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Nuclear Phosphoinositides-Versatile Regulators of Genome Functions. Cells 2019; 8:cells8070649. [PMID: 31261688 PMCID: PMC6678639 DOI: 10.3390/cells8070649] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022] Open
Abstract
The many functions of phosphoinositides in cytosolic signaling were extensively studied; however, their activities in the cell nucleus are much less clear. In this review, we summarize data about their nuclear localization and metabolism, and review the available literature on their involvements in chromatin remodeling, gene transcription, and RNA processing. We discuss the molecular mechanisms via which nuclear phosphoinositides, in particular phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2), modulate nuclear processes. We focus on PI(4,5)P2’s role in the modulation of RNA polymerase I activity, and functions of the nuclear lipid islets—recently described nucleoplasmic PI(4,5)P2-rich compartment involved in RNA polymerase II transcription. In conclusion, the high impact of the phosphoinositide–protein complexes on nuclear organization and genome functions is only now emerging and deserves further thorough studies.
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Application of vitamin D and vitamin D analogs in acute myelogenous leukemia. Exp Hematol 2017; 50:1-12. [DOI: 10.1016/j.exphem.2017.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/16/2017] [Accepted: 01/26/2017] [Indexed: 12/18/2022]
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3
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Martelli AM, Ognibene A, Buontempo F, Fini M, Bressanin D, Goto K, McCubrey JA, Cocco L, Evangelisti C. Nuclear phosphoinositides and their roles in cell biology and disease. Crit Rev Biochem Mol Biol 2011; 46:436-57. [DOI: 10.3109/10409238.2011.609530] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Hughes PJ, Marcinkowska E, Gocek E, Studzinski GP, Brown G. Vitamin D3-driven signals for myeloid cell differentiation--implications for differentiation therapy. Leuk Res 2009; 34:553-65. [PMID: 19811822 DOI: 10.1016/j.leukres.2009.09.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 09/05/2009] [Accepted: 09/07/2009] [Indexed: 10/20/2022]
Abstract
Primitive myeloid leukemic cell lines can be driven to differentiate to monocyte-like cells by 1alpha,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), and, therefore, 1,25(OH)(2)D(3) may be useful in differentiation therapy of myeloid leukemia and myelodysplastic syndromes (MDS). Recent studies have provided important insights into the mechanism of 1,25(OH)(2)D(3)-stimulated differentiation. For myeloid progenitors to complete monocytic differentiation a complex network of intracellular signals has to be activated and/or inactivated in a precise temporal and spatial pattern. 1,25(OH)(2)D(3) achieves this change to the 'signaling landscape' by (i) direct genomic modulation of the level of expression of key regulators of cell signaling and differentiation pathways, and (ii) activation of intracellular signaling pathways. An improved understanding of the mode of action of 1,25(OH)(2)D(3) is facilitating the development of new therapeutic regimens.
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Affiliation(s)
- Philip J Hughes
- School of Immunity and Infection, College of Medical and Dental Sciences, The University of Birmingham, Vincent Drive, Edgbaston, Birmingham, West Midlands B15 2TT, UK
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5
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Missiroli S, Etro D, Buontempo F, Ye K, Capitani S, Neri LM. Nuclear translocation of active AKT is required for erythroid differentiation in erythropoietin treated K562 erythroleukemia cells. Int J Biochem Cell Biol 2008; 41:570-7. [PMID: 18694847 DOI: 10.1016/j.biocel.2008.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 06/25/2008] [Accepted: 07/10/2008] [Indexed: 11/28/2022]
Abstract
Erythroid differentiation of human erythroleukemia cell line K562 induced by erythropoietin is a complex process that involves modifications at nuclear level, including nuclear translocation of phosphatidyl-inositol 3-kinase. In this work we show that erythropoietin stimulation of K562 cells can induce nuclear translocation of active Akt, a downstream molecule of the phosphatidyl-inositol 3-kinase signaling pathway. Akt shows a peak of activity in whole cell homogenates at earlier stage when compared to the nucleus, which shows a peak delayed of 10 min. Akt increases its intranuclear amount and activity rapidly and transiently in response to EPO. Almost all Akt kinase that translocates to the nucleus shows a marked phosphorylation on serine 473. Nuclear enzyme translocation is blocked by the phosphatidyl-inositol 3-kinase inhibitor Ly294002 or Wortmannin. The specific Akt pharmacological inhibitor VI, VII and VIII that act as blocking enzyme activation inhibited translocation as well, whereas Akt inhibitor IX, that inhibits Akt activity, did not block Akt nuclear translocation. When cells were treated by means of siRNA sequences or with the Akt inhibitors the differentiation process was arrested, thus showing the requirement of the nuclear translocation of the active enzyme to differentiate. These findings strongly suggest that the intranuclear translocation of active Akt kinase represents an important step in the signaling pathway that mediates erythropoietin-induced erythroid differentiation.
