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Kanemaru K, Nakamura Y. Activation Mechanisms and Diverse Functions of Mammalian Phospholipase C. Biomolecules 2023; 13:915. [PMID: 37371495 DOI: 10.3390/biom13060915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Phospholipase C (PLC) plays pivotal roles in regulating various cellular functions by metabolizing phosphatidylinositol 4,5-bisphosphate in the plasma membrane. This process generates two second messengers, inositol 1,4,5-trisphosphate and diacylglycerol, which respectively regulate the intracellular Ca2+ levels and protein kinase C activation. In mammals, six classes of typical PLC have been identified and classified based on their structure and activation mechanisms. They all share X and Y domains, which are responsible for enzymatic activity, as well as subtype-specific domains. Furthermore, in addition to typical PLC, atypical PLC with unique structures solely harboring an X domain has been recently discovered. Collectively, seven classes and 16 isozymes of mammalian PLC are known to date. Dysregulation of PLC activity has been implicated in several pathophysiological conditions, including cancer, cardiovascular diseases, and neurological disorders. Therefore, identification of new drug targets that can selectively modulate PLC activity is important. The present review focuses on the structures, activation mechanisms, and physiological functions of mammalian PLC.
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Affiliation(s)
- Kaori Kanemaru
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
| | - Yoshikazu Nakamura
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
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2
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Mongiorgi S, De Stefano A, Ratti S, Indio V, Astolfi A, Casalin I, Pellagatti A, Paolini S, Parisi S, Cavo M, Pession A, McCubrey JA, Suh PG, Manzoli L, Boultwood J, Finelli C, Cocco L, Follo MY. A miRNA screening identifies miR-192-5p as associated with response to azacitidine and lenalidomide therapy in myelodysplastic syndromes. Clin Epigenetics 2023; 15:27. [PMID: 36803590 PMCID: PMC9940408 DOI: 10.1186/s13148-023-01441-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 02/06/2023] [Indexed: 02/22/2023] Open
Abstract
BACKGROUND miRNAs are small non-coding RNAs that regulate gene expression and are linked to cancer development and progression. miRNA profiles are currently studied as new prognostic factors or therapeutic perspectives. Among hematological cancers, myelodysplastic syndromes at higher risk of evolution into acute myeloid leukemia are treated with hypomethylating agents, like azacitidine, alone or in combination with other drugs, such as lenalidomide. Recent data showed that, during azacitidine and lenalidomide therapy, the concurrent acquisition of specific point mutations affecting inositide signalling pathways is associated with lack or loss of response to therapy. As these molecules are implicated in epigenetic processes, possibly involving miRNA regulation, and in leukemic progression, through the regulation of proliferation, differentiation and apoptosis, here we performed a new miRNA expression analysis of 26 high-risk patients with myelodysplastic syndromes treated with azacitidine and lenalidomide at baseline and during therapy. miRNA array data were processed, and bioinformatic results were correlated with clinical outcome to investigate the translational relevance of selected miRNAs, while the relationship between selected miRNAs and specific molecules was experimentally tested and proven. RESULTS Patients' overall response rate was 76.9% (20/26 cases): complete remission (5/26, 19.2%), partial remission (1/26, 3.8%), marrow complete remission (2/26, 7.7%), hematologic improvement (6/26, 23.1%), hematologic improvement with marrow complete remission (6/26, 23.1%), whereas 6/26 patients (23.1%) had a stable disease. miRNA paired analysis showed a statistically significant up-regulation of miR-192-5p after 4 cycles of therapy (vs baseline), that was confirmed by real-time PCR analyses, along with an involvement of BCL2, that was proven to be a miR-192-5p target in hematopoietic cells by luciferase assays. Furthermore, Kaplan-Meier analyses showed a significant correlation between high levels of miR-192-5p after 4 cycles of therapy and overall survival or leukemia-free survival, that was stronger in responders, as compared with patients early losing response and non-responders. CONCLUSIONS This study shows that high levels of miR-192-5p are associated with higher overall survival and leukemia-free survival in myelodysplastic syndromes responding to azacitidine and lenalidomide. Moreover, miR-192-5p specifically targets and inhibits BCL2, possibly regulating proliferation and apoptosis and leading to the identification of new therapeutic targets.
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Affiliation(s)
- Sara Mongiorgi
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy
| | - Alessia De Stefano
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy
| | - Stefano Ratti
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy
| | - Valentina Indio
- "Giorgio Prodi" Cancer Research Center, University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Annalisa Astolfi
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Irene Casalin
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy
| | - Andrea Pellagatti
- Blood Cancer UK Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, OX3 9DU, UK
| | - Stefania Paolini
- IRCCS - Azienda Ospedaliero-Universitaria di Bologna, Institute of Hematology " L. e A. Seràgnoli", University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Sarah Parisi
- IRCCS - Azienda Ospedaliero-Universitaria di Bologna, Institute of Hematology " L. e A. Seràgnoli", University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Michele Cavo
- IRCCS - Azienda Ospedaliero-Universitaria di Bologna, Institute of Hematology " L. e A. Seràgnoli", University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Andrea Pession
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Division of Pediatrics, University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27858, USA
| | - Pann-Ghill Suh
- Korea Brain Research Institute, Daegu, 41062, South Korea
| | - Lucia Manzoli
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy
| | - Jacqueline Boultwood
- Blood Cancer UK Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, OX3 9DU, UK
| | - Carlo Finelli
- IRCCS - Azienda Ospedaliero-Universitaria di Bologna, Institute of Hematology " L. e A. Seràgnoli", University of Bologna, Via Massarenti 9, 40138, Bologna, Italy
| | - Lucio Cocco
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy.
| | - Matilde Y Follo
- Cellular Signalling Laboratory, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio 48, 40126, Bologna, Italy.
