagawa both gene products was observed to be under the etai., 1987). control of regulatory elements of the E. coti Pho regu- Phosphate transport has been examined in several other lon. Sequencing of the region upstream of the trans- bacterial species and recent evidence suggests that a lationai start site of the oprP gene revealed a 'Pho phosphate-starvation-inducible regulon, similar to that box' with strong homology to the E.
    [Show full text]
  • Phosphate Uptake by the Phosphonate Transport System Phncde Raffaele Stasi†, Henrique Iglesias Neves† and Beny Spira*
    Stasi et al. BMC Microbiology (2019) 19:79 https://doi.org/10.1186/s12866-019-1445-3 RESEARCH ARTICLE Open Access Phosphate uptake by the phosphonate transport system PhnCDE Raffaele Stasi†, Henrique Iglesias Neves† and Beny Spira* Abstract Background: Phosphate is a fundamental nutrient for all creatures. It is thus not surprising that a single bacterium carries different transport systems for this molecule, each usually operating under different environmental conditions. The phosphonate transport system of E. coli K-12 is cryptic due to an 8 bp insertion in the phnE ORF. Results: Here we report that an E. coli K-12 strain carrying the triple knockout pitA pst ugp reverted the phnE mutation when plated on complex medium containing phosphate as the main phosphorus source. It is also shown that PhnCDE takes up orthophosphate with transport kinetics compatible with that of the canonical transport system PitA and that Pi-uptake via PhnCDE is sufficient to enable bacterial growth. Ugp, a glycerol phosphate transporter, is unable to take up phosphate. Conclusions: The phosphonate transport system, which is normally cryptic in E. coli laboratory strains is activated upon selection in rich medium and takes up orthophosphate in the absence of the two canonical phosphate-uptake systems. Based on these findings, the PhnCDE system can be considered a genuine phosphate transport system. Keywords: Phosphonates, Phosphate, Phn, PHO regulon Background phosphatase (AP). Genes belonging to the PHO regu- Phosphorus is a macronutrient of utmost importance to lon are synchronously induced by Pi-shortage [2]. For the all living beings. It is thus not surprising that bacte- sake of simplicity, the operons pstSCAB-phoU, ugpBAEC, ria developed several different mechanisms of phospho- phnCDEFGHIJKLMNOP will be respectively shortened to rus acquisition.
    [Show full text]
  • From Prokaryotic to Eukaryotic Cells
    This is a repository copy of Pi sensing and signaling: from prokaryotic to eukaryotic cells. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/95967/ Version: Accepted Version Article: Wanjun, QI, Baldwin, SA, Muench, SP orcid.org/0000-0001-6869-4414 et al. (1 more author) (2016) Pi sensing and signaling: from prokaryotic to eukaryotic cells. Biochemical Society Transactions, 44 (3). pp. 766-773. ISSN 0300-5127 https://doi.org/10.1042/BST20160026 © 2016, The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society. This is an author produced version of a paper published in Biochemical Society Transactions. Uploaded in accordance with the publisher's self-archiving policy. Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal
    [Show full text]
  • Molecular Mechanisms of Phosphate Sensing, Transport and Signalling in Streptomyces and Related Actinobacteria
    International Journal of Molecular Sciences Review Molecular Mechanisms of Phosphate Sensing, Transport and Signalling in Streptomyces and Related Actinobacteria Juan Francisco Martín * and Paloma Liras Department of Molecular Biology, Microbiology Section, University of León, 24071 León, Spain; [email protected] * Correspondence: [email protected] Abstract: Phosphorous, in the form of phosphate, is a key element in the nutrition of all living beings. In nature, it is present in the form of phosphate salts, organophosphates, and phosphonates. Bacteria transport inorganic phosphate by the high affinity phosphate transport system PstSCAB, and the low affinity PitH transporters. The PstSCAB system consists of four components. PstS is the phosphate binding protein and discriminates between arsenate and phosphate. In the Streptomyces species, the PstS protein, attached to the outer side of the cell membrane, is glycosylated and released as a soluble protein that lacks its phosphate binding ability. Transport of phosphate by the PstSCAB system is drastically regulated by the inorganic phosphate concentration and mediated by binding of phosphorylated PhoP to the promoter of the PstSCAB operon. In Mycobacterium smegmatis, an additional high affinity transport system, PhnCDE, is also under PhoP regulation. Additionally, Streptomyces have a duplicated low affinity phosphate transport system encoded by the pitH1–pitH2 genes. In this system phosphate is transported as a metal-phosphate complex in simport with protons. Expression of pitH2, but not that of pitH1 in Streptomyces coelicolor, is regulated by PhoP. Interestingly, in many Streptomyces species, three gene clusters pitH1–pstSCAB–ppk (for a polyphosphate kinase), are linked in a supercluster formed by nine genes related to phosphate metabolism.