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Affiliation(s)
- Silvia Missiroli
- Dipartimento di Morfologia ed Embriologia, Sezione di Anatomia Umana, Signal Transduction Unit, Universita' di Ferrara, Ferrara, Italy
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6
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The presence of a secretory phospholipase A2 in the nuclei of neuronal and glial cells of rat brain cortex. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:1345-52. [DOI: 10.1016/j.bbalip.2007.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 08/09/2007] [Accepted: 08/10/2007] [Indexed: 01/22/2023]
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7
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Sun L, Mao G, Kunapuli SP, Dhanasekaran DN, Rao AK. Alternative splice variants of phospholipase C-beta2 are expressed in platelets: effect on Galphaq-dependent activation and localization. Platelets 2007; 18:217-23. [PMID: 17497434 DOI: 10.1080/09537100601016133] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Phospholipase C (PLC) beta2 plays a pivotal role in G-protein dependent signal transduction in platelets. We have previously demonstrated in platelets, leukocytes and human erythroleukemia cells the presence of transcripts of two forms of PLC-beta2 generated by alternative splicing. They differ by 45 nucleotides in the carboxyl-terminal region and are designated as PLC-beta2a and PLC-beta2b, with and without by 15 amino acid residues (corresponding to 864-878). The presence of the two variants has not been shown at the protein level in cells. Moreover, the carboxy-terminal region of PLC-beta has been implicated in Galphaq activation, particulate association, and nuclear localization, suggesting that the PLC-beta2 splice variants may be regulated differentially. We demonstrate for the first time that both PLC-beta2 isoforms are expressed in platelets at the protein level. Studies in CV-1 cells transfected with PLC-beta2a or beta2b cDNAs, along with constitutively activated Galphaq (Q209L), showed that inositolphosphate formation was comparable between the two variants. However, the nuclear localization of the two isoforms was different with a higher cytoplasmic to nuclear ratio for PLC-beta2b compared to PLC-beta2a, suggesting that a great proportion of the total PLC-beta2a was in the nucleus relative to PLC-beta2b. There was no difference in the relative distribution of the two variants between the cytosol and particulate fractions. Both PLC-beta2 alternative splice variants are expressed at the protein level in platelets. In transfected CV-1 cells, PLC-beta2a is relatively more enriched in the nuclei than PLC-beta2b suggesting that the two variants may have different effects in cell proliferation and differentiation.
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Affiliation(s)
- Liansheng Sun
- Sol Sherry Thrombosis Research Center, Philadelphia, PA 19140, USA
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8
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Visnjic D, Banfic H. Nuclear phospholipid signaling: phosphatidylinositol-specific phospholipase C and phosphoinositide 3-kinase. Pflugers Arch 2007; 455:19-30. [PMID: 17558519 DOI: 10.1007/s00424-007-0288-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 05/08/2007] [Indexed: 10/23/2022]
Abstract
Over the last 20 years, numerous studies have demonstrated the existence of nuclear phosphoinositide signaling distinct from the one at the plasma membrane. The activation of phosphatidylinositol-specific phospholipase C (PI-PLC) and phosphoinositide 3-kinase (PI3K), the generation of diacylglycerol, and the accumulation of the 3-phosphorylated phosphoinositides have been documented in the nuclei of different cell types. In this review, we summarize some recent studies of the subnuclear localization, mechanisms of activation, and the possible physiological roles of the nuclear PI-PLC and PI-3 kinases in the regulation of cell cycle, survival, and differentiation.
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Affiliation(s)
- Dora Visnjic
- Department of Physiology and Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Salata 3, 10 000, Zagreb, Croatia
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9
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Cocco L, Faenza I, Fiume R, Maria Billi A, Gilmour RS, Manzoli FA. Phosphoinositide-specific phospholipase C (PI-PLC) β1 and nuclear lipid-dependent signaling. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:509-21. [PMID: 16624616 DOI: 10.1016/j.bbalip.2006.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 03/02/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
Over the last years, evidence has suggested that phosphoinositides, which are involved in the regulation of a large variety of cellular processes both in the cytoplasm and in the plasma membrane, are present also within the nucleus. A number of advances has resulted in the discovery that phosphoinositide-specific phospholipase C signalling in the nucleus is involved in cell growth and differentiation. Remarkably, the nuclear inositide metabolism is regulated independently from that present elsewhere in the cell. Even though nuclear inositol lipids hydrolysis generates second messengers such as diacylglycerol and inositol 1,4,5-trisphosphate, it is becoming increasingly clear that in the nucleus polyphosphoinositides may act by themselves to influence pre-mRNA splicing and chromatin structure. Among phosphoinositide-specific phospholipase C, the beta(1) isoform appears to be one of the key players of the nuclear lipid signaling. This review aims at highlighting the most significant and up-dated findings about phosphoinositide-specific phospholipase C beta(1) in the nucleus.
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Affiliation(s)
- Lucio Cocco
- Cellular Signalling Laboratory, Department of Human Anatomical Sciences, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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10
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Brugnoli F, Bovolenta M, Benedusi M, Miscia S, Capitani S, Bertagnolo V. PLC-β2 monitors the drug-induced release of differentiation blockade in tumoral myeloid precursors. J Cell Biochem 2006; 98:160-73. [PMID: 16408290 DOI: 10.1002/jcb.20749] [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: 11/06/2022]
Abstract
The differentiation therapy in treatment of acute promyelocytic leukemia (APL), based on the administration of all-trans retinoic acid (ATRA), is currently flanked with the use of As2O3, a safe and effective agent for patients showing a resistance to ATRA treatment. A synergy between ATRA and As3O3 was also reported in inducing granulocytic differentiation of APL-derived cells. We have demonstrated that phospholipase C-beta2 (PLC-beta2), highly expressed in neutrophils and nearly absent in tumoral promyelocytes, largely increases during ATRA treatment of APL-derived cells and strongly correlates with the responsiveness of APL patients to ATRA-based differentiating therapies. Here we report that, in APL-derived cells, low doses of As3O3 induce a slight increase of PLC-beta2 together with a moderate maturation, and cooperate with ATRA to provoke a significant increase of PLC-beta2 expression. Remarkably, the amounts of PLC-beta2 draw a parallel with the differentiation levels reached by both ATRA-responsive and -resistant cells treated with ATRA/As2O3 combinations. PLC-beta2 is not necessary for the progression of tumoral promyelocytes along the granulocytic lineage and is unable to overcome the differentiation block or to potentiate the agonist-induced maturation. On the other hand, since its expression closely correlates with the differentiation level reached by APL-derived cells induced to maturate by drugs presently employed in APL therapies, PLC-beta2 represents indeed a specific marker to test the ability of differentiation agents to induce the release of the maturation blockade of tumoral myeloid precursors.