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De Stefano A, Marvi MV, Fazio A, McCubrey JA, Suh PG, Ratti S, Ramazzotti G, Manzoli L, Cocco L, Follo MY. Advances in MDS/AML and inositide signalling. Adv Biol Regul 2023; 87:100955. [PMID: 36706610 DOI: 10.1016/j.jbior.2023.100955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/18/2023] [Indexed: 01/22/2023]
Abstract
Aberrant signaling pathways regulating proliferation and differentiation of hematopoietic stem cells (HSCs) can contribute to disease pathogenesis and neoplastic growth. Phosphoinositides (PIs) are inositol phospholipids that are implicated in the regulation of critical signaling pathways: aberrant regulation of Phospholipase C (PLC) beta1, PLCgamma1 and the PI3K/Akt/mTOR pathway play essential roles in the pathogenesis of Myelodysplastic Syndromes (MDS) and Acute Myeloid Leukemia (AML).
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Affiliation(s)
- Alessia De Stefano
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Maria Vittoria Marvi
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Antonietta Fazio
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Pann-Ghill Suh
- Korea Brain Research Institute, Daegu, Republic of Korea; School of Life Sciences, UNIST, Ulsan, Republic of Korea
| | - Stefano Ratti
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Giulia Ramazzotti
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Lucia Manzoli
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Lucio Cocco
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
| | - Matilde Y Follo
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy.
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Follo MY. Meet the Editorial Board Member. Mini Rev Med Chem 2022. [DOI: 10.2174/138955752208220316101914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Matilde Yung Follo
- Department of Morphological and Molecular Sciences
University of Bologna
Italy
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Modulation of DNA Damage Response by Sphingolipid Signaling: An Interplay that Shapes Cell Fate. Int J Mol Sci 2020; 21:ijms21124481. [PMID: 32599736 PMCID: PMC7349968 DOI: 10.3390/ijms21124481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
Although once considered as structural components of eukaryotic biological membranes, research in the past few decades hints at a major role of bioactive sphingolipids in mediating an array of physiological processes including cell survival, proliferation, inflammation, senescence, and death. A large body of evidence points to a fundamental role for the sphingolipid metabolic pathway in modulating the DNA damage response (DDR). The interplay between these two elements of cell signaling determines cell fate when cells are exposed to metabolic stress or ionizing radiation among other genotoxic agents. In this review, we aim to dissect the mediators of the DDR and how these interact with the different sphingolipid metabolites to mount various cellular responses.
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Bradford EM, Thompson CA, Goretsky T, Yang GY, Rodriguez LM, Li L, Barrett TA. Myo-inositol reduces β-catenin activation in colitis. World J Gastroenterol 2017; 23:5115-5126. [PMID: 28811707 PMCID: PMC5537179 DOI: 10.3748/wjg.v23.i28.5115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/31/2017] [Accepted: 05/09/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To assess dietary myo-inositol in reducing stem cell activation in colitis, and validate pβ-cateninS552 as a biomarker of recurrent dysplasia.
METHODS We examined the effects of dietary myo-inositol treatment on inflammation, pβ-cateninS552 and pAkt levels by histology and western blot in IL-10-/- and dextran sodium sulfate-treated colitic mice. Additionally, we assessed nuclear pβ-cateninS552 in patients treated with myo-inositol in a clinical trial, and in patients with and without a history of colitis-induced dysplasia.
RESULTS In mice, pβ-cateninS552 staining faithfully reported the effects of myo-inositol in reducing inflammation and intestinal stem cell activation. In a pilot clinical trial of myo-inositol administration in patients with a history of low grade dysplasia (LGD), two patients had reduced numbers of intestinal stem cell activation compared to the placebo control patient. In humans, pβ-cateninS552 staining discriminated ulcerative colitis patients with a history of LGD from those with benign disease.
CONCLUSION Enumerating crypts with increased numbers of pβ-cateninS552 - positive cells can be utilized as a biomarker in colitis-associated cancer chemoprevention trials.
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Mongiorgi S, Finelli C, Yang YR, Clissa C, McCubrey JA, Billi AM, Manzoli L, Suh PG, Cocco L, Follo MY. Inositide-dependent signaling pathways as new therapeutic targets in myelodysplastic syndromes. Expert Opin Ther Targets 2015; 20:677-87. [PMID: 26610046 DOI: 10.1517/14728222.2016.1125885] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Nuclear inositide signaling pathways specifically regulate cell proliferation and differentiation. Interestingly, the modulation of nuclear inositides in hematological malignancies can differentially affect erythropoiesis or myelopoiesis. This is particularly important in patients with myelodysplastic syndromes (MDS), who show both defective erythroid and myeloid differentiation, as well as an increased risk of evolution into acute myeloid leukemia (AML). AREAS COVERED This review focuses on the structure and function of specific nuclear inositide enzymes, whose impairment could be linked with disease pathogenesis and cancer. The authors, stemming from literature and published data, discuss and describe the role of nuclear inositides, focusing on specific enzymes and demonstrating that targeting these molecules could be important to develop innovative therapeutic approaches, with particular reference to MDS treatment. EXPERT OPINION Demethylating therapy, alone or in combination with other drugs, is the most common and current therapy for MDS patients. Nuclear inositide signaling molecules have been demonstrated to be important in hematopoietic differentiation and are promising new targets for developing a personalized MDS therapy. Indeed, these enzymes can be ideal targets for drug design and their modulation can have several important downstream effects to regulate MDS pathogenesis and prevent MDS progression to AML.
