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Yazgili AS, Ebstein F, Meiners S. The Proteasome Activator PA200/PSME4: An Emerging New Player in Health and Disease. Biomolecules 2022; 12:1150. [PMID: 36009043 PMCID: PMC9406137 DOI: 10.3390/biom12081150] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022] Open
Abstract
Proteasomes comprise a family of proteasomal complexes essential for maintaining protein homeostasis. Accordingly, proteasomes represent promising therapeutic targets in multiple human diseases. Several proteasome inhibitors are approved for treating hematological cancers. However, their side effects impede their efficacy and broader therapeutic applications. Therefore, understanding the biology of the different proteasome complexes present in the cell is crucial for developing tailor-made inhibitors against specific proteasome complexes. Here, we will discuss the structure, biology, and function of the alternative Proteasome Activator 200 (PA200), also known as PSME4, and summarize the current evidence for its dysregulation in different human diseases. We hereby aim to stimulate research on this enigmatic proteasome regulator that has the potential to serve as a therapeutic target in cancer.
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Affiliation(s)
- Ayse Seda Yazgili
- Comprehensive Pneumology Center (CPC), Helmholtz Center Munich, Max-Lebsche Platz 31, 81377 Munich, Germany
| | - Frédéric Ebstein
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Klinikum DZ/7, 17475 Greifswald, Germany
| | - Silke Meiners
- Research Center Borstel/Leibniz Lung Center, Parkallee 1-40, 23845 Borstel, Germany
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 23845 Sülfeld, Germany
- Institute of Experimental Medicine, Christian-Albrechts University Kiel, 24118 Kiel, Germany
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2
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Zubair M, Hamzah R, Griffin R, Ali N. Identification and functional characterization of multiple inositol polyphosphate phosphatase1 (Minpp1) isoform-2 in exosomes with potential to modulate tumor microenvironment. PLoS One 2022; 17:e0264451. [PMID: 35235602 PMCID: PMC8890658 DOI: 10.1371/journal.pone.0264451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/10/2022] [Indexed: 01/06/2023] Open
Abstract
Inositol polyphosphates (InsPs) play key signaling roles in diverse cellular functions, including calcium homeostasis, cell survival and death. Multiple inositol polyphosphate phosphatase 1 (Minpp1) affects the cellular levels of InsPs and cell functions. The Minpp1 is an endoplasmic reticulum (ER) resident but localizes away from its cytosolic InsPs substrates. The current study examines the heterogeneity of Minpp1 and the potential physiologic impact of Minpp1 isoforms, distinct motifs, subcellular distribution, and enzymatic potential. The NCBI database was used to analyze the proteome diversity of Minpp1 using bioinformatics tools. The analysis revealed that translation of three different Minpp1 variants resulted in three isoforms of Minpp1 of varying molecular weights. A link between the minpp1 variant-2 gene and ER-stress, using real-time PCR, suggests a functional similarity between minpp1 variant-1 and variant-2. A detailed study on motifs revealed Minpp1 isoform-2 is the only other isoform, besides isoform-1, that carries a phosphatase motif for InsPs hydrolysis but no ER-retention signal. The confocal microscopy revealed that the Minpp1 isoform-1 predominantly localized near the nucleus with a GRP-78 ER marker, while Minpp1 isoform-2 was scattered more towards the cell periphery where it co-localizes with the plasma membrane-destined multivesicular bodies biomarker CD63. MCF-7 cells were used to establish that Minpp1 isoform-2 is secreted into exosomes. Brefeldin A treatment resulted in overexpression of the exosome-associated Minpp1 isoform-2, suggesting its secretion via an unconventional route involving endocytic-generated vesicles and a link to ER stress. Results further demonstrated that the exosome-associated Minpp1 isoform-2 was enzymatically active. Overall, the data support the possibility that an extracellular form of enzymatically active Minpp1 isoform-2 mitigates any anti-proliferative actions of extracellular InsPs, thereby also impacting the makeup of the tumor microenvironment.
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Affiliation(s)
- Mohd Zubair
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR, United States of America
| | - Rabab Hamzah
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, United States of America
| | - Robert Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Nawab Ali
- Department of Biology, University of Arkansas at Little Rock, Little Rock, AR, United States of America
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3
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Ricaña CL, Dick RA. Inositol Phosphates and Retroviral Assembly: A Cellular Perspective. Viruses 2021; 13:v13122516. [PMID: 34960784 PMCID: PMC8703376 DOI: 10.3390/v13122516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.
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4
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Role of Inositols and Inositol Phosphates in Energy Metabolism. Molecules 2020; 25:molecules25215079. [PMID: 33139672 PMCID: PMC7663797 DOI: 10.3390/molecules25215079] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Recently, inositols, especially myo-inositol and inositol hexakisphosphate, also known as phytic acid or IP6, with their biological activities received much attention for their role in multiple health beneficial effects. Although their roles in cancer treatment and prevention have been extensively reported, interestingly, they may also have distinctive properties in energy metabolism and metabolic disorders. We review inositols and inositol phosphate metabolism in mammalian cells to establish their biological activities and highlight their potential roles in energy metabolism. These molecules are known to decrease insulin resistance, increase insulin sensitivity, and have diverse properties with importance from cell signaling to metabolism. Evidence showed that inositol phosphates might enhance the browning of white adipocytes and directly improve insulin sensitivity through adipocytes. In addition, inositol pyrophosphates containing high-energy phosphate bonds are considered in increasing cellular energetics. Despite all recent advances, many aspects of the bioactivity of inositol phosphates are still not clear, especially their effects on insulin resistance and alteration of metabolism, so more research is needed.
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5
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Nelson N, Wundenberg T, Lin H, Rehbach C, Horn S, Windhorst S, Jücker M. Characterization of the substrate specificity of the inositol 5-phosphatase SHIP1. Biochem Biophys Res Commun 2020; 524:366-370. [PMID: 32005521 DOI: 10.1016/j.bbrc.2020.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 01/02/2020] [Indexed: 10/25/2022]
Abstract
SHIP1 is an inositol 5-phosphatase which is well established for its tumour suppressor potential in leukaemia. Enzymatically, two SHIP1 substrates, PtdIns(3,4,5)P3 and Ins(1,3,4,5)P4 have been identified to date. Additional substrates were found for the homologue SHIP2. In this study, we identified new inositol phosphate (InsP) substrates of SHIP1 by metal dye detection high-performance liquid chromatography and compared the substrate profiles of SHIP1 and SHIP2. We were able to verify Ins(1,3,4,5)P4 as a substrate of SHIP1 and interestingly found Ins(1,2,3,4,5)P5 and Ins(2,3,4,5)P4 to be preferably used as substrates and Ins(1,4,5,6)P4 and Ins(2,4,5,6)P4 to be weak substrates. All of those except Ins(2,3,4,5)P4 are also known substrates of SHIP2 indicating a possible exclusive role of Ins(2,3,4,5)P4 hydrolysis for SHIP1 but not SHIP2 function.
