Relevant bibliographies by topics / Inositol polyphosphate phosphatases

Academic literature on the topic 'Inositol polyphosphate phosphatases'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Inositol polyphosphate phosphatases"

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Eramo, Matthew J., and Christina A. Mitchell. "Regulation of PtdIns(3,4,5)P3/Akt signalling by inositol polyphosphate 5-phosphatases." Biochemical Society Transactions 44, no. 1 (February 9, 2016): 240–52. http://dx.doi.org/10.1042/bst20150214.

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The phosphoinositide 3-kinase (PI3K) generated lipid signals, PtdIns(3,4,5)P3 and PtdIns(3,4)P2, are both required for the maximal activation of the serine/threonine kinase proto-oncogene Akt. The inositol polyphosphate 5-phosphatases (5-phosphatases) hydrolyse the 5-position phosphate from the inositol head group of PtdIns(3,4,5)P3 to yield PtdIns(3,4)P2. Extensive work has revealed several 5-phosphatases inhibit PI3K-driven Akt signalling, by decreasing PtdIns(3,4,5)P3 despite increasing cellular levels of PtdIns(3,4)P2. The roles that 5-phosphatases play in suppressing cell proliferation and transformation are slow to emerge; however, the 5-phosphatase PIPP [proline-rich inositol polyphosphate 5-phosphatase; inositol polyphosphate 5-phosphatase (INPP5J)] has recently been identified as a putative tumour suppressor in melanoma and breast cancer and SHIP1 [SH2 (Src homology 2)-containing inositol phosphatase 1] inhibits haematopoietic cell proliferation. INPP5E regulates cilia stability and INPP5E mutations have been implicated ciliopathy syndromes. This review will examine 5-phosphatase regulation of PI3K/Akt signalling, focussing on the role PtdIns(3,4,5)P3 5-phosphatases play in developmental diseases and cancer.
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Zhang, Qingxiu, and Francois X. Claret. "Phosphatases: The New Brakes for Cancer Development?" Enzyme Research 2012 (October 31, 2012): 1–11. http://dx.doi.org/10.1155/2012/659649.

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The phosphatidylinositol 3-kinase (PI3K) pathway plays a pivotal role in the maintenance of processes such as cell growth, proliferation, survival, and metabolism in all cells and tissues. Dysregulation of the PI3K/Akt signaling pathway occurs in patients with many cancers and other disorders. This aberrant activation of PI3K/Akt pathway is primarily caused by loss of function of all negative controllers known as inositol polyphosphate phosphatases and phosphoprotein phosphatases. Recent studies provided evidence of distinct functions of the four main phosphatases—phosphatase and tensin homologue deleted on chromosome 10 (PTEN), Src homology 2-containing inositol 5′-phosphatase (SHIP), inositol polyphosphate 4-phosphatase type II (INPP4B), and protein phosphatase 2A (PP2A)—in different tissues with respect to regulation of cancer development. We will review the structures and functions of PTEN, SHIP, INPP4B, and PP2A phosphatases in suppressing cancer progression and their deregulation in cancer and highlight recent advances in our understanding of the PI3K/Akt signaling axis.
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Jia, Qi, Defeng Kong, Qinghua Li, Song Sun, Junliang Song, Yebao Zhu, Kangjing Liang, Qingming Ke, Wenxiong Lin, and Jinwen Huang. "The Function of Inositol Phosphatases in Plant Tolerance to Abiotic Stress." International Journal of Molecular Sciences 20, no. 16 (August 16, 2019): 3999. http://dx.doi.org/10.3390/ijms20163999.

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Inositol signaling is believed to play a crucial role in various aspects of plant growth and adaptation. As an important component in biosynthesis and degradation of myo-inositol and its derivatives, inositol phosphatases could hydrolyze the phosphate of the inositol ring, thus affecting inositol signaling. Until now, more than 30 members of inositol phosphatases have been identified in plants, which are classified intofive families, including inositol polyphosphate 5-phosphatases (5PTases), suppressor of actin (SAC) phosphatases, SAL1 phosphatases, inositol monophosphatase (IMP), and phosphatase and tensin homologue deleted on chromosome 10 (PTEN)-related phosphatases. The current knowledge was revised here in relation to their substrates and function in response to abiotic stress. The potential mechanisms were also concluded with the focus on their activities of inositol phosphatases. The general working model might be that inositol phosphatases would degrade the Ins(1,4,5)P3 or phosphoinositides, subsequently resulting in altering Ca2+ release, abscisic acid (ABA) signaling, vesicle trafficking or other cellular processes.
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Astle, Megan V., Kristy A. Horan, Lisa M. Ooms, and Christina A. Mitchell. "The inositol polyphosphate 5-phosphatases: traffic controllers, waistline watchers and tumour suppressors?" Biochemical Society Symposia 74 (January 12, 2007): 161–81. http://dx.doi.org/10.1042/bss2007c15.