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Affiliation(s)
- Sara Mongiorgi
- a Cellular Signalling Laboratory, Institute of Human Anatomy, Department of Biomedical and Neuromotor Sciences , University of Bologna , Bologna , Italy
| | - Carlo Finelli
- b Institute of Hematology "L e A Seràgnoli" , S. Orsola-Malpighi Hospital , Bologna , Italy
| | - Yong Ryoul Yang
- c School of Life Sciences , Ulsan National Institute of Science and Technology , Ulsan , Republic of Korea
| | - Cristina Clissa
- b Institute of Hematology "L e A Seràgnoli" , S. Orsola-Malpighi Hospital , Bologna , Italy.,d Hematology and Transplant Center , AORMN , Pesaro , Italy
| | - James A McCubrey
- e Department of Microbiology & Immunology, Brody School of Medicine , East Carolina University , Greenville , NC , USA
| | - Anna Maria Billi
- a Cellular Signalling Laboratory, Institute of Human Anatomy, Department of Biomedical and Neuromotor Sciences , University of Bologna , Bologna , Italy
| | - Lucia Manzoli
- a Cellular Signalling Laboratory, Institute of Human Anatomy, Department of Biomedical and Neuromotor Sciences , University of Bologna , Bologna , Italy
| | - Pann-Ghill Suh
- c School of Life Sciences , Ulsan National Institute of Science and Technology , Ulsan , Republic of Korea
| | - Lucio Cocco
- a Cellular Signalling Laboratory, Institute of Human Anatomy, Department of Biomedical and Neuromotor Sciences , University of Bologna , Bologna , Italy
| | - Matilde Y Follo
- a Cellular Signalling Laboratory, Institute of Human Anatomy, Department of Biomedical and Neuromotor Sciences , University of Bologna , Bologna , Italy
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Goto K, Tanaka T, Nakano T, Okada M, Hozumi Y, Topham MK, Martelli AM. DGKζ under stress conditions: “to be nuclear or cytoplasmic, that is the question”. Adv Biol Regul 2014; 54:242-253. [PMID: 24119575 DOI: 10.1016/j.jbior.2013.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 08/31/2013] [Indexed: 06/02/2023]
Abstract
Eukaryotic cells have evolved to possess a distinct subcellular compartment, the nucleus, separated from the cytoplasm in a manner that allows the precise operation of the chromatin, thereby permitting controlled access to the regulatory elements in the DNA for transcription and replication. In the cytoplasm, genetic information contained in the DNA sequence is translated into proteins, including enzymes that catalyze various reactions, such as metabolic processes, energy control, and responses to changing environments. One mechanism that regulates these events involves phosphoinositide turnover signaling, which generates a lipid second messenger, diacylglycerol (DG). Since DG acts as a potent activator of several signaling molecules, it should be tightly regulated to keep cellular responsiveness within a physiological range. DG kinase (DGK) metabolizes DG by phosphorylating it to generate phosphatidic acid, thus serving as a critical regulator of DG signaling. Phosphoinositide turnover is employed differentially in the nucleus and the cytoplasm. A member of the DGK family, DGKζ, localizes to the nucleus in various cell types and is considered to regulate nuclear DG signaling. Recent studies have provided evidence that DGKζ shuttles between the nucleus and the cytoplasm in neurons under pathophysiological conditions. Transport of a signal regulator between the nucleus and the cytoplasm should be a critical function for maintaining basic processes in the nucleus, such as cell cycle regulation and gene expression, and to ensure communication between nuclear processes and cytoplasmic functions. In this review, a series of studies on nucleocytoplasmic translocation of DGKζ have been summarized, and the functional implications of this phenomenon in postmitotic neurons and cancer cells under stress conditions are discussed.
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10
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Liu Y, Bankaitis VA. Phosphoinositide phosphatases in cell biology and disease. Prog Lipid Res 2010; 49:201-17. [PMID: 20043944 PMCID: PMC2873057 DOI: 10.1016/j.plipres.2009.12.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 12/03/2009] [Accepted: 12/03/2009] [Indexed: 01/10/2023]
Abstract
Phosphoinositides are essential signaling molecules linked to a diverse array of cellular processes in eukaryotic cells. The metabolic interconversions of these phospholipids are subject to exquisite spatial and temporal regulation executed by arrays of phosphatidylinositol (PtdIns) and phosphoinositide-metabolizing enzymes. These include PtdIns- and phosphoinositide-kinases that drive phosphoinositide synthesis, and phospholipases and phosphatases that regulate phosphoinositide degradation. In the past decade, phosphoinositide phosphatases have emerged as topics of particular interest. This interest is driven by the recent appreciation that these enzymes represent primary mechanisms for phosphoinositide degradation, and because of their ever-increasing connections with human diseases. Herein, we review the biochemical properties of six major phosphoinositide phosphatases, the functional involvements of these enzymes in regulating phosphoinositide metabolism, the pathologies that arise from functional derangements of individual phosphatases, and recent ideas concerning the involvements of phosphoinositide phosphatases in membrane traffic control.
