101
|
Chattopadhyay R, Raghavan S, Rao GN. Resolvin D1 via prevention of ROS-mediated SHP2 inactivation protects endothelial adherens junction integrity and barrier function. Redox Biol 2017; 12:438-455. [PMID: 28319894 PMCID: PMC5357675 DOI: 10.1016/j.redox.2017.02.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 02/27/2017] [Indexed: 01/30/2023] Open
Abstract
Resolvins are a novel class of lipid mediators that play an important role in the resolution of inflammation, although the underlying mechanisms are not very clear. To explore the anti-inflammatory mechanisms of resolvins, we have studied the effects of resolvin D1 (RvD1) on lipopolysaccharide (LPS)-induced endothelial barrier disruption as it is linked to propagation of inflammation. We found that LPS induces endothelial cell (EC) barrier disruption via xanthine oxidase (XO)-mediated reactive oxygen species (ROS) production, protein tyrosine phosphatase SHP2 inactivation and Fyn-related kinase (Frk) activation leading to tyrosine phosphorylation of α-catenin and VE-cadherin and their dissociation from each other affecting adherens junction (AJ) integrity and thereby increasing endothelial barrier permeability. RvD1 attenuated LPS-induced AJ disassembly and endothelial barrier permeability by arresting tyrosine phosphorylation of α-catenin and VE-cadherin and their dislocation from AJ via blockade of XO-mediated ROS production and thereby suppression of SHP2 inhibition and Frk activation. We have also found that the protective effects of RvD1 on EC barrier function involve ALX/FPR2 and GPR32 as inhibition or neutralization of these receptors negates its protective effects. LPS also increased XO activity, SHP2 cysteine oxidation and its inactivation, Frk activation, α-catenin and VE-cadherin tyrosine phosphorylation and their dissociation from each other leading to AJ disruption with increased vascular permeability in mice arteries and RvD1 blocked all these effects. Thus, RvD1 protects endothelial AJ and its barrier function from disruption by inflammatory mediators such as LPS via a mechanism involving the suppression of XO-mediated ROS production and blocking SHP2 inactivation.
Collapse
Affiliation(s)
- Rima Chattopadhyay
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Somasundaram Raghavan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Gadiparthi N Rao
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| |
Collapse
|
102
|
González-Mariscal I, Martín-Montalvo A, Ojeda-González C, Rodríguez-Eguren A, Gutiérrez-Ríos P, Navas P, Santos-Ocaña C. Balanced CoQ 6 biosynthesis is required for lifespan and mitophagy in yeast. MICROBIAL CELL 2017; 4:38-51. [PMID: 28357388 PMCID: PMC5349121 DOI: 10.15698/mic2017.02.556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coenzyme Q is an essential lipid with redox capacity that is present in all
organisms. In yeast its biosynthesis depends on a multiprotein complex in which
Coq7 protein has both catalytic and regulatory functions. Coq7 modulates
CoQ6 levels through a phosphorylation cycle, where
dephosphorylation of three amino acids (Ser/Thr) by the mitochondrial
phosphatase Ptc7 increases the levels of CoQ6. Here we analyzed the
role of Ptc7 and the phosphorylation state of Coq7 in yeast mitochondrial
function. The conversion of the three Ser/Thr to alanine led to a permanently
active form of Coq7 that caused a 2.5-fold increase of CoQ6 levels,
albeit decreased mitochondrial respiratory chain activity and oxidative stress
resistance capacity. This resulted in an increase in endogenous ROS production
and shortened the chronological life span (CLS) compared to wild type. The null
PTC7 mutant (ptc7∆) strain showed a lower
biosynthesis rate of CoQ6 and a significant shortening of the CLS.
The reduced CLS observed in ptc7Δ was restored by the
overexpression of PTC7 but not by the addition of exogenous
CoQ6. Overexpression of PTC7 increased mitophagy
in a wild type strain. This finding suggests an additional Ptc7 function beyond
the regulation of CoQ biosynthesis. Genetic disruption of PTC7
prevented mitophagy activation in conditions of nitrogen deprivation. In brief,
we show that, in yeast, Ptc7 modulates the adaptation to respiratory metabolism
by dephosphorylating Coq7 to supply newly synthesized CoQ6, and by
activating mitophagy to remove defective mitochondria at stationary phase,
guaranteeing a proper CLS in yeast.
Collapse
Affiliation(s)
- Isabel González-Mariscal
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Aléjandro Martín-Montalvo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Cristina Ojeda-González
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Adolfo Rodríguez-Eguren
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Purificación Gutiérrez-Ríos
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Plácido Navas
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| | - Carlos Santos-Ocaña
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC, CIBERER Instituto de Salud Carlos III, Sevilla, 41013, Spain
| |
Collapse
|
103
|
Palma A, Tinti M, Paoluzi S, Santonico E, Brandt BW, Hooft van Huijsduijnen R, Masch A, Heringa J, Schutkowski M, Castagnoli L, Cesareni G. Both Intrinsic Substrate Preference and Network Context Contribute to Substrate Selection of Classical Tyrosine Phosphatases. J Biol Chem 2017; 292:4942-4952. [PMID: 28159843 DOI: 10.1074/jbc.m116.757518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/31/2017] [Indexed: 01/19/2023] Open
Abstract
Reversible tyrosine phosphorylation is a widespread post-translational modification mechanism underlying cell physiology. Thus, understanding the mechanisms responsible for substrate selection by kinases and phosphatases is central to our ability to model signal transduction at a system level. Classical protein-tyrosine phosphatases can exhibit substrate specificity in vivo by combining intrinsic enzymatic specificity with the network of protein-protein interactions, which positions the enzymes in close proximity to their substrates. Here we use a high throughput approach, based on high density phosphopeptide chips, to determine the in vitro substrate preference of 16 members of the protein-tyrosine phosphatase family. This approach helped identify one residue in the substrate binding pocket of the phosphatase domain that confers specificity for phosphopeptides in a specific sequence context. We also present a Bayesian model that combines intrinsic enzymatic specificity and interaction information in the context of the human protein interaction network to infer new phosphatase substrates at the proteome level.
Collapse
Affiliation(s)
- Anita Palma
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Michele Tinti
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Serena Paoluzi
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Elena Santonico
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Bernd Willem Brandt
- the Centre for Integrative Bioinformatics, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and
| | | | - Antonia Masch
- the Institut für Biochemie & Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, 06108 Halle, Germany
| | - Jaap Heringa
- the Centre for Integrative Bioinformatics, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and
| | - Mike Schutkowski
- the Institut für Biochemie & Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, 06108 Halle, Germany
| | - Luisa Castagnoli
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Gianni Cesareni
- From the Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy,
| |
Collapse
|
104
|
Abstract
The stressosome is a multi-protein signal integration and transduction hub found in a wide range of bacterial species. The role that the stressosome plays in regulating the transcription of genes involved in the general stress response has been studied most extensively in the Gram-positive model organism Bacillus subtilis. The stressosome receives and relays the signal(s) that initiate a complex phosphorylation-dependent partner switching cascade, resulting in the activation of the alternative sigma factor σB. This sigma factor controls transcription of more than 150 genes involved in the general stress response. X-ray crystal structures of individual components of the stressosome and single-particle cryo-EM reconstructions of stressosome complexes, coupled with biochemical and single cell analyses, have permitted a detailed understanding of the dynamic signalling behaviour that arises from this multi-protein complex. Furthermore, bioinformatics analyses indicate that genetic modules encoding key stressosome proteins are found in a wide range of bacterial species, indicating an evolutionary advantage afforded by stressosome complexes. Interestingly, the genetic modules are associated with a variety of signalling modules encoding secondary messenger regulation systems, as well as classical two-component signal transduction systems, suggesting a diversification in function. In this chapter we review the current research into stressosome systems and discuss the functional implications of the unique structure of these signalling complexes.
Collapse
|
105
|
Verma M, Gupta SJ, Chaudhary A, Garg VK. Protein tyrosine phosphatase 1B inhibitors as antidiabetic agents - A brief review. Bioorg Chem 2016; 70:267-283. [PMID: 28043717 DOI: 10.1016/j.bioorg.2016.12.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/29/2016] [Accepted: 12/20/2016] [Indexed: 01/16/2023]
Abstract
Diabetes mellitus and obesity are one of the most common health issues spread throughout world and raised the medical attention to find the new effective agents to treat these disease state. Occurrence of the drug resistance to the insulin and leptin receptor is also challenging major issues. The molecules that can overcome this resistance problem could be effective for the treatment of both type II diabetes and obesity. Protein Tyrosine Phosphatase (PTP) has emerged as new promising targets for therapeutic purpose in recent years. Protein Tyrosine Phosphatase 1B (PTP 1B) act as a negative regulator of insulin and leptin receptor signalling pathways. Several approaches have been successfully applied to find out potent and selective inhibitors. This article reviews PTP 1B inhibitors; natural, synthetic and semi-synthetic that showed inhibition towards enzyme as a major target for the management of type II diabetes. These studies could be contributing the future development of PTP 1B inhibitors as drugs.