    [Show full text]
  • Isolation and Characterization of Bacterial Phosphorous Metabolism Genes from Complex Microbial Communities
    Isolation and characterization of bacterial phosphorous metabolism genes from complex microbial communities by Adi Rolider A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Doctor of Philosophy in Biology Waterloo, Ontario, Canada, 2009 ©Adi Rolider 2009 Author’s declaration I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. Abstract Phosphorous (P) is an essential nutrient, playing a central role in the life of a bacterial cell. It is involved in cellular metabolic pathways, cell signaling and is a component of many of the cell’s macromolecules. Since a majority of the biosphere’s microorganisms have not yet been cultured, much more can be learned about the biochemical and genetic mechanisms that govern bacterial P metabolism. The function-driven approach to metagenomics was applied to study P metabolism in the bacterial communities present in pulp and municipal wastewater treatment plant activated sludge and soil, leading to the isolation and identification of three new phosphatases, genes involved in P transport, regulation of P related functions and additional genes which may be important for the bacterial cell’s adaptation to the above communities. The identification of two new nonspecific acid phosphatases (NSAPs) phoNACX6.13 and phoNBCX4.10 and an alkaline phosphatase, phoAACX6.71, belonging to the nucleotide pyrophosphatase phosphodiesterase (NPP) family is reported here. The genes for the three phosphatases were cloned, sequenced, and analysed for upstream regulatory sequences in addition to biochemical characterization of their protein products.
    [Show full text]
  • Studies of Phou in Escherichia Coli: Metal Binding, Dimerization,Protein/Protein Interactions, and a Signaling Complex Model
    Brigham Young University BYU ScholarsArchive Theses and Dissertations 2014-12-01 Studies of PhoU in Escherichia coli: Metal Binding, Dimerization,Protein/Protein Interactions, and a Signaling Complex Model Stewart G. Gardner Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Gardner, Stewart G., "Studies of PhoU in Escherichia coli: Metal Binding, Dimerization,Protein/Protein Interactions, and a Signaling Complex Model" (2014). Theses and Dissertations. 5685. https://scholarsarchive.byu.edu/etd/5685 This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Studies of PhoU in Escherichia coli: Metal Binding, Dimerization, Protein/Protein Interactions, and a Signaling Complex Model Stewart G. Gardner A dissertation submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Doctor of Philosophy William R. McCleary, Chair Joel Shelby Griffitts Brent Lynn Nielsen Julianne House Grose Zachary Thomas Aanderud Department of Microbiology and Molecular Biology Brigham Young University December 2014 Copyright ©2014 Stewart G. Gardner All Rights Reserved ABSTRACT Studies of PhoU in Escherichia coli: Metal Binding, Dimerization, Protein/Protein Interactions and a Signaling Complex Model Stewart G. Gardner Department of Microbiology and Molecular Biology, BYU Doctor of Philosophy Phosphate is an essential nutrient for all forms of life. Escherichia coli has a PhoR/PhoB two component regulatory system that controls the expression of various genes whose products allow the cell to thrive in low phosphate environments.
    [Show full text]
  • Budding Yeast Escape Commitment to the Phosphate Starvation Program Using Gene Expression Noise
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Current Biology 23, 2051–2057, October 21, 2013 ª2013 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2013.08.043 Report Budding Yeast Escape Commitment to the Phosphate Starvation Program Using Gene Expression Noise Noam Vardi,1 Sagi Levy,1 Michael Assaf,2 Miri Carmi,1 stage, the Pho regulon will be induced, resulting in the upregu- and Naama Barkai1,* lation of high-affinity transporters and downregulation of the 1Department of Molecular Genetics, Weizmann Institute of low-affinity ones. The phosphate influx will therefore become Science, Rehovot 7610001, Israel dependent on the high-affinity transporters alone, which at 2Racah Institute of Physics, Hebrew University of Jerusalem, this point work at maximal velocity, returning the phosphate Jerusalem 91904, Israel influx back to its maximum level. Maintaining the starvation program induced at intermediate phosphate therefore necessi- tates some positive feedback to maintain Pho4p active despite Summary the high phosphate influx. Further, replenishing phosphate at this stage will not be sensed by the cells, as it will not increase Cells must rapidly adapt to changes in nutrient availability. In phosphate uptake (Figure 1B). We therefore predicted that if budding yeast, limitation of phosphate rapidly induces the phosphate is replenished when cells are in intermediate phos- expression of the Pho regulon genes [1–4]. This starvation phate, the starvation program will remain active. Only when program depends on the transcription factor Pho4, which phosphate levels are reduced further, to a level that is compa- translocates to the nucleus within minutes when cells are rable to the dissociation constant of the high-affinity trans- transferred to a low-phosphate medium [5].
