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Phuyal S, Farhan H. Multifaceted Rho GTPase Signaling at the Endomembranes. Front Cell Dev Biol 2019; 7:127. [PMID: 31380367 PMCID: PMC6646525 DOI: 10.3389/fcell.2019.00127] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 06/28/2019] [Indexed: 12/14/2022] Open
Abstract
The Rho family of small GTPases orchestrates fundamental biological processes such as cell cycle progression, cell migration, and actin cytoskeleton dynamics, and their aberrant signaling is linked to numerous human diseases and disorders. Traditionally, active Rho GTPase proteins were proposed to reside and function predominantly at the plasma membrane. While this view still holds true, it is emerging that active pool of multiple Rho GTPases are in part localized to endomembranes such as endosomes and the Golgi. In this review, we will focus on the intracellular pools and discuss how their local activation contributes to the shaping of various cellular processes. Our main focus will be on Rho signaling from the endosomes, Golgi, mitochondria and nucleus and how they regulate multiple cellular events such as receptor trafficking, cell proliferation and differentiation, cell migration and polarity.
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Affiliation(s)
- Santosh Phuyal
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Hesso Farhan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Nucleoligands-repurposing G Protein-coupled Receptor Ligands to Modulate Nuclear-localized G Protein-coupled Receptors in the Cardiovascular System. J Cardiovasc Pharmacol 2019; 71:193-204. [PMID: 28858907 DOI: 10.1097/fjc.0000000000000535] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
There is significant evidence that internal pools of G protein-coupled receptors (GPCRs) exist and may be affected by both endogenous signaling molecules and hydrophobic pharmaceutical ligands, once assumed to only affect cell surface versions of these receptors. Here, we discuss evidence that the biology of nuclear GPCRs in particular is complex, rich, and highly interactive with GPCR signaling from the cell surface. Caging existing GPCR ligands may be an excellent means of further stratifying the phenotypic effects of known pharmacophores such as β-adrenergic, angiotensin II, and type B endothelin receptor ligands in the cardiovascular system. We describe some synthetic strategies we have used to design ligands to go from in cellulo to in vivo experiments. We also consider how surface and intracellular GPCR signaling might be integrated and ways to dissect this. If they could be selectively targeted, nuclear GPCRs and their associated nucleoligands would represent a completely novel area for exploration by Pharma.
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Abdrabou A, Wang Z. Post-Translational Modification and Subcellular Distribution of Rac1: An Update. Cells 2018; 7:cells7120263. [PMID: 30544910 PMCID: PMC6316090 DOI: 10.3390/cells7120263] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/27/2022] Open
Abstract
Rac1 is a small GTPase that belongs to the Rho family. The Rho family of small GTPases is a subfamily of the Ras superfamily. The Rho family of GTPases mediate a plethora of cellular effects, including regulation of cytoarchitecture, cell size, cell adhesion, cell polarity, cell motility, proliferation, apoptosis/survival, and membrane trafficking. The cycling of Rac1 between the GTP (guanosine triphosphate)- and GDP (guanosine diphosphate)-bound states is essential for effective signal flow to elicit downstream biological functions. The cycle between inactive and active forms is controlled by three classes of regulatory proteins: Guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine-nucleotide-dissociation inhibitors (GDIs). Other modifications include RNA splicing and microRNAs; various post-translational modifications have also been shown to regulate the activity and function of Rac1. The reported post-translational modifications include lipidation, ubiquitination, phosphorylation, and adenylylation, which have all been shown to play important roles in the regulation of Rac1 and other Rho GTPases. Moreover, the Rac1 activity and function are regulated by its subcellular distribution and translocation. This review focused on the most recent progress in Rac1 research, especially in the area of post-translational modification and subcellular distribution and translocation.
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Affiliation(s)
- Abdalla Abdrabou
- Department of Medical Genetics, and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Zhixiang Wang
- Department of Medical Genetics, and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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Phospholipase D inhibitors reduce human prostate cancer cell proliferation and colony formation. Br J Cancer 2017; 118:189-199. [PMID: 29136407 PMCID: PMC5785744 DOI: 10.1038/bjc.2017.391] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/17/2017] [Accepted: 10/02/2017] [Indexed: 12/12/2022] Open
Abstract
Background: Phospholipases D1 and D2 (PLD1/2) hydrolyse cell membrane glycerophospholipids to generate phosphatidic acid, a signalling lipid, which regulates cell growth and cancer progression through effects on mTOR and PKB/Akt. PLD expression and/or activity is raised in breast, colorectal, gastric, kidney and thyroid carcinomas but its role in prostate cancer (PCa), the major cancer of men in the western world, is unclear. Methods: PLD1 protein expression in cultured PNT2C2, PNT1A, P4E6, LNCaP, PC3, PC3M, VCaP, 22RV1 cell lines and patient-derived PCa cells was analysed by western blotting. PLD1 protein localisation in normal, benign prostatic hyperplasia (BPH), and castrate-resistant prostate cancer (CRPC) tissue sections and in a PCa tissue microarray (TMA) was examined by immunohistochemistry. PLD activity in PCa tissue was assayed using an Amplex Red method. The effect of PLD inhibitors on PCa cell viability was measured using MTS and colony forming assays. Results: PLD1 protein expression was low in the luminal prostate cell lines (LNCaP, VCaP, 22RV1) compared with basal lines (PC3 and PC3M). PLD1 protein expression was elevated in BPH biopsy tissue relative to normal and PCa samples. In normal and BPH tissue, PLD1 was predominantly detected in basal cells as well in some stromal cells, rather than in luminal cells. In PCa tissue, luminal cells expressed PLD1. In a PCa TMA, the mean peroxidase intensity per DAB-stained Gleason 6 and 7 tissue section was significantly higher than in sections graded Gleason 9. In CRPC tissue, PLD1 was expressed prominently in the stromal compartment, in luminal cells in occasional glands and in an expanding population of cells that co-expressed chromogranin A and neurone-specific enolase. Levels of PLD activity in normal and PCa tissue samples were similar. A specific PLD1 inhibitor markedly reduced the survival of both prostate cell lines and patient-derived PCa cells compared with two dual PLD1/PLD2 inhibitors. Short-term exposure of PCa cells to the same specific PLD1 inhibitor significantly reduced colony formation. Conclusions: A new specific inhibitor of PLD1, which is well tolerated in mice, reduces PCa cell survival and thus has potential as a novel therapeutic agent to reduce prostate cancer progression. Increased PLD1 expression may contribute to the hyperplasia characteristic of BPH and in the progression of castrate-resistant PCa, where an expanding population of neuroendocrine-like cells express PLD1.
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Abstract
G protein-coupled receptors (GPCRs) play key physiological roles and represent a significant target for drug development. However, historically, drugs were developed with the understanding that GPCRs as a therapeutic target exist solely on cell surface membranes. More recently, GPCRs have been detected on intracellular membranes, including the nuclear membrane, and the concept that intracellular GPCRs are functional is become more widely accepted. Nuclear GPCRs couple to effectors and regulate signaling pathways, analogous to their counterparts at the cell surface, but may serve distinct biological roles. Hence, the physiological responses mediated by GPCR ligands, or pharmacological agents, result from the integration of their actions at extracellular and intracellular receptors. The net effect depends on the ability of a given ligand or drug to access intracellular receptors, as dictated by its structure, lipophilic properties, and affinity for nuclear receptors. This review will discuss angiotensin II, endothelin, and β-adrenergic receptors located on the nuclear envelope in cardiac cells in terms of their origin, activation, and role in cardiovascular function and pathology.
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Tong J, Li L, Ballermann B, Wang Z. Phosphorylation and Activation of RhoA by ERK in Response to Epidermal Growth Factor Stimulation. PLoS One 2016; 11:e0147103. [PMID: 26816343 PMCID: PMC4729484 DOI: 10.1371/journal.pone.0147103] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/29/2015] [Indexed: 12/21/2022] Open
Abstract
The small GTPase RhoA has been implicated in various cellular activities, including the formation of stress fibers, cell motility, and cytokinesis. In addition to the canonical GTPase cycle, recent findings have suggested that phosphorylation further contributes to the tight regulation of Rho GTPases. Indeed, RhoA is phosphorylated on serine 188 (188S) by a number of protein kinases. We have recently reported that Rac1 is phosphorylated on threonine 108 (108T) by extracellular signal-regulated kinases (ERK) in response to epidermal growth factor (EGF) stimulation. Here, we provide evidence that RhoA is phosphorylated by ERK on 88S and 100T in response to EGF stimulation. We show that ERK interacts with RhoA and that this interaction is dependent on the ERK docking site (D-site) at the C-terminus of RhoA. EGF stimulation enhanced the activation of the endogenous RhoA. The phosphomimetic mutant, GFP-RhoA S88E/T100E, when transiently expressed in COS-7 cells, displayed higher GTP-binding than wild type RhoA. Moreover, the expression of GFP-RhoA S88E/T100E increased actin stress fiber formation in COS-7 cells, which is consistent with its higher activity. In contrast to Rac1, phosphorylation of RhoA by ERK does not target RhoA to the nucleus. Finally, we show that regardless of the phosphorylation status of RhoA and Rac1, substitution of the RhoA PBR with the Rac1 PBR targets RhoA to the nucleus and substitution of Rac1 PBR with RhoA PBR significantly reduces the nuclear localization of Rac1. In conclusion, ERK phosphorylates RhoA on 88S and 100T in response to EGF, which upregulates RhoA activity.