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Phosphoinositide signals regulate cell proliferation, differentiation, cytoskeletal rearrangement and intracellular trafficking. Hydrolysis of PtdIns(4,5)P2 and PtdIns(3,4,5)P3, by inositol polyphosphate 5-phosphatases regulates synaptic vesicle recycling (synaptojanin-1), hematopoietic cell function [SHIP1(SH2-containing inositol polyphosphate 5-phosphatase-1)], renal cell function [OCRL (oculocerebrorenal syndrome of Lowe)] and insulin signalling (SHIP2). We present here a detailed review of the characteristics of the ten mammalian 5-phosphatases. Knockout mouse phenotypes and underexpression studies are associated with significant phenotypic changes, indicating non-redundant roles, despite, in many cases, overlapping substrate specificity and tissue expression. The extraordinary complexity in the control of phosphoinositide signalling continues to be revealed.
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Chellapandi, Paulchamy, and Jayachandrabal Balachandramohan. "Computational Evaluation of Designed Phosphatase from Conserved Sequence Scratch for Diverse Substrate Specificity." International Journal Bioautomation 26, no. 3 (September 2022): 297–310. http://dx.doi.org/10.7546/ijba.2022.26.3.000553.

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The ability to design efficient enzymes for a broad class of different reactions would be of tremendous practical interest in both science and industry. Computer-assisted designing is a novel approach to generating industrial enzymes for biotechnological applications. Objectives: The main aim of this study was to design an enzyme construct with diverse substrate-binding specificity based on the evolutionary conservation of archaeal vanadium-dependent phosphatases. Materials and methods: A rational 3D structural model of enzyme construct was developed from conserved sequence scratch encompassing a vanadium-binding site and functional domain. Substrate-binding specificity of the designed enzyme was computed with different myo-inositol polyphosphate analogous by a molecular docking program. Results: A designed enzyme has shown more substrate-binding specificity with 1D-myo-inositol 3, 4, 5, 6-tetrakisphosphate. Its catalytic function closely resembled myo-inositol polyphosphate-5-phosphatase and multiple inositol polyphosphate phosphatases. Moreover, the enzyme construct was energetically stable with a low degree of conformational changes upon substrate-binding. Conclusion: Substrate specificity and catalytic competence of designed enzymes were computationally evaluated for further biotechnological applications.
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Mitchell, Christina A., Rajendra Gurung, Anne M. Kong, Jennifer M. Dyson, April Tan, and Lisa M. Ooms. "Inositol Polyphosphate 5-Phosphatases: Lipid Phosphatases With Flair." IUBMB Life (International Union of Biochemistry and Molecular Biology: Life) 53, no. 1 (January 1, 2002): 25–36. http://dx.doi.org/10.1080/15216540210815.

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Mitchell, C. A. "THE REGULATION OF INOSITOL TRISPHOSPHATE BY INOSITOL POLYPHOSPHATE 5-PHOSPHATASES." Biochemical Society Transactions 24, no. 4 (November 1, 1996): 621S. http://dx.doi.org/10.1042/bst024621sa.

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Noakes, Christopher J., Grace Lee, and Martin Lowe. "The PH domain proteins IPIP27A and B link OCRL1 to receptor recycling in the endocytic pathway." Molecular Biology of the Cell 22, no. 5 (March 2011): 606–23. http://dx.doi.org/10.1091/mbc.e10-08-0730.