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Affiliation(s)
- Nina Nelson
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Torsten Wundenberg
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | | | - Christoph Rehbach
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Stefan Horn
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany; Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Sabine Windhorst
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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Cruz A, Verma M, Wolozin B. The Pathophysiology of Tau and Stress Granules in Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1184:359-372. [PMID: 32096049 DOI: 10.1007/978-981-32-9358-8_26] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This chapter discusses the relationship between tau, RNA binding proteins and stress granules, which exhibit an intimate bidirectional relationship affecting the functions of both tau and the translational stress response. We describe how tau becomes hyperphosphorylated and oligomerized as part of an endogenous mechanism to promote the translational stress response through interaction with RNA binding proteins. Prior studies demonstrate that dysfunction of RNA binding proteins biology is sufficient to cause neurodegenerative diseases, such as amyotrophic lateral sclerosis and frontotemporal dementia. Emerging evidence indicates that tau-mediated neurodegeneration also occurs through a mechanism that is mediated by RNA binding proteins and the translational stress response. Discovery of the role of RNA metabolism in tauopathy opens a wide variety of novel therapeutic approaches. Multiple studies have already shown that approaches reducing the levels of selected RNA binding proteins or inhibiting the translational stress response can intervene in the pathophysiology of motoneuron diseases. Emerging studies show that reducing the levels of selected RNA binding proteins or inhibiting the translational stress response also reduces neurodegeneration in models of tauopathy and Aβ mediated degeneration. The combined impact of these studies indicate that RNA binding proteins and RNA metabolism represent a valuable new frontier for the investigation and treatment tauopathies.
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Affiliation(s)
- Anna Cruz
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Mamta Verma
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Benjamin Wolozin
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA. .,Department of Neurology, Boston University School of Medicine, Boston, MA, USA. .,Program in Neuroscience, Boston University School of Medicine, Boston, MA, USA.
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7
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Wundenberg T, Nalaskowski MM, Löser B, Fanick W, Hackl T, Fürnkranz U, Rehbach C, Lin H, Mayr GW. A novel 6-pyrophosphorylating IP6 kinase (IP6-6K) discovered in the protozoon Trichomonas vaginalis. Mol Biochem Parasitol 2019; 227:53-63. [DOI: 10.1016/j.molbiopara.2018.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
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8
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Looker HC, Merchant ML, Rane MJ, Nelson RG, Kimmel PL, Rovin BH, Klein JB, Mauer M. Urine inositol pentakisphosphate 2-kinase and changes in kidney structure in early diabetic kidney disease in type 1 diabetes. Am J Physiol Renal Physiol 2018; 315:F1484-F1492. [PMID: 30132343 DOI: 10.1152/ajprenal.00183.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the association of urine inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IPP2K) with the presence and progression of diabetic kidney disease (DKD) lesions. Urine IPP2K was measured at baseline by quantitative liquid chromatography-mass spectrometry in 215 participants from the Renin-Angiotensin System Study who had type 1 diabetes and were normoalbuminuric and normotensive with normal or increased glomerular filtration rate (GFR). Urine IPP2K was detectable in 166 participants. Participants with IPP2K below the limit of quantification (LOQ) were assigned concentrations of LOQ/√2. All concentrations were then standardized to urine creatinine (Cr) concentration. Kidney morphometric data were available from biopsies at baseline and after 5 yr. Relationships of IPP2K/Cr with morphometric variables were assessed by linear regression after adjustment for age, sex, diabetes duration, hemoglobin A1c, mean arterial pressure, treatment assignment, and, for longitudinal analyses, baseline structure. Baseline mean age was 29.7 yr, mean diabetes duration 11.2 yr, median albumin excretion rate 5.0 μg/min, and mean iohexol GFR 129 ml·min-1·1.73m-2. Higher IPP2K/Cr was associated with higher baseline peripheral glomerular total filtration surface density [Sv(PGBM/glom), tertile 3 vs. tertile 1 β = 0.527, P = 0.011] and with greater preservation of Sv(PGBM/glom) after 5 yr ( tertile 3 vs. tertile 1 β = 0.317, P = 0.013). Smaller increases in mesangial fractional volume ( tertile 3 vs. tertile 1 β = -0.578, P = 0.018) were observed after 5 yr in men with higher urine IPP2K/Cr concentrations. Higher urine IPP2K/Cr is associated with less severe kidney lesions at baseline and with preservation of kidney structure over 5 yr in individuals with type 1 diabetes and no clinical evidence of DKD at baseline.
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Affiliation(s)
- Helen C Looker
- Chronic Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases , Phoenix, Arizona
| | - Michael L Merchant
- Division of Nephrology and Hypertension, University of Louisville , Louisville, Kentucky
| | - Madhavi J Rane
- Department of Biochemistry and Molecular Genetics, University of Louisville , Louisville, Kentucky
| | - Robert G Nelson
- Chronic Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases , Phoenix, Arizona
| | - Paul L Kimmel
- Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases , Bethesda, Maryland
| | - Brad H Rovin
- Division of Nephrology, Ohio State University , Columbus, Ohio
| | - Jon B Klein
- Department of Medicine, University of Louisville , Louisville, Kentucky
| | - Michael Mauer
- Division of Renal Diseases and Hypertension, University of Minnesota , Minneapolis, Minnesota
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9
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Aponte-Santamaría C, Obser T, Grässle S, Oyen F, Budde U, Schneppenheim S, Baldauf C, Gräter F, Schneider SW, Schneppenheim R, Brehm MA, Huck V. von Willebrand disease type 2A phenotypes IIC, IID and IIE: A day in the life of shear-stressed mutant von Willebrand factor. Thromb Haemost 2017; 112:96-108. [DOI: 10.1160/th13-11-0902] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/11/2014] [Indexed: 11/05/2022]
Abstract
SummaryThe bleeding disorder von Willebrand disease (VWD) is caused by mutations of von Willebrand factor (VWF), a multimeric glycoprotein essential for platelet-dependent primary haemostasis. VWD type 2A–associated mutations each disrupt VWF biosynthesis and function at different stages, depending on the VWF domain altered by the mutation. These effects cause considerable heterogeneity in phenotypes and symptoms. To characterise the molecular mechanisms underlying the specific VWF deficiencies in VWD 2A/IIC, IID and IIE, we investigated VWF variants with patient-derived mutations either in the VWF pro-peptide or in domains D3 or CK. Additionally to static assays and molecular dynamics (MD) simulations we used microfluidic approaches to perform a detailed investigation of the shear-dependent function of VWD 2A mutants. For each group, we found distinct characteristics in their intracellular localisation visualising specific defects in biosynthesis which are correlated to respective multimer patterns. Using microfluidic assays we further determined shear flow-dependent characteristics in polymer-platelet-aggregate formation, platelet binding and string formation for all mutants. The phenotypes observed under flow conditions were not related to the mutated VWF domain. By MD simulations we further investigated how VWD 2A/IID mutations might alter the ability of VWF to form carboxy-terminal dimers. In conclusion, our study offers a comprehensive picture of shear-dependent and shear-independent dysfunction of VWD type 2A mutants. Furthermore, our microfluidic assay might open new possibilities for diagnosis of new VWD phenotypes and treatment choice for VWD patients with shear-dependent VWF dysfunctions that are currently not detectable by static tests.