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Affiliation(s)
- Yang Liu
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090, USA
| | - Vytas A. Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7090, USA
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Follo MY, Mongiorgi S, Finelli C, Clissa C, Ramazzotti G, Fiume R, Faenza I, Manzoli L, Martelli AM, Cocco L. Nuclear inositide signaling in myelodysplastic syndromes. J Cell Biochem 2010; 109:1065-71. [PMID: 20058233 DOI: 10.1002/jcb.22483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Myelodysplastic syndromes (MDS) are defined as clonal hematopoietic stem-cell disorders characterized by ineffective hematopoiesis in one or more of the lineages of the bone marrow. Although distinct morphologic subgroups exist, the natural history of MDS is progression to acute myeloid leukemia (AML). However, the molecular the mechanisms the underlying MDS evolution to AML are not completely understood. Inositides are key cellular second messengers with well-established roles in signal transduction pathways, and nuclear metabolism elicited by phosphoinositide-specific phospholipase C (PI-PLC) beta1 and Akt plays an important role in the control of the balance between cell cycle progression and apoptosis in both normal and pathologic conditions. Recent findings evidenced the role played by nuclear lipid signaling pathways, which could become promising therapeutic targets in MDS. This review will provide a concise and updated revision of the state of art on this topic.
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Affiliation(s)
- Matilde Y Follo
- Cellular Signaling Laboratory, Department of Human Anatomical Sciences, University of Bologna, via Irnerio 48, 40126 Bologna, Italy
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Farooqui AA. Lipid Mediators in the Neural Cell Nucleus: Their Metabolism, Signaling, and Association with Neurological Disorders. Neuroscientist 2009; 15:392-407. [DOI: 10.1177/1073858409337035] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lipid mediators are important endogenous regulators of neural cell proliferation, differentiation, oxidative stress, inflammation, and apoptosis. They originate from enzymic degradation of glycerophospholipids, sphingolipids, and cholesterol by phospholipases, sphingomyelinases, and cytochrome P450 hydroxylases, respectively. Arachidonic acid-derived lipid mediators are called eicosanoids. Eicosanoids have emerged as key regulators of cell proliferation, differentiation, oxidative stress, and neuroinflammation. Another arachidonic acid-derived lipid mediator is lipoxin. Eicosanoids have proinflammatory effects, whereas lipoxins produce antiinflammatrory effects. The crossponding lipid mediators of docosahexaenoic acid metabolism are named docosanoids. They include resolvins, protectins, and neuroprotectins. Docosanoids produce antioxidant, anti-inflammatory, and antiapoptotic effects in the brain tissue. Other glycerophospholipid-derived lipid mediators are platelet-activating factor, lysophosphatidic acid, and endocannabinoids. Degradation of sphingolipids also results in the generation of sphingolipid-derived lipid mediators. Sphingolipid-derived lipid mediators are ceramide, ceramide 1-phosphate, sphingosine, and sphingosine 1-phosphate. They mediate cellular differentiation, cell growth, and apoptosis. Similarly, cholesterol-derived lipid mediators hydroxycholesterol and oxycholesterol produce apoptosis. Most of these mediators originate from the plasma membrane. The nucleus has its own set of enzymes and lipid mediators that originate from the nuclear envelope and matrix. The purpose of this commentary is to describe basic and clinical information on lipid mediators in the nucleus.
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Affiliation(s)
- Akhlaq A. Farooqui
- Department of Molecular Cellular Biochemistry, The Ohio
State University, Columbus, Ohio,
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Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus. Biochem J 2009; 422:53-60. [PMID: 19496756 DOI: 10.1042/bj20090654] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although the class II phosphoinositide 3-kinase enzymes PI3K-C2alpha and PI3K-C2beta act acutely downstream of cell surface receptors they have also been localized to nuclei in mammalian cells. As with the class I PI3K enzymes, the relationship between the pools of enzyme present in cytoplasm and nuclei remains poorly understood. In this study we test the hypothesis that PI3K-C2beta translocates to nuclei in response to growth factor stimulation. Fractionating homogenates of quiescent cells revealed that less than 5% of total PI3K-C2beta resides in nuclei. Stimulation with epidermal growth factor sequentially increased levels of this enzyme, firstly in the cytosol and secondly in the nuclei. Using detergent-treated nuclei, we showed that PI3K-C2beta co-localized with lamin A/C in the nuclear matrix. This was confirmed biochemically, and a phosphoinositide kinase assay showed a statistically significant increase in nuclear PI3K-C2beta levels and lipid kinase activity following epidermal growth factor stimulation. C-terminal deletion and point mutations of PI3K-C2beta demonstrated that epidermal growth factor-driven translocation to the nucleus is dependent on a sequence of basic amino acid residues (KxKxK) that form a nuclear localization motif within the C-terminal C2 domain. Furthermore, when this sequence was expressed as an EGFP (enhanced green fluorescent protein) fusion protein, it translocated fluorescence into nuclei with an efficiency dependent upon copy number. These data demonstrate that epidermal growth factor stimulates the appearance of PI3K-C2beta in nuclei. Further, this effect is dependent on a nuclear localization signal present within the C-terminal C2 domain, indicating its bimodal function regulating phospholipid binding and shuttling PI3K-C2beta into the nucleus.