Collapse
Affiliation(s)
- Mansi Verma
- Department of Pharmaceutical Technology, Meerut Institute of Engineering & Technology, Baghpat By-pass Crossing, NH-58, Delhi-Haridwar Highway, Meerut 250005, India.
| | - Shyam Ji Gupta
- Department of Chemistry, Indian Institute of Chemical Biology (CSIR), 4, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, W.B., India
| | - Anurag Chaudhary
- Department of Pharmaceutical Technology, Meerut Institute of Engineering & Technology, Baghpat By-pass Crossing, NH-58, Delhi-Haridwar Highway, Meerut 250005, India
| | - Vipin K Garg
- Department of Pharmaceutical Technology, Meerut Institute of Engineering & Technology, Baghpat By-pass Crossing, NH-58, Delhi-Haridwar Highway, Meerut 250005, India
| |
Collapse
|
106
|
Bellomo E, Birla Singh K, Massarotti A, Hogstrand C, Maret W. The metal face of protein tyrosine phosphatase 1B. Coord Chem Rev 2016; 327-328:70-83. [PMID: 27890939 PMCID: PMC5115158 DOI: 10.1016/j.ccr.2016.07.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 07/01/2016] [Accepted: 07/01/2016] [Indexed: 01/12/2023]
Abstract
A new paradigm in metallobiochemistry describes the activation of inactive metalloenzymes by metal ion removal. Protein tyrosine phosphatases (PTPs) do not seem to require a metal ion for enzymatic activity. However, both metal cations and metal anions modulate their enzymatic activity. One binding site is the phosphate binding site at the catalytic cysteine residue. Oxyanions with structural similarity to phosphate, such as vanadate, inhibit the enzyme with nanomolar to micromolar affinities. In addition, zinc ions (Zn2+) inhibit with picomolar to nanomolar affinities. We mapped the cation binding site close to the anion binding site and established a specific mechanism of inhibition occurring only in the closed conformation of the enzyme when the catalytic cysteine is phosphorylated and the catalytic aspartate moves into the active site. We discuss this dual inhibition by anions and cations here for PTP1B, the most thoroughly investigated protein tyrosine phosphatase. The significance of the inhibition in phosphorylation signaling is becoming apparent only from the functions of PTP1B in the biological context of metal cations as cellular signaling ions. Zinc ion signals complement redox signals but provide a different type of control and longer lasting inhibition on a biological time scale owing to the specificity and affinity of zinc ions for coordination environments. Inhibitor design for PTP1B and other PTPs is a major area of research activity and interest owing to their prominent roles in metabolic regulation in health and disease, in particular cancer and diabetes. Our results explain the apparent dichotomy of both cations (Zn2+) and oxyanions such as vanadate inhibiting PTP1B and having insulin-enhancing ("anti-diabetic") effects and suggest different approaches, namely targeting PTPs in the cell by affecting their physiological modulators and considering a metallodrug approach that builds on the knowledge of the insulin-enhancing effects of both zinc and vanadium compounds.
Collapse
Affiliation(s)
- Elisa Bellomo
- Metal Metabolism Group, Division of Diabetes and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Kshetrimayum Birla Singh
- Metal Metabolism Group, Division of Diabetes and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Alberto Massarotti
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale “A. Avogadro”, Novara, Italy
| | - Christer Hogstrand
- Metal Metabolism Group, Division of Diabetes and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Wolfgang Maret
- Metal Metabolism Group, Division of Diabetes and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK
| |
Collapse
|
107
|
Qian M, Shan Y, Guan S, Zhang H, Wang S, Han W. Structural Basis of Fullerene Derivatives as Novel Potent Inhibitors of Protein Tyrosine Phosphatase 1B: Insight into the Inhibitory Mechanism through Molecular Modeling Studies. J Chem Inf Model 2016; 56:2024-2034. [PMID: 27649447 DOI: 10.1021/acs.jcim.6b00482] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Protein tyrosine phosphatase 1B (PTP1B) has become an outstanding target for the treatment of diabetes and obesity. Recent research has demonstrated that some fullerene derivatives serve as a new nanoscale-class of potent inhibitors of PTP1B, but the specific mechanism remains unclear. Several molecular modeling methods (molecular docking, molecular dynamics simulations, and molecular mechanics/generalized Born surface area calculations) were integrated to provide insight into the binding mode and inhibitory mechanism of the new class of fullerene inhibitors. The results reveal that PTP1B with an open WPD loop is more susceptible to the combination with the fullerene inhibitor because of their comparable shapes and sizes. When the WPD loop fluctuates to the open conformation, the inhibitor falls into the active pocket and induces conformational rotation of the WPD loop. This rotation is closely related to the reduction of the catalytic activity of PTP1B. In addition, it is suggested that compound 1, like compound 2, is a competitive inhibitor since it blocks the active site to prevent the binding of the substrate. The high binding affinity of fullerene-based compounds and the transition of the WPD loop, caused by the specific structural property of the hydrophobic fullerene core and the appended polar groups, make these fullerene derivatives efficient competitive inhibitors. The theoretical results provide useful clues for further investigation of the noval inhibitors of PTP1B at the nanoscale.
Collapse
Affiliation(s)
- Mengdan Qian
- Institute of Theoretical Chemistry, Jilin University , Changchun 130023, China
| | - Yaming Shan
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, National Engineering Laboratory for AIDS Vaccine, School of Life Science, Jilin University , Changchun 130012, China
| | - Shanshan Guan
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, National Engineering Laboratory for AIDS Vaccine, School of Life Science, Jilin University , Changchun 130012, China
| | - Hao Zhang
- Institute of Theoretical Chemistry, Jilin University , Changchun 130023, China
| | - Song Wang
- Institute of Theoretical Chemistry, Jilin University , Changchun 130023, China
| | - Weiwei Han
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, National Engineering Laboratory for AIDS Vaccine, School of Life Science, Jilin University , Changchun 130012, China.,Department of Computer Science, C. S. Bond Life Sciences Center, University of Missouri , Columbia, Missouri 65211, United States
| |
Collapse
|
108
|
Wang L, Zhao J, Ren J, Hall KH, Moorman JP, Yao ZQ, Ning S. Protein phosphatase 1 abrogates IRF7-mediated type I IFN response in antiviral immunity. Eur J Immunol 2016; 46:2409-2419. [PMID: 27469204 DOI: 10.1002/eji.201646491] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/12/2016] [Accepted: 07/26/2016] [Indexed: 02/04/2023]
Abstract
Interferon (IFN) regulatory factor 7 (IRF7) plays a key role in the production of IFN-α in response to viral infection, and phosphorylation at IRF7 C-terminal serine sites is prelude to its function. However, phosphatases that negatively regulate IRF7 phosphorylation and activity have not been reported. In this study, we have identified a conserved protein phosphatase 1 (PP1)-binding motif in human and mouse IRF7 proteins, and shown that PP1 physically interacts with IRF7. Exogenous expression of PP1 subunits (PP1α, β, or γ) ablates IKKε-stimulated IRF7 phosphorylation and dramatically attenuates IRF7 transcriptional activity. Inhibition of PP1 activity significantly increases IRF7 phosphorylation and IRF7-mediated IFN-α production in response to Newcastle disease virus (NDV) infection or Toll-like receptor 7 (TLR7) challenge, leading to impaired viral replication. In addition, IFN treatment, TLR challenges and viral infection induce PP1 expression. Our findings disclose for the first time a pivotal role for PP1 in impeding IRF7-mediated IFN-α production in host immune responses.
Collapse
Affiliation(s)
- Ling Wang
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Juan Zhao
- Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Junping Ren
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Kenton H Hall
- Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Jonathan P Moorman
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Zhi Q Yao
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Shunbin Ning
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA. .,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.
| |
Collapse
|
109
|
Burroughs AM, Aravind L. RNA damage in biological conflicts and the diversity of responding RNA repair systems. Nucleic Acids Res 2016; 44:8525-8555. [PMID: 27536007 PMCID: PMC5062991 DOI: 10.1093/nar/gkw722] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/08/2016] [Indexed: 12/16/2022] Open
Abstract
RNA is targeted in biological conflicts by enzymatic toxins or effectors. A vast diversity of systems which repair or ‘heal’ this damage has only recently become apparent. Here, we summarize the known effectors, their modes of action, and RNA targets before surveying the diverse systems which counter this damage from a comparative genomics viewpoint. RNA-repair systems show a modular organization with extensive shuffling and displacement of the constituent domains; however, a general ‘syntax’ is strongly maintained whereby systems typically contain: a RNA ligase (either ATP-grasp or RtcB superfamilies), nucleotidyltransferases, enzymes modifying RNA-termini for ligation (phosphatases and kinases) or protection (methylases), and scaffold or cofactor proteins. We highlight poorly-understood or previously-uncharacterized repair systems and components, e.g. potential scaffolding cofactors (Rot/TROVE and SPFH/Band-7 modules) with their respective cognate non-coding RNAs (YRNAs and a novel tRNA-like molecule) and a novel nucleotidyltransferase associating with diverse ligases. These systems have been extensively disseminated by lateral transfer between distant prokaryotic and microbial eukaryotic lineages consistent with intense inter-organismal conflict. Components have also often been ‘institutionalized’ for non-conflict roles, e.g. in RNA-splicing and in RNAi systems (e.g. in kinetoplastids) which combine a distinct family of RNA-acting prim-pol domains with DICER-like proteins.
Collapse
Affiliation(s)
- A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| |
Collapse
|
110
|
Phosphoprotein Phosphatase 1 Is Required for Extracellular Calcium-Induced Keratinocyte Differentiation. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3062765. [PMID: 27340655 PMCID: PMC4909930 DOI: 10.1155/2016/3062765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/05/2016] [Indexed: 11/17/2022]
Abstract
Extracellular calcium is a major regulator of keratinocyte differentiation in vitro and appears to play that role in vivo, but the mechanism is unclear. We have previously demonstrated that, following calcium stimulation, PIP5K1α is recruited by the E-cadherin-β-catenin complex to the plasma membrane where it provides the substrate PIP2 for both PI3K and PLC-γ1. This signaling pathway is critical for calcium-induced generation of second messengers including IP3 and intracellular calcium and keratinocyte differentiation. In this study, we explored the upstream regulatory mechanism by which calcium activates PIP5K1α and the role of this activation in calcium-induced keratinocyte differentiation. We found that treatment of human keratinocytes in culture with calcium resulted in an increase in serine dephosphorylation and PIP5K1α activation. PP1 knockdown blocked extracellular calcium-induced increase in serine dephosphorylation and activity of PIP5K1α and induction of keratinocyte differentiation markers. Knockdown of PLC-γ1, the downstream effector of PIP5K1α, blocked upstream dephosphorylation and PIP5K1α activation induced by calcium. Coimmunoprecipitation revealed calcium induced recruitment of PP1 to the E-cadherin-catenin-PIP5K1α complex in the plasma membrane. These results indicate that PP1 is recruited to the extracellular calcium-dependent E-cadherin-catenin-PIP5K1α complex in the plasma membrane to activate PIP5K1α, which is required for PLC-γ1 activation leading to keratinocyte differentiation.