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Franco-Echevarría E, Sanz-Aparicio J, Troffer-Charlier N, Poterszman A, González B. Crystallization and Preliminary X-Ray Diffraction Analysis of a Mammal Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase. Protein J 2017; 36:240-248. [PMID: 28429156 DOI: 10.1007/s10930-017-9717-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) is an enzyme that catalyses the formation of phytic acid (IP6) from IP5 and ATP. In mammals, IP6 is involved in multiple events such as DNA repair and mRNA edit and it is the precursor of inositol pyrophosphates, emerging compounds shown to have an essential role in apoptosis. In addition, IP5 2-K have functions in cells independently of its catalytic activity, for example in rRNA biogenesis. We pursue the structure determination of a mammal IP5 2-K by Protein Crystallography. For this purpose, we have designed protocols for recombinant expression and purification of Mus musculus IP5 2-K (mIP5 2-K). The recombinant protein has been expressed in two different hosts, E. coli and insect cells using the LSLt and GST fusion proteins, respectively. Both macromolecule preparations yielded crystals of similar quality. Best crystals diffracted to 4.3 Å (E. coli expression) and 4.0 Å (insect cells expression) maximum resolution. Both type of crystals belong to space group P212121 with an estimated solvent content compatible with the presence of two molecules per asymmetric unit. Gel filtration experiments are in agreement with this enzyme being a monomer. Crystallographic data analysis is currently undergoing.
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Affiliation(s)
- Elsa Franco-Echevarría
- Departament of Crystallography and Structural Biology, Insitute of Physical-Chemistry "Rocasolano," CSIC, Serrano 119, 28006, Madrid, Spain
| | - Julia Sanz-Aparicio
- Departament of Crystallography and Structural Biology, Insitute of Physical-Chemistry "Rocasolano," CSIC, Serrano 119, 28006, Madrid, Spain
| | - Nathalie Troffer-Charlier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, 1 rue Laurent Fries, BP 10142, 67404, Illkirch Cedex, France
| | - Arnaud Poterszman
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, 1 rue Laurent Fries, BP 10142, 67404, Illkirch Cedex, France
| | - Beatriz González
- Departament of Crystallography and Structural Biology, Insitute of Physical-Chemistry "Rocasolano," CSIC, Serrano 119, 28006, Madrid, Spain.
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11
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Franco-Echevarría E, Sanz-Aparicio J, Brearley CA, González-Rubio JM, González B. The crystal structure of mammalian inositol 1,3,4,5,6-pentakisphosphate 2-kinase reveals a new zinc-binding site and key features for protein function. J Biol Chem 2017; 292:10534-10548. [PMID: 28450399 PMCID: PMC5481561 DOI: 10.1074/jbc.m117.780395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/25/2017] [Indexed: 12/28/2022] Open
Abstract
Inositol 1,3,4,5,6-pentakisphosphate 2-kinases (IP5 2-Ks) are part of a family of enzymes in charge of synthesizing inositol hexakisphosphate (IP6) in eukaryotic cells. This protein and its product IP6 present many roles in cells, participating in mRNA export, embryonic development, and apoptosis. We reported previously that the full-length IP5 2-K from Arabidopsis thaliana is a zinc metallo-enzyme, including two separated lobes (the N- and C-lobes). We have also shown conformational changes in IP5 2-K and have identified the residues involved in substrate recognition and catalysis. However, the specific features of mammalian IP5 2-Ks remain unknown. To this end, we report here the first structure for a murine IP5 2-K in complex with ATP/IP5 or IP6. Our structural findings indicated that the general folding in N- and C-lobes is conserved with A. thaliana IP5 2-K. A helical scaffold in the C-lobe constitutes the inositol phosphate-binding site, which, along with the participation of the N-lobe, endows high specificity to this protein. However, we also noted large structural differences between the orthologues from these two eukaryotic kingdoms. These differences include a novel zinc-binding site and regions unique to the mammalian IP5 2-K, as an unexpected basic patch on the protein surface. In conclusion, our findings have uncovered distinct features of a mammalian IP5 2-K and set the stage for investigations into protein-protein or protein-RNA interactions important for IP5 2-K function and activity.
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Affiliation(s)
- Elsa Franco-Echevarría
- From the Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain and
| | - Julia Sanz-Aparicio
- From the Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain and
| | - Charles A Brearley
- the School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Juana M González-Rubio
- From the Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain and
| | - Beatriz González
- From the Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, 28006 Madrid, Spain and
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12
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Poblete-Durán N, Prades-Pérez Y, Vera-Otarola J, Soto-Rifo R, Valiente-Echeverría F. Who Regulates Whom? An Overview of RNA Granules and Viral Infections. Viruses 2016; 8:v8070180. [PMID: 27367717 PMCID: PMC4974515 DOI: 10.3390/v8070180] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
After viral infection, host cells respond by mounting an anti-viral stress response in order to create a hostile atmosphere for viral replication, leading to the shut-off of mRNA translation (protein synthesis) and the assembly of RNA granules. Two of these RNA granules have been well characterized in yeast and mammalian cells, stress granules (SGs), which are translationally silent sites of RNA triage and processing bodies (PBs), which are involved in mRNA degradation. This review discusses the role of these RNA granules in the evasion of anti-viral stress responses through virus-induced remodeling of cellular ribonucleoproteins (RNPs).
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Affiliation(s)
- Natalia Poblete-Durán
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Yara Prades-Pérez
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago 8330024, Chile.
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
| | - Fernando Valiente-Echeverría
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, 8389100, Chile.
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13
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Aditi, Glass L, Dawson TR, Wente SR. An amyotrophic lateral sclerosis-linked mutation in GLE1 alters the cellular pool of human Gle1 functional isoforms. Adv Biol Regul 2015; 62:25-36. [PMID: 26776475 DOI: 10.1016/j.jbior.2015.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/04/2015] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal late onset motor neuron disease with underlying cellular defects in RNA metabolism. In prior studies, two deleterious heterozygous mutations in the gene encoding human (h)Gle1 were identified in ALS patients. hGle1 is an mRNA processing modulator that requires inositol hexakisphosphate (IP6) binding for function. Interestingly, one hGLE1 mutation (c.1965-2A>C) results in a novel 88 amino acid C-terminal insertion, generating an altered protein. Like hGle1A, at steady state, the altered protein termed hGle1-IVS14-2A>C is absent from the nuclear envelope rim and localizes to the cytoplasm. hGle1A performs essential cytoplasmic functions in translation and stress granule regulation. Therefore, we speculated that the ALS disease pathology results from altered cellular pools of hGle1 and increased cytoplasmic hGle1 activity. GFP-hGle1-IVS14-2A>C localized to stress granules comparably to GFP-hGle1A, and rescued stress granule defects following siRNA-mediated hGle1 depletion. As described for hGle1A, overexpression of the hGle1-IVS14-2A>C protein also induced formation of larger SGs. Interestingly, hGle1A and the disease associated hGle1-IVS14-2A>C overexpression induced the formation of distinct cytoplasmic protein aggregates that appear similar to those found in neurodegenerative diseases. Strikingly, the ALS-linked hGle1-IVS14-2A>C protein also rescued mRNA export defects upon depletion of endogenous hGle1, acting in a potentially novel bi-functional manner. We conclude that the ALS-linked hGle1-c.1965-2A>C mutation generates a protein isoform capable of both hGle1A- and hGle1B-ascribed functions, and thereby uncoupled from normal mechanisms of hGle1 regulation.