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The role of the inositol polyphosphate 5-phosphatases in cellular function and human disease. Biochem J 2009; 419:29-49. [PMID: 19272022 DOI: 10.1042/bj20081673] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phosphoinositides are membrane-bound signalling molecules that regulate cell proliferation and survival, cytoskeletal reorganization and vesicular trafficking by recruiting effector proteins to cellular membranes. Growth factor or insulin stimulation induces a canonical cascade resulting in the transient phosphorylation of PtdIns(4,5)P(2) by PI3K (phosphoinositide 3-kinase) to form PtdIns(3,4,5)P(3), which is rapidly dephosphorylated either by PTEN (phosphatase and tensin homologue deleted on chromosome 10) back to PtdIns(4,5)P(2), or by the 5-ptases (inositol polyphosphate 5-phosphatases), generating PtdIns(3,4)P(2). The 5-ptases also hydrolyse PtdIns(4,5)P(2), forming PtdIns4P. Ten mammalian 5-ptases have been identified, which share a catalytic mechanism similar to that of the apurinic/apyrimidinic endonucleases. Gene-targeted deletion of 5-ptases in mice has revealed that these enzymes regulate haemopoietic cell proliferation, synaptic vesicle recycling, insulin signalling, endocytosis, vesicular trafficking and actin polymerization. Several studies have revealed that the molecular basis of Lowe's syndrome is due to mutations in the 5-ptase OCRL (oculocerebrorenal syndrome of Lowe). Futhermore, the 5-ptases SHIP [SH2 (Src homology 2)-domain-containing inositol phosphatase] 2, SKIP (skeletal muscle- and kidney-enriched inositol phosphatase) and 72-5ptase (72 kDa 5-ptase)/Type IV/Inpp5e (inositol polyphosphate 5-phosphatase E) are implicated in negatively regulating insulin signalling and glucose homoeostasis in specific tissues. SHIP2 polymorphisms are associated with a predisposition to insulin resistance. Gene profiling studies have identified changes in the expression of various 5-ptases in specific cancers. In addition, 5-ptases such as SHIP1, SHIP2 and 72-5ptase/Type IV/Inpp5e regulate macrophage phagocytosis, and SHIP1 also controls haemopoietic cell proliferation. Therefore the 5-ptases are a significant family of signal-modulating enzymes that govern a plethora of cellular functions by regulating the levels of specific phosphoinositides. Emerging studies have implicated their loss or gain of function in human disease.
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Mellman DL, Anderson RA. A novel gene expression pathway regulated by nuclear phosphoinositides. ACTA ACUST UNITED AC 2009; 49:11-28. [DOI: 10.1016/j.advenzreg.2009.01.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Trubiani O, Guarnieri S, Eleuterio E, Di Giuseppe F, Orciani M, Angelucci S, Di Primio R. Insights into nuclear localization and dynamic association of CD38 in Raji and K562 cells. J Cell Biochem 2008; 103:1294-308. [PMID: 17786980 DOI: 10.1002/jcb.21510] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
CD38 is a type II transmembrane glycoprotein found mainly on the plasma membrane involved in the metabolism of cADPR and NAADP, two nucleotides with calcium mobilizing activity independent of inositol trisphosphate. Recent data report the presence of CD38 in different cellular compartments raising new questions about its effective role in cellular metabolism. In rat hepatocyte nuclei, CD38 has been proposed as a responsive to cADPR integral inner membrane protein suggesting that the nuclear envelope may also be an important source of Ca2+ stores. Further reports indicating that CD38 is localized in nuclear compartments in a variety of cell types and tissues including brain, liver, eye, spleen, and bone raise the condition of resolving the question concerning the effective presence of CD38 within the nucleus. Here we report data supporting the presence of CD38 at nuclear level independently of expression of surface CD38. We utilized two different human leukemia cell lines expressing or not expressing CD38 molecule on their cell surface. The morphological and biochemical results including enzymatic activity and proteomic determinations explain the effective nuclear localization of CD38 in human Raji and K562 cells. Since cell nucleus is a complex and highly dynamic environment with many functionally specialized regions, the nuclear localization of specific proteins represents an important mechanism in signal transduction. The presence of CD38 at the interchromatin region whether linked to nuclear scaffold or stored in nuclear structures as micronuclei and Cajal bodies co-localizing with coilin, suggests its involvement in nuclear processes including transcription, replication, repairing and splicing.