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Affiliation(s)
- Junfeng Tong
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Laiji Li
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Barbara Ballermann
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Zhixiang Wang
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- * E-mail:
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Hsu CY, Chang ZF, Lee HH. Immunohistochemical evaluation of ROCK activation in invasive breast cancer. BMC Cancer 2015; 15:943. [PMID: 26626121 PMCID: PMC4665871 DOI: 10.1186/s12885-015-1948-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 11/20/2015] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Two isoforms of Rho-associated coiled-coil kinase (ROCK), ROCKI and ROCKII, play an important role in many cellular processes. Despite the accumulating evidence showing that ROCK could be a potential cancer therapeutic target, the relevant tumor types to ROCK activation are not well clarified. The aim of this study was to evaluate the ROCK activation status in different tumor types of breast cancer. RESULTS We evaluated the immunoreactivities of phosphorylation-specific antibodies of ROCKI and ROCKII to inform their kinase activation in 275 of breast carcinoma tissues, including 56 of carcinoma in situ, 116 of invasive carcinoma, and 103 of invasive carcinoma with metastasis. ROCKII activation signal detected in nucleus was significantly correlated with tumor metastasis, while ROCKI and cytosolic ROCKII activation signals made no significant difference in that metastasis. Furthermore, nuclear ROCKII activation signal was associated with poor clinical outcome and correlated with late tumor stage, low expression of estrogen receptor (ER) and progesterone receptor (PR), overexpression of human epidermal growth factor receptor 2 (HER2) and high Ki67 labeling index. CONCLUSIONS Nuclear ROCKII activation signal might contribute to the tumor metastasis in breast cancer. Differences in ROCK activation that underlie the phenotypes of breast cancer could enhance our understanding for the use of ROCK inhibitors in cancer therapy.
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Affiliation(s)
- Chih-Yi Hsu
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shipai Rd, Taipei, Taiwan ROC. .,Department of Pathology, National Yang-Ming University School of Medicine, No. 155, Sec. 2, Linong St, Taipei, Taiwan ROC.
| | - Zee-Fen Chang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155, Sec. 2, Linong St, Taipei, Taiwan ROC.
| | - Hsiao-Hui Lee
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, 11221 No. 155, Sec. 2, Linong Street, Taipei, Taiwan ROC.
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Lee SJ, Yi T, Ahn SH, Lim DK, Hong JY, Cho YK, Lim J, Song SU, Kwon SW. Senescing Human Bone-Marrow-Derived Clonal Mesenchymal Stem Cells Have Altered Lysophospholipid Composition and Functionality. J Proteome Res 2014; 13:1438-49. [DOI: 10.1021/pr400990k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Seul Ji Lee
- College
of Pharmacy, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151742, Korea
| | - TacGhee Yi
- HomeoTherapy, Co. Ltd., 3ga, Sinheung-dong, Incheon 400-711, Korea
| | - Soo Hyun Ahn
- Department
of Statistics, Seoul National University, Seoul, Korea
| | - Dong Kyu Lim
- College
of Pharmacy, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151742, Korea
| | - Ji Yeon Hong
- College
of Pharmacy, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151742, Korea
| | - Yun Kyoung Cho
- HomeoTherapy, Co. Ltd., 3ga, Sinheung-dong, Incheon 400-711, Korea
| | - Johan Lim
- Department
of Statistics, Seoul National University, Seoul, Korea
| | - Sun U. Song
- HomeoTherapy, Co. Ltd., 3ga, Sinheung-dong, Incheon 400-711, Korea
| | - Sung Won Kwon
- College
of Pharmacy, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151742, Korea
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Shah ZH, Jones DR, Sommer L, Foulger R, Bultsma Y, D'Santos C, Divecha N. Nuclear phosphoinositides and their impact on nuclear functions. FEBS J 2013; 280:6295-310. [PMID: 24112514 DOI: 10.1111/febs.12543] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/11/2013] [Accepted: 09/16/2013] [Indexed: 12/23/2022]
Abstract
Polyphosphoinositides (PPIn) are important lipid molecules whose levels are de-regulated in human diseases such as cancer, neurodegenerative disorders and metabolic syndromes. PPIn are synthesized and degraded by an array of kinases, phosphatases and lipases which are localized to various subcellular compartments and are subject to regulation in response to both extra- and intracellular cues. Changes in the activities of enzymes that metabolize PPIn lead to changes in the profiles of PPIn in various subcellular compartments. Understanding how subcellular PPIn are regulated and how they affect downstream signaling is critical to understanding their roles in human diseases. PPIn are present in the nucleus, and their levels are changed in response to various stimuli, suggesting that they may serve to regulate specific nuclear functions. However, the lack of nuclear downstream targets has hindered the definition of which pathways nuclear PPIn affect. Over recent years, targeted and global proteomic studies have identified a plethora of potential PPIn-interacting proteins involved in many aspects of transcription, chromatin remodelling and mRNA maturation, suggesting that PPIn signalling within the nucleus represents a largely unexplored novel layer of complexity in the regulation of nuclear functions.
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Affiliation(s)
- Zahid H Shah
- Cancer Research UK Inositide Laboratory, Paterson Institute for Cancer Research, Manchester, UK
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Don-Salu-Hewage AS, Chan SY, McAndrews KM, Chetram MA, Dawson MR, Bethea DA, Hinton CV. Cysteine (C)-x-C receptor 4 undergoes transportin 1-dependent nuclear localization and remains functional at the nucleus of metastatic prostate cancer cells. PLoS One 2013; 8:e57194. [PMID: 23468933 PMCID: PMC3585330 DOI: 10.1371/journal.pone.0057194] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 01/18/2013] [Indexed: 01/01/2023] Open
Abstract
The G-protein coupled receptor (GPCR), Cysteine (C)-X-C Receptor 4 (CXCR4), plays an important role in prostate cancer metastasis. CXCR4 is generally regarded as a plasma membrane receptor where it transmits signals that support transformation, progression and eventual metastasis. Due to the central role of CXCR4 in tumorigenesis, therapeutics approaches such as antagonist and monoclonal antibodies have focused on receptors that exist on the plasma membrane. An emerging concept for G-protein coupled receptors is that they may localize to and associate with the nucleus where they retain function and mediate nuclear signaling. Herein, we demonstrate that CXCR4 associated with the nucleus of malignant prostate cancer tissues. Likewise, expression of CXCR4 was detected in nuclear fractions among several prostate cancer cell lines, compared to normal prostate epithelial cells. Our studies identified a nuclear pool of CXCR4 and we defined a nuclear transport pathway for CXCR4. We reveal a putative nuclear localization sequence (NLS), ‘RPRK’, within CXCR4 that contributed to nuclear localization. Additionally, nuclear CXCR4 interacted with Transportinβ1 and Transportinβ1-binding to CXCR4 promoted its nuclear translocation. Importantly, Gαi immunoprecipitation and calcium mobilization studies indicated that nuclear CXCR4 was functional and participated in G-protein signaling, revealing that the nuclear pool of CXCR4 retained function. Given the suggestion that functional, nuclear CXCR4 may be a mechanism underlying prostate cancer recurrence, increased metastatic ability and poorer prognosis after tumors have been treated with therapy that targets plasma membrane CXCR4, these studies addresses a novel mechanism of nuclear signaling for CXCR4, a novel mechanism of clinical targeting, and demonstrate an active nuclear pool that provides important new information to illuminate what has been primarily clinical reports of nuclear CXCR4.