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Affiliation(s)
- Aditi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Laura Glass
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - T Renee Dawson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Susan R Wente
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.
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14
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Jiao C, Summerlin M, Bruzik KS, Hanakahi L. Synthesis of Biotinylated Inositol Hexakisphosphate To Study DNA Double-Strand Break Repair and Affinity Capture of IP6-Binding Proteins. Biochemistry 2015; 54:6312-22. [PMID: 26397942 DOI: 10.1021/acs.biochem.5b00642] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inositol hexakisphosphate (IP6) is a soluble inositol polyphosphate, which is abundant in mammalian cells. Despite the participation of IP6 in critical cellular functions, few IP6-binding proteins have been characterized. We report on the synthesis, characterization, and application of biotin-labeled IP6 (IP6-biotin), which has biotin attached at position 2 of the myo-inositol ring via an aminohexyl linker. Like natural IP6, IP6-biotin stimulated DNA ligation by nonhomologous end joining (NHEJ) in vitro. The Ku protein is a required NHEJ factor that has been shown to bind IP6. We found that IP6-biotin could affinity capture Ku and other required NHEJ factors from human cell extracts, including the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), XRCC4, and XLF. Direct binding studies with recombinant proteins show that Ku is the only NHEJ factor with affinity for IP6-biotin. DNA-PKcs, XLF, and the XRCC4:ligase IV complex interact with Ku in cell extracts and likely interact indirectly with IP6-biotin. IP6-biotin was used to tether streptavidin to Ku, which inhibited NHEJ in vitro. These proof-of-concept experiments suggest that molecules like IP6-biotin might be used to molecularly target biologically important proteins that bind IP6. IP6-biotin affinity capture experiments show that numerous proteins specifically bind IP6-biotin, including casein kinase 2, which is known to bind IP6, and nucleolin. Protein binding to IP6-biotin is selective, as IP3, IP4, and IP5 did not compete for binding of proteins to IP6-biotin. Our results document IP6-biotin as a useful tool for investigating the role of IP6 in biological systems.
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Affiliation(s)
- Chensong Jiao
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago , 833 South Wood Street (M/C 781), Chicago, Illinois 60612, United States
| | - Matthew Summerlin
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago , Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, Illinois 61107, United States
| | - Karol S Bruzik
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago , 833 South Wood Street (M/C 781), Chicago, Illinois 60612, United States
| | - Leslyn Hanakahi
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago , Rockford Health Sciences Campus, 1601 Parkview Avenue, Rockford, Illinois 61107, United States
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15
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Phillippy BQ, Perera IY, Donahue JL, Gillaspy GE. Certain Malvaceae Plants Have a Unique Accumulation of myo-Inositol 1,2,4,5,6-Pentakisphosphate. PLANTS (BASEL, SWITZERLAND) 2015; 4:267-83. [PMID: 27135328 PMCID: PMC4844327 DOI: 10.3390/plants4020267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/19/2015] [Indexed: 01/28/2023]
Abstract
Methods used to quantify inositol phosphates in seeds lack the sensitivity and specificity necessary to accurately detect the lower concentrations of these compounds contained in the leaves of many plants. In order to measure inositol hexakisphosphate (InsP₆) and inositol pentakisphosphate (InsP₅) levels in leaves of different plants, a method was developed to concentrate and pre-purify these compounds prior to analysis. Inositol phosphates were extracted from leaves with diluted HCl and concentrated on small anion exchange columns. Reversed-phase solid phase extraction cartridges were used to remove compounds that give peaks that sometimes interfere during HPLC. The method permitted the determination of InsP₆ and InsP₅ concentrations in leaves as low as 10 µM and 2 µM, respectively. Most plants analyzed contained a high ratio of InsP₆ to InsP₅. In contrast, certain members of the Malvaceae family, such as cotton (Gossypium) and some hibiscus (Hibiscus) species, had a preponderance of InsP₅. Radiolabeling of cotton seedlings also showed increased amounts of InsP₅ relative to InsP₆. Why some Malvaceae species exhibit a reversal of the typical ratios of these inositol phosphates is an intriguing question for future research.
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Affiliation(s)
- Brian Q Phillippy
- Plant and Microbial Biology, Campus Box 7612, North Carolina State University, Raleigh, NC 27695, USA.
| | - Imara Y Perera
- Plant and Microbial Biology, Campus Box 7612, North Carolina State University, Raleigh, NC 27695, USA.
| | - Janet L Donahue
- Biochemistry, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA.
| | - Glenda E Gillaspy
- Biochemistry, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA.
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16
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Kuo HF, Chang TY, Chiang SF, Wang WD, Charng YY, Chiou TJ. Arabidopsis inositol pentakisphosphate 2-kinase, AtIPK1, is required for growth and modulates phosphate homeostasis at the transcriptional level. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:503-15. [PMID: 25155524 DOI: 10.1111/tpj.12650] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 05/07/2023]
Abstract
Inositol hexakisphosphate (IP6 ) provides a phosphorous reservoir in plant seeds; in addition, along with its biosynthesis intermediates and derivatives, IP6 also plays important roles in diverse developmental and physiological processes. Disruption of the Arabidopsis inositol pentakisphosphate 2-kinase coding gene AtIPK1 was previously shown to reduce IP6 content in vegetative tissues and affect phosphate (Pi) sensing. Here we show that AtIPK1 is required for sustaining plant growth, as null mutants are non-viable. An incomplete loss-of-function mutant, atipk1-1, exhibited disturbed Pi homeostasis and overaccumulated Pi as a consequence of increased Pi uptake activity and root-to-shoot Pi translocation. The atipk1-1 mutants also showed a Pi deficiency-like root system architecture with reduced primary root and enhanced lateral root growth. Transcriptome analysis indicated that a subset of Pi starvation-responsive genes was transcriptionally perturbed in the atipk1-1 mutants and the expression of multiple genes involved in Pi uptake, allocation, and remobilization was increased. Genetic and transcriptional analyses suggest that disturbance of Pi homeostasis caused by atipk1 mutation involved components in addition to PHR1(-like) transcription factors. Notably, the transcriptional increase of a number of Pi starvation-responsive genes in the atipk1-1 mutants is correlated with the reduction of histone variant H2A.Z occupation in chromatin. The myo-inositol-1-phosphate synthase mutants, atmips1 and atmips2 with comparable reduction in vegetative IP6 to that in the atipk1-1 mutants did not overaccumulate Pi, suggesting that Pi homeostasis modulated by AtIPK1 is not solely attributable to IP6 level. This study reveals that AtIPK1 has important roles in growth and Pi homeostasis.
