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Tabuena DR, Jang SS, Grone B, Yip O, Aery Jones EA, Blumenfeld J, Liang Z, Koutsodendris N, Rao A, Ding L, Zhang AR, Hao Y, Xu Q, Yoon SY, Leon SD, Huang Y, Zilberter M. Neuronal APOE4-induced Early Hippocampal Network Hyperexcitability in Alzheimer's Disease Pathogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.28.555153. [PMID: 37693533 PMCID: PMC10491126 DOI: 10.1101/2023.08.28.555153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The full impact of apolipoprotein E4 (APOE4), the strongest genetic risk factor for Alzheimer's disease (AD), on neuronal and network function remains unclear. We found hippocampal region-specific network hyperexcitability in young APOE4 knock-in (E4-KI) mice which predicted cognitive deficits at old age. Network hyperexcitability in young E4-KI mice was mediated by hippocampal region-specific subpopulations of smaller and hyperexcitable neurons that were eliminated by selective removal of neuronal APOE4. Aged E4-KI mice exhibited hyperexcitable granule cells, a progressive inhibitory deficit, and E/I imbalance in the dentate gyrus, exacerbating hippocampal hyperexcitability. Single-nucleus RNA-sequencing revealed neuronal cell type-specific and age-dependent transcriptomic changes, including Nell2 overexpression in E4-KI mice. Reducing Nell2 expression in specific neuronal types of E4-KI mice with CRISPRi rescued their abnormal excitability phenotypes, implicating Nell2 overexpression as a cause of APOE4-induced hyperexcitability. These findings highlight the early transcriptomic and electrophysiological alterations underlying APOE4-induced hippocampal network dysfunction and its contribution to AD pathogenesis with aging.
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Ha CM, Kim DH, Lee TH, Kim HR, Choi J, Kim Y, Kang D, Park JW, Ojeda SR, Jeong JK, Lee BJ. Transcriptional Regulatory Role of NELL2 in Preproenkephalin Gene Expression. Mol Cells 2022; 45:537-549. [PMID: 35950455 PMCID: PMC9385569 DOI: 10.14348/molcells.2022.2051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 03/28/2022] [Accepted: 04/03/2022] [Indexed: 12/23/2022] Open
Abstract
Preproenkephalin (PPE) is a precursor molecule for multiple endogenous opioid peptides Leu-enkephalin (ENK) and Met-ENK, which are involved in a wide variety of modulatory functions in the nervous system. Despite the functional importance of ENK in the brain, the effect of brain-derived factor(s) on PPE expression is unknown. We report the dual effect of neural epidermal growth factor (EGF)-likelike 2 (NELL2) on PPE gene expression. In cultured NIH3T3 cells, transfection of NELL2 expression vectors induced an inhibition of PPE transcription intracellularly, in parallel with downregulation of protein kinase C signaling pathways and extracellular signal-regulated kinase. Interestingly, these phenomena were reversed when synthetic NELL2 was administered extracellularly. The in vivo disruption of NELL2 synthesis resulted in an increase in PPE mRNA level in the rat brain, suggesting that the inhibitory action of intracellular NELL2 predominates the activation effect of extracellular NELL2 on PPE gene expression in the brain. Biochemical and molecular studies with mutant NELL2 structures further demonstrated the critical role of EGF-like repeat domains in NELL2 for regulation of PPE transcription. These are the first results to reveal the spatio-specific role of NELL2 in the homeostatic regulation of PPE gene expression.