Collapse
|
111
|
Tong QH, Tao T, Xie LQ, Lu HJ. ELISA–PLA: A novel hybrid platform for the rapid, highly sensitive and specific quantification of proteins and post-translational modifications. Biosens Bioelectron 2016; 80:385-391. [DOI: 10.1016/j.bios.2016.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/20/2016] [Accepted: 02/02/2016] [Indexed: 12/01/2022]
|
112
|
Matalon O, Fried S, Ben-Shmuel A, Pauker MH, Joseph N, Keizer D, Piterburg M, Barda-Saad M. Dephosphorylation of the adaptor LAT and phospholipase C-γ by SHP-1 inhibits natural killer cell cytotoxicity. Sci Signal 2016; 9:ra54. [PMID: 27221712 DOI: 10.1126/scisignal.aad6182] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Natural killer (NK) cells discriminate between healthy cells and virally infected or transformed self-cells by tuning activating and inhibitory signals received through cell surface receptors. Inhibitory receptors inhibit NK cell function by recruiting and activating the tyrosine phosphatase Src homology 2 (SH2) domain-containing protein tyrosine phosphatase-1 (SHP-1) to the plasma membrane. However, to date, the guanine nucleotide exchange factor VAV1 is the only direct SHP-1 substrate identified in NK cells. We reveal that the adaptor protein linker for activation of T cells (LAT) as well as phospholipase C-γ1 (PLC-γ1) and PLC-γ2 are SHP-1 substrates. Dephosphorylation of Tyr(132) in LAT by SHP-1 in NK cells abrogated the recruitment of PLC-γ1 and PLC-γ2 to the immunological synapse between the NK cell and a cancer cell target, which reduced NK cell degranulation and target cell killing. Furthermore, the ubiquitylation of LAT by the E3 ubiquitin ligases c-Cbl and Cbl-b, which was induced by LAT phosphorylation, led to the degradation of LAT in response to the engagement of inhibitory receptors on NK cells, which abrogated NK cell cytotoxicity. Knockdown of the Cbl proteins blocked LAT ubiquitylation, which promoted NK cell function. Expression of a ubiquitylation-resistant mutant LAT blocked inhibitory receptor signaling, enabling cells to become activated. Together, these data identify previously uncharacterized SHP-1 substrates and inhibitory mechanisms that determine the response of NK cells.
Collapse
Affiliation(s)
- Omri Matalon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Sophia Fried
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Aviad Ben-Shmuel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Maor H Pauker
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Noah Joseph
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Danielle Keizer
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Marina Piterburg
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Mira Barda-Saad
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| |
Collapse
|
113
|
Abstract
The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs). A similar number of two-component systems are also present, indicating that these two signal transduction mechanisms are both important in the adaptation of this bacterial pathogen to its environment. The M. tuberculosis phosphoproteome includes hundreds of Ser- and Thr-phosphorylated proteins that participate in all aspects of M. tuberculosis biology, supporting a critical role for the STPKs in regulating M. tuberculosis physiology. Nine of the STPKs are receptor type kinases, with an extracytoplasmic sensor domain and an intracellular kinase domain, indicating that these kinases transduce external signals. Two other STPKs are cytoplasmic and have regulatory domains that sense changes within the cell. Structural analysis of some of the STPKs has led to advances in our understanding of the mechanisms by which these STPKs are activated and regulated. Functional analysis has provided insights into the effects of phosphorylation on the activity of several proteins, but for most phosphoproteins the role of phosphorylation in regulating function is unknown. Major future challenges include characterizing the functional effects of phosphorylation for this large number of phosphoproteins, identifying the cognate STPKs for these phosphoproteins, and determining the signals that the STPKs sense. Ultimately, combining these STPK-regulated processes into larger, integrated regulatory networks will provide deeper insight into M. tuberculosis adaptive mechanisms that contribute to tuberculosis pathogenesis. Finally, the STPKs offer attractive targets for inhibitor development that may lead to new therapies for drug-susceptible and drug-resistant tuberculosis.
Collapse
|
114
|
Mayfield JE, Burkholder NT, Zhang YJ. Dephosphorylating eukaryotic RNA polymerase II. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:372-87. [PMID: 26779935 DOI: 10.1016/j.bbapap.2016.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 12/20/2022]
Abstract
The phosphorylation state of the C-terminal domain of RNA polymerase II is required for the temporal and spatial recruitment of various factors that mediate transcription and RNA processing throughout the transcriptional cycle. Therefore, changes in CTD phosphorylation by site-specific kinases/phosphatases are critical for the accurate transmission of information during transcription. Unlike kinases, CTD phosphatases have been traditionally neglected as they are thought to act as passive negative regulators that remove all phosphate marks at the conclusion of transcription. This over-simplified view has been disputed in recent years and new data assert the active and regulatory role phosphatases play in transcription. We now know that CTD phosphatases ensure the proper transition between different stages of transcription, balance the distribution of phosphorylation for accurate termination and re-initiation, and prevent inappropriate expression of certain genes. In this review, we focus on the specific roles of CTD phosphatases in regulating transcription. In particular, we emphasize how specificity and timing of dephosphorylation are achieved for these phosphatases and consider the various regulatory factors that affect these dynamics.
Collapse
Affiliation(s)
- Joshua E Mayfield
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Nathaniel T Burkholder
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Yan Jessie Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
| |
Collapse
|
115
|
Sain D, Kumari C, Kumar A, Nayek HP, Dey S. Lead ion induced chemodosimeter approach of a tripodal hydroxyl-quinoline based phospho-ester through P–O bond cleavage. Dalton Trans 2016; 45:9187-92. [DOI: 10.1039/c6dt00941g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pb2+ induced phosphoester hydrolysis followed by the formation of a penta coordinated chelate complex of lead.
Collapse
Affiliation(s)
- Dibyendu Sain
- Department of Applied Chemistry
- Indian School of Mines
- Dhanbad
- India
| | - Chanda Kumari
- Department of Applied Chemistry
- Indian School of Mines
- Dhanbad
- India
| | - Ashish Kumar
- Department of Applied Chemistry
- Indian School of Mines
- Dhanbad
- India
| | - Hari Pada Nayek
- Department of Applied Chemistry
- Indian School of Mines
- Dhanbad
- India
| | - Swapan Dey
- Department of Applied Chemistry
- Indian School of Mines
- Dhanbad
- India
| |
Collapse
|
116
|
Rebelo S, Santos M, Martins F, da Cruz e Silva EF, da Cruz e Silva OA. Protein phosphatase 1 is a key player in nuclear events. Cell Signal 2015; 27:2589-98. [DOI: 10.1016/j.cellsig.2015.08.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/31/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022]
|
117
|
Sengelaub CA, Navrazhina K, Ross JB, Halberg N, Tavazoie SF. PTPRN2 and PLCβ1 promote metastatic breast cancer cell migration through PI(4,5)P2-dependent actin remodeling. EMBO J 2015; 35:62-76. [PMID: 26620550 PMCID: PMC4717998 DOI: 10.15252/embj.201591973] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Altered abundance of phosphatidyl inositides (PIs) is a feature of cancer. Various PIs mark the identity of diverse membranes in normal and malignant cells. Phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P2) resides predominantly in the plasma membrane, where it regulates cellular processes by recruiting, activating, or inhibiting proteins at the plasma membrane. We find that PTPRN2 and PLCβ1 enzymatically reduce plasma membrane PI(4,5)P2 levels in metastatic breast cancer cells through two independent mechanisms. These genes are upregulated in highly metastatic breast cancer cells, and their increased expression associates with human metastatic relapse. Reduction in plasma membrane PI(4,5)P2 abundance by these enzymes releases the PI(4,5)P2‐binding protein cofilin from its inactive membrane‐associated state into the cytoplasm where it mediates actin turnover dynamics, thereby enhancing cellular migration and metastatic capacity. Our findings reveal an enzymatic network that regulates metastatic cell migration through lipid‐dependent sequestration of an actin‐remodeling factor.
Collapse
Affiliation(s)
- Caitlin A Sengelaub
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Kristina Navrazhina
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Jason B Ross
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Nils Halberg
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Sohail F Tavazoie
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| |
Collapse
|
118
|
Naresh S, Atreja SK. Detection, Localization and Tyrosine Phosphorylation Status of Ser/Thr Protein Phosphatase1γ in Freshly Ejaculated, In Vitro Capacitated and Cryopreserved Buffalo Spermatozoa. Reprod Domest Anim 2015; 50:901-9. [PMID: 26478561 DOI: 10.1111/rda.12598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/29/2015] [Indexed: 12/25/2022]
Abstract
Several recent studies have indicated the important roles of Ser/Thr protein phosphatase1γ (PP1γ) in regulating the motility and capacitation of mammalian spermatozoa. Here, we report the presence and distribution of PP1γ protein in freshly ejaculated, in vitro capacitated and cryopreserved buffalo spermatozoa. The presence of PP1γ and its distribution were assessed by Western blotting and indirect immunofluorescence techniques, whereas the isoforms of PP1γ and their tyrosine phosphorylation status were identified by using 2D electrophoresis. The number of isoforms and the status of tyrosine phosphorylation of PP1γ were increased in capacitated spermatozoa when compared with freshly ejaculated spermatozoa. Differential pattern of expression and tyrosine phosphorylation of PP1γ were observed in cryopreserved spermatozoa, wherein some isoforms were degraded and some were tyrosine phosphorylated. In addition, immunofluorescence technique revealed that PP1γ was localized to principle, mid-piece, post-acrosomal and equatorial regions of buffalo spermatozoa. Differential distribution of tyrosine-phosphorylated proteins were observed in fresh, capacitated and cryopreserved spermatozoa. The tyrosine phosphorylation of several proteins (20, 37, 38, 52, 60, 79 and 100 kDa) were increased when sperm cells were incubated with PP1γ inhibitor, okadaic acid. Together, our results suggest that buffalo spermatozoa express different isoforms of PP1γ protein. The protein expression and tyrosine phosphorylation of PP1γ were increased during capacitation. Furthermore, the differential pattern of expression and tyrosine phosphorylation of PP1γ were observed in cryopreserved spermatozoa. In addition, the inhibition of PP1γ protein increases protein tyrosine phosphorylation in capacitation.