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Mutation of the inositol polyphosphate 5-phosphatase OCRL1 results in two disorders in humans, namely Lowe syndrome (characterized by ocular, nervous system, and renal defects) and type 2 Dent disease (in which only the renal symptoms are evident). The disease mechanisms of these syndromes are poorly understood. Here we identify two novel OCRL1-binding proteins, termed inositol polyphosphate phosphatase interacting protein of 27 kDa (IPIP27)A and B (also known as Ses1 and 2), that also bind the related 5-phosphatase Inpp5b. The IPIPs bind to the C-terminal region of these phosphatases via a conserved motif similar to that found in the signaling protein APPL1. IPIP27A and B, which form homo- and heterodimers, localize to early and recycling endosomes and the trans-Golgi network (TGN). The IPIPs are required for receptor recycling from endosomes, both to the TGN and to the plasma membrane. Our results identify IPIP27A and B as key players in endocytic trafficking and strongly suggest that defects in this process are responsible for the pathology of Lowe syndrome and Dent disease.
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Drayer, A. L., X. Pesesse, F. De Smedt, D. Communi, C. Moreau, and C. Erneux. "The family of inositol and phosphatidylinositol polyphosphate 5-phosphatases." Biochemical Society Transactions 24, no. 4 (November 1, 1996): 1001–5. http://dx.doi.org/10.1042/bst0241001.

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Antibus, Robert K., Robert L. Sinsabaugh, and Arthur E. Linkins. "Phosphatase activities and phosphorus uptake from inositol phosphate by ectomycorrhizal fungi." Canadian Journal of Botany 70, no. 4 (April 1, 1992): 794–801. http://dx.doi.org/10.1139/b92-101.

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To better understand the physiological importance of acid phosphatase activity we examined the effects of inorganic and organic phosphorus growth sources on enzyme activity and 32P uptake in several ectomycorrhizal fungi. Mycelium of eight isolates from four basidiomycete species demonstrated optimal p-nitrophenyl phosphatase activity at pH 4.5 or 5.0. Acid phosphatase activities varied between strains of Scleroderma citrinum and between the species examined. Interspecific differences in isozyme patterns of whole cell extracts were apparent in native polyacrylamide gels. The isoelectric points of the predominant phosphatases in whole cell extracts were in the pH 5.0 to 5.5 range. Growth of fungi on inositol hexaphosphate versus inorganic P did not affect the isozyme patterns detected by either electrophoretic method. Growth on inositol hexaphosphate affected surface and soluble activities towards p-nitrophenyl phosphate and inositol phosphate to different degrees in species examined. Phytase activity was sufficient to produce a net release of P in all isolates. Growth on inositol hexaphosphate was associated with increased uptake of 32P from inositol polyphosphate in four of five species examined. Acid phosphatase, measured with p-nitrophenyl phosphate, was positively correlated with 32P uptake. Decreased phytase activities measured for inositol hexaphosphate grown mycelium were associated with increased P influx in such mycelium. Both phosphatase activity and 32P uptake were subject to inorganic P inhibition with 32P uptake demonstrating a greater sensitivity. These results provide further evidence for the role of surface acid phosphatases in organic P utilization by ectomycorrhizal fungi. Key words: acid phosphatase, ectomycorrhizal fungi, phytase.
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Dissertations / Theses on the topic "Inositol polyphosphate phosphatases"

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Kong, Anne Mandy 1973. "Cloning and characterisation of a novel 72 kDa inositol polyphosphate 5-phosphatase." Monash University, Dept. of Biochemistry and Molecular Biology, 2001. http://arrow.monash.edu.au/hdl/1959.1/9036.

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Li, Arthur. "Structure-function studies of multiple inositol polyphosphate phosphatases from gut commensal bacteria." Thesis, University of East Anglia, 2014. https://ueaeprints.uea.ac.uk/56898/.

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Inositol hexakisphosphate (InsP6) is the main storage form of phosphorous in animal feeds. Phytases are enzymes (myo-inositol hexakisphosphate phosphohydrolases) that break down InsP6 by hydrolysis to release inorganic phosphate. Non-ruminant animals do not produce phytases needed to digest dietary InsP6, instead relying on enzymes produced by their gut microbiota. A similar situation is found in humans where several members of the commensal bacteria have been found to produce multiple inositol polyphosphate phosphatases (Minpp) which display phytase activity. In this study, high resolution X-ray crystal structures of Minpps from two human commensal gut bacteria, Bacteroides thetaiotaomicron (BtMinpp) and Bifidobacterium longum (BlMinpp), were solved and refined. High performance liquid chromatography was employed to analyse the products of InsP6 hydrolysis, revealing that Minpps attack InsP6 with high positional promiscuity, unlike bacterial and fungal phytases which display high catalytic specificity. Site-directed mutagenesis was employed to further investigate the catalytic promiscuity of BtMinpp, mutagenizing its active site to mimic that of PhyA, a specific 3- phytase from Aspergillus niger. Further experiments introduced active site residues from human Minpp. The results of these studies reveal that by altering key active site residues, the positional specificity and the ratios of the InsP5 products generated by BtMinpp action can be altered, opening the possibility of engineering catalytic flexibility into phytases used as commercial animal feed additives. Disulfide bridges were engineered into BtMinpp with the aim of enhancing its thermostability – an attractive characteristic for animal feed enzymes. Sites for potential disulfide bridges were identified and a one such mutant was produced. However, the engineered protein did not show a significant enhancement in thermostability. The results of experiments described in this thesis provide novel insights into the hydrolysis of InsP6 by Minpps that suggest a role as precursors for a new generation of phytases for the animal feed industry.
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Zietek, Monika. "Characterisation of bacterial multiple inositol polyphosphate phosphatases relevant to the animal feed industry." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/67804/.