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Affiliation(s)
- Ayesha S. Don-Salu-Hewage
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia, United States of America
- Department of Biological Sciences, Clark Atlanta University, Atlanta, Georgia, United States of America
| | - Siu Yuen Chan
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, PRC
| | - Kathleen M. McAndrews
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Mahandranauth A. Chetram
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia, United States of America
- Department of Biological Sciences, Clark Atlanta University, Atlanta, Georgia, United States of America
| | - Michelle R. Dawson
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Danaya A. Bethea
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia, United States of America
| | - Cimona V. Hinton
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, Georgia, United States of America
- * E-mail:
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Jang YH, Min DS. Nuclear localization of phospholipase D1 mediates the activation of nuclear protein kinase C(alpha) and extracellular signal-regulated kinase signaling pathways. J Biol Chem 2010; 286:4680-9. [PMID: 21113078 DOI: 10.1074/jbc.m110.162602] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Recent studies highlight the existence of a nuclear lipid metabolism related to cellular proliferation. However, the importance of nuclear phosphatidylcholine (PC) metabolism is poorly understood. Therefore, we were interested in nuclear PC as a source of second messengers and, particularly, nuclear localization of PC-specific phospholipase D (PLD). In the present study we have identified the nuclear localization sequence (NLS) of PLD1 whose mutation abolished its nuclear import. Recently, we reported that caspase-mediated cleavage of PLD1 generates the N-terminal fragment (NF-PLD1) and C-terminal fragment (CF-PLD1). Here we show that CF-PLD1 but not NF-PLD1, is exclusively imported into the nucleus via its functional NLS, whereas only some portions of intact PLD1 were localized into the nucleus. The NLS of intact PLD1 or CF-PLD1 is required for interaction with importin-β, which is known to mediate nuclear import. The amount of intact PLD1 or CF-PLD1 translocated into nucleus is correlated with its binding affinity with importin-β. Ultimately, nuclear localization of intact PLD1 but not CF-PLD1 mediates the activation of nuclear protein kinase Cα and extracellular signal-regulated kinase signaling pathways. Taken together, we propose that nuclear localization of PLD1 via the NLS and its interaction with importin-β may provide new insights on the functional role of nuclear PLD1 signaling.
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Affiliation(s)
- Young Hoon Jang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 609-735, Korea
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Kim S, Kim H, Lee Y, Hyun JW, Lee YH, Shin MK, Min DS, Shin T. The expression and cellular localization of phospholipase D isozymes in the developing mouse testis. J Vet Sci 2007; 8:209-12. [PMID: 17679764 PMCID: PMC2868124 DOI: 10.4142/jvs.2007.8.3.209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To examine the involvement of phospholipase D (PLD) isozymes in postnatal testis development, the expression of PLD1 and PLD2 was examined in the mouse testis at postnatal weeks 1, 2, 4, and 8 using Western blot analysis and immunohistochemistry. The expression of both PLD1 and PLD2 increased gradually with development from postnatal week 1 to 8. Immunohistochemically, PLD immunoreactivity was detected in some germ cells in the testis and interstitial Leydig cells at postnatal week 1. PLD was mainly detected in the spermatocytes and residual bodies of spermatids in the testis after 8 weeks after birth. The intense immunostaining of PLD in Leydig cells remained unchanged by postnatal week 8. These findings suggest that PLD isozymes are involved in the spermatogenesis of the mouse testis.
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Affiliation(s)
- Seungjoon Kim
- Department of Veterinary Medicine, College of Applied Life Sciences, Cheju National University, Jeju, Korea
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16
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Grabocka E, Wedegaertner PB. Disruption of oligomerization induces nucleocytoplasmic shuttling of leukemia-associated rho Guanine-nucleotide exchange factor. Mol Pharmacol 2007; 72:993-1002. [PMID: 17609419 DOI: 10.1124/mol.107.035162] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The rgsRhoGEFs comprise a subfamily of three guanine nucleotide exchange factors, which function in linking heterotrimeric G-proteins to the monomeric RhoGTPase. Here, we reveal the novel finding that oligomerization of leukemia-associated RhoGEF (LARG) functions to prevent nucleocytoplasmic shuttling and to retain LARG in the cytoplasm. We establish that oligomerization is mediated by a predicted coiled-coil sequence (amino acids 1507-1520) in the extreme C terminus of LARG and that substitution of isoleucines 1507/1510 with alanines disrupts homo-oligomerization and leads to nucleocytoplasmic shuttling via the CRM1 nuclear transport pathway. In addition, we demonstrate that induced dimerization of an otherwise nuclear monomeric LARG mutant promotes cytoplasmic localization. Furthermore, we establish that nuclear import of monomeric LARG is mediated by the nuclear localization sequence (29)PTDKKQK(35) in the extreme N terminus. We propose that nucleocytoplasmic shuttling provides a mechanism for spatially regulating the activity of LARG toward its cytoplasmic targets and potentially new nuclear targets.
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Affiliation(s)
- Elda Grabocka
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 S. 10 Street, 839 BLSB, Philadelphia, PA 19107, USA
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Albert CJ, Anbukumar DS, Monda JK, Eckelkamp JT, Ford DA. Myocardial lipidomics. Developments in myocardial nuclear lipidomics. FRONT BIOSCI-LANDMRK 2007; 12:2750-60. [PMID: 17127277 PMCID: PMC2717739 DOI: 10.2741/2269] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The development of electrospray ionization mass spectrometry has been critical for the analyses of lipidomes from subcellular organelles. The myocardial nuclear lipidome likely has a key role in the molecular regulation of gene expression. In fact, recent studies have suggested that specific phospholipid classes bind and regulate specific transcription factors. The dynamic regulation of the myocardial nuclear lipidome may be critical in mediating long-term pathological responses to stresses such as ischemia, tachycardia, and hypertension. In this brief review, the preparation of myocardial nuclei is discussed, and the resulting nuclear lipidome from rat and rabbit are shown as examples. The rabbit myocardial nuclear lipidome contains relatively more plasmenylcholine/phosphatidylcholine molecular species in comparison to that ratio observed in the rat myocardial nuclear lipidome. The composition of the rat myocardial nuclear choline glycerophospholipid pool was relatively enriched with molecular species containing arachidonic acid and docosahexaenoic acid in comparison to that in the rabbit myocardial nuclear choline glycerophospholipid pool. While the ethanolamine glycerophospholipids of the rabbit myocardial nuclei are enriched with arachidonic acid and plasmalogens, the ethanolamine glycerophospholipid profile from rat myocardial nuclei show less plasmalogen and more species containing docosahexaenoic acid. Last, significant differences in the ethanolamine glycerophospholipid molecular species were observed in the rabbit heart lipidomes from the nucleus and the mitochondria. Quantitation of these lipid species in hearts subjected to pathophysiological stresses may provide important information on the role of the myocardial nuclear lipidome on long-term cardiac cell function.
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Affiliation(s)
- Carolyn J Albert
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1402 S. Grand Blvd., St. Louis, MO 63104, USA
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Liao JJ, Huang MC, Graler M, Huang Y, Qiu H, Goetzl EJ. Distinctive T cell-suppressive signals from nuclearized type 1 sphingosine 1-phosphate G protein-coupled receptors. J Biol Chem 2006; 282:1964-72. [PMID: 17121832 DOI: 10.1074/jbc.m608597200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) generated by cells of innate immunity and the type 1 S1P G protein-coupled receptor (S1P(1)) on mobile T cells constitute a major system for control of lymphoid organ traffic and tissue migration of T cells. Now we show that T cell activation mediated by the T cell antigen receptor translocates plasma membrane S1P(1) to nuclear envelope membranes for association there with G(i/o), Erk (1/2), and other proteins that plasma membrane S1P(1) uses to signal T cell proliferation. However, nuclear S1P(1) and plasma membrane S1P(1) transduce opposite effects of S1P on T cell proliferation and relevant signaling as exemplified by respective decreases and increases in T cell nuclear concentrations of both phospho-Erk and active (phosphorylated) c-Jun. T cell antigen receptor-mediated activation of T cells therefore both eliminates migration responses to S1P by down-regulation of plasma membrane S1P(1) and translocates the S1P-S1P(1) axis into the nuclear domain where signals are directed to transcriptional control of immune functions other than migration.
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Affiliation(s)
- Jia-Jun Liao
- Department of Medicine, University of California, San Francisco, California 94143, USA
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Gayral S, Déléris P, Laulagnier K, Laffargue M, Salles JP, Perret B, Record M, Breton-Douillon M. Selective activation of nuclear phospholipase D-1 by g protein-coupled receptor agonists in vascular smooth muscle cells. Circ Res 2006; 99:132-9. [PMID: 16778131 DOI: 10.1161/01.res.0000232323.86227.8b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent studies highlight the existence of an autonomous nuclear lipid metabolism related to cellular proliferation. However, the importance of nuclear phosphatidylcholine (PC) metabolism is poorly understood. Therefore, we were interested in nuclear PCs as a source of second messengers and, particularly, nuclear phospholipase D (PLD) identification in membrane-free nuclei isolated from pig aorta vascular smooth muscle cells (VSMCs). Using immunoblot experiment, in vitro PLD assay with fluorescent substrate and confocal microscopy analysis, we demonstrated that only PLD1 is expressed in VSMC nucleus, whereas PLD1 and PLD2 are present in VSMC. Inhibition of RhoA and protein kinase Czeta (PKCzeta) by C3-exoenzyme and PKCzeta pseudosubstrate inhibitor, respectively, conducted a decrease of phosphatidylethanol production. On the other hand, treatment of intact VSMCs, but not nuclei, with phosphoinositide 3-kinase (PI3K) inhibitors prevented partially nuclear PLD1 activity, indicating for the first time that PI3K may have a role in nuclear PLD regulation. In addition, lysophosphatidic acid (LPA) or angiotensin II treatment of VSMCs resulted in an increase of intranuclear PLD activity, whereas platelet-derived growth factor and epidermal growth factor have no significant effect. Moreover, pertussis toxin induced a decrease of LPA-stimulated nuclear PLD1 activity, suggesting that heterotrimeric G(i)/G(0) protein involvement in intranuclear PLD1 regulation. We also show that LPA-induced nuclear PLD1 activation implied PI3K/PKCzeta pathway activation and PKCzeta nuclear translocation as well as nuclear RhoA activation. Thus, the characterization of an endogenous PLD1 that could regulate PC metabolism inside VSMC nucleus provides a new role for this enzyme in control of vascular fibroproliferative disorders.