    [Show full text]
  • The Potential for Polyphosphate Metabolism in Archaea and Anaerobic Polyphosphate Formation in Methanosarcina Mazei Fabiana S
    www.nature.com/scientificreports OPEN The potential for polyphosphate metabolism in Archaea and anaerobic polyphosphate formation in Methanosarcina mazei Fabiana S. Paula1,2,6*, Jason P. Chin 3,6, Anna Schnürer2, Bettina Müller2, Panagiotis Manesiotis 4, Nicholas Waters 1,5, Katrina A. Macintosh 3, John P. Quinn3, Jasmine Connolly1, Florence Abram1, John W. McGrath3 & Vincent O’Flaherty 1* Inorganic polyphosphate (polyP) is ubiquitous across all forms of life, but the study of its metabolism has been mainly confned to bacteria and yeasts. Few reports detail the presence and accumulation of polyP in Archaea, and little information is available on its functions and regulation. Here, we report that homologs of bacterial polyP metabolism proteins are present across the major taxa in the Archaea, suggesting that archaeal populations may have a greater contribution to global phosphorus cycling than has previously been recognised. We also demonstrate that polyP accumulation can be induced under strictly anaerobic conditions, in response to changes in phosphate (Pi) availability, i.e. Pi starvation, followed by incubation in Pi replete media (overplus), in cells of the methanogenic archaeon Methanosarcina mazei. Pi-starved M. mazei cells increased transcript abundance of the alkaline phosphatase (phoA) gene and of the high-afnity phosphate transport (pstSCAB-phoU) operon: no increase in polyphosphate kinase 1 (ppk1) transcript abundance was observed. Subsequent incubation of Pi-starved M. mazei cells under Pi replete conditions, led to a 237% increase in intracellular polyphosphate content and a > 5.7-fold increase in ppk1 gene transcripts. Ppk1 expression in M. mazei thus appears not to be under classical phosphate starvation control.
    [Show full text]
  • Environmental Factors Influence Virulence of Pseudomonas
    Environmental factors influence virulence of Pseudomonas aeruginosa Von der Fakultät für Lebenswissenschaften der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigte D i s s e r t a t i o n von Ahmed Mahmoud Haddad Abd Ellah aus Sohaj / Ägypten 1. Referent: Professor Dr. Jürgen Wehland 2. Referent: Professor Dr. Susanne Häußler eingereicht am: 14.06.2010 Mündliche Prüfung (Disputation) am: 24.08.2010 Druckjahr 2010 Vorveröffentlichungen der Dissertation Teilergebnisse aus dieser Arbeit wurden mit Genehmigung der Fakultät für Lebenswissenschaften, vertreten durch den Mentor der Arbeit, in folgenden Beiträgen vorab veröffentlicht: Publikationen Ahmed Haddad, Vanessa Jensen, Tanja Becker, Susanne Häussler (2009). The Pho regulon influences biofilm formation and type three secretion in Pseudomonas aeruginosa. Environmental Microbiology Reports 1(6), 488–494. Tagungsbeiträge Ahmed Haddad, Tanja Becker, Susanne Häußler. Biofilm formation and the expression of the type three secretion system are regulted by PhoB in Pseudomonas aeruginosa. Poster. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie, Dresden, 2008. Ahmed Haddad, Vanessa Jensen, Tanja Becker, Susanne Häußler. Biofilm formation and the expression of the type three secretion system are regulated by PhoB in Pseudomonas aeruginosa. Poster. XII. International Conference on Pseudomonas, Hannover, 2009. [3] I. CONTENTS Contents 1 INTRODUCTION ..............................................................................................