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Phytases are enzymes that degrade phytate, the main storage form of phosphorus in plants. Animal feed industries use plant-based feed with abundant phytate content. Without the supplementation with phytases, the animals would not be able to access the phosphorus in the form of phosphate stored in the phytate molecule. This thesis describes research carried out to characterise a group of bacterial phytases from Bacteroides thetaiotaomicron, Bifidobacterium infantis and Bifidobacterium pseudocatenulatum with comparisons to an existing commercial phytase, Quantum Blue. The enzymatic properties, product profiles, binding and thermostability were examined and the structure of the binding site at various stages of the catalytic cycle was investigated with the aid of active site mutagenesis. X-ray structure of the active site mutant helped elucidate the structure of the intermediate and product-bound forms of the Bifidobacterium infantis phytase. Further mutagenesis experiments examined the function of disulphide bridges in the enzyme. The experimental results described in this work provide novel insights into the hydrolysis of phytate by bacterial phytases, the conformational changes during the catalytic cycle and the contribution of disulphide links to thermostability of the enzyme. These results lay the foundations of the work toward optimisation of phytases for use by the industry of the animal feed supplements.
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Burnette, Ryan Nelson. "A Physiological, Biochemical and Structural Analysis of Inositol Polyphosphate 5-Phosphatases from Arabidopsis thaliana and Humans." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29874.

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The complete role of inositol signaling in plants and humans is still elusive. The plant Arabidopsis thaliana contains fifteen predicted inositol polyphosphate 5- phosphatases (5PTases, E.C. 3.1.3.36) that have the potential to remove a 5-phosphate from various inositol second messenger substrates. To examine the substrate specificity of one of these Arabidopsis thaliana 5PTases (At5PTases), recombinant At5PTase1 was obtained from a Drosophila melanogaster expression system and analyzed biochemically. This analysis revealed that At5PTase1 has the ability to catalyze the hydrolysis of four potential inositol second messenger substrates. To determine whether At5PTase1 can be used to alter the signal transduction pathway of the major drought-sensing hormone abscisic acid (ABA), plants ectopically expressing At5PTase1 under the control of a constitutive promoter were characterized. This characterization revealed that plants ectopically expressing At5PTase1 had an altered response to ABA. These plants have stomata that are insensitive to ABA, and have lower basal and ABA-induced inositol (1,4,5)-trisphosphate [Ins(1,4,5)P₃] levels. In addition, At5PTase1 mRNA and protein levels are transiently regulated by ABA. These data strongly suggest that At5PTase1 can act as a signal terminator of ABA signal transduction. Like the Arabidopsis At5PTase1, a human 5PTase, Ocrl, has the ability to catalyze the hydrolysis of a 5-phosphate from several inositol-containing substrates. The loss of functional Ocrl protein results in a rare genetic disorder known as Lowe oculocerebrorenal syndrome. To gather information concerning the specificity determinants of the Ocrl protein, a structure-function analysis of Ocrl was conducted using a vibrational technique, difference Fourier transform infrared (FT-IR) spectroscopy. Upon the introduction of Ins(1,4,5)P₃ substrate, structural changes in carboxylic acid and histidine residues were observed. The net result of changes in these residues indicates that upon Ins(1,4,5)P₃ introduction, a carboxylic acid-containing residue is protonated, and a histidine residue is deprotonated. This interpretation supports the idea that the deprotonation of the histidine residue is concomitant with the coordination of a divalent cation upon Ins(1,4,5)P₃ introduction. This work allows for the proposal of a new model for the role of the active site histidine of OCRL.
Ph. D.
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Dyson, Jennifer Maree 1975. "The SH2-containing inositol polyphosphate 5-phosphatase-2 (SHIP-2) regulates the actin cytoskeleton." Monash University, Dept. of Biochemistry and Molecular Biology, 2002. http://arrow.monash.edu.au/hdl/1959.1/7718.