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Affiliation(s)
- Federica Brugnoli
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, University of Ferrara, Ferrara, Italy
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11
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Lukinovic-Skudar V, Donlagic L, Banfíc H, Visnjic D. Nuclear phospholipase C-β1b activation during G2/M and late G1 phase in nocodazole-synchronized HL-60 cells. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:148-56. [PMID: 15863362 DOI: 10.1016/j.bbalip.2004.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 12/08/2004] [Accepted: 12/17/2004] [Indexed: 10/25/2022]
Abstract
In this study, the activity of nuclear phosphatidylinositol-specific phosholipase C (PI-PLC) was investigated in HL-60 cells blocked at G(2)/M phase by the addition of nocodazole, and released into medium as synchronously progressing cells. Two peaks of an increase in the nuclear PI-PLC activities were detected; an early peak reached a maximum at 1 h after release from the nocodazole block, and a second increase was detected at 8.5 h after the release. Immunoprecipitation studies indicated that the increase in the activity was due to the activation of the nuclear PI-PLC-beta(1). Western blot analysis demonstrated no changes in the level of both a and b splicing variants of PI-PLC-beta(1) in the nuclei of cells isolated at either 1 h or 8.5 h after the block. However, an increase in the serine-phosphorylation of PI-PLC-beta(1b) was detected in the nuclei of HL-60 cells isolated at 1 and 8.5 h after the block, and the presence of MEK-inhibitor PD98059 completely inhibited both the serine phosphorylation and the increase in the PI-PLC activities in vitro. The presence of PI-PLC inhibitor prevented the progression of HL-60 cells through the G(1) into S phase of the cell cycle. These results demonstrate that two peaks of nuclear PI-PLC activities, which are due to a PD98059-sensitive phosphorylation of nuclear PLC-beta(1b) on serine, occur at the G(2)/M and late G(1) phase and are necessary for the progression of the cells through the cell cycle.
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Affiliation(s)
- Vesna Lukinovic-Skudar
- Department of Physiology and Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Croatia
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12
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Yamamori T, Inanami O, Nagahata H, Kuwabara M. Phosphoinositide 3-kinase regulates the phosphorylation of NADPH oxidase component p47(phox) by controlling cPKC/PKCdelta but not Akt. Biochem Biophys Res Commun 2004; 316:720-30. [PMID: 15033459 DOI: 10.1016/j.bbrc.2004.02.108] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Indexed: 11/20/2022]
Abstract
Superoxide production by NADPH oxidase is essential for the bactericidal properties of phagocytes. Phosphorylation of p47(phox), one of the cytosolic components of NADPH oxidase, is a crucial step of the oxidase activation. Some evidences suggest that phosphoinositide 3-kinase (PI3K) is involved in p47(phox) phosphorylation, but it has not been fully understood how PI3K regulates it. The aim of this study was to examine the mechanism underlying the PI3K regulation of p47(phox) phosphorylation. Pharmacological inhibition of PI3K attenuated both fMLP-stimulated p47(phox) phosphorylation and NADPH oxidase activity in HL-60 cells differentiated to a neutrophil-like phenotype. Although fMLP elicited Akt activation in a PI3K-dependent manner, an Akt inhibitor had no effect on the oxidase activity triggered by fMLP. In vitro kinase assay revealed that Akt was unable to catalyze p47(phox) phosphorylation. Interestingly, the activation of cPKC and PKCdelta after fMLP stimulation was dependent on PI3K. Furthermore, PI3K inhibitors reduced the activation of phospholipase Cgamma2 without affecting tyrosine phosphorylation on it. These results suggest that PI3K regulates the phosphorylation of NADPH oxidase component p47(phox) by controlling diacylglycerol-dependent PKCs but not Akt.
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Affiliation(s)
- Tohru Yamamori
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Weeber EJ, Caldwell KK. Delay fear conditioning modifies phospholipase C-β1a signaling in the hippocampus and frontal cortex. Pharmacol Biochem Behav 2004; 78:155-64. [PMID: 15159145 DOI: 10.1016/j.pbb.2004.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Revised: 03/02/2004] [Accepted: 03/04/2004] [Indexed: 11/30/2022]
Abstract
The use of the single-trial fear conditioning paradigm allows for control over the exact moment when an animal is exposed to a learning event, making it possible to study both the initial neurobiological changes that are associated with learning and changes that take place over long periods of time. In the present study, we performed detailed analyses of the alterations in phosphatidylinositol-specific phospholipase C-beta1a (PLC-beta1a) levels and enzyme activities in subcellular fractions prepared from the hippocampal formation (HPF) and medial frontal cortex (MFC) 1, 3, 5, 7, 24, and 72 h following single-trial fear conditioning. We observed tissue- and time-dependent changes in both PLC-beta1a enzyme activity and anti-PLC-beta1a immunoreactivity in each subcellular fraction. Based on these observations, we hypothesize that changes in PLC-beta1a catalytic activity and subcellular distribution play important roles in neuronal signaling processes that are required for fear-conditioned learning and memory.