Collapse
Affiliation(s)
- S Naresh
- Reproductive Biochemistry Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana, India
| | - S K Atreja
- Reproductive Biochemistry Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana, India
| |
Collapse
|
119
|
McLauchlan CC, Peters BJ, Willsky GR, Crans DC. Vanadium–phosphatase complexes: Phosphatase inhibitors favor the trigonal bipyramidal transition state geometries. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.12.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
120
|
Matange N. Revisiting bacterial cyclic nucleotide phosphodiesterases: cyclic AMP hydrolysis and beyond. FEMS Microbiol Lett 2015; 362:fnv183. [PMID: 26424768 DOI: 10.1093/femsle/fnv183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2015] [Indexed: 12/15/2022] Open
Abstract
Cyclic-3',5'-adenosine monophosphate (cAMP) is a universal second messenger that regulates vital activities in bacteria and eukaryotes. Enzymes that hydrolyze cAMP, called phosphodiesterases (PDEs), negatively regulate the levels of this messenger molecule and are therefore crucial for signal 'termination'. In this minireview, I shall summarize the available literature on bacterial cAMP-PDEs, with particular emphasis on enzymes belonging to the ubiquitously encoded Class III PDE family exemplified by CpdA from Escherichia coli and Rv0805 from Mycobacterium tuberculosis. Using available biochemical, structural and biological information, I shall make a case for re-examining the functions of these enzymes as merely regulators of intrabacterial cAMP levels and suggest that some members of this class may have evolved cAMP-independent functions as well. Finally, I shall highlight the major lacunae in our understanding of these enzymes and present unanswered questions in the area.
Collapse
Affiliation(s)
- Nishad Matange
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, India
| |
Collapse
|
121
|
Hu J, Neiswinger J, Zhang J, Zhu H, Qian J. Systematic Prediction of Scaffold Proteins Reveals New Design Principles in Scaffold-Mediated Signal Transduction. PLoS Comput Biol 2015; 11:e1004508. [PMID: 26393507 PMCID: PMC4578958 DOI: 10.1371/journal.pcbi.1004508] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/03/2015] [Indexed: 12/03/2022] Open
Abstract
Scaffold proteins play a crucial role in facilitating signal transduction in eukaryotes by bringing together multiple signaling components. In this study, we performed a systematic analysis of scaffold proteins in signal transduction by integrating protein-protein interaction and kinase-substrate relationship networks. We predicted 212 scaffold proteins that are involved in 605 distinct signaling pathways. The computational prediction was validated using a protein microarray-based approach. The predicted scaffold proteins showed several interesting characteristics, as we expected from the functionality of scaffold proteins. We found that the scaffold proteins are likely to interact with each other, which is consistent with previous finding that scaffold proteins tend to form homodimers and heterodimers. Interestingly, a single scaffold protein can be involved in multiple signaling pathways by interacting with other scaffold protein partners. Furthermore, we propose two possible regulatory mechanisms by which the activity of scaffold proteins is coordinated with their associated pathways through phosphorylation process. Despite their importance in the signaling transduction, there is no systematic effort in identifying and characterizing the scaffold proteins in humans. In this work, we predicted scaffold proteins by integrating the available protein-protein interactions and kinase-substrate relationships. The predicted scaffold proteins showed characteristics for known scaffold proteins, suggesting the fidelity of our prediction. More importantly, the systematic prediction of scaffold proteins provides biological insights in the scaffold-mediated signal transduction. We found that scaffold proteins are likely to form complexes, suggesting that scaffold proteins could participate in diverse signaling pathways through the combinatorial interactions among scaffold proteins. Furthermore, the regulation of scaffold proteins’ activities has not been extensively studied. Our bioinformatics analysis proposed that scaffold proteins themselves might be regulated through phosphorylation process.
Collapse
Affiliation(s)
- Jianfei Hu
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Johnathan Neiswinger
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Heng Zhu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- Center for High-Throughput Biology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
122
|
Ma GX, Zhou RQ, Song ZH, Zhu HH, Zhou ZY, Zeng YQ. Molecular mechanism of serine/threonine protein phosphatase 1 (PP1cα-PP1r7) in spermatogenesis of Toxocara canis. Acta Trop 2015; 149:148-54. [PMID: 26026715 DOI: 10.1016/j.actatropica.2015.05.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 05/20/2015] [Accepted: 05/25/2015] [Indexed: 01/21/2023]
Abstract
Toxocariasis is one of the most important, but neglected, zoonoses, which is mainly caused by Toxocara canis. To better understand the role of serine/threonine protein phosphatase 1 (PP1) in reproductive processes of male adult T. canis, differential expression analysis was used to reveal the profiles of PP1 catalytic subunit α (PP1cα) gene Tc-stp-1 and PP1 regulatory subunit 7 (PP1r7) gene TcM-1309. Indirect fluorescence immunocytochemistry was carried out to determine the subcellular distribution of PP1cα. Double-stranded RNA interference (RNAi) assays were employed to illustrate the function and mechanism of PP1cα in male adult reproduction. Real-time quantitative PCR (qPCR) showed transcriptional consistency of Tc-stp-1 and TcM-1309 in sperm-producing germline tissues and localization research showed cytoplasmic distribution of PP1cα in sf9 cells, which indicated relevant involvements of PP1cα and PP1r7 in spermatogenesis. Moreover, spatiotemporal transcriptional differences of Tc-stp-1 were determined by gene knockdown analysis, which revealed abnormal morphologies and blocked meiotic divisions of spermatocytes by phenotypic aberration scanning, thereby highlighting the crucial involvement of PP1cα in spermatogenesis. These results revealed a PP1cα-PP1r7 mechanism by which PP1 regulates kinetochore-microtubule interactions in spermatogenesis and provided important clues to identify novel drug or vaccine targets for toxocariasis control.
Collapse
Affiliation(s)
- Guang Xu Ma
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, People's Republic of China
| | - Rong Qiong Zhou
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, People's Republic of China.
| | - Zhen Hui Song
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, People's Republic of China
| | - Hong Hong Zhu
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, People's Republic of China
| | - Zuo Yong Zhou
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, People's Republic of China
| | - Yuan Qin Zeng
- College of Life Sciences, Southwest University, Chongqing 402460, People's Republic of China
| |
Collapse
|
123
|
Seo H, Cho S. PTP Inhibitor V Inhibits Dual-specificity Phosphatase 22 (DUSP22) Activity. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Huiyun Seo
- College of Pharmacy; Chung-Ang University; Seoul 156-756 Republic of Korea
| | - Sayeon Cho
- College of Pharmacy; Chung-Ang University; Seoul 156-756 Republic of Korea
| |
Collapse
|
124
|
Gupta S, Jadaun A, Kumar H, Raj U, Varadwaj PK, Rao A. Exploration of new drug-like inhibitors for serine/threonine protein phosphatase 5 ofPlasmodium falciparum: a docking and simulation study. J Biomol Struct Dyn 2015; 33:2421-41. [DOI: 10.1080/07391102.2015.1051114] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
125
|
Grundler V, Faltermann S, Fent K, Gademann K. Preparation of Fluorescent Microcystin Derivatives by Direct Arginine Labelling and Their Biological Evaluation. Chembiochem 2015; 16:1657-62. [DOI: 10.1002/cbic.201500181] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Indexed: 11/09/2022]
|
126
|
Abstract
Calcineurin-like metallophosphoesterases (MPEs) form a large superfamily of binuclear metal-ion-centre-containing enzymes that hydrolyse phosphomono-, phosphodi- or phosphotri-esters in a metal-dependent manner. The MPE domain is found in Mre11/SbcD DNA-repair enzymes, mammalian phosphoprotein phosphatases, acid sphingomyelinases, purple acid phosphatases, nucleotidases and bacterial cyclic nucleotide phosphodiesterases. Despite this functional diversity, MPEs show a remarkably similar structural fold and active-site architecture. In the present review, we summarize the available structural, biochemical and functional information on these proteins. We also describe how diversification and specialization of the core MPE fold in various MPEs is achieved by amino acid substitution in their active sites, metal ions and regulatory effects of accessory domains. Finally, we discuss emerging roles of these proteins as non-catalytic protein-interaction scaffolds. Thus we view the MPE superfamily as a set of proteins with a highly conserved structural core that allows embellishment to result in dramatic and niche-specific diversification of function.
Collapse
|
127
|
Jain CK, Gupta M, Prasad Y, Wadhwa G, Sharma SK. Homology modelling and molecular dynamics simulations of a protein serine/threonine phosphatase stp1 in Staphylococcus aureusN315: a potential drug target. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2014.902535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
128
|
Structural and Biochemical Analysis of Tyrosine Phosphatase Related to Biofilm Formation A (TpbA) from the Opportunistic Pathogen Pseudomonas aeruginosa PAO1. PLoS One 2015; 10:e0124330. [PMID: 25909591 PMCID: PMC4409338 DOI: 10.1371/journal.pone.0124330] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/03/2015] [Indexed: 01/08/2023] Open
Abstract
Biofilms are important for cell communication and growth in most bacteria, and are responsible for a number of human clinical infections and diseases. TpbA (PA3885) is a dual specific tyrosine phosphatase (DUSP) that negatively regulates biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa PAO1 by converting extracellular quorum sensing signals into internal gene cascade reactions that result in reduced biofilm formation. We have determined the three-dimensional crystal structure of wild-type TpbA from P. aeruginosa PAO1 in the phosphate-bound state and a TpbA (C132S) mutant with phosphotyrosine. Comparison between the phosphate-bound structure and the previously reported ligand-free TpbA structure reveals the extent of conformational changes that occur upon substrate binding. The largest changes occur in the functional loops that define the substrate binding site, including the PTP, general acid and α4-α5 loops. We further show that TpbA efficiently catalyzes the hydrolysis of two phosphotyrosine peptides derived from the periplasmic domain of TpbB (YfiN, PA1120), with a strong preference for dephosphorylating Tyr48 over Tyr62. This work adds to the small repertoire of DUSP structures in both the ligand-free and ligand-bound states, and provides a starting point for further study of the role of TpbA in biofilm formation.