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Ananieva-Stoyanova, Elitsa Antonova. "Identification and Functional Role of Myo-Inositol Polyphosphate 5-Phosphatase Protein Complexes." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28028.

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To survive, an organism must constantly adjust its internal state to changes in the environment from which it receives signals. The signals set off a chain of events referred to signal transduction. Signal transduction systems are especially important in multicellular organisms, such as plants and animals, because of the need to coordinate the activities of hundreds to trillions of cells. Plants, in particular, have a special need for perceiving signals from their environment because of their static nature. As in the animal cell, the first steps in perception of a signal include signal interaction with a receptor, signal amplification through second messenger production, and signal termination through second messenger hydrolysis. Myo-inositol polyphosphate 5-phosphatases (5PTases) (EC 3.1.3.56) have unique signal terminating abilities toward the second messenger inositol trisphosphate (Ins (1,4,5)P3, InsP3). In Arabidopsis thaliana there are 15 members of the 5PTase family, the majority of which contain a single 5PTase catalytic domain. Four members of the Arabidopsis 5PTase family, however, have a unique protein domain structure, with additional N-terminal WD40 repeats that are implicated in protein-protein interactions. The research presented here focused on the identification of 5PTase interacting proteins and the characterization of their functional role in Arabidopsis. To accomplish this goal, I examined a 5PTase13-interacting protein, the sucrose (Suc) nonfermenting-1-related kinase, SnRK1.1, an important energy sensor that is highly conserved among eukaryotes. My identification of a 5PTase13:SnRK1.1 complex points to the novel interaction of this metabolic modulator and inositol signaling/metabolism. 5PTase13 , however, plays a regulatory role in other plant specific processes as well, since I also identified the Arabidopsis homolog (Atp80) of the human WDR48 (HsWDR48, Hsp80) as a novel protein interactor of 5PTase13. My results indicate that Atp80 is important for leaf emergence, development and senescence likely via a regulatory interaction with 5PTase13 and PINOID â binding protein (PBP1).
Ph. D.
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Blockmans, Marianne. "Etude de la régulation et de la surexpression de l'inositol polyphosphate 5-phosphatase SHIP2 chez la souris." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210375.

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SHIP2 (SH2 domain-containing inositol polyphosphate 5-phosphatase type 2) est un enzyme de la famille des inositol polyphosphate 5-phosphatases qui déphosphoryle le PtdIns(3,4,5)P3, second messager intervenant dans différentes voies de signalisation cellulaire et impliqué dans de nombreux processus biologiques.

La surexpression de SHIP2 en cellule, de même que son invalidation chez la souris, ont montré un rôle de cet enzyme dans le contrôle négatif de la cascade de signalisation de l’insuline et dans la sensibilité à cette hormone. Par ailleurs, plusieurs études de polymorphismes chez l’homme ont montré une association entre ce gène et le diabète de type2.

La découverte au sein de notre laboratoire de la délétion d’un motif semblable à ceux présents dans les régions déstabilisatrices de type AU-riche dans la région 3’non codante (3’UTR) du gène SHIP2 chez des patients atteints de diabète de type 2, nous a conduit à explorer le rôle de cette région dans le contrôle de l’expression de SHIP2.

Dans ce but, nous avons entrepris d’identifier des protéines capables de lier ce motif AU-riche et d’entraîner l’ARN de SHIP2 vers la dégradation, et ce par deux techniques distinctes :l’une in vivo chez la levure (le triple hybride) et l’autre in vitro, par l’intermédiaire d’une sonde ARN biotinylée. Malheureusement, aucune de ces deux techniques ne nous a permis d’identifier des protéines se liant à l’ARNm de SHIP2. D’autre part, l’analyse de souris génétiquement modifiées présentant dans la région 3’UTR de SHIP2 une mutation similaire à celle observée chez les patients diabétiques n’a pas montré une augmentation significative d’expression de SHIP2 comme on aurait pu s’y attendre.

Malgré les différentes techniques mises en place, nous ne sommes pas parvenus à caractériser le rôle joué par le 3’UTR de SHIP2 sur le contrôle de son expression.