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Affiliation(s)
- Edwin J Weeber
- Department of Neurosciences, MSC08 4740, University of New Mexico, Albuquerque, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA
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Bertagnolo V, Brugnoli F, Marchisio M, Celeghini C, Carini C, Capitani S. Association of PI 3-K with tyrosine phosphorylated Vav is essential for its activity in neutrophil-like maturation of myeloid cells. Cell Signal 2004; 16:423-33. [PMID: 14709332 DOI: 10.1016/j.cellsig.2003.09.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The importance of the Vav family of signal transduction molecules in hematopoietic cells has long been acknowledged, even though its role and its regulatory mechanism are not completely understood. We have previously demonstrated that tyrosine-phosphorylated Vav, also located inside the nucleus of myeloid cells, is up-regulated during maturation of promyelocytic precursors induced by all-trans-retinoic acid (ATRA). Here, we report that the tyrosine phosphorylation of Vav during granulocytic maturation is dependent on the tyrosine kinase Syk and is essential for the morphological changes of the cell nucleus. These ATRA-induced events are independent on the guanine nucleotide exchange activity of Vav. We also found that, in differentiating cells, and in both cytoplasmic and nuclear compartments, tyrosine phosphorylated Vav associates with the regulatory subunit of phosphoinositide 3-kinase (PI 3-K). The Vav/p85 interaction is essential for the ATRA-induced PI 3-K activity and for association of PI 3-K with actin, particularly in the nucleus. Our data indicate an unprecedented crucial function for Vav in modulating the morphological maturation process of myeloid cells in a GDP-GTP exchange factor (GEF)-independent manner and suggest a role of Vav as an adaptor protein responsible of targeting PI 3-K to its intranuclear substrates.
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Affiliation(s)
- Valeria Bertagnolo
- Signal Transduction Unit, Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, University of Ferrara, Ferrara, Italy
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Abstract
Strong evidence has been accumulating over the last 15 years suggesting that phosphoinositides, which are involved in the regulation of a large variety of cellular processes in the cytoplasm and in the plasma membrane, are present within the nucleus. Several advances have resulted in the discovery that nuclear phosphoinositides are involved in cell growth and differentiation. Remarkably, the nuclear inositide metabolism is regulated independently from that present elsewhere in the cell. Although nuclear inositol lipids generate second messengers such as diacylglycerol and inositol 1,4,5-trisphosphate, it is becoming increasingly clear that in the nucleus polyphosphoinositides may act by themselves to influence pre-mRNA splicing and chromatin structure. This review aims at highlighting the most significant and updated findings about inositol lipid metabolism in the nucleus.
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Affiliation(s)
- Alberto M Martelli
- Cellular Signalling Laboratory, Department of Human Anatomical Sciences, University of Bologna, via Irnerio 48, 40126, Bologna, Italy
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16
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Bertagnolo V, Puviani AC, Brogli M, Carini C, Brugnoli F, Colamussi ML, Bellini G, Morsiani E, Capitani S. Retinoic acid maintains differentiated cell morphology and functions in long-term cultured porcine hepatocytes: obtaining functional cells for prolonged treatments with bioartificial liver. Int J Artif Organs 2003; 26:498-506. [PMID: 12866655 DOI: 10.1177/039139880302600608] [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: 11/16/2022]
Abstract
Porcine hepatocytes show several immunological characteristics and enzymatic activities of human liver, representing an ideal xenogenic source of cells as biological component of bioartificial liver (BAL). Isolated hepatocytes rapidly lose their specific metabolic activities and their typical morphology when cultured in the presence of serum. Since in BAL porcine hepatocytes are perfused by the patient's plasma, procedures able to minimize de-differentiation of cells could be useful for long-term treatment of acute liver failure (ALF). In this work we found that, in the presence of micromolar concentration of All trans-retinoic acid (ATRA), porcine parenchymal liver cells undergo to a lower extent the de-differentiating effects of long-term culture in the presence of serum. The evaluation of lidocaine metabolism showed that ATRA-treated cells retain specific hepatocyte function for a significantly longer time when compared to control hepatocytes. A tyrosine phosphorylation of PLC-gamma1 was observed in concomitance with the ATRA-induced maximal functional activity. An increased expression of PLC-beta3 and PKC-alpha and -beta2 was also evidentiated at the longer time points explored, when the effects of ATRA in preservation of the differentiated morphology were maximal. These results provide the first evidence that ATRA plays a differentiating role in adult porcine hepatocytes cultured under de-differentiating conditions. The administration of ATRA to isolated parenchymal cells from pig liver may provide functional hepatocytes for prolonged treatment with BAL.