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Affiliation(s)
- Stéphanie Gayral
- Département Lipoprotéines and Médiateurs Lipidiques, CPTP, INSERM Unité 563, Bâtiment C, CHU Purpan, BP 3028, 31024 Toulouse Cedex 3, France
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20
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Déléris P, Gayral S, Breton-Douillon M. Nuclear Ptdlns(3,4,5)P3 signaling: an ongoing story. J Cell Biochem 2006; 98:469-85. [PMID: 16645993 DOI: 10.1002/jcb.20695] [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: 12/28/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (Ptdlns(3,4,5)P(3)) is linked to a variety of cellular functions, such as growth, cell survival, and differentiation. Ptdlns(3,4,5)P(3) is primarily synthesized by class I phosphoinositide 3-kinases and its hydrolysis by two 3-phosphoinositide 3-phosphatases, PTEN and SHIP proteins, leads to the production of two other second messengers, Ptdlns(4,5)P(2) and Ptdlns(3,4)P(2), respectively. Evidence accumulated over the last years strongly suggest that Ptdlns(3,4,5)P(3) is an important component of signaling pathway operating within the nucleus. Moreover, recent advances indicated that nuclear translocation of cell surface receptors could activate nuclear phosphoinositide 3-kinase suggesting a new mode of signal transduction. The aim of this review is intended to summarize the state of our knowledge on nuclear Ptdlns(3,4,5)P(3) and its metabolizing enzymes, and to highlight the emerging roles for intranuclear Ptdlns(3,4,5)P(3).
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Affiliation(s)
- Paul Déléris
- Laboratoire de Signalisation et Croissance Cellulaire, Institut de Recherche en Immunovirologie et Cancérologie, Université de Montréal, Montréal, QC H3T 1J4 Canada
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21
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Boer PA, Gontijo JAR. Nuclear localization of SP, CGRP, and NK1R in a subpopulation of dorsal root ganglia subpopulation cells in rats. Cell Mol Neurobiol 2006; 26:191-207. [PMID: 16763782 DOI: 10.1007/s10571-006-9020-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Accepted: 10/31/2005] [Indexed: 12/20/2022]
Abstract
Signals generated by renal pelvic afferent nerves in response to stimulation are transmitted from peripheral processes of dorsal root ganglia neurons to their central terminals in the dorsal horn of the spinal cord to cause the release of neuropeptides, including SP and CGRP. All of the cellular activities of SP are considered to be mediated through interaction with NK(1)R located on the cell surface. We have investigated the colocalization and subcellular distribution of NK(1)R, SP, and CGRP in different subpopulations of neurons that innervate renal tissue. Our findings therefore provide the first evidence for the presence of NK(1)R, SP, and CGRP in the nuclei of DGR neural cells. The physiological significance of this localization remains unknown. One possibility is that pelvic sensory neurons may regulate their responses to different stimuli by modulating the ratio of CGRP and SP release and/or nuclear NK(1)R expression.
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Affiliation(s)
- Patrícia Aline Boer
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970, SP, Brazil
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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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23
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Tanaka T, Nishimura D, Wu RC, Amano M, Iso T, Kedes L, Nishida H, Kaibuchi K, Hamamori Y. Nuclear Rho kinase, ROCK2, targets p300 acetyltransferase. J Biol Chem 2006; 281:15320-9. [PMID: 16574662 DOI: 10.1074/jbc.m510954200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Rho-associated coiled-coil protein kinase (ROCK) is an effector for the small GTPase Rho and plays a pivotal role in diverse cellular activities, including cell adhesion, cytokinesis, and gene expression, primarily through an alteration of actin cytoskeleton dynamics. Here, we show that ROCK2 is localized in the nucleus and associates with p300 acetyltransferase both in vitro and in cells. Nuclear ROCK2 is present in a large protein complex and partially cofractionates with p300 by gel filtration analysis. By immunofluorescence, ROCK2 partially colocalizes with p300 in distinct insoluble nuclear structures. ROCK2 phosphorylates p300 in vitro, and nuclear-restricted expression of constitutively active ROCK2 induces p300 phosphorylation in cells. p300 acetyltransferase activity is dependent on its phosphorylation status in cells, and p300 phosphorylation by ROCK2 results in an increase in its acetyltransferase activity in vitro. These observations suggest that nucleus-localized ROCK2 targets p300 for phosphorylation to regulate its acetyltransferase activity.
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Affiliation(s)
- Toru Tanaka
- Department of Medicine and Center for Cardiovascular Development, Baylor College of Medicine, Houston, TX 77030, USA
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24
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Jacques D, Sader S, Perreault C, Abdel-Samad D, Jules F, Provost C. NPY, ET-1, and Ang II nuclear receptors in human endocardial endothelial cellsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell. Can J Physiol Pharmacol 2006; 84:299-307. [PMID: 16902577 DOI: 10.1139/y05-158] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neuropeptide Y (NPY), endothelin-1 (ET-1), and angiotensin II (Ang II) are peptides that are known to play many important roles in cardiovascular homeostasis. The physiological actions of these peptides are thought to be primarily mediated by plasma membrane receptors that belong to the G-protein-coupled receptor superfamily. However, there is increasing evidence that suggests the existence of functional G-protein-coupled receptors at the level of the nucleus and that the nucleus could be a cell within a cell. Here, we review our work showing the presence in the nucleus of the NPY Y1receptor, the ETAand ETBreceptors, as well as the AT1and AT2receptors and their respective ligands. This work was carried out in 20-week-old fetal human endocardial endothelial cells. Our results demonstrate that nuclear Y1, AT1, and ETAreceptors modulate nuclear calcium in these cells.
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Affiliation(s)
- Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Sherbrooke, North, Canada.
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25
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Affiliation(s)
- J Vane
- The William Harvey Research Institute, Charterhouse Square, London, UK
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26
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Boivin B, Chevalier D, Villeneuve LR, Rousseau E, Allen BG. Functional endothelin receptors are present on nuclei in cardiac ventricular myocytes. J Biol Chem 2003; 278:29153-63. [PMID: 12756260 DOI: 10.1074/jbc.m301738200] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelins are thought to act through two specific, plasmalemmal G protein-coupled receptor subtypes, ETAR and ETBR. However, in subfractionated cardiac membranes, ETAR immunoreactivity was detected only in the plasma membrane whereas ETBR immunoreactivity was detected predominantly in membranes of intracellular origin. Confocal microscopy demonstrated the presence of intracellular ETAR and ETBR in ventricular myocytes. ETAR were primarily on plasma membrane (surface membranes and transverse-tubules) and to a lesser extent on the nucleus while ETBR localized primarily to the nuclei. Western blot analysis of nuclei isolated from the heart indicated the presence of endothelin receptors: both ETAR and ETBR copurified with nucleoporin 62, whereas markers of endoplasmic reticulum and Golgi membranes were depleted. Radioligand binding studies revealed that isolated nuclei contain specific [125I]ET-1 binding sites. Specific [125I]ET-1 binding was reduced by 70-80% using the ETAR-selective antagonist BQ610 and 20-30% using the ETBR-specific antagonist BQ788. IRL-1620, an ETBR-specific agonist, also reduced [125I]ET-1 binding. Furthermore, ET-1 and IRL-1620 altered the incorporation of 32P into nuclear proteins and caused a transient increase in nuclear Ca2+ concentration. Hence, cardiac nuclei possess both ETAR and ETBR subtypes, which are functional with respect to ligand binding and are coupled to signaling mechanisms within the nuclear membrane.
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Affiliation(s)
- Benoit Boivin
- Institut de Cardiologie de Montréal, Centre de Recherche, 5000 rue Bélanger, Montréal, Québec H1T 1C8, Canada
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Shiraishi T, Imai S, Uda Y. The presence of ceramidase activity in liver nuclear membrane. Biol Pharm Bull 2003; 26:775-9. [PMID: 12808285 DOI: 10.1248/bpb.26.775] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This report presents a demonstration of ceramidase activity in the nuclear membrane or envelope of mammalian livers. The products of ceramidase reaction were identified by means of TLC for released fatty acid and HPLC for sphingosine. The ceramidase activity was maximum over a broad neutral to alkaline region ranging from pH 7.0 to 8.8. This activity was inhibited by N-oleoylethanolamine known as a specific inhibitor for ceramidase and by anandamide to a similar extent. The enzymatic study suggests that the nuclear ceramidase has different properties from other ceramidase reported previously. As sphingomyelinase, one of enzymes involved in the sphingomyelin cycle, are known to be present in the nuclear membrane, it is now evident that at least two enzymes involved in the sphingomyelin cycle are present in the nuclear membrane.