Collapse
|
129
|
Wagner S, Schütz A, Rademann J. Light-switched inhibitors of protein tyrosine phosphatase PTP1B based on phosphonocarbonyl phenylalanine as photoactive phosphotyrosine mimetic. Bioorg Med Chem 2015; 23:2839-47. [PMID: 25907367 DOI: 10.1016/j.bmc.2015.03.074] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 11/24/2022]
Abstract
Phosphopeptide mimetics containing the 4-phosphonocarbonyl phenylalanine (pcF) as a photo-active phosphotyrosine isoster are developed as potent, light-switchable inhibitors of the protein tyrosine phosphatase PTP1B. The photo-active inhibitors 6-10 are derived from phosphopeptide substrates and are prepared from the suitably protected pcF building block 12 by Fmoc-based solid phase peptide synthesis. All pcF-containing peptides are moderate inhibitors of PTP1B with KI values between 10 and 50μM. Irradiation of the inhibitors at 365nm in the presence of the protein PTP1B amplify the inhibitory activity of pcF-peptides up to 120-fold, switching the KI values of the best inhibitors to the sub-micromolar range. Photo-activation of the inhibitors results in the formation of triplet intermediates of the benzoylphosphonate moiety, which deactivate PTP1B following an oxidative radical mechanism. Deactivation of PTP1B proceeds without covalent crosslinking of the protein target with the photo-switched inhibitors and can be reverted by subsequent addition of reducing agent dithiothreitol (DTT).
Collapse
Affiliation(s)
- Stefan Wagner
- Freie Universität Berlin, Institute of Pharmacy, Medicinal Chemistry, Königin-Luise-Str. 2+4, 14195 Berlin, Germany
| | - Anja Schütz
- Max-Delbrück-Center for Molecular Medicine (MDC), Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Jörg Rademann
- Freie Universität Berlin, Institute of Pharmacy, Medicinal Chemistry, Königin-Luise-Str. 2+4, 14195 Berlin, Germany.
| |
Collapse
|
130
|
Rice stripe tenuivirus nonstructural protein 3 hijacks the 26S proteasome of the small brown planthopper via direct interaction with regulatory particle non-ATPase subunit 3. J Virol 2015; 89:4296-310. [PMID: 25653432 DOI: 10.1128/jvi.03055-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED The ubiquitin/26S proteasome system plays a vital role in regulating host defenses against pathogens. Previous studies have highlighted different roles for the ubiquitin/26S proteasome in defense during virus infection in both mammals and plants, but their role in the vectors that transmit those viruses is still unclear. In this study, we determined that the 26S proteasome is present in the small brown planthopper (SBPH) (Laodelphax striatellus) and has components similar to those in plants and mammals. There was an increase in the accumulation of Rice stripe virus (RSV) in the transmitting vector SBPH after disrupting the 26S proteasome, indicating that the SBPH 26S proteasome plays a role in defense against RSV infection by regulating RSV accumulation. Yeast two-hybrid analysis determined that a subunit of the 26S proteasome, named RPN3, could interact with RSV NS3. Transient overexpression of RPN3 had no effect on the RNA silencing suppressor activity of RSV NS3. However, NS3 could inhibit the ability of SBPH rpn3 to complement an rpn3 mutation in yeast. Our findings also indicate that the direct interaction between RPN3 and NS3 was responsible for inhibiting the complementation ability of RPN3. In vivo, we found an accumulation of ubiquitinated protein in SBPH tissues where the RSV titer was high, and silencing of rpn3 resulted in malfunction of the SBPH proteasome-mediated proteolysis. Consequently, viruliferous SBPH in which RPN3 was repressed transmitted the virus more effectively as a result of higher accumulation of RSV. Our results suggest that the RSV NS3 protein is able to hijack the 26S proteasome in SBPH via a direct interaction with the RPN3 subunit to attenuate the host defense response. IMPORTANCE We show, for the first time, that the 26S proteasome components are present in the small brown planthopper and play a role in defense against its vectored plant virus (RSV). In turn, RSV encodes a protein that subverts the SBPH 26S proteasome via direct interaction with the 26S proteasome subunit RPN3. Our results imply that the molecular arms race observed in plant hosts can be extended to the insect vector that transmits those viruses.
Collapse
|
131
|
Hobiger K, Friedrich T. Voltage sensitive phosphatases: emerging kinship to protein tyrosine phosphatases from structure-function research. Front Pharmacol 2015; 6:20. [PMID: 25713537 PMCID: PMC4322731 DOI: 10.3389/fphar.2015.00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/21/2015] [Indexed: 02/03/2023] Open
Abstract
The transmembrane protein Ci-VSP from the ascidian Ciona intestinalis was described as first member of a fascinating family of enzymes, the voltage sensitive phosphatases (VSPs). Ci-VSP and its voltage-activated homologs from other species are stimulated by positive membrane potentials and dephosphorylate the head groups of negatively charged phosphoinositide phosphates (PIPs). In doing so, VSPs act as control centers at the cytosolic membrane surface, because they intervene in signaling cascades that are mediated by PIP lipids. The characteristic motif CX5RT/S in the active site classifies VSPs as members of the huge family of cysteine-based protein tyrosine phosphatases (PTPs). Although PTPs have already been well-characterized regarding both, structure and function, their relationship to VSPs has drawn only limited attention so far. Therefore, the intention of this review is to give a short overview about the extensive knowledge about PTPs in relation to the facts known about VSPs. Here, we concentrate on the structural features of the catalytic domain which are similar between both classes of phosphatases and their consequences for the enzymatic function. By discussing results obtained from crystal structures, molecular dynamics simulations, and mutagenesis studies, a possible mechanism for the catalytic cycle of VSPs is presented based on that one proposed for PTPs. In this way, we want to link the knowledge about the catalytic activity of VSPs and PTPs.
Collapse
Affiliation(s)
- Kirstin Hobiger
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-Universität Marburg Marburg, Germany
| | - Thomas Friedrich
- Max-Volmer-Laboratory of Biophysical Chemistry, Institute of Chemistry, Technische Universität Berlin Berlin, Germany
| |
Collapse
|
132
|
Using positive-ion electrospray ionization mass spectrometry and H/D exchange study phosphoryl group transfer reactions involved in amino acid ester isopropyl phosphoramidates of Brefeldin A. Anal Chim Acta 2015; 853:391-401. [PMID: 25467484 DOI: 10.1016/j.aca.2014.09.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 08/22/2014] [Accepted: 09/29/2014] [Indexed: 11/21/2022]
Abstract
As mini-chemical models, amino acid ester isopropyl phosphoramidates of Brefeldin A (compounds 2a-2d) were synthesized and investigated by electrospray ionization tandem mass spectrometry in combination with H/D exchange. To further confirm the fragments's structures, off-line Fourier transform resonance tandem mass spectrometry (FT-ICR-MS/MS) was also performed. The fragmentation rules of compounds 2a-2d have been summarized and the plausible schemes for the fragmentation pathways were proposed. In this study, one dephosphorylated ion and two phosphorylated ions were observed in ESI-MS(2) spectra of [M+Na](+) ions for compounds 2a-2d. The possible mechanisms about phosphorylation and dephosphorylation were proposed and confirmed by H/D exchange. For the "dephosphorylation" rearrangement, a nitrogen atom was migrated from the phosphoryl group to the carbon atom of Brefeldin A's backbone with losing a molecule of C3H7PO3 (122 Da). For the "phosphorylation" rearrangement, an oxygen atom of one phosphoryl group attacked the sideward phosphorus atom to form a nine-member ring intermediate, then two steps of CH covalent bond cleavage with consecutive migration of hydrogen atom to lose a molecule of C16H20O2 (244 Da). The two proposed rearrangement mechanisms about phosphoryl group transfer might be valuable for the structure analysis of other analogs and provide insights into elucidating the dynamic process of the phosphorylation-dephosphorylation of proteins.
Collapse
|
133
|
Mort M, Carlisle FA, Waite AJ, Elliston L, Allen ND, Jones L, Hughes AC. Huntingtin Exists as Multiple Splice Forms in Human Brain. J Huntingtons Dis 2015; 4:161-71. [PMID: 26397897 DOI: 10.3233/jhd-150151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND A CAG repeat expansion in HTT has been known to cause Huntington's disease for over 20 years. The genomic sequence of the 67 exon HTT is clear but few reports have detailed alternative splicing or alternative transcripts. Most eukaryotic genes with multiple exons show alternative splicing that increases the diversity of the transcriptome and proteome: it would be surprising if a gene with 67 known exons in its two major transcripts did not present some alternative transcripts. OBJECTIVE To investigate the presence of alternative transcripts directly in human HTT. METHODS An overlapping RT-PCR based approach was used to determine novel HTT splice variants in human brain from HD patients and controls and 3D protein homology modelling employed to investigate their significance on the function of the HTT protein. RESULTS Here we show multiple previously unreported novel transcripts of HTT. Of the 22 splice variants found, eight were in-frame with the potential to encode novel HTT protein isoforms. Two splice variants were selected for further study; HTT Δex4,5,6 which results in the skipping of exons 4, 5 and 6 and HTTex41b which includes a novel exon created via partial retention of intron 41. 3D protein homology modelling showed that both splice variants are of potential functional significance leading to the loss of a karyopherin nuclear localisation signal and alterations to sites of posttranslational modification. CONCLUSIONS The identification of novel HTT transcripts has implications for HTT protein isoform expression and function. Understanding the functional significance of HTT alternative splicing would be critical to guide the design of potential therapeutics in HD that aim to reduce the toxic HTT transcript or protein product including RNA silencing and correction of mis-splicing in disease.