Dans le but de caractériser l’effet d’une surexpression de SHIP2 et de déterminer si une surexpression de ce gène pouvait mimer le phénotype de diabète de type 2 observé au sein de la population, nous avons généré des souris transgéniques d’addition par transgenèse lentivirale.

Deux axes phénotypiques majeurs ont été explorés chez ces souris :le métabolisme du glucose et la prise de poids consécutive à divers régimes alimentaire.

Les souris transgéniques présentent un retard dans la captation du glucose en réponse à une surcharge en glucose, s’accompagnant d’un défaut de sécrétion d’insuline. Par contre, aucune altération de la sensibilité à l’insuline n’est observée suite à une injection de cette hormone. Cette absence d’altération de la sensibilité à l’insuline est également soutenue par le fait qu’aucune altération de la captation de glucose n’est observée chez des souris surexprimant le transgène spécifiquement dans le muscle squelettique.

Les analyses de prise de poids des souris transgéniques ont révélé une résistance à l’obésité des mâles transgéniques lorsqu’ils sont soumis à un régime alimentaire riche en graisse. Par contre, aucune différence n’est observée sous régime alimentaire conventionnel ou faible en graisse. La plus faible prise de poids des souris transgéniques sous régime riche en graisse s’accompagnant d’une plus faible prise de nourriture, un rôle de SHIP2 dans la régulation du comportement alimentaire et de l’appétit n’est pas à exclure.

En conclusion, la surexpression de SHIP2 chez la souris provoque une intolérance au glucose induite, en tout cas en partie, par une plus faible sécrétion d’insuline, ainsi qu’une résistance à l’obésité induite par un régime riche en graisse.


Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished

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Ghani, Sana. "The role of inositol polyphosphate 4-phosphatase type II alpha (Inpp4bα) in mature osteoclasts «in vivo»." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110487.

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Osteopetrosis is a genetic disorder resulting from excessive amount of bone due to a defect in osteoclasts. Our laboratory characterized the Ostm1 gene that is responsible for the most severe form of osteopetrosis in mice and humans. In addition, our laboratory then identified the Inositol polyphosphate 4- phosphatase type II alpha (Inpp4b alpha) gene in a differential display screen with reduced expression in Ostm1 deficient osteoclasts. Following characterization of the mouse Inpp4b gene, its role in bone biology was investigated. First, Inpp4b alpha co-localized with F-actin in the podosome subunits, which forms the actin ring of the osteoclast cytoskeletal structure that is essential for osteoclast resorption activity. Second, expression of the phosphatase-inactive Inpp4b in RAW 264.7 OCLs resulted in the formation of multiple, small actin rings leading to poor bone resorption. This result suggested that the phosphatase catalytic activity of Inpp4b alpha is crucial for osteoclast actin ring formation and cytoskeletal dynamics in vitro. We then hypothesized that Inpp4b alpha can be an essential phosphatase involved in the osteoclast cytoskeleton and resorption activity in vivo. Toward this aim, we decided to overexpress three forms of Inpp4b in transgenic mice: the native Inpp4b alpha, the Inpp4b alpha phosphatase inactive form (C845A), and the native form missing the lipid binding C2 domain. Specific expression of these transgenes was targeted with the human Ctsk promoter, which is specifically expressed in mature osteoclasts. These mice were also crossed with Inpp4b knockout mice to avoid interference with expression of endogenous Inpp4b and to mimic a knock-in situation. The expression of Inpp4b alpha (C845A) OCLs differentiated in ex vivo presented multiple, small actin rings and disruption in cytoskeletal rearrangement correlating with previous results. The expression of Inpp4b alpha missing the C2 domain had a diffused podosome belt, similar to osteoclasts derived from the Inpp4b knockout mice. These results illustrated that Inpp4b alpha plays a major role in the osteoclast cytoskeletal rearrangements in vivo, and this is directly dependent on the catalytic activity of the Inpp4b phosphatase.
L'ostéopétrose est un désordre génétique résultant d'une accumulation osseuse dûe à un défaut des ostéoclastes. Nôtre laboratoire a caractérisé la mutation du gène Ostm1 en tant que responsable de la forme la plus sévère d'ostéopétrose chez la souris et l'humain. De plus, nôtre laboratoire a parallèlement identifié une diminution de l'expression du gène Inositol polyphosphate 4- phosphatase type II alpha (Inpp4b alpha) dans les ostéoclastes déficients d'Ostm1. À la suite de la caractérisation du gène Inpp4b chez la souris, l'importance de ce gène dans la biologie du tissu osseux a été établie : D'une part, Inpp4b alpha co-localise avec la F-actine qui forme les anneaux d'actine constituant des sous-unités du podosome, une structure responsable de l'activité de résorption des ostéoclastes. D'autre part, l'expression de la forme inactive d'Inpp4b dans la lignée ostéoclastique RAW 264.7 entraîne la formation de petits et multiples anneaux d'actine résultant en une faible résorption osseuse. Ce résultat suggère que l'activité catalytique de la phosphatase Inpp4b alpha soit cruciale pour la formation des anneaux d'actine et de la dynamique du cytosquelette des ostéoclastes in vitro. À la lumière de ces résultats, nous avons émis l'hypothèse qu'Inpp4b alpha est une importante phosphatase impliquée dans le cytosquelette ainsi que dans l'activité de résorption des ostéoclastes in vivo. Pour ce faire, nous avons surexprimé trois formes d'Inpp4b dans des souris transgéniques: la forme native d'Inpp4b alpha, la forme inactive d'Inpp4b alpha (C845A), ainsi que la forme native manquant le domaine de liaison aux lipides C2. La spécificité d'expression de ces transgènes a été ciblée dans les ostéoclastes matures en utilisant le promoteur de Ctsk humain. Ces souris ont été croisées avec des souris Inpp4b knockout afin d'éviter l'interférence avec l'expression d'Inpp4b endogène ainsi que de mimer un knock-in. Les ostéoclastes exprimant la forme inactive d'Inpp4b alpha(C845A) et différentiés ex vivo présentent de petits et multiples anneaux d'actine, ainsi qu'un défaut du réarrangement du cytosquelette tel qu'observé précédemment. Les ostéoclastes démontrant l'expression d'Inpp4b alpha sans domaine C2 présentent une ceinture de podosomes diffuse, comparable à celle observée dans les souris Inpp4b knockout. Ces résultats illustrent l'importance de la phosphatase Inpp4b alpha dans le réarrangement du cytosquelette des ostéoclastes in vivo, et ceci dépend directement de l'activité catalytique d'Inpp4b.
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Ercetin, Mustafa Edib. "Molecular Characterization and Loss-of-Function Analysis of an Arabidopsis thaliana Gene Encoding a Phospholipid-Specific Inositol Polyphosphate 5-Phosphatase." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27884.