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Affiliation(s)
- Takayuki Shiraishi
- Department of Health Chemistry, Faculty of Pharmaceutical Science, Niigata University of Pharmacy and Applied Life Sciences, 5-13-2 Kamishin-eicho, Niigata 950-2081, Japan.
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28
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Antony P, Kanfer JN, Freysz L. Retinoic acid specifically activates an oleate-dependent phospholipase D in the nuclei of LA-N-1 neuroblastoma cells. FEBS Lett 2003; 541:93-6. [PMID: 12706826 DOI: 10.1016/s0014-5793(03)00313-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Earlier studies showed that treatment of LA-N-1 cells with TPA, a tumoral promoter, leads to the stimulation of a G protein-regulated phospholipase D (PLD) in the nuclei. Now we demonstrate that retinoic acid, a cellular differentiation inducing agent, activates a nuclear oleate-dependent PLD in LA-N-1 cells. Treatment of the nuclei with retinoic acid induces the breakdown of phosphatidylcholine (PtdCho). Our results indicate that PLD is regulated differentially depending on the nature of the stimulatory agent. These results strongly suggest the existence of two nuclear PLD isoforms in LA-N-1 nuclei that hydrolyze PtdCho.
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Affiliation(s)
- Pierre Antony
- Institut de Chimie Biologique, Faculte de Medecine, Laboratoire de Neurobiologie Moleculaire des Interactions Cellulaires, Strasbourg, France.
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29
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Jacques D, Sader S, Perreault C, Fournier A, Pelletier G, Beck-Sickinger AG, Descorbeth M. Presence of neuropeptide Y and the Y1 receptor in the plasma membrane and nuclear envelope of human endocardial endothelial cells: modulation of intracellular calcium. Can J Physiol Pharmacol 2003; 81:288-300. [PMID: 12733827 DOI: 10.1139/y02-165] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aims of the present study were to investigate the presence and distribution of NPY and the Y1 receptor in endocardial endothelial cells (EECs), to verify if EECs can release NPY, and to determine if the effect of NPY on intracellular calcium is mediated via the Y1 receptor. Immunofluorescence, 3-D confocal microscopy and radioimmunoassay techniques were used on 20-week-old human fetal EECs. Our results showed that NPY and the Y1 receptor are present in human EECs (hEECs) and that their distributions are similar, the fluorescence labelling being higher in the nucleus and more particularly at the level of the nuclear envelope when compared with the cytosol. Using radioimmunoassay, we demonstrated that EECs are a source of NPY and can secrete this peptide upon a sustained increase of intracellular calcium ([Ca]i). Using fluo-3 and 3-D confocal microscopy technique, superfusion of hEECs as well as EECs isolated from rat adult hearts with increasing concentrations of NPY induced a dose-dependent, sustained increase in free cytosolic and nuclear Ca2+ levels. This effect of NPY on EEC [Ca]i was completely reversible upon washout of NPY and was partially blocked by BIBP3226, a selective Y1 receptor antagonist. The results suggest that NPY and Y1 receptors are present in the EECs of 20-week-old human fetal heart and they share the same distribution and localization inside the cell. In addition, EECs are able to secrete NPY in response to an increase in [Ca]i, and the Y1 receptor as well as other NPY receptors seem to participate in mediating the effects of NPY on [Ca]i in these cells. Thus, NPY released by EECs may modulate excitation-secretion coupling of these cells.
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Affiliation(s)
- Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada.
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30
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Niedernberg A, Blaukat A, Schöneberg T, Kostenis E. Regulated and constitutive activation of specific signalling pathways by the human S1P5 receptor. Br J Pharmacol 2003; 138:481-93. [PMID: 12569073 PMCID: PMC1573682 DOI: 10.1038/sj.bjp.0705055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1 We tested the hypothesis, whether G Protein-coupled receptors (GPCRs) may differentially regulate specific signalling pathways by constitutive and agonist-induced activation using the human sphingosine 1-phosphate receptor S1P(5) as a model. 2 S1P(5) receptor-expressing HEK293 cells exhibited a high degree of basal activity for both inhibition of adenylyl cyclase and extracellular signal regulated kinase (ERK) when cultured in serum, which contains high levels of sphingosine 1-phosphate (S1P). However, basal activity was independent of the presence of S1P: (i) constitutive activity remained when cells were cultured in delipidated serum, (ii) addition of S1P to delipidated serum did not increase basal S1P(5) receptor signalling. 3 Conversely, constitutive inhibition of forskolin-stimulated adenylyl cyclase was further enhanced by S1P in S1P(5)-HEK293 cells. 4 Transfection of several mammalian cell lines (CHO-K1, HEK293, NIH-3T3, RH7777) with the S1P(5) receptor induced cell rounding, which was more pronounced in the presence of S1P-containing serum. Rounded cell morphology did not correlate with apoptotic cell death, but led to detachment of cells. 5 Cell surface ELISA assays showed that a fraction of plasma membrane S1P(5) receptors were dose-dependently internalized with S1P. 6 These data reveal that intrinsic inhibition of unstimulated adenylyl cyclase or ERK activity by the S1P(5) receptor is insensitive to ligand modulation. Conversely, effects on forskolin-stimulated adenylyl cyclase, cell morphology and internalization can be further augmented with S1P. Our results suggest that different signal transduction pathways are not equally activated through constitutively active GPCRs with promiscuous signalling characteristics.
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Affiliation(s)
- Anke Niedernberg
- Disease group Cardiovascular Diseases, Aventis Pharma, Building H825, 65926 Frankfurt, Germany
| | - Andree Blaukat
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Torsten Schöneberg
- Institut für Pharmakologie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Thielallee 69-73, 14195 Berlin, Germany
| | - Evi Kostenis
- Disease group Cardiovascular Diseases, Aventis Pharma, Building H825, 65926 Frankfurt, Germany
- Author for correspondence:
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Nanjundan M, Possmayer F. Pulmonary phosphatidic acid phosphatase and lipid phosphate phosphohydrolase. Am J Physiol Lung Cell Mol Physiol 2003; 284:L1-23. [PMID: 12471011 DOI: 10.1152/ajplung.00029.2002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The lung contains two distinct forms of phosphatidic acid phosphatase (PAP). PAP1 is a cytosolic enzyme that is activated through fatty acid-induced translocation to the endoplasmic reticulum, where it converts phosphatidic acid (PA) to diacylglycerol (DAG) for the biosynthesis of phospholipids and neutral lipids. PAP1 is Mg(2+) dependent and sulfhydryl reagent sensitive. PAP2 is a six-transmembrane-domain integral protein localized to the plasma membrane. Because PAP2 degrades sphingosine-1-phosphate (S1P) and ceramide-1-phosphate in addition to PA and lyso-PA, it has been renamed lipid phosphate phosphohydrolase (LPP). LPP is Mg(2+) independent and sulfhydryl reagent insensitive. This review describes LPP isoforms found in the lung and their location in signaling platforms (rafts/caveolae). Pulmonary LPPs likely function in the phospholipase D pathway, thereby controlling surfactant secretion. Through lowering the levels of lyso-PA and S1P, which serve as agonists for endothelial differentiation gene receptors, LPPs regulate cell division, differentiation, apoptosis, and mobility. LPP activity could also influence transdifferentiation of alveolar type II to type I cells. It is considered likely that these lipid phosphohydrolases have critical roles in lung morphogenesis and in acute lung injury and repair.
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Affiliation(s)
- Meera Nanjundan
- Department of Obstetrics and Gynaecology, Canadian Institutes of Health Research Group in Fetal and Neonatal Health and Development, The University of Western Ontario, 339 Windermere Road, London, Ontario, Canada N6A 5A5
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Abstract
Accumulating evidence has recognized phospholipase D (PLD) as an important element in signal transduction of cell responses, including proliferation and differentiation, However, its role in pro-apoptotic, anti-apoptotic or pro-survival signaling is not well-understood. Involvement of PLD in these signaling mechanisms is considered to differ depending on the cell type and the extracellular stimulus.
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Affiliation(s)
- Yoshinori Nozawa
- Department of Environmental Cell Responses, Gifu International Institute of Biotechnology, Mitakecho 2193-128, Kanigun, Gifu 505-0116, Japan.