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Affiliation(s)
- V Bertagnolo
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, University of Ferrara, Ferrara, Italy
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17
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Bertagnolo V, Marchisio M, Pierpaoli S, Colamussi ML, Brugnoli F, Visani G, Zauli G, Capitani S. Selective up‐regulation of phospholipase C‐β2 during granulocytic differentiation of normal and leukemic hematopoietic progenitors. J Leukoc Biol 2002. [DOI: 10.1189/jlb.71.6.957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Valeria Bertagnolo
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
| | - Marco Marchisio
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
- Department of Biomorphology, University “G.D’Annunzio”, Chieti, Italy
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Sabina Pierpaoli
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
| | - Maria Luisa Colamussi
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
| | - Federica Brugnoli
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
| | - Giuseppe Visani
- L.A. Seragnoli Institute of Haematology, University of Bologna, Italy; and
| | - Giorgio Zauli
- Department of Normal Human Morphology, University of Trieste, Italy
| | - Silvano Capitani
- Signal Transduction Unit/Laboratory of Cell Biology, Section of Human Anatomy, Department of Morphology and Embryology, and Italy
- MIUR ICSI (Interdisciplinary Center for the Study of Inflammation), University of Ferrara, Italy
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18
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Neri LM, Bortul R, Borgatti P, Tabellini G, Baldini G, Capitani S, Martelli AM. Proliferating or differentiating stimuli act on different lipid-dependent signaling pathways in nuclei of human leukemia cells. Mol Biol Cell 2002; 13:947-64. [PMID: 11907274 PMCID: PMC99611 DOI: 10.1091/mbc.01-02-0086] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Previous results have shown that the human promyelocytic leukemia HL-60 cell line responds to either proliferating or differentiating stimuli. When these cells are induced to proliferate, protein kinase C (PKC)-beta II migrates toward the nucleus, whereas when they are exposed to differentiating agents, there is a nuclear translocation of the alpha isoform of PKC. As a step toward the elucidation of the early intranuclear events that regulate the proliferation or the differentiation process, we show that in the HL-60 cells, a proliferating stimulus (i.e., insulin-like growth factor-I [IGF-I]) increased nuclear diacylglycerol (DAG) production derived from phosphatidylinositol (4,5) bisphosphate, as indicated by the inhibition exerted by 1-O-octadeyl-2-O-methyl-sn-glycero-3-phosphocholine and U-73122 (1-[6((17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione), which are pharmacological inhibitors of phosphoinositide-specific phospholipase C. In contrast, when HL-60 cells were induced to differentiate along the granulocytic lineage by dimethyl sulfoxide, we observed a rise in the nuclear DAG mass, which was sensitive to either neomycin or propranolol, two compounds with inhibitory effect on phospholipase D (PLD)-mediated DAG generation. In nuclei of dimethyl sulfoxide-treated HL-60 cells, we observed a rise in the amount of a 90-kDa PLD, distinct from PLD1 or PLD2. When a phosphatidylinositol (4,5) bisphosphate-derived DAG pool was generated in the nucleus, a selective translocation of PKC-beta II occurred. On the other hand, nuclear DAG derived through PLD, recruited PKC-alpha to the nucleus. Both of these PKC isoforms were phosphorylated on serine residues. These results provide support for the proposal that in the HL-60 cell nucleus there are two independently regulated sources of DAG, both of which are capable of acting as the driving force that attracts to this organelle distinct, DAG-dependent PKC isozymes. Our results assume a particular significance in light of the proposed use of pharmacological inhibitors of PKC-dependent biochemical pathways for the therapy of cancer disease.
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Affiliation(s)
- Luca M Neri
- Dipartimento di Morfologia ed Embriologia, Sezione di Anatomia Umana Normale, Università di Ferrara, 44100 Ferrara, Italy
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Cocco L, Martelli AM, Barnabei O, Manzoli FA. Nuclear inositol lipid signaling. ADVANCES IN ENZYME REGULATION 2001; 41:361-84. [PMID: 11384755 DOI: 10.1016/s0065-2571(00)00017-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- L Cocco
- Cellular Signaling Laboratory, Department of Anatomical Sciences, University of Bologna, Via Irnerio, 48, I-40126, Bologna, Italy
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20
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Cocco L, Martelli AM, Gilmour RS, Rhee SG, Manzoli FA. Nuclear phospholipase C and signaling. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1530:1-14. [PMID: 11341954 DOI: 10.1016/s1388-1981(00)00169-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- L Cocco
- Cellular Signaling Laboratory, Department of Anatomical Sciences and Skeletal Muscle Pathophysiology, University of Bologna, Italy.
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21
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Avazeri N, Courtot AM, Pesty A, Duquenne C, Lefèvre B. Cytoplasmic and nuclear phospholipase C-beta 1 relocation: role in resumption of meiosis in the mouse oocyte. Mol Biol Cell 2000; 11:4369-80. [PMID: 11102530 PMCID: PMC15079 DOI: 10.1091/mbc.11.12.4369] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The location of the phospholipase C beta 1-isoform (PLC-beta 1) in the mouse oocyte and its role in the resumption of meiosis were examined. We used specific monoclonal antibodies to monitor the in vitro dynamics of the subcellular distribution of the enzyme from the release of the oocyte from the follicle until breakdown of the germinal vesicle (GVBD) by Western blotting, electron microscope immunohistochemistry, and confocal microscope immunofluorescence. PLC-beta 1 became relocated to the oocyte cortex and the nucleoplasm during the G2/M transition, mainly in the hour preceding GVBD. The enzyme was a 150-kDa protein, corresponding to PLC-beta 1a. Its synthesis in the cytoplasm increased during this period, and it accumulated in the nucleoplasm. GVBD was dramatically inhibited by the microinjection of anti-PLC-beta1 monoclonal antibody into the germinal vesicle (GV) only when this accumulation was at its maximum. In contrast, PLC-gamma 1 was absent from the GV from the time of release from the follicle until 1 h later, and microinjection of anti-PLC-gamma 1 into the GV did not affect GVBD. Our results demonstrate a relationship between the relocation of PLC-beta 1 and its role in the first step of meiosis.