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Affiliation(s)
- Chang Man Ha
- Brain Research Core Facilities and Global Relation Center of Research Strategy Office, Korea Brain Research Institute, Daegu 41068, Korea
| | - Dong Hee Kim
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Tae Hwan Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Han Rae Kim
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Jungil Choi
- Bioenvironmental Science & Technology Division, Korea Institute of Toxicology, Jinju 52834, Korea
| | - Yoonju Kim
- Brain Research Core Facilities and Global Relation Center of Research Strategy Office, Korea Brain Research Institute, Daegu 41068, Korea
| | - Dasol Kang
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Jeong Woo Park
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Sergio R. Ojeda
- Division of Neuroscience, Oregon National Primate Research Center/Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Jin Kwon Jeong
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
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3
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Shaker MR, Kahtan A, Prasad R, Lee JH, Pietrogrande G, Leeson HC, Sun W, Wolvetang EJ, Slonchak A. Neural Epidermal Growth Factor-Like Like Protein 2 Is Expressed in Human Oligodendroglial Cell Types. Front Cell Dev Biol 2022; 10:803061. [PMID: 35265611 PMCID: PMC8899196 DOI: 10.3389/fcell.2022.803061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/06/2022] [Indexed: 01/14/2023] Open
Abstract
Neural epidermal growth factor-like like 2 (NELL2) is a cytoplasmic and secreted glycosylated protein with six epidermal growth factor-like domains. In animal models, NELL2 is predominantly expressed in neural tissues where it regulates neuronal differentiation, polarization, and axon guidance, but little is known about the role of NELL2 in human brain development. In this study, we show that rostral neural stem cells (rNSC) derived from human-induced pluripotent stem cell (hiPSC) exhibit particularly strong NELL2 expression and that NELL2 protein is enriched at the apical side of neural rosettes in hiPSC-derived brain organoids. Following differentiation of human rostral NSC into neurons, NELL2 remains robustly expressed but changes its subcellular localization from >20 small cytoplasmic foci in NSC to one–five large peri-nuclear puncta per neuron. Unexpectedly, we discovered that in human brain organoids, NELL2 is readily detectable in the oligodendroglia and that the number of NELL2 puncta increases as oligodendrocytes mature. Artificial intelligence-based machine learning further predicts a strong association of NELL2 with multiple human white matter diseases, suggesting that NELL2 may possess yet unexplored roles in regulating oligodendrogenesis and/or myelination during human cortical development and maturation.
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Affiliation(s)
- Mohammed R Shaker
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Amna Kahtan
- St Cloud Technical & Community College, St Cloud, MN, United States
| | - Renuka Prasad
- Department of Anatomy, Brain Korea 21 Plus Program for Biomedical Science, Korea University College of Medicine, Seoul, South Korea
| | - Ju-Hyun Lee
- Department of Anatomy, Brain Korea 21 Plus Program for Biomedical Science, Korea University College of Medicine, Seoul, South Korea
| | - Giovanni Pietrogrande
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Hannah C Leeson
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Woong Sun
- Department of Anatomy, Brain Korea 21 Plus Program for Biomedical Science, Korea University College of Medicine, Seoul, South Korea
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Andrii Slonchak
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
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4
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Kim HR, Kim DH, An JY, Kang D, Park JW, Hwang EM, Seo EJ, Jang IH, Ha CM, Lee BJ. NELL2 Function in Axon Development of Hippocampal Neurons. Mol Cells 2020; 43:581-589. [PMID: 32597395 PMCID: PMC7332358 DOI: 10.14348/molcells.2020.0032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/06/2020] [Accepted: 05/24/2020] [Indexed: 02/07/2023] Open
Abstract
Neurons have multiple dendrites and single axon. This neuronal polarity is gradually established during early processes of neuronal differentiation: generation of multiple neurites (stages 1-2); differentiation (stage 3) and maturation (stages 4-5) of an axon and dendrites. In this study, we demonstrated that the neuron-specific n-glycosylated protein NELL2 is important for neuronal polarization and axon growth using cultured rat embryonic hippocampal neurons. Endogenous NELL2 expression was gradually increased in parallel with the progression of developmental stages of hippocampal neurons, and overexpression of NELL2 stimulated neuronal polarization and axon growth. In line with these results, knockdown of NELL2 expression resulted in deterioration of neuronal development, including inhibition of neuronal development progression, decreased axon growth and increased axon branching. Inhibitor against extracellular signal-regulated kinase (ERK) dramatically inhibited NELL2-induced progression of neuronal development and axon growth. These results suggest that NELL2 is an important regulator for the morphological development for neuronal polarization and axon growth.