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Bregoli L, Tu-Sekine B, Raben DM. DGK and nuclear signaling nuclear diacylglycerol kinases in IIC9 cells. ADVANCES IN ENZYME REGULATION 2002; 42:213-26. [PMID: 12123717 DOI: 10.1016/s0065-2571(01)00032-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Lisa Bregoli
- Department of Physiology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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Freyberg Z, Bourgoin S, Shields D. Phospholipase D2 is localized to the rims of the Golgi apparatus in mammalian cells. Mol Biol Cell 2002; 13:3930-42. [PMID: 12429836 PMCID: PMC133604 DOI: 10.1091/mbc.02-04-0059] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Phospholipase D (PLD) hydrolyzes phosphatidylcholine to generate phosphatidic acid, a molecule known to have multiple physiological roles, including release of nascent secretory vesicles from the trans-Golgi network. In mammalian cells two forms of the enzyme, PLD1 and PLD2, have been described. We recently demonstrated that PLD1 is localized to the Golgi apparatus, nuclei, and to a lesser extent, plasma membrane. Due to its low abundance, the intracellular localization of PLD2 has been characterized only indirectly through overexpression of chimeric proteins. Using antibodies specific to PLD2, together with immunofluorescence microscopy, herein we demonstrate that a significant fraction of endogenous PLD2 localized to the perinuclear Golgi region and was also distributed throughout cells in dense cytoplasmic puncta; a fraction of which colocalized with caveolin-1 and the plasma membrane. On treatment with brefeldin A, PLD2 translocated into the nucleus in a manner similar to PLD1, suggesting a potential role in nuclear signaling. Most significantly, cryoimmunogold electron microscopy demonstrated that in pituitary GH(3) cells >90% of PLD2 present in the Golgi apparatus was localized to cisternal rims and peri-Golgi vesicles exclusively. The data are consistent with a model whereby PLD2 plays a role in Golgi vesicular transport.
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Affiliation(s)
- Zachary Freyberg
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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35
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Jones DR, D'Santos CS, Mérida I, Divecha N. T lymphocyte nuclear diacylglycerol is derived from both de novo synthesis and phosphoinositide hydrolysis. Int J Biochem Cell Biol 2002; 34:158-68. [PMID: 11809418 DOI: 10.1016/s1357-2725(01)00108-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Novel phospholipid metabolism in T lymphocytes and the generation of biologically active lipid second messengers (LSMs) has attracted much attention in recent years. Despite this interest, no reports have attempted to characterise such events in the nuclei of these cells. In order to gain insight into the structural relationships between the lipids diglyceride (DG) and phosphatidic acid (PtdOH) and their structural precursors phosphatidylcholine (PtdCho) and phosphatidylinositides (PtdIns) in the nuclei of CTLL-2 T lymphocytes, an analysis of their molecular species was performed. The results clearly indicated that there were two pools of DG. The major pool consisted primarily of saturated and monunsaturated structures whereas the minor pool consisted of more unsaturated species, most likely derived from PtdIns. Only the latter pool was found to be accessible to endogenous nuclear diacylglycerol kinase (DGK) activity which showed partial inhibition with the recognised DGK inhibitor R59949. Molecular species analysis of the endogenous nuclear PtdOH revealed it to be distinct from that generated by the endogenous DGK, but instead resembled that of PtdCho species. We were unable to detect enzymatic activities which targeted PtdCho (PtdCho-phospholipase C (PtdCho-PLC), PtdCho-phospholipase D (PtdCho-PLD) and sphingomyelin synthase (SMS)) but instead a detectable PtdOH phosphatase (PAP) activity. We propose that, in exponentially growing CTLL-2 cells, synthesis de novo represents one of the routes for the biosynthesis of structural phospholipids which may be the source of biologically active LSMs in the nucleus.
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Affiliation(s)
- David R Jones
- Department of Immunology and Oncology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049 Madrid, Spain.
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36
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Ramírez de Molina A, Penalva V, Lucas L, Lacal JC. Regulation of choline kinase activity by Ras proteins involves Ral-GDS and PI3K. Oncogene 2002; 21:937-46. [PMID: 11840339 DOI: 10.1038/sj.onc.1205144] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2001] [Revised: 10/19/2001] [Accepted: 10/31/2001] [Indexed: 11/09/2022]
Abstract
Ras proteins are molecular switches that control signaling pathways critical in the onset of a variety of human cancers. The signaling pathways activated by Ras proteins are those controlled by its direct effectors such as the serine-threonine protein kinase Raf-1, the exchange factor for other GTPases Ral-GDS, and the lipid kinase PI3K. As a consequence of Ras activation, a number of additional enzymes are affected, including several members of the serine-threonine intracellular proteins kinases as well as enzymes related to phospholipid metabolism regulation such as phospholipases A2 and D, and choline kinase. The precise mechanisms by which ras oncogenes impinge into these later molecules and their relevance to the onset of the carcinogenic process is still not fully understood. Here we have investigated the mechanism of regulation of choline kinase by Ras proteins and found no direct link between PLD and choline kinase activation. We provide evidence that Ras proteins regulate the activity of choline kinase through its direct effectors Ral-GDS and PI3K, while the Raf pathways seems to be not relevant in this process. The importance of Ras-dependent activation of choline kinase is discussed.
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Affiliation(s)
- Ana Ramírez de Molina
- Instituto de Investigaciones Biomédicas, CSIC, Arturo Duperier 4, 28029 Madrid, Spain
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Mamoon AM, Baker RC, Farley JM. Activation of phospholipase D in porcine tracheal smooth muscle: role of phosphatidylinositol 3-kinase and RhoA activation. Eur J Pharmacol 2001; 433:7-16. [PMID: 11755129 DOI: 10.1016/s0014-2999(01)01439-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Muscarinic receptor agonists transiently activate phospholipase D in tracheal smooth muscle. Muscarinic activation of phospholipase D in this tissue is dependent on activation of protein kinase C and an unidentified pathway that is not protein kinase C dependent. Cholinergic agents have also been shown to activate phospholipase D by pathways linked to the small G protein, RhoA. This study explores the relationship between muscarinic activation of phophatidylinositol 3-kinase and activation of RhoA, and examines whether phospholipase D activation is dependent on either pathway in tracheal smooth muscle. Wortmannin or 2-(4-morphonyl)-8-phenyl-4H-1-benzopyran-4-one (LY-294002), putative specific inhibitors of phophatidylinositol 3-kinase, significantly inhibit acetylcholine-induced formation of phosphatidylethanol and also block acetylcholine-induced translocation of RhoA to the membrane. In previous experiments calphostin C, a protein kinase C inhibitor, partially inhibited both acetylcholine-induced and phorbol-12-myristate-13-acetate (PMA)-induced phosphatidylethanol formation. In the present study calphostin C did not block acetylcholine-induced RhoA translocation to the membrane. However, the Rho kinase inhibitor, N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632), significantly inhibited acetylcholine-induced phosphatidylethanol formation, but had no effect on activation of phospholipase D by PMA. Acetylcholine treatment also stimulated the phosphorylation of the 110-kDa subunit of phosphatidylinositol 3-kinase. Phosphorylation of phosphatidylinositol 3-kinase 110-kDa subunit could be blocked by wortmannin in a concentration-dependent manner, and acetylcholine-induced phosphatidylinositol 3-kinase activity was significantly inhibited by wortmannin. LY-294002 also inhibited acetylcholine-induced phosphorylation of 110-kDa subunit and activation of phosphatidylinositol 3-kinase. These results suggest that acetylcholine stimulation translocates RhoA to the membrane by a phosphatidylinositol 3-kinase-dependent mechanism and acetylcholine-induced phospholipase D stimulation is at least partly mediated via phosphatidylinositol 3-kinase, however, protein kinase C appears to activate phospholipase D independent of phosphatidylinositol 3-kinase or RhoA activation in porcine tracheal smooth muscle.
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Affiliation(s)
- A M Mamoon
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA
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38
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Aznar S, Lacal JC. Searching new targets for anticancer drug design: the families of Ras and Rho GTPases and their effectors. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 67:193-234. [PMID: 11525383 DOI: 10.1016/s0079-6603(01)67029-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Ras superfamily of low-molecular-weight GTPases are proteins that, in response to diverse stimuli, control key cellular processes such as cell growth and development, apoptosis, lipid metabolism, cytoarchitecture, membrane trafficking, and transcriptional regulation. More than 100 genes of this superfamily grouped in six subfamilies have been described so far, pointing to the complexities and specificities of their cellular functions. Dysregulation of members of at least two of these families (the Ras and the Rho families) is involved in the events that lead to the uncontrolled proliferation and invasiveness of human tumors. In recent years, the cloning and characterization of downstream effectors for Ras and Rho proteins have given crucial clues to the specific pathways that lead to aberrant cellular growth and ultimately to tumorigenesis. A direct link between the functions of some of these effectors with the appearance of transformed cells and their ability to proliferate and invade surrounding tissues has been made. Accordingly, drugs that specifically alter their functions display antineoplasic properties, and some of these drugs are already under clinical trials. In this review, we survey the progress made in understanding the underlying molecular connections between carcinogenesis and the specific cellular functions elicited by some of these effectors. We also discuss new drugs with antineoplastic or antimetastatic activity that are targeted to specific effectors for Ras or Rho proteins.