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Affiliation(s)
- N Avazeri
- Institut National de la Santé et de la Recherche Médicale Unité 355, 92140 Clamart, France
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22
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Di Pietro R, Miscia S, Cataldi A, Rana R. Age-dependent variations in the expression of PLC isoforms upon mitogenic stimulation of peripheral blood T cells from healthy donors. Br J Haematol 2000; 111:1209-14. [PMID: 11167763 DOI: 10.1046/j.1365-2141.2000.02492.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The activation of phosphoinositide-specific phospholipase C (PLC) is one of the early responses to various growth factors and it is known that these functions are altered with ageing. In the present investigation, the expression and cellular distribution of PLC isoenzymes in immunocompetent T lymphocytes from a test group of healthy individuals over 65 years old and a comparison group of healthy donors below 30 years old were compared using Western blot and confocal microscopy. All lymphocyte samples responded biochemically to phytohaemagglutinin (PHA) stimulation, as shown by at least 10-fold increases in the beta(3) isoform and nuclear translocation of the beta(1), beta(2), beta(3), beta(4), gamma(1) and gamma(2) isoforms; however, consistent differences in the expression of the beta(2) isoform in unstimulated T cells and of the beta(2) and gamma(2) isoforms in stimulated T cells suggest that altered functions of the PLC pathway may have an age-dependent impact on signal transduction events.
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Affiliation(s)
- R Di Pietro
- Istituto di Morfologia Umana Normale, Università G. D'Annunzio, Chieti Scalo, Italy.
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23
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Di Pietro R, Miscia S, Cataldi A, Rana R. Age-dependent variations in the expression of PLC isoforms upon mitogenic stimulation of peripheral blood T cells from healthy donors. Br J Haematol 2000. [DOI: 10.1111/j.1365-2141.2000.02492.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Rebecchi MJ, Pentyala SN. Structure, function, and control of phosphoinositide-specific phospholipase C. Physiol Rev 2000; 80:1291-335. [PMID: 11015615 DOI: 10.1152/physrev.2000.80.4.1291] [Citation(s) in RCA: 725] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phosphoinositide-specific phospholipase C (PLC) subtypes beta, gamma, and delta comprise a related group of multidomain phosphodiesterases that cleave the polar head groups from inositol lipids. Activated by all classes of cell surface receptor, these enzymes generate the ubiquitous second messengers inositol 1,4, 5-trisphosphate and diacylglycerol. The last 5 years have seen remarkable advances in our understanding of the molecular and biological facets of PLCs. New insights into their multidomain arrangement and catalytic mechanism have been gained from crystallographic studies of PLC-delta(1), while new modes of controlling PLC activity have been uncovered in cellular studies. Most notable is the realization that PLC-beta, -gamma, and -delta isoforms act in concert, each contributing to a specific aspect of the cellular response. Clues to their true biological roles were also obtained. Long assumed to function broadly in calcium-regulated processes, genetic studies in yeast, slime molds, plants, flies, and mammals point to specific and conditional roles for each PLC isoform in cell signaling and development. In this review we consider each subtype of PLC in organisms ranging from yeast to mammals and discuss their molecular regulation and biological function.
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Affiliation(s)
- M J Rebecchi
- Departments of Anesthesiology and Physiology and Biophysics, School of Medicine, State University of New York, Stony Brook, New York 11794, USA.
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25
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Abstract
Fyn protein tyrosine kinase is present in the unfertilized and fertilized egg, becomes activated within minutes following fertilization, and has been localized to the cortical cytoplasm and spindle apparatus of the zygote. In order to establish the expression pattern of Fyn in the early embryo, we examined the distribution pattern of Fyn by immunofluorescence microscopy. Fyn protein is distributed evenly among cells of the cleavage stage zebrafish embryo and is concentrated in the cortical region of each cell. During blastula and gastrula stages, Fyn was expressed in all cells, however a subpopulation of cells exhibited strong nuclear staining for Fyn. Nuclear Fyn staining was not observed after the gastrula period of development, nor in the adult zebrafish. Immunoprecipitation of Fyn from isolated mid-blastula nuclei confirmed Fyn was present in the nucleus. This is, to our knowledge, the first demonstration of Fyn kinase, which lacks a nuclear localization signal, present in the nucleus. The transient compartmentalization of Fyn in the nucleus could be important in nuclear signaling.