    [Show full text]
  • Phosphorus Deprivation Responses and Phosphonate Utilization in a Thermophilic Synechococcus Sp
    JOURNAL OF BACTERIOLOGY, Dec. 2008, p. 8171–8184 Vol. 190, No. 24 0021-9193/08/$08.00ϩ0 doi:10.1128/JB.01011-08 Copyright © 2008, American Society for Microbiology. All Rights Reserved. Phosphorus Deprivation Responses and Phosphonate Utilization in a Thermophilic Synechococcus sp. from Microbial Matsᰔ† Melissa M. Adams,1,2 María R. Go´mez-García,1 Arthur R. Grossman,1 and Devaki Bhaya1* Carnegie Institution for Science, Department of Plant Biology, Stanford University, Stanford, California 94305,1 and Department of Biology, Stanford University, Stanford, California 943052 Received 22 July 2008/Accepted 3 October 2008 The genomes of two closely related thermophilic cyanobacterial isolates, designated Synechococcus isolate OS-A and Synechococcus isolate OS-B؅, from the microbial mats of Octopus Spring (Yellowstone National Park) have been sequenced. An extensive suite of genes that are controlled by phosphate levels constitute the Downloaded from putative Pho regulon in these cyanobacteria. We examined physiological responses of an axenic OS-B؅ isolate as well as transcript abundances of Pho regulon genes as the cells acclimated to phosphorus-limiting condi- tions. Upon imposition of phosphorus deprivation, OS-B؅ stopped dividing after three to four doublings, and absorbance spectra measurements indicated that the cells had lost most of their phycobiliproteins and chlorophyll a. Alkaline phosphatase activity peaked and remained high after 48 h of phosphorus starvation, and there was an accumulation of transcripts from putative Pho regulon genes. Interestingly, the genome of jb.asm.org Synechococcus isolate OS-B؅ harbors a cluster of phn genes that are not present in OS-A isolates. The proteins encoded by the phn genes function in the transport and metabolism of phosphonates, which could serve as an alternative phosphorus source when exogenous phosphate is low.
    [Show full text]
  • Phosphate in Virulence of Candida Albicans and Candida Glabrata
    Journal of Fungi Review Phosphate in Virulence of Candida albicans and Candida glabrata Julia R. Köhler *, Maikel Acosta-Zaldívar y and Wanjun Qi y Division of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, MA 02115, USA; [email protected] (M.A.-Z.); [email protected] (W.Q.) * Correspondence: [email protected] These authors contributed equally. y Received: 4 March 2020; Accepted: 22 March 2020; Published: 26 March 2020 Abstract: Candida species are the most commonly isolated invasive human fungal pathogens. A role for phosphate acquisition in their growth, resistance against host immune cells, and tolerance of important antifungal medications is becoming apparent. Phosphorus is an essential element in vital components of the cell, including chromosomes and ribosomes. Producing the energy currency of the cell, ATP, requires abundant inorganic phosphate. A comparison of the network of regulators and effectors that controls phosphate acquisition and intracellular distribution, the PHO regulon, between the model yeast Saccharomyces cerevisiae, a plant saprobe, its evolutionarily close relative C. glabrata, and the more distantly related C. albicans, highlights the need to coordinate phosphate homeostasis with adenylate biosynthesis for ATP production. It also suggests that fungi that cope with phosphate starvation as they invade host tissues, may link phosphate acquisition to stress responses as an efficient mechanism of anticipatory regulation. Recent work indicates that connections among the PHO regulon, Target of Rapamycin Complex 1 signaling, oxidative stress management, and cell wall construction are based both in direct signaling links, and in the provision of phosphate for sufficient metabolic intermediates that are substrates in these processes.
    [Show full text]
  • Overexpression, Purification, Crystallization and Preliminary X-Ray
    Jeong and Lee Appl Biol Chem (2019) 62:66 https://doi.org/10.1186/s13765-019-0473-x NOTE Open Access Overexpression, purifcation, crystallization and preliminary X-ray crystallographic characterization of the receiver domain of the response regulator PhoP from Enterococcus faecalis ATCC 29212 Yoon Chae Jeong and Ki Seog Lee* Abstract Phosphate (Pho) regulon plays a critical role in bacterial phosphate homeostasis. It is regulated by two-component system (TCS) that comprises a sensor histidine kinase and transcriptional response regulator (RR). PhoP from Entero- coccus faecalis (EfPhoP) belongs to the OmpR subfamily of RRs. It has not yet been structurally characterized because it is difcult to crystallize it to full-length form. In this study, a truncated form of EfPhoP containing the receiver domain (EfPhoP-RD) was constructed, purifed to homogeneity and crystallized using the hanging-drop vapour-difu- sion method. The crystal of EfPhoP-RD difracted to 3.5 Å resolution and belonged to the orthorhombic space group C2221, with unit-cell parameters a 118.74, b 189.83, c 189.88 Å. The asymmetric unit contains approximately 12 = = = 3 1 molecules, corresponding to a Matthews coefcient (Vm) of 2.50 Å Da− with a solvent content of 50.9%. Keywords: Phosphate (Pho) regulon, Two-component system, Response regulator, PhoP, Enterococcus faecalis Introduction that include physiological and biochemical responses to Phosphorous is one of cellular component important overcome the defciency of this nutrient [6]. for many biological and biochemical processes in living A unique mechanism associated with the maintenance organisms, such as the formations of nucleic acids (DNA of Pi in bacteria as a regulatory circuit is the phosphate and RNA) and membrane phospholipids, post-transla- (Pho) regulon that is regulated by a two-component tional modifcations for signal transduction, etc.
    [Show full text]