Collapse
Affiliation(s)
- Matthew Mort
- Institute of Medical Genetics, Cardiff University, Heath Park, Cardiff, UK
| | - Francesca A Carlisle
- Institute of Psychological Medicine and Clinical Neuroscience, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, UK
| | - Adrian J Waite
- Institute of Psychological Medicine and Clinical Neuroscience, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, UK
| | - Lyn Elliston
- Institute of Psychological Medicine and Clinical Neuroscience, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, UK
| | - Nicholas D Allen
- Cardiff School of Biosciences, Sir Martin Evans Building, Museum Avenue, Cardiff, UK
| | - Lesley Jones
- Institute of Psychological Medicine and Clinical Neuroscience, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, UK
| | - Alis C Hughes
- Institute of Psychological Medicine and Clinical Neuroscience, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, UK
| |
Collapse
|
134
|
Santos M, Domingues SC, Costa P, Muller T, Galozzi S, Marcus K, da Cruz e Silva EF, da Cruz e Silva OA, Rebelo S. Identification of a novel human LAP1 isoform that is regulated by protein phosphorylation. PLoS One 2014; 9:e113732. [PMID: 25461922 PMCID: PMC4252041 DOI: 10.1371/journal.pone.0113732] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/30/2014] [Indexed: 12/30/2022] Open
Abstract
Lamina associated polypeptide 1 (LAP1) is an integral protein of the inner nuclear membrane that is ubiquitously expressed. LAP1 binds to lamins and chromatin, probably contributing to the maintenance of the nuclear envelope architecture. Moreover, LAP1 also interacts with torsinA and emerin, proteins involved in DYT1 dystonia and X-linked Emery-Dreifuss muscular dystrophy disorder, respectively. Given its relevance to human pathological conditions, it is important to better understand the functional diversity of LAP1 proteins. In rat, the LAP1 gene (TOR1AIP1) undergoes alternative splicing to originate three LAP1 isoforms (LAP1A, B and C). However, it remains unclear if the same occurs with the human TOR1AIP1 gene, since only the LAP1B isoform had thus far been identified in human cells. In silico analysis suggested that, across different species, potential new LAP1 isoforms could be generated by alternative splicing. Using shRNA to induce LAP1 knockdown and HPLC-mass spectrometry analysis the presence of two isoforms in human cells was described and validated: LAP1B and LAP1C; the latter is putatively N-terminal truncated. LAP1B and LAP1C expression profiles appear to be dependent on the specific tissues analyzed and in cultured cells LAP1C was the major isoform detected. Moreover, LAP1B and LAP1C expression increased during neuronal maturation, suggesting that LAP1 is relevant in this process. Both isoforms were found to be post-translationally modified by phosphorylation and methionine oxidation and two LAP1B/LAP1C residues were shown to be dephosphorylated by PP1. This study permitted the identification of the novel human LAP1C isoform and partially unraveled the molecular basis of LAP1 regulation.
Collapse
Affiliation(s)
- Mariana Santos
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Sara C. Domingues
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Patrícia Costa
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Thorsten Muller
- Department of Functional Proteomics, Medical Proteome Center, Ruhr University Bochum, Bochum, Germany
| | - Sara Galozzi
- Department of Functional Proteomics, Medical Proteome Center, Ruhr University Bochum, Bochum, Germany
| | - Katrin Marcus
- Department of Functional Proteomics, Medical Proteome Center, Ruhr University Bochum, Bochum, Germany
| | - Edgar F. da Cruz e Silva
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Odete A. da Cruz e Silva
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| |
Collapse
|
135
|
Pandey R, Mohmmed A, Pierrot C, Khalife J, Malhotra P, Gupta D. Genome wide in silico analysis of Plasmodium falciparum phosphatome. BMC Genomics 2014; 15:1024. [PMID: 25425018 PMCID: PMC4256932 DOI: 10.1186/1471-2164-15-1024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 11/12/2014] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Eukaryotic cellular machineries are intricately regulated by several molecular mechanisms involving transcriptional control, post-translational control and post-translational modifications of proteins (PTMs). Reversible protein phosphorylation/dephosphorylation process, which involves kinases as well as phosphatases, represents an important regulatory mechanism for diverse pathways and systems in all organisms including human malaria parasite, Plasmodium falciparum. Earlier analysis on P. falciparum protein-phosphatome revealed presence of 34 phosphatases in Plasmodium genome. Recently, we re-analysed P. falciparum phosphatome aimed at identifying parasite specific phosphatases. RESULTS Plasmodium database (PlasmoDB 9.2) search, combined with PFAM and CDD searches, revealed 67 candidate phosphatases in P. falciparum. While this number is far less than the number of phosphatases present in Homo sapiens, it is almost the same as in other Plasmodium species. These Plasmodium phosphatase proteins were classified into 13 super families based on NCBI CDD search. Analysis of proteins expression profiles of the 67 phosphatases revealed that 44 phosphatases are expressed in both schizont as well as gametocytes stages. Fourteen phosphatases are common in schizont, ring and trophozoite stages, four phosphatases are restricted to gametocytes, whereas another three restricted to schizont stage. The phylogenetic trees for each of the known phosphatase super families reveal a considerable phylogenetic closeness amongst apicomplexan organisms and a considerable phylogenetic distance with other eukaryotic model organisms included in the study. The GO assignments and predicted interaction partners of the parasite phosphatases indicate its important role in diverse cellular processes. CONCLUSION In the study presented here, we reviewed the P. falciparum phosphatome to show presence of 67 candidate phosphatases in P. falciparum genomes/proteomes. Intriguingly, amongst these phosphatases, we could identify six Plasmodium specific phosphatases and 33 putative phosphatases that do not have human orthologs, thereby suggesting that these phosphatases have the potential to be explored as novel antimalarial drug targets.
Collapse
Affiliation(s)
| | | | | | - Jamal Khalife
- Structural and Computational Biology group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
| | | | | |
Collapse
|
136
|
Xia F, Zhang Q, Tian K, Zhu H. Theoretical studies on the effect of sulfur substitution for the methanolysis of cyclic and acyclic phosphate esters. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
137
|
Andrews LD, Zalatan JG, Herschlag D. Probing the Origins of Catalytic Discrimination between Phosphate and Sulfate Monoester Hydrolysis: Comparative Analysis of Alkaline Phosphatase and Protein Tyrosine Phosphatases. Biochemistry 2014; 53:6811-9. [PMID: 25299936 PMCID: PMC4222534 DOI: 10.1021/bi500765p] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Catalytic promiscuity, the ability
of enzymes to catalyze multiple
reactions, provides an opportunity to gain a deeper understanding
of the origins of catalysis and substrate specificity. Alkaline phosphatase
(AP) catalyzes both phosphate and sulfate monoester hydrolysis reactions
with a ∼1010-fold preference for phosphate monoester
hydrolysis, despite the similarity between these reactions. The preponderance
of formal positive charge in the AP active site, particularly from
three divalent metal ions, was proposed to be responsible for this
preference by providing stronger electrostatic interactions with the
more negatively charged phosphoryl group versus the sulfuryl group.
To test whether positively charged metal ions are required to achieve
a high preference for the phosphate monoester hydrolysis reaction,
the catalytic preference of three protein tyrosine phosphatases (PTPs),
which do not contain metal ions, were measured. Their preferences
ranged from 5 × 106 to 7 × 107, lower
than that for AP but still substantial, indicating that metal ions
and a high preponderance of formal positive charge within the active
site are not required to achieve a strong catalytic preference for
phosphate monoester over sulfate monoester hydrolysis. The observed
ionic strength dependences of kcat/KM values for phosphate and sulfate monoester
hydrolysis are steeper for the more highly charged phosphate ester
with both AP and the PTP Stp1, following the dependence expected based
on the charge difference of these two substrates. However, the dependences
for AP were not greater than those of Stp1 and were rather shallow
for both enzymes. These results suggest that overall electrostatics
from formal positive charge within the active site is not the major
driving force in distinguishing between these reactions and that substantial
discrimination can be attained without metal ions. Thus, local properties
of the active site, presumably including multiple positioned dipolar
hydrogen bond donors within the active site, dominate in defining
this reaction specificity.
Collapse
Affiliation(s)
- Logan D. Andrews
- Department of Chemical and Systems
Biology, ‡Department of Chemistry, and §Department of
Biochemistry, Stanford University, Stanford, California 94305-5307, United States
| | - Jesse G. Zalatan
- Department of Chemical and Systems
Biology, ‡Department of Chemistry, and §Department of
Biochemistry, Stanford University, Stanford, California 94305-5307, United States
| | - Daniel Herschlag
- Department of Chemical and Systems
Biology, ‡Department of Chemistry, and §Department of
Biochemistry, Stanford University, Stanford, California 94305-5307, United States
| |
Collapse
|
138
|
Xiao P, Wang X, Wang HM, Fu XL, Cui FA, Yu X, Wen SS, Bi WX, Sun JP. The second-sphere residue T263 is important for the function and catalytic activity of PTP1B via interaction with the WPD-loop. Int J Biochem Cell Biol 2014; 57:84-95. [PMID: 25450460 DOI: 10.1016/j.biocel.2014.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/21/2014] [Accepted: 10/04/2014] [Indexed: 10/24/2022]
Abstract
Protein tyrosine phosphatases have diverse substrate specificities and intrinsic activities that lay the foundations for the fine-tuning of a phosphorylation network to precisely regulate cellular signal transduction. All classical PTPs share common catalytic mechanisms, and the important catalytic residues in the first sphere of their active sites have been well characterized. However, little attention has been paid to the second-sphere residues that are potentially important in defining the intrinsic activity and substrate specificity of PTPs. Here, we find that a conserved second-sphere residue, Thr263, located in the surface Q-loop is important for both the function and activity of PTPs. Using PTP1B as a study model, we found that mutations of Thr263 impaired the negative regulation role of PTP1B in insulin signaling. A detailed mechanistic study utilizing steady-state kinetics, Brønsted analysis and pH dependence in the presence of pNPP or phosphopeptide substrates revealed that Thr263 is required for the stabilization of the leaving group during catalysis. Further crystallographic studies and structural comparison revealed that Thr263 regulates the general acid function through modulation of the WPD-loop by the T263:F182/Y/H interaction pair, which is conserved in 26 out of 32 classical PTPs. In addition, the hydrophobic interaction between Thr263 and Arg1159 of the insulin receptor contributes to the substrate specificity of PTP1B. Taken together, our findings demonstrate the general role of the second-sphere residue Thr263 in PTP catalysis. Our findings suggest that the second sphere residues of PTP active site may play important roles in PTP-mediated function in both normal and diseased states.