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Affiliation(s)
- Han Rae Kim
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- Present address: Department of Pharmacology and Physiology, School of Medicine & Health Sciences, The George Washington University, Washington, D.C. 20037, USA
- These authors contributed equally to this work.
| | - Dong Hee Kim
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- These authors contributed equally to this work.
| | - Ji Young An
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
- These authors contributed equally to this work.
| | - Dasol Kang
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
| | - Jeong Woo Park
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 079, Korea
| | - Eun Jin Seo
- Department of Oral Biochemistry, Dental and Life Science Institute, Pusan National University School of Dentistry, Yangsan 50612, Korea
| | - Il Ho Jang
- Department of Oral Biochemistry, Dental and Life Science Institute, Pusan National University School of Dentistry, Yangsan 50612, Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities of Korea Brain Research Institute, Daegu 1068, Korea,
| | - Byung Ju Lee
- Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 4460, Korea
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Jeong JK, Kim JG, Kim HR, Lee TH, Park JW, Lee BJ. A Role of Central NELL2 in the Regulation of Feeding Behavior in Rats. Mol Cells 2017; 40:186-194. [PMID: 28301916 PMCID: PMC5386956 DOI: 10.14348/molcells.2017.2278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/21/2017] [Accepted: 03/06/2017] [Indexed: 12/02/2022] Open
Abstract
A brain-enriched secreting signal peptide, NELL2, has been suggested to play multiple roles in the development, survival, and activity of neurons in mammal. We investigated here a possible involvement of central NELL2 in regulating feeding behavior and metabolism. In situ hybridization and an im-munohistochemical approach were used to determine expression of NELL2 as well as its colocalization with proopiomelanocortin (POMC) and neuropeptide Y (NPY) in the rat hypothalamus. To investigate the effect of NELL2 on feeding behavior, 2 nmole of antisense NELL2 oligodeoxynucleotide was administered into the lateral ventricle of adult male rat brains for 6 consecutive days, and changes in daily body weight, food, and water intake were monitored. Metabolic state-dependent NELL2 expression in the hypothalamus was tested in vivo using a fasting model. NELL2 was noticeably expressed in the hypothalamic nuclei controlling feeding behavior. Furthermore, all arcuatic POMC and NPY positive neurons produced NELL2. The NELL2 gene expression in the hypothalamus was up-regulated by fasting. However, NELL2 did not affect POMC and NPY gene expression in the hypothalamus. A blockade of NELL2 production in the hypothalamus led to a reduction in daily food intake, followed by a loss in body weight without a change in daily water intake in normal diet condition. NELL2 did not affect short-term hunger dependent appetite behavior. Our data suggests that hypothalamic NELL2 is associated with appetite behavior, and thus central NELL2 could be a new therapeutic target for obesity.