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Affiliation(s)
- Hui-Fen Kuo
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
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17
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Mahboubi H, Stochaj U. Nucleoli and Stress Granules: Connecting Distant Relatives. Traffic 2014; 15:1179-93. [DOI: 10.1111/tra.12191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 06/30/2014] [Accepted: 06/30/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Hicham Mahboubi
- Department of Physiology; McGill University; 3655 Promenade Sir William Osler Montreal Quebec H3G 1Y6 Canada
| | - Ursula Stochaj
- Department of Physiology; McGill University; 3655 Promenade Sir William Osler Montreal Quebec H3G 1Y6 Canada
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18
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Thomas MP, Potter BVL. The enzymes of human diphosphoinositol polyphosphate metabolism. FEBS J 2013; 281:14-33. [PMID: 24152294 PMCID: PMC4063336 DOI: 10.1111/febs.12575] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/10/2013] [Accepted: 10/15/2013] [Indexed: 12/22/2022]
Abstract
Diphospho-myo-inositol polyphosphates have many roles to play, including roles in apoptosis, vesicle trafficking, the response of cells to stress, the regulation of telomere length and DNA damage repair, and inhibition of the cyclin-dependent kinase Pho85 system that monitors phosphate levels. This review focuses on the three classes of enzymes involved in the metabolism of these compounds: inositol hexakisphosphate kinases, inositol hexakisphosphate and diphosphoinositol-pentakisphosphate kinases and diphosphoinositol polyphosphate phosphohydrolases. However, these enzymes have roles beyond being mere catalysts, and their interactions with other proteins have cellular consequences. Through their interactions, the three inositol hexakisphosphate kinases have roles in exocytosis, diabetes, the response to infection, and apoptosis. The two inositol hexakisphosphate and diphosphoinositol-pentakisphosphate kinases influence the cellular response to phosphatidylinositol (3,4,5)-trisphosphate and the migration of pleckstrin homology domain-containing proteins to the plasma membrane. The five diphosphoinositol polyphosphate phosphohydrolases interact with ribosomal proteins and transcription factors, as well as proteins involved in membrane trafficking, exocytosis, ubiquitination and the proteasomal degradation of target proteins. Possible directions for future research aiming to determine the roles of these enzymes are highlighted.
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Affiliation(s)
- Mark P Thomas
- Department of Pharmacy & Pharmacology, University of Bath, UK
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19
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Gokhale NA, Zaremba A, Janoshazi AK, Weaver JD, Shears SB. PPIP5K1 modulates ligand competition between diphosphoinositol polyphosphates and PtdIns(3,4,5)P3 for polyphosphoinositide-binding domains. Biochem J 2013; 453:413-26. [PMID: 23682967 PMCID: PMC3931004 DOI: 10.1042/bj20121528] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We describe new signalling consequences for PPIP5K1 (diphosphoinositol pentakisphosphate kinase type 1)-mediated phosphorylation of InsP6 and 5-InsP7 to 1-InsP7 and InsP8. In NIH 3T3 cells, either hyperosmotic stress or receptor activation by PDGF (platelet-derived growth factor) promoted translocation of PPIP5K1 from the cytoplasm to the plasma membrane. The PBD1 (polyphosphoinositide-binding domain) in PPIP5K1 recapitulated that translocation. Mutagenesis of PBD1 to reduce affinity for PtdIns(3,4,5)P3 prevented translocation. Using surface plasmon resonance, we found that PBD1 association with vesicular PtdIns(3,4,5)P3 was inhibited by InsP6 and diphosphoinositol polyphosphates. However, the inhibition by PPIP5K1 substrates (IC50: 5-InsP7=5 μM and InsP6=7 μM) was substantially more potent than that of the PPIP5K1 products (IC50: InsP8=32 μM and 1-InsP7=43 μM). This rank order of ligand competition with PtdIns(3,4,5)P3 was also exhibited by the PH (pleckstrin homology) domains of Akt (also known as protein kinase B), GRP1 (general receptor for phosphoinositides 1) and SIN1 (stress-activated protein kinase-interaction protein 1). We propose that, in vivo, PH domain binding of InsP6 and 5-InsP7 suppresses inappropriate signalling ('noise') from stochastic increases in PtdIns(3,4,5)P3. That restraint may be relieved by localized depletion of InsP6 and 5-InsP7 at the plasma membrane following PPIP5K1 recruitment. We tested this hypothesis in insulin-stimulated L6 myoblasts, using mTOR (mechanistic/mammalian target of rapamycin)-mediated phosphorylation of Akt on Ser473 as a readout for SIN1-mediated translocation of mTORC (mTOR complex) 2 to the plasma membrane [Zoncu, Efeyan and Sabatini (2011) Nat. Rev. Mol. Cell Biol. 12, 21-35]. Knockdown of PPIP5K1 expression was associated with a 40% reduction in Ser473 phosphorylation. A common feature of PtdIns(3,4,5)P3-based signalling cascades may be their regulation by PPIP5K1.
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Affiliation(s)
- Nikhil A. Gokhale
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, U.S.A
| | - Angelika Zaremba
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, U.S.A
| | - Agnes K. Janoshazi
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, U.S.A
| | - Jeremy D. Weaver
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, U.S.A
| | - Stephen B. Shears
- Inositol Signaling Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, U.S.A
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20
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Barker CJ, Berggren PO. New Horizons in Cellular Regulation by Inositol Polyphosphates: Insights from the Pancreaticβ-Cell. Pharmacol Rev 2013; 65:641-69. [DOI: 10.1124/pr.112.006775] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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21
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Brehm MA, Wundenberg T, Williams J, Mayr GW, Shears SB. A non-catalytic role for inositol 1,3,4,5,6-pentakisphosphate 2-kinase in the synthesis of ribosomal RNA. J Cell Sci 2012. [PMID: 23203802 DOI: 10.1242/jcs.110031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fundamental to the life and destiny of every cell is the regulation of protein synthesis through ribosome biogenesis, which begins in the nucleolus with the production of ribosomal RNA (rRNA). Nucleolar organization is a highly dynamic and tightly regulated process; the structural factors that direct nucleolar assembly and disassembly are just as important in controlling rRNA synthesis as are the catalytic activities that synthesize rRNA. Here, we report that a signaling enzyme, inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5K) is also a structural component in the nucleolus. We demonstrate that IP5K has functionally significant interactions with three proteins that regulate rRNA synthesis: protein kinase CK2, TCOF1 and upstream-binding-factor (UBF). Through molecular modeling and mutagenic studies, we identified an Arg-Lys-Lys tripeptide located on the surface of IP5K that mediates its association with UBF. Nucleolar IP5K spatial dynamics were sensitive to experimental procedures (serum starvation or addition of actinomycin D) that inhibited rRNA production. We show that IP5K makes stoichiometrically sensitive contributions to the architecture of the nucleoli in intact cells, thereby influencing the degree of rRNA synthesis. Our study adds significantly to the biological significance of IP5K; previously, it was the kinase activity of this protein that had attracted attention. Our demonstration that IP5K 'moonlights' as a molecular scaffold offers an unexpected new example of how the biological sophistication of higher organisms can arise from gene products acquiring multiple functions, rather than by an increase in gene number.
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Affiliation(s)
- Maria A Brehm
- Inositol Signaling Section, Laboratory of Signal Transduction, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
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22
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Shears SB, Ganapathi SB, Gokhale NA, Schenk TMH, Wang H, Weaver JD, Zaremba A, Zhou Y. Defining signal transduction by inositol phosphates. Subcell Biochem 2012; 59:389-412. [PMID: 22374098 PMCID: PMC3925325 DOI: 10.1007/978-94-007-3015-1_13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ins(1,4,5)P(3) is a classical intracellular messenger: stimulus-dependent changes in its levels elicits biological effects through its release of intracellular Ca(2+) stores. The Ins(1,4,5)P(3) response is "switched off" by its metabolism to a range of additional inositol phosphates. These metabolites have themselves come to be collectively described as a signaling "family". The validity of that latter definition is critically examined in this review. That is, we assess the strength of the hypothesis that Ins(1,4,5)P(3) metabolites are themselves "classical" signals. Put another way, what is the evidence that the biological function of a particular inositol phosphate depends upon stimulus dependent changes in its levels? In this assessment, examples of an inositol phosphate acting as a cofactor (i.e. its function is not stimulus-dependent) do not satisfy our signaling criteria. We conclude that Ins(3,4,5,6)P(4) is, to date, the only Ins(1,4,5)P(3) metabolite that has been validated to act as a second messenger.