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Affiliation(s)
- Oriana Trubiani
- Department of Oral Science, University "G. D'Annunzio", Chieti-Pescara, Italy
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17
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Evangelisti C, Tazzari PL, Riccio M, Fiume R, Hozumi Y, Falà F, Goto K, Manzoli L, Cocco L, Martelli AM. Nuclear diacylglycerol kinase‐ζ is a negative regulator of cell cycle progression in C2C12 mouse myoblasts. FASEB J 2007; 21:3297-307. [PMID: 17488950 DOI: 10.1096/fj.07-8336com] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The nucleus contains diacylglycerol kinases (DGKs), i.e., the enzymes that, by converting diacylglycerol (DG) into phosphatidic acid, terminate DG-dependent events. It has been demonstrated that nuclear DGK-zeta interferes with cell cycle progression. We previously reported that nuclear DGK-zeta expression increased during myogenic differentiation, whereas its down-regulation impaired differentiation. Here, we evaluated the possible involvement of nuclear DGK-zeta in cell cycle progression of C2C12 myoblasts. Overexpression of a wild-type DGK-zeta, which mainly localized to the nucleus (but not of a kinase dead mutant or of a mutant that did not enter the nucleus), blocked the cells in the G1 phase of the cell cycle, as demonstrated by in situ analysis of biotinylated-16-dUTP incorporated into newly synthesized DNA and by flow cytometry. In contrast, down-regulation of endogenous DGK-zeta by short interfering RNA (siRNA) increased the number of cells in both the S and G2/M phases of the cell cycle. Cell cycle arrest of cells overexpressing wild-type DGK-zeta was accompanied by decreased levels of retinoblastoma protein phosphorylated on Ser-807/811. Down-regulation of endogenous DGK-zeta, using siRNA, prevented the cell cycle block characterizing C2C12 cell myogenic differentiation. Overall, our results identify nuclear DGK-zeta as a key determinant of cell cycle progression and differentiation of C2C12 cells.
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Affiliation(s)
- Camilla Evangelisti
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Cell Signalling Laboratory, Università di Bologna, via Irnerio 48, 40126 Bologna, Italy
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18
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Tzeng HF, Chen JY, Huang SW, Wang YJ, Yang CS. Simultaneous determination ofmyo-inositol andscyllo-inositol by MEKC as a rapid monitoring tool for inositol levels. Electrophoresis 2007; 28:1221-8. [PMID: 17351885 DOI: 10.1002/elps.200600683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A simple and rapid MEKC method was developed for the simultaneous determination of myo-inositol, scyllo-inositol, and glucose. Prior to electrophoretic separation, the nonfluorescent inositols and glucose were derivatized by N-methylisatoic anhydride at 25 degrees C for 10 min so that they could be detected by a fluorescence detector during separation. The good separation with high efficiency by MEKC was achieved in 13 min with a glycine buffer containing SDS and PEG 4000. Several parameters affecting the separation were studied, including the pH of BGE, the concentrations of glycine, SDS, and PEG 4000, and the applied voltage. Using glycerol as an internal standard, the linear ranges of the method for myo-inositol, scyllo-inositol, and glucose were 0.03-10, 0.01-5, and 0.05-20 mM; the concentration LODs of myo-inositol, scyllo-inositol, and glucose were 0.020, 0.0078, and 0.026 mM, respectively. The method was applied to analyze extracellular myo-inositol and glucose in the microdialysates from rat brain cortex of ischemia animal model and intracellular myo-inositol and scyllo-inositol in the rat brain extract.
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Affiliation(s)
- Huey-Fen Tzeng
- Department of Applied Chemistry, National Chi Nan University, Puli, Nantou, Taiwan.
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19
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Bunce MW, Gonzales ML, Anderson RA. Stress-ING out: phosphoinositides mediate the cellular stress response. ACTA ACUST UNITED AC 2006; 2006:pe46. [PMID: 17090802 DOI: 10.1126/stke.3602006pe46] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Phosphoinositides regulate numerous cellular processes required for growth, proliferation, and motility. Whereas phosphoinositide signal transduction pathways within the cytosol have been well characterized, nuclear signaling pathways remain poorly understood. Accumulating experimental data have now started to uncover critical functions for nuclear phosphoinositides. In particular, phosphoinositides modulate the activity of the tumor suppressor protein ING2 in response to extracellular stress. These findings highlight a previously uncharacterized function for phosphoinositides and implicate their metabolism in signaling pathways critical for cell survival.
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Affiliation(s)
- Matthew W Bunce
- Department of Pharmacology, University of Wisconsin, Madison, WI 53706, USA
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20
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Evangelisti C, Riccio M, Faenza I, Zini N, Hozumi Y, Goto K, Cocco L, Martelli AM. Subnuclear localization and differentiation-dependent increased expression of DGK-zeta in C2C12 mouse myoblasts. J Cell Physiol 2006; 209:370-8. [PMID: 16897754 DOI: 10.1002/jcp.20744] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diacylglycerol kinases (DGKs) catalyze phosphorylation of diacylglycerol (DG) to yield phosphatidic acid (PA). Previous evidence has shown that the nucleus contains several DGK isoforms. In this study, we have analyzed the expression and subnuclear localization of DGK-zeta employing C2C12 mouse myoblasts. Immunocytochemistry coupled to confocal laser scanning microscopy showed that both endogenous and green fluorescent protein-tagged overexpressed DGK-zeta localized mostly to the nucleus. In contrast, overexpressed DGK-alpha, -beta, -delta, and -iota did not migrate to the nucleus. DGK-zeta was present in the nuclear speckle domains, as also revealed by immuno-electron microscopy analysis. Moreover, DGK-zeta co-localized and interacted with phosphoinositide-specific phospholipase Cbeta1 (PLCbeta1), that is involved in inositide-dependent signaling pathways important for the regulation of cell proliferation and differentiation. Furthermore, we report that DGK-zeta associated with nuclear matrix, the fundamental organizing principle of the nucleus where many cell functions take place, including DNA replication, gene expression, and protein phosphorylation. Nuclear DGK-zeta increased during myogenic differentiation of C2C12 cells, while DGK-zeta down-regulation by siRNA markedly impaired differentiation. Overall, our findings further support the importance of speckles and nuclear matrix in lipid-dependent signaling and suggest that nuclear DGK-zeta might play some fundamental role during myogenic differentiation of C2C12 cells.