Collapse
Affiliation(s)
- Peng Xiao
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China; Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China
| | - Xiao Wang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China; Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China
| | - Hong-Mei Wang
- Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China; Department of Physiology, Shandong University, School of Medicine, Jinan, Shandong, China
| | - Xiao-Lei Fu
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China; Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China; Department of Public Health, Shandong University, School of Medicine, Jinan, Shandong, China
| | - Fu-ai Cui
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China
| | - Xiao Yu
- Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China; Department of Public Health, Shandong University, School of Medicine, Jinan, Shandong, China
| | - Shi-shuai Wen
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China; Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China
| | - Wen-Xiang Bi
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China.
| | - Jin-Peng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University, School of Medicine, Jinan, Shandong, China; Shandong Provincial School Key Laboratory for Protein Science of Chronic Degenerative Diseases, Jinan, Shandong, China; Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.
| |
Collapse
|
139
|
Protein phosphatase 2A (PP2A) regulatory subunits ParA and PabA orchestrate septation and conidiation and are essential for PP2A activity in Aspergillus nidulans. EUKARYOTIC CELL 2014; 13:1494-506. [PMID: 25280816 DOI: 10.1128/ec.00201-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Protein phosphatase 2A (PP2A) is a major intracellular protein phosphatase that regulates multiple aspects of cell growth and metabolism. Different activities of PP2A and subcellular localization are determined by its regulatory subunits. Here we identified and characterized the functions of two protein phosphatase regulatory subunit homologs, ParA and PabA, in Aspergillus nidulans. Our results demonstrate that ParA localizes to the septum site and that deletion of parA causes hyperseptation, while overexpression of parA abolishes septum formation; this suggests that ParA may function as a negative regulator of septation. In comparison, PabA displays a clear colocalization pattern with 4',6-diamidino-2-phenylindole (DAPI)-stained nuclei, and deletion of pabA induces a remarkable delayed-septation phenotype. Both parA and pabA are required for hyphal growth, conidiation, and self-fertilization, likely to maintain normal levels of PP2A activity. Most interestingly, parA deletion is capable of suppressing septation defects in pabA mutants, suggesting that ParA counteracts PabA during the septation process. In contrast, double mutants of parA and pabA led to synthetic defects in colony growth, indicating that ParA functions synthetically with PabA during hyphal growth. Moreover, unlike the case for PP2A-Par1 and PP2A-Pab1 in yeast (which are negative regulators that inactivate the septation initiation network [SIN]), loss of ParA or PabA fails to suppress defects of temperature-sensitive mutants of the SEPH kinase of the SIN. Thus, our findings support the previously unrealized evidence that the B-family subunits of PP2A have comprehensive functions as partners of heterotrimeric enzyme complexes of PP2A, both spatially and temporally, in A. nidulans.
Collapse
|
140
|
Lu X, Yarbrough WG. Negative regulation of RelA phosphorylation: emerging players and their roles in cancer. Cytokine Growth Factor Rev 2014; 26:7-13. [PMID: 25438737 DOI: 10.1016/j.cytogfr.2014.09.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 09/03/2014] [Indexed: 01/25/2023]
Abstract
NF-κB signaling contributes to human disease processes, notably inflammatory diseases and cancer. Many advances have been made in understanding mechanisms responsible for abnormal NF-κB activation with RelA post-translational modification, particularly phosphorylation, proven to be critical for RelA function. While the majority of studies have focused on identifying kinases responsible for NF-κB phosphorylation and pathway activation, recently progress has also been made in understanding the negative regulators important for restraining RelA activity. Here we summarize negative regulators of RelA phosphorylation, their targeting sites in RelA and biological functions through negative regulation of RelA activation. Finally, we emphasize the tumor suppressor-like roles that these negative regulators can assume in human cancers.
Collapse
Affiliation(s)
- Xinyuan Lu
- Department of Cancer Biology, Vanderbilt University, Nashville, TN, USA; Department of Medicine, University of California at San Francisco, San Francisco, CA, USA
| | - Wendell G Yarbrough
- Division of Otolaryngology, Department of Surgery, Yale University, New Haven, CT, USA; Department of Pathology, Yale University, New Haven, CT, USA; Yale Cancer Center, New Haven, CT, USA.
| |
Collapse
|
141
|
Hsu F, Mao Y. The structure of phosphoinositide phosphatases: Insights into substrate specificity and catalysis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:698-710. [PMID: 25264170 DOI: 10.1016/j.bbalip.2014.09.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 12/17/2022]
Abstract
Phosphoinositides (PIs) are a group of key signaling and structural lipid molecules involved in a myriad of cellular processes. PI phosphatases, together with PI kinases, are responsible for the conversion of PIs between distinctive phosphorylation states. PI phosphatases are a large collection of enzymes that are evolved from at least two disparate ancestors. One group is distantly related to endonucleases, which apply divalent metal ions for phosphoryl transfer. The other group is related to protein tyrosine phosphatases, which contain a highly conserved active site motif Cys-X5-Arg (CX5R). In this review, we focus on structural insights to illustrate current understandings of the molecular mechanisms of each PI phosphatase family, with emphasis on their structural basis for substrate specificity determinants and catalytic mechanisms. This article is part of a Special Issue entitled Phosphoinositides.
Collapse
Affiliation(s)
- FoSheng Hsu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
142
|
Bakke J, Haj FG. Protein-tyrosine phosphatase 1B substrates and metabolic regulation. Semin Cell Dev Biol 2014; 37:58-65. [PMID: 25263014 DOI: 10.1016/j.semcdb.2014.09.020] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/15/2014] [Accepted: 09/21/2014] [Indexed: 01/19/2023]
Abstract
Metabolic homeostasis requires integration of complex signaling networks which, when deregulated, contribute to metabolic syndrome and related disorders. Protein-tyrosine phosphatase 1B (PTP1B) has emerged as a key regulator of signaling networks that are implicated in metabolic diseases such as obesity and type 2 diabetes. In this review, we examine mechanisms that regulate PTP1B-substrate interaction, enzymatic activity and experimental approaches to identify PTP1B substrates. We then highlight findings that implicate PTP1B in metabolic regulation. In particular, insulin and leptin signaling are discussed as well as recently identified PTP1B substrates that are involved in endoplasmic reticulum stress response, cell-cell communication, energy balance and vesicle trafficking. In summary, PTP1B exhibits exquisite substrate specificity and is an outstanding pharmaceutical target for obesity and type 2 diabetes.
Collapse
Affiliation(s)
- Jesse Bakke
- Department of Nutrition, University of California Davis, One Shields Ave, Davis, CA 95616, United States
| | - Fawaz G Haj
- Department of Nutrition, University of California Davis, One Shields Ave, Davis, CA 95616, United States; Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of California Davis, Sacramento, CA 95817, United States; Comprehensive Cancer Center, University of California Davis, Sacramento, CA 95817, United States.
| |
Collapse
|
143
|
Abstract
Precise control of the balance between protein phosphorylation, catalyzed by protein kinases, and protein dephosphorylation, catalyzed by protein phosphatases, is essential for cellular homeostasis. Dysregulation of this balance leads to pathophysiological states, driving diseases such as cancer, heart disease, and diabetes. Aberrant phosphorylation of components of the pathways that control cell growth and cell survival are particularly prevalent in cancer. One of the most studied tumor suppressors in these pathways is the lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome ten), which dephosphorylates the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate (PIP3), thus preventing activation of the oncogenic kinase AKT (v-akt murine thymoma viral oncogene homolog). In 2005, the discovery of a family of protein phosphatases whose members directly dephosphorylate and inactivate AKT introduced a new negative regulator of the phosphoinositide 3-kinase (PI3K) oncogenic pathway. Pleckstrin homology domain leucine-rich repeat protein phosphatase (PHLPP) isozymes comprise a novel tumor suppressor family whose two members, PHLPP1 and PHLPP2, are deleted as frequently as PTEN in cancers such as those of the prostate. PHLPP is thus a novel therapeutic target to suppress oncogenic pathways and is a potential candidate biomarker to stratify patients for the appropriate targeted therapeutics. This review discusses the role of PHLPP in terminating AKT signaling and how pharmacological intervention would impact this pathway.
Collapse
Affiliation(s)
- Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093;
| | | |
Collapse
|
144
|
Gao Y, Nelson SW. Autoinhibition of bacteriophage T4 Mre11 by its C-terminal domain. J Biol Chem 2014; 289:26505-26513. [PMID: 25077970 DOI: 10.1074/jbc.m114.583625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mre11 and Rad50 form a stable complex (MR) and work cooperatively in repairing DNA double strand breaks. In the bacteriophage T4, Rad50 (gene product 46) enhances the nuclease activity of Mre11 (gene product 47), and Mre11 and DNA in combination stimulate the ATPase activity of Rad50. The structural basis for the cross-activation of the MR complex has been elusive. Various crystal structures of the MR complex display limited protein-protein interfaces that mainly exist between the C terminus of Mre11 and the coiled-coil domain of Rad50. To test the role of the C-terminal Rad50 binding domain (RBD) in Mre11 activation, we constructed a series of C-terminal deletions and mutations in bacteriophage T4 Mre11. Deletion of the RBD in Mre11 eliminates Rad50 binding but only has moderate effect on its intrinsic nuclease activity; however, the additional deletion of the highly acidic flexible linker that lies between RBD and the main body of Mre11 increases the nuclease activity of Mre11 by 20-fold. Replacement of the acidic residues in the flexible linker with alanine elevates the Mre11 activity to the level of the MR complex when combined with deletion of RBD. Nuclease activity kinetics indicate that Rad50 association and deletion of the C terminus of Mre11 both enhance DNA substrate binding. Additionally, a short peptide that contains the flexible linker and RBD of Mre11 acts as an inhibitor of Mre11 nuclease activity. These results support a model where the Mre11 RBD and linker domain act as an autoinhibitory domain when not in complex with Rad50. Complex formation with Rad50 alleviates this inhibition due to the tight association of the RBD and the Rad50 coiled-coil.
Collapse
Affiliation(s)
- Yang Gao
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - Scott W Nelson
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011.
| |
Collapse
|
145
|
Jeong KW, Kang DI, Lee E, Shin A, Jin B, Park YG, Lee CK, Kim EH, Jeon YH, Kim EE, Kim Y. Structure and backbone dynamics of vanadate-bound PRL-3: comparison of 15N nuclear magnetic resonance relaxation profiles of free and vanadate-bound PRL-3. Biochemistry 2014; 53:4814-25. [PMID: 24983822 DOI: 10.1021/bi5003844] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Phosphatases of regenerating liver (PRLs) constitute a novel class of small, prenylated phosphatases with oncogenic activity. PRL-3 is particularly important in cancer metastasis and represents a potential therapeutic target. The flexibility of the WPD loop as well as the P-loop of protein tyrosine phosphatases is closely related to their catalytic activity. Using nuclear magnetic resonance spectroscopy, we studied the structure of vanadate-bound PRL-3, which was generated by addition of sodium orthovanadate to PRL-3. The WPD loop of free PRL-3 extended outside of the active site, forming an open conformation, whereas that of vanadate-bound PRL-3 was directed into the active site by a large movement, resulting in a closed conformation. We suggest that vanadate binding induced structural changes in the WPD loop, P-loop, helices α4-α6, and the polybasic region. Compared to free PRL-3, vanadate-bound PRL-3 has a longer α4 helix, where the catalytic R110 residue coordinates with vanadate in the active site. In addition, the hydrophobic cavity formed by helices α4-α6 with a depth of 14-15 Å can accommodate a farnesyl chain at the truncated prenylation motif of PRL-3, i.e., from R169 to M173. Conformational exchange data suggested that the WPD loop moves between open and closed conformations with a closing rate constant k(close) of 7 s(-1). This intrinsic loop flexibility of PRL-3 may be related to their catalytic rate and may play a role in substrate recognition.