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Key Words
- adenosine deaminase
- akt
- β-cells
- calcium
- camp
- camkii
- chloride channel
- clc3
- compartmentalization
- dna repair
- endosomes
- erk
- frizzled receptor
- gap1ip4bp
- mrna export
- ins(1,4,5)p3
- ins(1,4,5)p4 receptor
- ins(1,3,4)p3
- ins(1,3,4,5)p4
- ins(1,3,4,5)p4 receptor
- ins(1,4,5,6)p4
- ins(3,4,5,6)p4
- ins(1,3,4,5,6)p5
- insp6
- insulin
- ipmk
- ipk2
- ip5k
- itp
- itpk1
- itpkb
- lymphocytes
- ku
- neutrophils
- protein phosphatase
- ptdins(4,5)p2
- ptdins(3,4,5)p3
- ph domain
- pten
- rasa3
- transcription
- wnt ligand
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Affiliation(s)
- Stephen B Shears
- Inositol Signaling Section, Laboratory of Signal Transduction, NIEHS, NIH, DHHS, Research Triangle Park, 27709, NC, USA, USA,
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23
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Löser B, Nalaskowski MM, Fanick W, Lin H, Tannich E, Mayr GW. A novel Entamoeba histolytica inositol phosphate kinase catalyzes the formation of 5PP-Ins(1,2,3,4,6)P(5). Mol Biochem Parasitol 2011; 181:49-52. [PMID: 22001062 DOI: 10.1016/j.molbiopara.2011.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/15/2011] [Accepted: 09/20/2011] [Indexed: 11/28/2022]
Abstract
The parasitic protozoan Entamoeba histolytica is able to invade human tissues by secreting proteolytic enzymes. This secretion is regulated by inositol phosphate-mediated Ca(2+) release from internal stores. To further investigate the inositol phosphate metabolism of Entamoeba histolytica four putative inositol phosphate kinase genes (ehipk1-4) were identified and their expression analyzed by real-time quantitative PCR using RNA of trophozoites. Furthermore inositol phosphate kinase EhIPK1 was recombinantly expressed, purified and enzymatically characterized. Its main activity is the conversion of InsP(6) to 5PP-Ins(1,2,3,4,6)P(5), one of the main inositol phosphates found in Entamoeba histolytica. Remarkably, EhIPK1 possesses several additional enzymatic activities, e.g. the phosphorylation of the Ca(2+)-releasing second messenger Ins(1,4,5)P(3).We were able to identify several compounds with inhibitory potential against EhIPK1. Because of the important role of inositol phosphates in the invasion of human tissues by Entamoeba histolytica, inositol phosphate metabolizing enzymes are interesting targets for novel therapeutic approaches.
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Affiliation(s)
- Benjamin Löser
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
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Receptor-dependent compartmentalization of PPIP5K1, a kinase with a cryptic polyphosphoinositide binding domain. Biochem J 2011; 434:415-26. [PMID: 21222653 DOI: 10.1042/bj20101437] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The inositol pyrophosphates are multifunctional signalling molecules. One of the families of enzymes that synthesize the inositol pyrophosphates are the Vip1/PPIP5Ks (PP-InsP5 kinases). The kinase domains in Vip1/PPIP5Ks have been mapped to their N-terminus. Each of these proteins also possess a phosphatase-like domain of unknown significance. In the present study, we show that this phosphatase-like domain is not catalytically active. Instead, by using SPR (surface plasmon resonance) to study protein binding to immobilized lipid vesicles, we show that this domain is specialized for binding PtdIns(3,4,5)P3 (PPIP5K1 K(d)=96 nM; PPIP5K2 K(d)=705 nM). Both PtdIns(3,4)P2 and PtdIns(4,5)P2 are significantly weaker ligands, and no significant binding of PtdIns(3,5)P2 was detected. We confirm the functional importance of this domain in inositol lipid binding by site-directed mutagenesis. We present evidence that the PtdIns(3,4,5)P3-binding domain is an unusual hybrid, in which a partial PH (pleckstrin homology) consensus sequence is spliced into the phosphatase-like domain. Agonist-dependent activation of the PtdIns 3-kinase pathway in NIH 3T3 cells drives translocation of PPIP5K1 from the cytosol to the plasma membrane. We have therefore demonstrated receptor-regulated compartmentalization of inositol pyrophosphate synthesis in mammalian cells.
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Thomas MG, Loschi M, Desbats MA, Boccaccio GL. RNA granules: the good, the bad and the ugly. Cell Signal 2011; 23:324-34. [PMID: 20813183 PMCID: PMC3001194 DOI: 10.1016/j.cellsig.2010.08.011] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 08/20/2010] [Indexed: 12/13/2022]
Abstract
Processing bodies (PBs) and Stress Granules (SGs) are the founding members of a new class of RNA granules, known as mRNA silencing foci, as they harbour transcripts circumstantially excluded from the translationally active pool. PBs and SGs are able to release mRNAs thus allowing their translation. PBs are constitutive, but respond to stimuli that affect mRNA translation and decay, whereas SGs are specifically induced upon cellular stress, which triggers a global translational silencing by several pathways, including phosphorylation of the key translation initiation factor eIF2alpha, and tRNA cleavage among others. PBs and SGs with different compositions may coexist in a single cell. These macromolecular aggregates are highly conserved through evolution, from unicellular organisms to vertebrate neurons. Their dynamics is regulated by several signaling pathways, and depends on microfilaments and microtubules, and the cognate molecular motors myosin, dynein, and kinesin. SGs share features with aggresomes and related aggregates of unfolded proteins frequently present in neurodegenerative diseases, and may play a role in the pathology. Virus infections may induce or impair SG formation. Besides being important for mRNA regulation upon stress, SGs modulate the signaling balancing apoptosis and cell survival. Finally, the formation of Nuclear Stress Bodies (nSBs), which share components with SGs, and the assembly of additional cytosolic aggregates containing RNA -the UV granules and the Ire1 foci-, all of them induced by specific cell damage factors, contribute to cell survival.