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Affiliation(s)
- B J Rongish
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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26
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Yamaga M, Fujii M, Kamata H, Hirata H, Yagisawa H. Phospholipase C-delta1 contains a functional nuclear export signal sequence. J Biol Chem 1999; 274:28537-41. [PMID: 10497218 DOI: 10.1074/jbc.274.40.28537] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously observed, using a green fluorescent protein (GFP) fusion system, that PLC-delta1 is localized mainly at the plasma membrane and in the cytosol, whereas little is present in the nucleus in Madin-Darby canine kidney cells (Fujii, M., Ohtsubo, M., Ogawa, T., Kamata, H., Hirata, H., and Yagisawa, H. (1999) Biochem. Biophys. Res. Commun. 254, 284-291). Herein, we demonstrate that PLC-delta1 has a functional nuclear export signal (NES) sequence in amino acid residues 164-177 of the EF-hand domain. The fluorescence of NES-disrupted GFP/PLC-delta1 expressed in Madin-Darby canine kidney cells was present not only at the plasma membrane and in the cytosol but also in the nucleus. Moreover, treatment with leptomycin B, a specific inhibitor of NES-dependent nuclear export, resulted in the accumulation of GFP/PLC-delta1 in the nucleus. A site-directed mutant containing a pleckstrin homology domain, which does not bind inositol 1,4,5-trisphosphate and cannot hydrolyze phosphatidylinositol 4,5-bisphosphate in vitro, accumulated in the nucleus to a much greater extent than wild-type GFP/PLC-delta1 after treatment with leptomycin B. These results suggest that PLC-delta1 is shuttled between the cytoplasm and the nucleus; its nuclear export is dependent on the leucine-rich NES sequence and its active nuclear import is regulated by an unidentified signal(s).
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Affiliation(s)
- M Yamaga
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Harima Science Garden City, Hyogo 678-1297, Japan
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Neri LM, Marchisio M, Colamussi ML, Bertagnolo V. Monocytic differentiation of HL-60 cells is characterized by the nuclear translocation of phosphatidylinositol 3-kinase and of definite phosphatidylinositol-specific phospholipase C isoforms. Biochem Biophys Res Commun 1999; 259:314-20. [PMID: 10362505 DOI: 10.1006/bbrc.1999.0786] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Immunochemical and immunocytochemical data indicate that nuclei of HL-60 cells contain different enzymes involved in the phosphoinositide cycle, such as PI 3-K and the phosphatidylinositol-specific PLC isoforms beta3, gamma1 and gamma2. These enzymes translocate differently to the nuclear fraction when HL-60 cells are treated with differentiating doses of vitamin D3: PI 3-K translocated progressively to the nucleus in parallel with full differentiation until 96 hours. PLC beta3 increased until 72 hours of treatment and then lowered its intranuclear amount and PLC gamma1 was unchanged at all the examined times. PLC gamma2 nuclear translocation increased progressively until 96 hours of vitamin D3 administration. A fourth PLC isozyme, beta2, present in the cytoplasm of untreated cells, translocates to the cytoplasm after vitamin D3 addition and reaches the highest concentration at the end of monocytic differentiation. Terminal monocytic differentiation was characterized at the nuclear level by high levels of PI 3-K and PLC gamma2 and by the novel expression of PLC beta2. We then observed that the xi isoform of PKC, constitutively present in nuclei of HL-60 cells, translocated to the nucleus when cells were induced to differentiate along the monocytic lineage, but the nuclear translocation of PKC xi was blocked as a consequence of PI 3-K inhibition by Wortmannin. These findings indicate that the main components of the noncanonical and canonical inositol lipid signal transduction pathways, including PI 3-K, PLC beta2 and beta3, PLC gamma2, undergo nuclear translocation and may therefore play a relevant role during monocytic differentiation at the nuclear level. Furthermore, PKC xi nuclear translocation appears to be related to PI 3-K activity.
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Affiliation(s)
- L M Neri
- Section of Human Anatomy, University of Ferrara, Ferrara, Italy.
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28
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Martelli AM, Cocco L, Bareggi R, Tabellini G, Rizzoli R, Ghibellini MD, Narducci P. Insulin-like growth factor-I-dependent stimulation of nuclear phospholipase C-beta1 activity in Swiss 3T3 cells requires an intact cytoskeleton and is paralleled by increased phosphorylation of the phospholipase. J Cell Biochem 1999; 72:339-48. [PMID: 10022515 DOI: 10.1002/(sici)1097-4644(19990301)72:3<339::aid-jcb3>3.0.co;2-l] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Swiss 3T3 mouse fibroblasts were exposed to 10 microM colchicine to disrupt microtubules, then stimulated with insulin-like growth factor-I. Immunoprecipitation experiments showed that insulin-like growth factor-I receptor and insulin receptor substrate-1 were tyrosine phosphorylated to the same extent in both cells treated with colchicine and in those not exposed to the drug. Moreover, the activity of phosphatidylinositol 3-kinase was not affected by incubation with colchicine. While in nuclei prepared from cells not exposed to colchicine it was possible to detect an insulin-like growth factor-I-dependent increase in the mass of diacylglycerol, as well as stimulation of phospholipase C activity, no similar changes were observed in nuclei obtained from cells treated with colchicine. Activation of the nuclear phospholipase activity was paralleled by an increase of its phosphorylation. Immunofluorescent studies revealed that mitogen-activated protein kinase did not translocate towards the nucleus when the cytoskeleton was depolymerized. These results show that in Swiss 3T3 cells some as yet unknown events necessary for the insulin-like growth factor-I-dependent activation of nuclear polyphosphoinositide metabolism require the presence of an intact cytoskeleton and are situated down-stream the activation of insulin receptor substrate-1 and phosphatidylinositol 3-kinase. Activation of nuclear phospholipase C-beta1 might be linked to its phosphorylation and translocation of mitogen-activated protein kinase to the nucleus.
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Affiliation(s)
- A M Martelli
- Dipartimento di Morfologia Umana Normale, Università di Trieste, Italy.