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Abstract:
The phosphatidylinositol signaling pathway utilizes inositol-containing second messengers to mediate signaling events. The enzymes that metabolize phosphoinositides can in some cases serve to terminate the signaling actions of phosphoinositides. The inositol polyphosphate 5-phosphatases (5PTases) comprise a large protein family that hydrolyzes 5-phosphates from a variety of inositol phosphate and phosphoinositide substrates. I have examined the substrate specificity of the At5PTase11 protein from the model plant, Arabidopsis thaliana. The At5PTase11 gene (At1g47510) encodes an active 5PTase enzyme that can dephosphorylate the phosphoinositide substrates phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P2], and phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3]. In addition, the At5PTase11 gene is regulated by abscisic acid, jasmonic acid, and auxin, suggesting a role for phosphoinositide action in these signal transduction pathways. To further delineate the function of At5PTase11 in Arabidopsis thaliana, two independent T-DNA insertion mutant lines were isolated (At5ptase11-1 and At5ptase11-2). Analysis of At5ptase11 mutant lines revealed that At5ptase11 mutant seeds germinate slower compared to wild-type seeds. Moreover, At5ptase11 mutant seedlings demonstrated less hypocotyl growth when grown in the dark. These results indicate that At5PTase11 is required for the early stages of seed germination and seedling growth. Since there are 15 predicted 5PTases in Arabidopsis thaliana, a group of 5PTases have been analyzed to identify the 5PTases with similar substrate selectivity. At5PTase1 (At1g34120), At5PTase2 (At4g18010) and At5PTase3 (At1g71710) have been found to hydrolyze all four potential substrates, inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4], PtdIns(4,5)P2, and PtdIns(3,4,5)P3. At5PTase7 (At2g32010) hydrolyzed PtdIns(4,5)P2, and PtdIns(3,4,5)P3 which is similar to the substrate selectivity of At5PTase11. In addition, At5PTase4 (At3g63240), and At5PTase9 (At2g01900) hydrolyzed only PtdIns(4,5)P2. These results indicate that there are different groups of Arabidopsis thaliana 5PTases based on the substrate selectivity. These results suggest that Arabidopsis thaliana 5PTases with similar substrate selectivity may have overlapping functions. In summary, the findings that At5PTase11 is a phospholipid-specific 5PTase and At5PTase11 functions in the early stages of seed germination and seedling growth indicate that 5PTases play important roles in plant growth and development.
Ph. D.
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Rahden, Vanessa Alexandra van [Verfasser], and Kerstin [Akademischer Betreuer] Kutsche. "Auswirkungen einer Depletion der humanen Inositol-Polyphosphat-5-Phosphatase OCRL auf Transportwege des Mannose-6-Phosphat-Rezeptors / Vanessa Alexandra van Rahden. Betreuer: Kerstin Kutsche." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2011. http://d-nb.info/102041944X/34.