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Key Words
- atxn2, ataxin-2
- bicd, bicaudal d
- cbp, creb binding protein
- cpeb, cytoplasmic polyadenylation element binding protein
- dhc, dynein heavy chain
- dic, dynein intermediate chain
- fak, focal adhesion kinase
- fus/tls/hnrnp p2, fused in sarcoma
- g3bp, ras-gap sh3 domain binding protein
- gcn2, general control nonderepressible-2
- grb7, growth factor receptor-bound protein 7
- hap, hnrnp a1 interacting protein
- hdac6, histone deacetylase 6
- hri, heme-regulated inhibitor
- hsf, heat shock transcription factor
- khc, kinesin heavy chain
- klc, kinesin light chain
- mln51, metastatic lymph node 51
- nmd, nonsense mediated decay
- nsbs, nuclear stress bodies
- ogfod1, 2–14 oxoglutarate and fe(ii)-dependent oxygenase domain containing 1
- pb, processing body
- perk, pancreatic endoplasmic reticulum eif2alpha kinase
- pkr/eif2ak2, double stranded rna-dependent protein kinase
- pp1, protein phosphatase 1
- prp, prion protein
- rbp, rna binding protein
- rnp, ribonucleoparticle
- sam68, src associated in mitosis 68 kda
- member of star, signal transducer and activator of rna
- sca, spinocerebellar ataxia
- sg, stress granule
- sma, spinal muscular atrophy
- fmrp, fragile x mental retardation protein
- smn, survival of motor neuron
- tdp43, tar dna-binding protein 43
- traf2, tnf receptor associated factor 2
- uvgs, uv rna granules
- processing body
- stress granule
- kinesin
- dynein
- bicaudal d
- aggresome
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Affiliation(s)
- María Gabriela Thomas
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - Mariela Loschi
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
| | - María Andrea Desbats
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Instituto Leloir, Av. Patricias Argentinas 435, C1405 BWE Buenos Aires, Argentina
- CONICET, Buenos Aires, Argentina
- University of Buenos Aires
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26
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Merchant ML, Klein JB. Proteomic discovery of diabetic nephropathy biomarkers. Adv Chronic Kidney Dis 2010; 17:480-6. [PMID: 21044770 PMCID: PMC2987606 DOI: 10.1053/j.ackd.2010.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 09/14/2010] [Indexed: 02/07/2023]
Abstract
Diabetes mellitus (DM) is a complex systemic disease with complications that result from both genetic predisposition and dysregulated metabolic pathways. It is highly prevalent, with current estimates stating that there are 17.5 million diagnosed and 6.6 million undiagnosed patients with diabetes in the United States. DM and its complications impose a significant societal and economic burden. The medical costs of common microvascular complications of uncontrolled DM, diabetic nephropathy (DN) and diabetic retinopathy account for 29% and 15%, respectively, of the $116 billion worth expenditures associated with diabetes. A substantial gap exists in our knowledge related to the understanding of these complications. To advance therapy and decrease the societal burden of DM, there is a clear need for biomarkers that can diagnose DN at an early stage and predict its course. Proteomics has evolved into a high-throughput, analytical discipline used to analyze complex biological data sets. These open-ended, hypothesis-generating approaches, when appropriately designed and interpreted, are well suited to the study of the pathogenic mechanisms of diabetic microvascular disease and the identification of biomarkers of DN. In this study, we review the evolving role played by proteomics in expanding our understanding of the diagnosis and pathogenesis of DN.
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Shears SB, Gokhale NA, Wang H, Zaremba A. Diphosphoinositol polyphosphates: what are the mechanisms? ACTA ACUST UNITED AC 2010; 51:13-25. [PMID: 21035493 DOI: 10.1016/j.advenzreg.2010.09.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 09/17/2010] [Indexed: 12/30/2022]
Abstract
In countries where adulthood is considered to be attained at age eighteen, 2011 can be the point at which the diphosphoinositol polyphosphates might formally be described as "coming of age", since these molecules were first fully defined in 1993 (Menniti et al., 1993; Stephens et al., 1993b). But from a biological perspective, these polyphosphates cannot quite be considered to have matured into the status of being independently-acting intracellular signals. This review has discussed several of the published proposals for mechanisms by which the diphosphoinositol polyphosphates might act. We have argued that all of these hypotheses need further development.We also still do not know a single molecular mechanism by which a change in the levels of a particular diphosphoinositol polyphosphate can be controlled. Yet, despite all these gaps in our understanding, there is an enduring anticipation that these molecules have great potential in the signaling field. Reflecting our expectations of all teenagers, it should be our earnest hope that in the near future the diphosphoinositol polyphosphates will finally grow up.
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Affiliation(s)
- Stephen B Shears
- Inositol Signaling Group, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
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Chaudhary K, Phadke G, Nistala R, Weidmeyer CE, McFarlane SI, Whaley-Connell A. The emerging role of biomarkers in diabetic and hypertensive chronic kidney disease. Curr Diab Rep 2010; 10:37-42. [PMID: 20425065 DOI: 10.1007/s11892-009-0080-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Currently used measures to assess kidney function and injury are largely inadequate. Markers such as serum creatinine, formulas to estimate glomerular filtration rate, cystatin C, and proteinuria largely identify an underlying disease process that is well established. Thus, there has been a recent effort to identify new biomarkers that reflect kidney function, early injury, and/or repair that ultimately can relate to progression or regression of damage. Several biomarkers emerged recently that are able to detect kidney damage earlier than is currently possible with traditional biomarkers such as serum creatinine and proteinuria. Identification of urine biomarkers has proven to be beneficial in recent years because of ease of handling, stability, and the ability to standardize the various markers to creatinine or other peptides generally already present in the urine. Recent markers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and podocin have garnered a lot of attention. The emergence of these and other biomarkers is largely because of the evolution of novel genomic and proteomic applications in investigations of acute kidney injury and chronic kidney disease. In this article, we focus on the applications of these biomarkers in disease.
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Affiliation(s)
- Kunal Chaudhary
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Missouri-Columbia School of Medicine, CE417, DC043.0, Five Hospital Drive, Columbia, MO 65212, USA
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Kedersha N, Anderson P. Regulation of translation by stress granules and processing bodies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 90:155-85. [PMID: 20374741 PMCID: PMC7102815 DOI: 10.1016/s1877-1173(09)90004-7] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stress necessitates rapid reprogramming of translation in order to facilitate an adaptive response and promote survival. Cytoplasmic stress granules (SGs) and processing bodies (PBs) are dynamic structures that form in response to stress-induced translational arrest. PBs are linked to mRNA silencing and decay, while SGs are more closely linked to translation and the sorting of specific mRNAs for different fates. While they share some components and can interact physically, SGs and PBs are regulated independently, house separate functions, and contain unique markers. SG formation is associated with numerous disease states, and the expanding list of SG-associated proteins integrates SG formation with other processes such as transcription, splicing, and survival. Growing evidence suggests that SG assembly is initiated by translational arrest, and mediates cross talk with many other signaling pathways.
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Affiliation(s)
- Nancy Kedersha
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Merchant ML, Perkins BA, Boratyn GM, Ficociello LH, Wilkey DW, Barati MT, Bertram CC, Page GP, Rovin BH, Warram JH, Krolewski AS, Klein JB. Urinary peptidome may predict renal function decline in type 1 diabetes and microalbuminuria. J Am Soc Nephrol 2009; 20:2065-74. [PMID: 19643930 DOI: 10.1681/asn.2008121233] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
One third of patients with type 1 diabetes and microalbuminuria experience an early, progressive decline in renal function that leads to advanced stages of chronic kidney disease and ESRD. We hypothesized that the urinary proteome may distinguish between stable renal function and early renal function decline among patients with type 1 diabetes and microalbuminuria. We followed patients with normal renal function and microalbuminuria for 10 to 12 yr and classified them into case patients (n = 21) with progressive early renal function decline and control subjects (n = 40) with stable renal function. Using liquid chromatography matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we identified three peptides that decreased in the urine of patients with early renal function decline [fragments of alpha1(IV) and alpha1(V) collagens and tenascin-X] and three peptides that increased (fragments of inositol pentakisphosphate 2-kinase, zona occludens 3, and FAT tumor suppressor 2). In renal biopsies from patients with early nephropathy from type 1 diabetes, we observed increased expression of inositol pentakisphosphate 2-kinase, which was present in granule-like cytoplasmic structures, and zona occludens 3. These results indicate that urinary peptide fragments reflect changes in expression of intact protein in the kidney, suggesting new potential mediators of diabetic nephropathy and candidate biomarkers for progressive renal function decline.