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Affiliation(s)
- Camilla Evangelisti
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia, Università di Bologna, Bologna, Italy
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21
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Zacks MA, Garg N. Recent developments in the molecular, biochemical and functional characterization of GPI8 and the GPI-anchoring mechanism [review]. Mol Membr Biol 2006; 23:209-25. [PMID: 16785205 DOI: 10.1080/09687860600601494] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Glycoconjugates are utilized by eukaryotic organisms ranging from yeast to humans for the cell surface expression of a wide variety of proteins and lipids. These glycoconjugates are expressed as enzymes or receptors and serve a diversity of functions, including cell signaling and cell survival. In parasitic protozoans, glycoconjugates play roles in infectivity, survival, virulence and immune evasion. Among the alternate glycoconjugate structures that have been identified, glycosylphosphatidylinositols (GPIs) represent a universal structure for the anchorage of proteins, lipids, and phosphosaccharides to cellular membranes. Biosynthesis of the GPI is a multi-step process that culminates in the attachment of the assembled GPI to a precursor protein. This final step in the transfer of the GPI to a protein is catalyzed by GPI8 of the putative transamidase complex (TAM). GPI8 functions dually to perform the proteolytic cleavage of the C-terminal signal sequence of the precursor protein, followed by the formation of an amide bond between the protein and the ethanolamine phosphate of the GPI. This review summarizes the current aggregate of biochemical, gene-disruption and active site mutagenesis studies, which provide evidence that GPI8 is responsible for the protein-GPI anchoring reaction. We describe recently published studies that have identified other potential components of the TAM complex and that have elucidated their likely role in protein-GPI attachment. Further, we discuss the biochemical, molecular and functional differences between protozoan and mammalian GPI8 and the protein-GPI anchoring machinery. Finally, we will present the implications of these studies for the development of anti-parasite drug therapies.
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Affiliation(s)
- Michele A Zacks
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas 77555-1070, USA
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22
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Jiang H, Sha SH, Schacht J. Kanamycin alters cytoplasmic and nuclear phosphoinositide signaling in the organ of Corti in vivo. J Neurochem 2006; 99:269-76. [PMID: 16903869 DOI: 10.1111/j.1471-4159.2006.04117.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aminoglycoside antibiotics strongly bind to phosphoinositides and affect their membrane distribution and metabolism. Kanamycin treatment also disrupts Rac/Rho signaling pathways to the actin cytoskeleton in the mouse inner ear in vivo. Here, we investigate the influence of kanamycin on phosphoinositide signaling in sensory cells (hair cells) of the mouse cochlea. Immunoreactivity to phosphatidylinositol-3,4,5-trisphosphate (PIP3) decreased in the organ of Corti, especially in outer hair cells, after 3-7 days of drug treatment, whereas imunoreactivity to phosphatidylinositol-4,5-bisphosphate (PIP2) increased. Immunoreactivity to PIP2 was present at the apical poles of outer hair cells, but appeared in their nuclei only after drug treatment. Furthermore, nuclear PIP2 formed a complex with histone H3 and attenuated its acetylation in outer hair cells. In agreement with reduced PIP3 signaling, phosphorylated Akt decreased in both the cytoplasm and nuclei of outer hair cells after kanamycin treatment. This study suggests that kanamycin disturbs the balance between PIP2 and PIP3, modifies gene transcription via histone acetylation and diminishes the PI3K/Akt survival pathway. These actions may contribute to the death of outer hair cells, which is a consequence of chronic kanamycin treatment.
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Affiliation(s)
- Hongyan Jiang
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan, USA
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23
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Kaadige MR, Ayer DE. The polybasic region that follows the plant homeodomain zinc finger 1 of Pf1 is necessary and sufficient for specific phosphoinositide binding. J Biol Chem 2006; 281:28831-6. [PMID: 16893883 DOI: 10.1074/jbc.m605624200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The plant homeodomain (PHD) zinc finger is one of 14 known zinc-binding domains. PHD domains have been found in more than 400 eukaryotic proteins and are characterized by a Cys(4)-His-Cys(3) zinc-binding motif that spans 50-80 residues. The precise function of PHD domains is currently unknown; however, the PHD domains of the ING1 and ING2 tumor suppressors have been shown recently to bind phosphoinositides (PIs). We have recently identified a novel PHD-containing protein, Pf1, as a binding partner for the abundant and ubiquitous transcriptional corepressor mSin3A. Pf1 contains two PHD zinc fingers, PHD1 and PHD2, and functions to bridge mSin3A to the TLE1 corepressor. Here, we show that PHD1, but not PHD2, binds several monophosporylated PIs but most strongly to PI(3)P. Surprisingly, a polybasic region that follows the PHD1 is necessary for PI(3)P binding. Furthermore, this polybasic region binds specifically to PI(3)P when fused to maltose-binding protein, PHD2, or as an isolated peptide, demonstrating that it is sufficient for specific PI binding. By exchanging the polybasic regions between different PHD fingers we show that this region is a strong determinant of PI binding specificity. These findings establish the Pf1 polybasic region as a phosphoinositide-binding module and suggest that the PHD domains function down-stream of phosphoinositide signaling triggered by the interaction between polybasic regions and phosphoinositides.