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Book chapters on the topic "Inositol polyphosphate phosphatases"

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Hakim, Sandra, Micka C. Bertucci, Sarah E. Conduit, David L. Vuong, and Christina A. Mitchell. "Inositol Polyphosphate Phosphatases in Human Disease." In Phosphoinositides and Disease, 247–314. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-5025-8_12.

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Appleton, Kathryn M., Ian Cushman, Yuri K. Peterson, Balachandran Manavalan, Shaherin Basith, Sangdun Choi, Akihiro Kimura, et al. "Inositol Polyphosphate-5-Phosphatase, 145 kDa." In Encyclopedia of Signaling Molecules, 932. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_100651.

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"Inositol Polyphosphate-5-Phosphatase G." In Encyclopedia of Signaling Molecules, 2607. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_105331.

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"Inositol Polyphosphate-5-Phosphatase, 145 kDa." In Encyclopedia of Signaling Molecules, 2607. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_105332.

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Conference papers on the topic "Inositol polyphosphate phosphatases"

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Ceyhan, Yasemin, Manqi Zhang, and Irina U. Agoulnik. "Abstract 2497: Inositol Polyphosphate 4-Phosphatase Type-II B protects mice from benign prostatic hyperplasia." In Proceedings: AACR Annual Meeting 2021; April 10-15, 2021 and May 17-21, 2021; Philadelphia, PA. American Association for Cancer Research, 2021. http://dx.doi.org/10.1158/1538-7445.am2021-2497.

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Arvind, M., B. Pattnaik, N. Bhatraju, and A. Agrawal. "Inositol Polyphosphate 4-Phosphatase Type 1 A (INPP4A): A Shuttling Enzyme Plays Important Role in Pulmonary Fibrosis." In American Thoracic Society 2021 International Conference, May 14-19, 2021 - San Diego, CA. American Thoracic Society, 2021. http://dx.doi.org/10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a4230.

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Chen, Keyue, Gizem E. Genc, John F. Woolley, Daniel K. C. Lee, Roberto J. Botelho, and Leonardo Salmena. "Abstract P175: Investigating inositol polyphosphate-4-phosphatase, type II (INPP4B) signaling and role in acute myeloid leukemia." In Abstracts: AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; October 7-10, 2021. American Association for Cancer Research, 2021. http://dx.doi.org/10.1158/1535-7163.targ-21-p175.

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Jiang, Chen Chen, Meng Na Chi, Su Tang Guo, James S. Wilmott, Xiang Yun Guo, Xu Guang Yan, Chun Yan Wang, et al. "Abstract 4718: Inositol polyphosphate 4-phosphatase II activates PI3K/SGK3 signaling to promote proliferation of human melanoma cells." In Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-4718.

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Kondo, N., T.-S. Kim, Y. Wanifuchi, Y. Hato, T. Hisada, M. Nishimoto, S. Nishikawa, and T. Toyama. "Abstract P6-07-34: The prognostic impact of inositol polyphosphate 5-phosphatase PIPP (INPP5J) expression in breast cancer tissue." In Abstracts: 2016 San Antonio Breast Cancer Symposium; December 6-10, 2016; San Antonio, Texas. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.sabcs16-p6-07-34.

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Rijal, Sewa, Nhu-Y. Nugyen, Tse-Chieh Teh, Natalie K. Rynkiewicz, Nik Cummings, Lisa Ooms, Sharon Avery, et al. "Abstract 5283: Elucidating a novel role for inositol polyphosphate 4-phosphatase type II (INPP4B) in mediating chemoresistance in acute myeloid leukemia." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-5283.

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