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Affiliation(s)
- S Aznar
- Instituto de Investigaciones Biomédicas, CSIC, Madrid, Spain
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Bregoli L, Baldassare JJ, Raben DM. Nuclear diacylglycerol kinase-theta is activated in response to alpha-thrombin. J Biol Chem 2001; 276:23288-95. [PMID: 11309392 DOI: 10.1074/jbc.m101501200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Currently, there is substantial evidence that nuclear lipid metabolism plays a critical role in a number of signal transduction cascades. Previous work from our laboratory showed that stimulation of quiescent fibroblasts with alpha-thrombin leads to the production of two lipid second messengers in the nucleus: an increase in nuclear diacylglycerol mass and an activation of phospholipase D, which catalyzes the hydrolysis of phosphatidylcholine to generate phosphatidic acid. Diacylglycerol kinase (DGK) catalyzes the conversion of diacylglycerol to phosphatidic acid, making it an attractive candidate for a signal transduction component. There is substantial evidence that this activity is indeed regulated in a number of signaling cascades (reviewed by van Blitterswijk, W. J., and Houssa, B. (1999) Chem. Phys. Lipids 98, 95-108). In this report, we show that the addition of alpha-thrombin to quiescent IIC9 fibroblasts results in an increase in nuclear DGK activity. The examination of nuclei isolated from quiescent IIC9 cells indicates that DGK-theta and DGK-delta are both present. We took advantage of the previous observations that phosphatidylserine inhibits DGK-delta (reviewed by Sakane, F., Imai, S., Kai, M., Wada, I., and Kanoh, H. (1996) J. Biol. Chem. 271, 8394-8401), and constitutively active RhoA inhibits DGK-theta (reviewed by Houssa, B., de Widt, J., Kranenburg, O., Moolenaar, W. H., and van Blitterswijk, W. J. (1999) J. Biol. Chem. 274, 6820-6822) to identify the activity induced by alpha-thrombin. Constitutively active RhoA inhibited the nuclear stimulated activity, whereas phosphatidylserine did not have an inhibitory effect. In addition, a monoclonal anti-DGK-theta antibody inhibited the alpha-thrombin-stimulated nuclear activity in vitro. These results demonstrate that DGK-theta is the isoform responsive to alpha-thrombin stimulation. Western blot and immunofluorescence microscopy analyses showed that alpha-thrombin induced the translocation of DGK-theta to the nucleus, implicating that this translocation is at least partly responsible for the increased nuclear activity. Taken together, these data are the first to demonstrate an agonist-induced activity of nuclear DGK-theta activity and a nuclear localization of DGK-delta.
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Affiliation(s)
- L Bregoli
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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40
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Freyberg Z, Sweeney D, Siddhanta A, Bourgoin S, Frohman M, Shields D. Intracellular localization of phospholipase D1 in mammalian cells. Mol Biol Cell 2001; 12:943-55. [PMID: 11294898 PMCID: PMC32278 DOI: 10.1091/mbc.12.4.943] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Phospholipase D (PLD) hydrolyzes phosphatidylcholine to generate phosphatidic acid. In mammalian cells this reaction has been implicated in the recruitment of coatomer to Golgi membranes and release of nascent secretory vesicles from the trans-Golgi network. These observations suggest that PLD is associated with the Golgi complex; however, to date, because of its low abundance, the intracellular localization of PLD has been characterized only indirectly through overexpression of chimeric proteins. We have used highly sensitive antibodies to PLD1 together with immunofluorescence and immunogold electron microscopy as well as cell fractionation to identify the intracellular localization of endogenous PLD1 in several cell types. Although PLD1 had a diffuse staining pattern, it was enriched significantly in the Golgi apparatus and was also present in cell nuclei. On fragmentation of the Golgi apparatus by treatment with nocodazole, PLD1 closely associated with membrane fragments, whereas after inhibition of PA synthesis, PLD1 dissociated from the membranes. Overexpression of an hemagglutinin-tagged form of PLD1 resulted in displacement of the endogenous enzyme from its perinuclear localization to large vesicular structures. Surprisingly, when the Golgi apparatus collapsed in response to brefeldin A, the nuclear localization of PLD1 was enhanced significantly. Our data show that the intracellular localization of PLD1 is consistent with a role in vesicle trafficking from the Golgi apparatus and suggest that it also functions in the cell nucleus.
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Affiliation(s)
- Z Freyberg
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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41
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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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42
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Michaelson D, Silletti J, Murphy G, D'Eustachio P, Rush M, Philips MR. Differential localization of Rho GTPases in live cells: regulation by hypervariable regions and RhoGDI binding. J Cell Biol 2001; 152:111-26. [PMID: 11149925 PMCID: PMC2193662 DOI: 10.1083/jcb.152.1.111] [Citation(s) in RCA: 549] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Determinants of membrane targeting of Rho proteins were investigated in live cells with green fluorescent fusion proteins expressed with or without Rho-guanine nucleotide dissociation inhibitor (GDI)alpha. The hypervariable region determined to which membrane compartment each protein was targeted. Targeting was regulated by binding to RhoGDI alpha in the case of RhoA, Rac1, Rac2, and Cdc42hs but not RhoB or TC10. Although RhoB localized to the plasma membrane (PM), Golgi, and motile peri-Golgi vesicles, TC10 localized to PMs and endosomes. Inhibition of palmitoylation mislocalized H-Ras, RhoB, and TC10 to the endoplasmic reticulum. Although overexpressed Cdc42hs and Rac2 were observed predominantly on endomembrane, Rac1 was predominantly at the PM. RhoA was cytosolic even when expressed at levels in vast excess of RhoGDI alpha. Oncogenic Dbl stimulated translocation of green fluorescent protein (GFP)-Rac1, GFP-Cdc42hs, and GFP-RhoA to lamellipodia. RhoGDI binding to GFP-Cdc42hs was not affected by substituting farnesylation for geranylgeranylation. A palmitoylation site inserted into RhoA blocked RhoGDI alpha binding. Mutations that render RhoA, Cdc42hs, or Rac1, either constitutively active or dominant negative abrogated binding to RhoGDI alpha and redirected expression to both PMs and internal membranes. Thus, despite the common essential feature of the CAAX (prenylation, AAX tripeptide proteolysis, and carboxyl methylation) motif, the subcellular localizations of Rho GTPases, like their functions, are diverse and dynamic.
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Affiliation(s)
- David Michaelson
- Department of Medicine, New York University School of Medicine, New York, New York 10016
- Department of Cell Biology, New York University School of Medicine, New York, New York 10016
| | - Joseph Silletti
- Department of Medicine, New York University School of Medicine, New York, New York 10016
- Department of Cell Biology, New York University School of Medicine, New York, New York 10016
| | - Gretchen Murphy
- Department of Biochemistry, New York University School of Medicine, New York, New York 10016
| | - Peter D'Eustachio
- Department of Biochemistry, New York University School of Medicine, New York, New York 10016
| | - Mark Rush
- Department of Biochemistry, New York University School of Medicine, New York, New York 10016
| | - Mark R. Philips
- Department of Medicine, New York University School of Medicine, New York, New York 10016
- Department of Cell Biology, New York University School of Medicine, New York, New York 10016
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43
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Williams SD, Hsu FF, Ford DA. Electrospray ionization mass spectrometry analyses of nuclear membrane phospholipid loss after reperfusion of ischemic myocardium. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31991-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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44
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Raben DM, Baldassare JJ. Phospholipid metabolism and nuclear envelope signaling. ADVANCES IN ENZYME REGULATION 2000; 40:97-123. [PMID: 10828348 DOI: 10.1016/s0065-2571(99)00023-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- D M Raben
- Department of Physiology, The Johns Hopkins University School of Medicine, 735 North Wolfe Street, Baltimore, MD 21205, USA
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45
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Cocco L, Martelli AM, Mazzotti G, Barnabei O, Manzoli FA. Inositides and the nucleus: phospholipase Cbeta family localization and signaling activity. ADVANCES IN ENZYME REGULATION 2000; 40:83-95. [PMID: 10828347 DOI: 10.1016/s0065-2571(99)00028-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- L Cocco
- Institute of Human Anatomy, University of Bologna, via Irnerio, 48 I, 40126, Bologna, Italy.
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46
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Liou JY, Shyue SK, Tsai MJ, Chung CL, Chu KY, Wu KK. Colocalization of prostacyclin synthase with prostaglandin H synthase-1 (PGHS-1) but not phorbol ester-induced PGHS-2 in cultured endothelial cells. J Biol Chem 2000; 275:15314-20. [PMID: 10809766 DOI: 10.1074/jbc.275.20.15314] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The subcellular colocalization of prostacyclin synthase (PGIS) with prostaglandin H synthase (PGHS) has not been delineated. To test the hypothesis that its colocalization with PGHS is crucial for prostacyclin synthesis, we determined subcellular locations of PGIS, PGHS-1, and PGHS-2 in bovine aortic endothelial cells by immunofluorescent confocal microscopy. PGIS and PGHS-1 were colocalized to nuclear envelope (NE) and endoplasmic reticulum (ER) in resting and adenovirus-infected bovine aortic endothelial cells. PGIS and PGHS-2 were also colocalized to ER in serum-treated or adenovirus-cyclooxygenase-2-infected cells. By contrast, PGIS was not colocalized with PGHS-2 in cells induced with phorbol 12-myristate 13-acetate where PGHS-2 was visualized primarily in vesicle-like structures. The lack of colocalization was accompanied by failed prostacyclin production. Resting ECV304 cells did not produce prostacyclin and had no detectable PGHS-1 and PGIS proteins. Confocal analysis showed abnormal colocalization of PGIS and PGHS-1 to a filamentous structure. Interestingly, the abundant PGIS and PGHS-1 expressed in adenovirus-infected ECV304 cells were colocalized to NE and ER, which synthesized a large quantity of prostacyclin. These findings underscore the importance of colocalization of PGHS and PGIS to ER and NE in prostacyclin synthesis.