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29
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Bertagnolo V, Marchisio M, Volinia S, Caramelli E, Capitani S. Nuclear association of tyrosine-phosphorylated Vav to phospholipase C-gamma1 and phosphoinositide 3-kinase during granulocytic differentiation of HL-60 cells. FEBS Lett 1998; 441:480-4. [PMID: 9891995 DOI: 10.1016/s0014-5793(98)01593-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The granulocytic differentiation of HL-60 cells induced by all-trans retinoic acid was accompanied by a progressive tyrosine phosphorylation of specific proteins in either cells or isolated nuclei. Among these phosphoproteins, we identified the Vav adaptor in whole cells as well as in the inner nuclear compartment, where the increase in its tyrosine phosphorylation level was more conspicuous. We also demonstrated the differentiation-dependent association of nuclear phosphorylated Vav to phospholipase C-gamma1 and to the p85 regulatory subunit of phosphoinositide 3-kinase. The role of the Vav/phospholipase C-gamma1/phosphoinositide 3-kinase phosphoprotein complexes in the nuclei of HL-60 induced to differentiate along the granulocytic lineage is discussed.
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Affiliation(s)
- V Bertagnolo
- Department of Morphology and Embryology, University of Ferrara, Italy
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30
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Marchisio M, Bertagnolo V, Colamussi ML, Capitani S, Neri LM. Phosphatidylinositol 3-kinase in HL-60 nuclei is bound to the nuclear matrix and increases during granulocytic differentiation. Biochem Biophys Res Commun 1998; 253:346-51. [PMID: 9878540 DOI: 10.1006/bbrc.1998.9787] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have used HL-60 leukemia cells to investigate phosphatidylinositol 3-kinase (PI 3-K) during granulocytic differentiation at the nuclear level. Nuclei of HL-60 cells showed a constitutive presence of PI 3-K that increased when cells were treated with differentiating doses of ATRA. PI 3-K was also detected tightly bound to nuclear matrices of HL-60 cells, isolated by nuclease treatment and high salt extraction. Four days of ATRA treatment induced a striking increase of nuclear matrix bound PI 3-K. In situ morphological analysis by confocal microscopy showed the translocation of PI 3-K to the nucleus and to the subnuclear fractions. PI 3-K enzymatic activity was stimulated during the granulocytic differentiation process and parallelled the increase in content of nuclei and subnuclear fractions. PI 3-K activity was recovered in nuclei also without the addition of exogenous substrates, consistent with the presence of both substrates and enzyme in the nucleus. These results indicate that specific intracellular localization of PI 3-K determines the production of different phosphoinositides in the sites of the enzyme translocation, and suggest that 3-phosphoinositide metabolism may play a specific role in the nucleus, candidating PI 3-K as a key enzyme in promoting granulocytic differentiation of HL-60 cells.
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Affiliation(s)
- M Marchisio
- Section of Human Anatomy, University of Ferrara, Italy
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31
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D'Santos CS, Clarke JH, Divecha N. Phospholipid signalling in the nucleus. Een DAG uit het leven van de inositide signalering in de nucleus. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1436:201-32. [PMID: 9838115 DOI: 10.1016/s0005-2760(98)00146-5] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Diverse methodologies, ranging from activity measurements in various nuclear subfractions to electron microscopy, have been used to demonstrate and establish that many of the key lipids and enzymes responsible for the metabolism of inositol lipids are resident in nuclei. PtdIns(4)P, PtdIns(4,5)P2 and PtdOH are all present in nuclei, as well as the corresponding enzyme activities required to synthesise and metabolise these compounds. In addition other non-inositol containing phospholipids such as phosphatidylcholine constitute a significant percentage of the total nuclear phospholipid content. We feel that it is pertinent to include this lipid in our discussion as it provides an alternative source of 1, 2-diacylglycerol (DAG) in addition to the hydrolysis of PtdIns(4, 5)P2. We discuss at length data related to the sources and possible consequences of nuclear DAG production as this lipid appears to be increasingly central to a number of general physiological functions. Data relating to the existence of alternative pathways of inositol phospholipid synthesis, the role of 3-phosphorylated inositol lipids and lipid compartmentalisation and transport are reviewed. The field has also expanded to a point where we can now also begin to address what role these lipids play in cellular proliferation and differentiation and hopefully provide avenues for further research.
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Affiliation(s)
- C S D'Santos
- The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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32
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Wang S, Zhou Y, Lukinius A, Oberg K, Skogseid B, Gobl A. Molecular cloning and characterization of a cDNA encoding mouse phospholipase C-beta3. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1393:173-8. [PMID: 9714794 DOI: 10.1016/s0005-2760(98)00074-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A cDNA encoding mouse PLC-beta3 (mPLC-beta3) was identified by screening a mouse kidney cDNA library and using the rapid amplification of cDNA ends (RACE) method. The predicted open reading frame was 3705 bp in length. The deduced 1235 amino acid (aa) sequence shares 95.3% and 92% homology with the sequences of rat and human PLC-beta3, respectively. The corresponding mRNA is highly expressed in kidney, skeletal muscle, liver, lung, heart and brain. In spleen, mPLC-beta3 mRNA was not detectable, which is in contrast to humans where there is a distinct expression. Using ultrastructural immunocytochemistry, mPLC-beta3 expression was detected in the heterochromatin of the nucleus in mouse brain neurons. The observation of PLC-beta3 nuclear localization suggests that PLC-beta3 may have intranuclear functions.
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Affiliation(s)
- S Wang
- Department of Internal Medicine, Uppsala University Hospital, S-751 85 Uppsala, Sweden
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