Collapse
Affiliation(s)
- Ki-Woong Jeong
- Department of Bioscience and Biotechnology and BioMolecular Informatics Center, Konkuk University , Seoul 143-701, South Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
146
|
Arai K, Wirth T. Rapid Electrochemical Deprotection of the Isonicotinyloxycarbonyl Group from Carbonates and Thiocarbonates in a Microfluidic Reactor. Org Process Res Dev 2014. [DOI: 10.1021/op500155f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kenta Arai
- School
of Chemistry, Cardiff University, Park
Place, Cardiff CF10 3AT, U.K
| | - Thomas Wirth
- School
of Chemistry, Cardiff University, Park
Place, Cardiff CF10 3AT, U.K
| |
Collapse
|
147
|
SidAhmed-Mezi M, Kurcewicz I, Rose C, Louvel J, Sokoloff P, Pumain R, Laschet JJ. Mass spectrometric detection and characterization of atypical membrane-bound zinc-sensitive phosphatases modulating GABAA receptors. PLoS One 2014; 9:e100612. [PMID: 24967814 PMCID: PMC4072668 DOI: 10.1371/journal.pone.0100612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/29/2014] [Indexed: 12/17/2022] Open
Abstract
Background GABAA receptor (GABAAR) function is maintained by an endogenous phosphorylation mechanism for which the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is the kinase. This phosphorylation is specific to the long intracellular loop I2 of the α1 subunit at two identified serine and threonine residues. The phosphorylation state is opposed by an unknown membrane-bound phosphatase, which inhibition favors the phosphorylated state of the receptor and contributes to the maintenance of its function. In cortical nervous tissue from epileptogenic areas in patients with drug-resistant epilepsies, both the endogenous phosphorylation and the functional state of the GABAAR are deficient. Methodology/Principal Findings The aim of this study is to characterize the membrane-bound phosphatases counteracting the endogenous phosphorylation of GABAAR. We have developed a new analytical tool for in vitro detection of the phosphatase activities in cortical washed membranes by liquid chromatography coupled to mass spectrometry. The substrates are two synthetic phosphopeptides, each including one of the identified endogenous phosphorylation sites of the I2 loop of GABAAR α1 subunit. We have shown the presence of multiple and atypical phosphatases sensitive to zinc ions. Patch-clamp studies of the rundown of the GABAAR currents on acutely isolated rat pyramidal cells using the phosphatase inhibitor okadaic acid revealed a clear heterogeneity of the phosphatases counteracting the function of the GABAAR. Conclusion/Significance Our results provide new insights on the regulation of GABAAR endogenous phosphorylation and function by several and atypical membrane-bound phosphatases specific to the α1 subunit of the receptor. By identifying specific inhibitors of these enzymes, novel development of antiepileptic drugs in patients with drug-resistant epilepsies may be proposed.
Collapse
Affiliation(s)
- Mounia SidAhmed-Mezi
- Inserm, Infantile Epilepsies and Brain Plasticity U1129, Paris, France
- University Paris Descartes, Paris, France
- CEA, Gif sur Yvette, France
- * E-mail: (MS); (JJL)
| | - Irène Kurcewicz
- University Paris Descartes, Paris, France
- Inserm, Centre de Psychiatrie et de Neurosciences U894, Paris, France
| | - Christiane Rose
- University Paris Descartes, Paris, France
- Inserm, Centre de Psychiatrie et de Neurosciences U894, Paris, France
| | - Jacques Louvel
- University Paris Descartes, Paris, France
- Inserm, Centre de Psychiatrie et de Neurosciences U894, Paris, France
| | - Pierre Sokoloff
- Institut de Recherche Pierre Fabre, Neurologie & Psychiatrie, Castres, France
| | - René Pumain
- Inserm, Infantile Epilepsies and Brain Plasticity U1129, Paris, France
- University Paris Descartes, Paris, France
- CEA, Gif sur Yvette, France
| | - Jacques J. Laschet
- Inserm, Infantile Epilepsies and Brain Plasticity U1129, Paris, France
- University Paris Descartes, Paris, France
- CEA, Gif sur Yvette, France
- * E-mail: (MS); (JJL)
| |
Collapse
|
148
|
Sierecki E, Newton AC. Biochemical characterization of the phosphatase domain of the tumor suppressor PH domain leucine-rich repeat protein phosphatase. Biochemistry 2014; 53:3971-81. [PMID: 24892992 PMCID: PMC4072346 DOI: 10.1021/bi500428j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
PH domain leucine-rich repeat protein
phosphatase (PHLPP) directly
dephosphorylates and inactivates Akt and protein kinase C and is therefore
a prime target for pharmacological intervention of two key signaling
pathways, the phosphatidylinositol 3-kinase and diacylglycerol signaling
pathways. Here we report on the first biochemical characterization
of the phosphatase domain of a PHLPP family member. The human PHLPP1
and PHLPP2 phosphatase domains were expressed and purified from bacteria
or insect cells and their activities compared to that of full-length
proteins immunoprecipitated from mammalian cells. Biochemical analyses
reveal that the PHLPP phosphatase domain effectively dephosphorylates
synthetic and peptidic substrates, that its activity is modulated
by metals and lipophilic compounds, and that it has relatively high
thermal stability. Mutational analysis of PHLPP2 reveals an unusual
active site architecture compared to the canonical architecture of
PP2C phosphatases and identifies key acidic residues (Asp 806, Glu
989, and Asp 1024) and bulky aromatic residues (Phe 783 and Phe 808)
whose mutation impairs activity. Consistent with a unique active site
architecture, we identify inhibitors that discriminate between PHLPP2
and PP2Cα. These data establish PHLPP as a member of the PP2C
family of phosphatases with a unique active site architecture.
Collapse
Affiliation(s)
- Emma Sierecki
- Department of Pharmacology, University of California San Diego , La Jolla, California 92093, United States
| | | |
Collapse
|
149
|
Campbell CO, Santiago DN, Guida WC, Manetsch R, Adams JH. In silico characterization of an atypical MAPK phosphatase of Plasmodium falciparum as a suitable target for drug discovery. Chem Biol Drug Des 2014; 84:158-68. [PMID: 24605883 DOI: 10.1111/cbdd.12315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 02/12/2014] [Accepted: 02/14/2014] [Indexed: 12/26/2022]
Abstract
Plasmodium falciparum, the causative agent of malaria, contributes to significant morbidity and mortality worldwide. Forward genetic analysis of the blood-stage asexual cycle identified the putative phosphatase from PF3D7_1305500 as an important element of intraerythrocytic development expressed throughout the life cycle. Our preliminary evaluation identified it as an atypical mitogen-activated protein kinase phosphatase. Additional bioinformatic analysis delineated a conserved signature motif and three residues with potential importance to functional activity of the atypical dual-specificity phosphatase domain. A homology model of the dual-specificity phosphatase domain was developed for use in high-throughput in silico screening of the available library of antimalarial compounds from ChEMBL-NTD. Seven compounds from this set with predicted affinity to the active site were tested against in vitro cultures, and three had reduced activity against a ∆PF3D7_1305500 parasite, suggesting PF3D7_1305500 is a potential target of the selected compounds. Identification of these compounds provides a novel starting point for a structure-based drug discovery strategy that moves us closer toward the discovery of new classes of clinical antimalarial drugs. These data suggest that mitogen-activated protein kinase phosphatases represent a potentially new class of P. falciparum drug target.
Collapse
|
150
|
Ahuja LG, Gopal B. Bi-domain protein tyrosine phosphatases reveal an evolutionary adaptation to optimize signal transduction. Antioxid Redox Signal 2014; 20:2141-59. [PMID: 24206235 DOI: 10.1089/ars.2013.5721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE The bi-domain protein tyrosine phosphatases (PTPs) exemplify functional evolution in signaling proteins for optimal spatiotemporal signal transduction. Bi-domain PTPs are products of gene duplication. The catalytic activity, however, is often localized to one PTP domain. The inactive PTP domain adopts multiple functional roles. These include modulation of catalytic activity, substrate specificity, and stability of the bi-domain enzyme. In some cases, the inactive PTP domain is a receptor for redox stimuli. Since multiple bi-domain PTPs are concurrently active in related cellular pathways, a stringent regulatory mechanism and selective cross-talk is essential to ensure fidelity in signal transduction. RECENT ADVANCES The inactive PTP domain is an activator for the catalytic PTP domain in some cases, whereas it reduces catalytic activity in other bi-domain PTPs. The relative orientation of the two domains provides a conformational rationale for this regulatory mechanism. Recent structural and biochemical data reveal that these PTP domains participate in substrate recruitment. The inactive PTP domain has also been demonstrated to undergo substantial conformational rearrangement and oligomerization under oxidative stress. CRITICAL ISSUES AND FUTURE DIRECTIONS The role of the inactive PTP domain in coupling environmental stimuli with catalytic activity needs to be further examined. Another aspect that merits attention is the role of this domain in substrate recruitment. These aspects have been poorly characterized in vivo. These lacunae currently restrict our understanding of neo-functionalization of the inactive PTP domain in the bi-domain enzyme. It appears likely that more data from these research themes could form the basis for understanding the fidelity in intracellular signal transduction.
Collapse
Affiliation(s)
- Lalima Gagan Ahuja
- 1 Molecular Biophysics Unit, Indian Institute of Science , Bangalore, India
| | | |
Collapse
|