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Affiliation(s)
- J Y Liou
- Institute of Biomedical Sciences, Academia Sinica, 128 Academic Rd. Sec. 2, Taipei 115, Taiwan
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47
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Kim Y, Han JM, Han BR, Lee KA, Kim JH, Lee BD, Jang IH, Suh PG, Ryu SH. Phospholipase D1 is phosphorylated and activated by protein kinase C in caveolin-enriched microdomains within the plasma membrane. J Biol Chem 2000; 275:13621-7. [PMID: 10788479 DOI: 10.1074/jbc.275.18.13621] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activities of phospholipase D (PLD) in diverse subcellular organelles have been identified but the details of regulatory mechanisms in such locations are unknown. Protein kinase C (PKC) is a major regulator of PLD. Serine 2, threonine 147, and serine 561 residues of phospholipase D1 (PLD1) were determined as sites of phosphorylation by PKC (Kim, Y., Han, J. M., Park, J. B., Lee, S. D., Oh, Y. S., Chung, C., Lee, T. G., Kim, J. H., Park, S. K., Yoo, J. S., Suh, P. G., Ryu, S. H. (1999) Biochemistry 38, 10344-10351). In our present study, a triple mutation of these phosphorylation sites diminished markedly phorbol 12-myristate 13-acetate (PMA)-induced PLD1 activity in COS-7 cells. We looked at the location of the PLD1 phosphorylation by PKC by observing PMA induced band shifts and by use of anti-phospho-PLD1 monoclonal antibody. The shifted PMA-induced proteins and the immunoreactivity of the anti-phospho-PLD1 antibody were mainly found in the caveolin-enriched membrane (CEM) fraction. Depletion of cellular cholesterol led to a loss of this compartmentalization of phosphorylated PLD1 in the CEM. Replacement of the cellular cholesterol led to the restoration of phosphorylated PLD1 in the CEM. Immunocytochemical studies of COS-7 cells revealed that PLD1 was localized in the plasma membrane as well as in the vesicular structures in the cytoplasm, but the phosphorylation of PLD1 occurred only in the plasma membrane. Our results, therefore, show that phosphorylation, and thereby activation, of PLD1 by PKC occurs in the caveolin and cholesterol-enriched low density domain of the plasma membrane in COS-7 cells.
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Affiliation(s)
- Y Kim
- Department of Life Science, Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
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48
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Peruzzi D, Calabrese G, Faenza I, Manzoli L, Matteucci A, Gianfrancesco F, Billi AM, Stuppia L, Palka G, Cocco L. Identification and chromosomal localisation by fluorescence in situ hybridisation of human gene of phosphoinositide-specific phospholipase C beta(1). BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1484:175-82. [PMID: 10760467 DOI: 10.1016/s1388-1981(00)00012-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Members of phosphoinositide-specific phospholipase C (PLC) families are central intermediary in signal transduction in response to the occupancy of receptors by many growth factors. Among PLC isoforms, the type beta(1) is of particular interest because of its reported nuclear localisation in addition to its presence at the plasma membrane. It has been previously shown that both the stimulation and the inhibition of the nuclear PLCbeta(1) under different stimuli implicate PLCbeta(1) as an important enzyme for mitogen-activated cell growth as well as for murine erythroleukaemia cell differentiation. The above findings hinting at a direct involvement of PLCbeta(1) in controlling the cell cycle in rodent cells, and the previously reported mapping of its gene in rat chromosome band 3q35-36, a region frequently rearranged in rat tumours induced by chemical carcinogenesis, prompted us to identify its human homologue. By screening a human foetal brain cDNA library with the rat PLCbeta(1) cDNA probe, we have identified a clone homologous to a sequence in gene bank called KIAA 0581, which encodes a large part of the human PLCbeta(1). By using this human cDNA in fluorescence in situ hybridisation on human metaphases, it has been possible to map human PLCbeta(1) on chromosome 20p12, confirming the synteny between rat chromosome 3 and human chromosome 20 and providing a novel locus of homology between bands q35-36 in rat and p12 in man. Since band 20p12 has been recently reported amplified and/or deleted in several solid tumours, the identification and chromosome mapping of human PLCbeta(1) could pave the way for further investigations on the role exerted both in normal human cells and in human tumours by PLCbeta(1), which has been shown to behave as a key signalling intermediate in the control of the cell cycle.
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Affiliation(s)
- D Peruzzi
- Cellular Signalling Laboratory, Institute of Anatomy at the University of Bologna, Via Irnerio 48, I-40126, Bologna, Italy
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Strassheim D, Porter RA, Phelps SH, Williams CL. Unique in vivo associations with SmgGDS and RhoGDI and different guanine nucleotide exchange activities exhibited by RhoA, dominant negative RhoA(Asn-19), and activated RhoA(Val-14). J Biol Chem 2000; 275:6699-702. [PMID: 10702222 DOI: 10.1074/jbc.275.10.6699] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We compared the in vivo characteristics of hemagglutinin (HA)-tagged RhoA, dominant negative RhoA(Asn-19), and activated RhoA(Val-14) stably expressed in Chinese hamster ovary (CHO) cells. Proteins co-precipitating with these HA-tagged GTPases were identified by peptide sequencing or by Western blotting. Dominant negative RhoA(Asn-19) co-precipitates with the guanine nucleotide exchange factor (GEF) SmgGDS but does not detectably interact with other expressed GEFs, such as Ost or Dbl. SmgGDS co-precipitates minimally with wild-type RhoA and does not detectably associate with RhoA(Val-14). The guanine nucleotide dissociation inhibitor RhoGDI co-precipitates with RhoA, and to a lesser extent with RhoA(Val-14), but does not detectably co-precipitate with RhoA(Asn-19). Wild-type RhoA is predominantly in the [(32)P]GDP-bound form, RhoA(Val-14) is predominantly in the [(32)P]GTP-bound form, and negligible levels of [(32)P]GDP or [(32)P]GTP are bound to RhoA(Asn-19) in (32)P-labeled cells. Immunofluorescence analyses indicate that HA-RhoA(Asn-19) is excluded from the nucleus and cell junctions. Microinjection of SmgGDS cDNA into CHO cells stably expressing HA-RhoA causes HA-RhoA to be excluded from the nucleus and cell junctions, similar to the distribution of RhoA(Asn-19). Our findings indicate that the expression of RhoA(Asn-19) may specifically inhibit signaling pathways that rely upon the SmgGDS-dependent activation of RhoA.
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Affiliation(s)
- D Strassheim
- Molecular Pharmacology Laboratory, Guthrie Research Institute, Sayre, Pennsylvania 18840, USA
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50
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Cocco L, Capitani S, Barnabei O, Gilmour RS, Rhee SG, Manzoli FA. Inositides in the nucleus: further developments on phospholipase C beta 1 signalling during erythroid differentiation and IGF-I induced mitogenesis. ADVANCES IN ENZYME REGULATION 1999; 39:287-97. [PMID: 10470379 DOI: 10.1016/s0065-2571(98)00025-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Inositol lipids originally shown to be metabolized in the cytosol have been detected also in the nucleus, where they are both synthesized and hydrolyzed. In the case of erythroid differentiation of murine erythroleukemia cells (Friend cells) it has been previously shown that PLC beta 1, which is the major nuclear PLC, undergoes down-regulation upon treatment with DMSO or tiazofurin which act as differentiative agents. On the contrary, i.e., during IGF-I induced mitogenesis, it has been shown that PLC beta 1 is rapidly activated and this event is essential for the onset of DNA synthesis. Even though its key role in cell growth has been shown, both the mechanism by which nuclear PLC beta 1 is activated and the direct relationship with erythroid differentiation are still unknown. We have addressed the question if PLC beta 1 expression and activity in the nucleus are directly related or not to the establishment of the differentiated state and we have checked the two main ways of activation, i.e., via G-protein or via phosphorylation, in order to establish whether nuclear PLC beta 1 is regulated the same way as the one at the plasma membrane or not. The data reported here show that nuclear PLC beta 1 is responsible for a continuous recycling of Friend cells, acting as a negative regulator of differentiation and that its activation is dependent on the phosphorylation state.
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Affiliation(s)
- L Cocco
- Institute of Anatomy, University of Bologna, Italy
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