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Affiliation(s)
- Mohan R Kaadige
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA
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24
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Goto K, Hozumi Y, Kondo H. Diacylglycerol, phosphatidic acid, and the converting enzyme, diacylglycerol kinase, in the nucleus. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:535-41. [PMID: 16731035 DOI: 10.1016/j.bbalip.2006.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Revised: 04/06/2006] [Accepted: 04/07/2006] [Indexed: 01/08/2023]
Abstract
There exists phosphoinositide (PI) cycle in the nucleus, which is operated differentially from the classical PI cycle at the plasma membrane. Evidence has been accumulated that nuclear PIs and the related enzymes are closely involved in a variety of nuclear processes, although the details remain to be elucidated. In this mini review, some components of PI cycle, i.e., diacylglycerol, phosphatidic acid, and the converting enzyme, diacylglycerol kinase, in the nucleus are discussed with focusing on the lipid metabolism, cell cycle regulation, and animal models.
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Affiliation(s)
- Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan.
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25
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Bunce MW, Bergendahl K, Anderson RA. Nuclear PI(4,5)P(2): a new place for an old signal. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:560-9. [PMID: 16750654 DOI: 10.1016/j.bbalip.2006.03.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Revised: 03/03/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
Over the last decades, evidence has accumulated suggesting that there is a distinct nuclear phosphatidylinositol pathway. One of the best examined nuclear lipid pathways is the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)) by PLC resulting in activation of nuclear PKC and production of inositol polyphosphates. However, there is a growing number of data that phosphoinositides are not only precursor for soluble inositol phosphates and diacylglycerol, instead they can act as second messengers themselves. They have been implicated to play a role in different important nuclear signaling events such as cell cycle progression, apoptosis, chromatin remodeling, transcriptional regulation and mRNA processing. This review focuses on the role of specifically PI4,5P(2) in the nucleus as a second messenger as well as a precursor for PI3,4,5P3, inositol polyphosphates and diacylglycerol.
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Affiliation(s)
- Matthew W Bunce
- Department of Pharmacology, University of Wisconsin Medical School, 1300 University Ave., Madison, WI 53706, USA
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26
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Martelli AM, Faenza I, Billi AM, Manzoli L, Evangelisti C, Falà F, Cocco L. Intranuclear 3'-phosphoinositide metabolism and Akt signaling: new mechanisms for tumorigenesis and protection against apoptosis? Cell Signal 2006; 18:1101-7. [PMID: 16516442 DOI: 10.1016/j.cellsig.2006.01.011] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 01/17/2006] [Accepted: 01/17/2006] [Indexed: 11/17/2022]
Abstract
Lipid second messengers, particularly those derived from the polyphosphoinositide metabolism, play a pivotal role in multiple cell signaling networks. Phosphoinositide 3-kinase (PI3K) generate 3'-phosphorylated inositol lipids that are key players in a multitude of cell functions. One of the best characterized targets of PI3K lipid products is the serine/threonine protein kinase Akt (protein kinase B, PKB). Recent findings have implicated the PI3K/Akt pathway in tumorigenesis because it stimulates cell proliferation and suppresses apoptosis. However, it was thought that this signal transduction network would exert its carcinogenetic effects mainly by operating in the cytoplasm. Evidence accumulated over the past 15 years has highlighted the presence of an autonomous nuclear inositol lipid cycle, and strongly suggests that lipid molecules are important components of signaling pathways operating at the nuclear level. PI3K, its lipid product phosphatidylinositol (3,4,5) trisphosphate (PtdIns(3,4,5)P3), and Akt have been identified within the nucleus and recent data suggest that they counteract apoptosis also by operating in this cell compartment through a block of caspase-activated DNase and inhibition of chromatin condensation. In this review, we shall summarize the most updated and intriguing findings about nuclear PI3K/PtdIns(3,4,5)P3/Akt in relationship with tumorigenesis and suppression of apoptotic stimuli.
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Affiliation(s)
- Alberto M Martelli
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia Umana, Cell Signalling Laboratory, Università di Bologna, via Irnerio 48, 40126 Bologna, Italy.
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27
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Cocco L, Martelli AM, Fiume R, Faenza I, Billi AM, Manzoli FA. Signal transduction within the nucleus: Revisiting phosphoinositide inositide–specific phospholipase Cβ1. ACTA ACUST UNITED AC 2006; 46:2-11. [PMID: 16846636 DOI: 10.1016/j.advenzreg.2006.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Lucio Cocco
- Cellular Signaling Laboratory, Department of Anatomical Sciences, University of Bologna, via Irnerio 48, 40126 Bologna, Italy.
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