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Abstract
The diphosphoinositol polyphosphates ("inositol pyrophosphates") are a specialized subgroup of the inositol phosphate signaling family. This review proposes that many of the current data concerning the metabolic turnover and biological effects of the diphosphoinositol polyphosphates are linked by a common theme: these polyphosphates act as metabolic messengers. This review will also discuss the latest proposals concerning possible molecular mechanisms of action of this intriguing class of molecules.
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Affiliation(s)
- Stephen B Shears
- Inositide Signaling Group, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
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Ins(1,4,5)P3 3-kinase-A overexpression induces cytoskeletal reorganization via a kinase-independent mechanism. Biochem J 2008; 414:407-17. [DOI: 10.1042/bj20080630] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present study, effects of increased IP3K-A [Ins(1,4,5)P3 3-kinase-A] expression were analysed. H1299 cells overexpressing IP3K-A formed branching protrusions, and under three-dimensional culture conditions, they exhibited a motile fibroblast-like morphology. They lost the ability to form actin stress fibres and showed increased invasive migration in vitro. Furthermore, expression levels of the mesenchymal marker proteins vimentin and N-cadherin were increased. The enzymatic function of IP3K-A is to phosphorylate the calcium-mobilizing second messenger Ins(1,4,5)P3 to (Ins(1,3,4,5)P4. Accordingly, cells overexpressing IP3K-A showed reduced calcium release and altered concentrations of InsPs, with decreasing concentrations of Ins(1,4,5)P3, InsP6 and Ins(1,2,3,4,5)P5, and increasing concentrations of Ins(1,3,4,5)P4. However, IP3K-A-induced effects on cell morphology do not seem to be dependent on enzyme activity, since a protein devoid of enzyme activity also induced the formation of branching protrusions. Therefore we propose that the morphological changes induced by IP3K-A are mediated by non-enzymatic activities of the protein.
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Anderson P, Kedersha N. Stress granules: the Tao of RNA triage. Trends Biochem Sci 2008; 33:141-50. [PMID: 18291657 DOI: 10.1016/j.tibs.2007.12.003] [Citation(s) in RCA: 839] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 12/07/2007] [Accepted: 12/11/2007] [Indexed: 12/12/2022]
Abstract
Cytoplasmic RNA structures such as stress granules (SGs) and processing bodies (PBs) are functional byproducts of mRNA metabolism, sharing substrate mRNA, dynamic properties and many proteins, but also housing separate components and performing independent functions. Each can exist independently, but when coordinately induced they are often tethered together in a cytosolic dance. Although both self-assemble in response to stress-induced perturbations in translation, several recent reports reveal novel proteins and RNAs that are components of these structures but also perform other cellular functions. Proteins that mediate splicing, transcription, adhesion, signaling and development are all integrated with SG and PB assembly. Thus, these ephemeral bodies represent more than just the dynamic sorting of mRNA between translation and decay.
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Affiliation(s)
- Paul Anderson
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, One Jimmy Fund Way, Boston, MA 02115, USA.
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Yang L, Reece JM, Cho J, Bortner CD, Shears SB. The nucleolus exhibits an osmotically regulated gatekeeping activity that controls the spatial dynamics and functions of nucleolin. J Biol Chem 2008; 283:11823-31. [PMID: 18299322 PMCID: PMC2431058 DOI: 10.1074/jbc.m800308200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 02/15/2008] [Indexed: 12/17/2022] Open
Abstract
We demonstrate that physiologically relevant perturbations in the osmotic environment rheostatically regulate a gatekeeping function for the nucleolus that controls the spatial dynamics and functions of nucleolin. HeLa cells and U2-OS osteosarcoma cells were osmotically challenged with 100-200 mm sorbitol, and the intranuclear distribution of nucleolin was monitored by confocal microscopy. Nucleolin that normally resides in the innermost fibrillar core of the nucleolus, where it assists rDNA transcription and replication, was expelled within 30 min of sorbitol addition. The nucleolin was transferred into the nucleoplasm, but it distributed there non-uniformly; locally high levels accumulated in 4',6-diamidino-2-phenylindole-negative zones containing euchromatic (transcriptionally active) DNA. Inositol pyrophosphates also responded within 30 min of hyperosmotic stress: levels of bisdiphosphoinositol tetrakisphosphate increased 6-fold, and this was matched by decreased levels of its precursor, diphosphoinositol pentakisphosphate. Such fluctuations in inositol pyrophosphate levels are of considerable interest, because, according to previously published in vitro data, they regulate the degree of phosphorylation of nucleolin through a novel kinase-independent phosphotransferase reaction ( Saiardi, A., Bhandari, A., Resnick, R., Cain, A., Snowman, A. M., and Snyder, S. H. (2004) Science 306, 2101-2105 ). However, by pharmacologically intervening in inositol pyrophosphate metabolism, we found that it did not supervise the osmotically driven switch in the biological activities of nucleolin in vivo.
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Affiliation(s)
- Ling Yang
- Inositol Signaling Group and
the Molecular Endocrinology Group,
NIEHS, National Institutes of Health, Department of Health and Human Services,
Research Triangle Park, North Carolina 27709 and
Reecent Technologies, LLC, Durham,
North Carolina 27713
| | - Jeff M. Reece
- Inositol Signaling Group and
the Molecular Endocrinology Group,
NIEHS, National Institutes of Health, Department of Health and Human Services,
Research Triangle Park, North Carolina 27709 and
Reecent Technologies, LLC, Durham,
North Carolina 27713
| | - Jaiesoon Cho
- Inositol Signaling Group and
the Molecular Endocrinology Group,
NIEHS, National Institutes of Health, Department of Health and Human Services,
Research Triangle Park, North Carolina 27709 and
Reecent Technologies, LLC, Durham,
North Carolina 27713
| | - Carl D. Bortner
- Inositol Signaling Group and
the Molecular Endocrinology Group,
NIEHS, National Institutes of Health, Department of Health and Human Services,
Research Triangle Park, North Carolina 27709 and
Reecent Technologies, LLC, Durham,
North Carolina 27713
| | - Stephen B. Shears
- Inositol Signaling Group and
the Molecular Endocrinology Group,
NIEHS, National Institutes of Health, Department of Health and Human Services,
Research Triangle Park, North Carolina 27709 and
Reecent Technologies, LLC, Durham,
North Carolina 27713
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Berggren PO, Barker CJ. A key role for phosphorylated inositol compounds in pancreatic β-cell stimulus–secretion coupling. ACTA ACUST UNITED AC 2008; 48:276-94. [DOI: 10.1016/j.advenzreg.2007.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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