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Affiliation(s)
- Jin Kwon Jeong
- Department of Pharmacology and Physiology, School of Medicine & Health Sciences, The George Washington University,
USA
| | - Jae Geun Kim
- Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University, Incheon 22012,
Korea
| | - Han Rae Kim
- Department of Biological Sciences, University of Ulsan, Ulsan 44610,
Korea
| | - Tae Hwan Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610,
Korea
| | - Jeong Woo Park
- Department of Biological Sciences, University of Ulsan, Ulsan 44610,
Korea
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 44610,
Korea
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Kim SR, Ha YM, Kim YM, Park EJ, Kim JW, Park SW, Kim HJ, Chung HT, Chang KC. Ascorbic acid reduces HMGB1 secretion in lipopolysaccharide-activated RAW 264.7 cells and improves survival rate in septic mice by activation of Nrf2/HO-1 signals. Biochem Pharmacol 2015; 95:279-89. [PMID: 25896849 DOI: 10.1016/j.bcp.2015.04.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 04/10/2015] [Indexed: 01/29/2023]
Abstract
High mobility group box 1 (HMGB1) is now recognized as a late mediator of sepsis. We tested hypothesis that ascorbic acid (AscA) induces heme oxygenase (HO)-1 which inhibits HMGB1 release in lipopolysaccharide (LPS)-stimulated cells and increases survival of septic mice. AscA increased HO-1 protein expression in a concentration- and time-dependent manner via Nrf2 activation in RAW 264.7 cells. HO-1 induction by AscA was significantly reduced by Nrf2 siRNA-transfected cells. Mutation of cysteine to serine of keap-1 proteins (C151S, C273S, and C288S) lost the ability of HO-1 induction by AscA, due to failure of translocation of Nrf-2 to nucleus. The PI3 kinase inhibitor, LY294002, inhibited HO-1 induction by AscA. Oxyhemoglobin (HbO2), LY294002, and ZnPPIX (HO-1 enzyme inhibitor) reversed effect of AscA on HMGB1 release. Most importantly, administration of AscA (200mg/kg, i.p.) significantly increased survival in LPS-induced endotoxemic mice. In cecal ligation and puncture (CLP)-induced septic mice, AscA reduced hepatic injury and serum HMGB1 and plasminogen activator inhibitor (PAI)-1 in a ZnPPIX-sensitive manner. In addition, AscA failed to increase survival in Nrf2 knockout mice by LPS. Thus, we concluded that high dose of AscA may be useful in the treatment of sepsis, at least, by activation of Nrf2/HO-1 signals.
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Affiliation(s)
- So Ra Kim
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Yu Mi Ha
- Department of Pharmacology, Dong-A University College of Medicine, Busan 602-714, Republic of Korea
| | - Young Min Kim
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Eun Jung Park
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Jung Whan Kim
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Sang Won Park
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Hye Jung Kim
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea
| | - Hun Taeg Chung
- School of Biological Sciences, University of Ulsan (HTC), Ulsan 680-749, Republic of Korea
| | - Ki Churl Chang
- Department of Pharmacology, School of Medicine and The Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Republic of Korea.
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Lee DY, Kim E, Lee YS, Ryu H, Park JY, Hwang EM. The cytosolic splicing variant of NELL2 inhibits PKCβ1 in glial cells. Biochem Biophys Res Commun 2014; 454:459-64. [PMID: 25450684 DOI: 10.1016/j.bbrc.2014.10.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022]
Abstract
NELL2 is an abundant glycoprotein containing EGF-like domain in the neural tissues where it has multiple physiological functions by interacting with protein kinase C (PKC). There are two different splicing variant forms of NELL2 identified so far. One is secreted NELL2 (sNELL2) which is a neuron-specific variant and the other is cytosolic NELL2 (cNELL2) which is non-secreted splicing variant of NELL2. Although cNELL2 structure was well characterized, the expression pattern or the cellular function of cNELL2 is not fully determined. In this study, we found that cNELL2 specifically interacts with PKCβ isotypes and inhibits PKCβ1 through direct binding to the N-terminal pseudosubstrate domain of PKCβ1. Here, we also demonstrate that cNELL2 is predominantly expressed and has inhibitory effects on the PKC downstream signaling pathways in astrocytes thereby establishing cNELL2 as an endogenous inhibitor of PKCβ1 in glia.
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Affiliation(s)
- Da Yong Lee
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | - Eunju Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Young-Sun Lee
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Hwani Ryu
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 136-703, Republic of Korea.
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon 305-350, Republic of Korea.
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Ha CM, Hwang EM, Kim E, Lee DY, Chang S, Lee BJ, Hong SG, Park JY. The molecular mechanism of NELL2 movement and secretion in hippocampal progenitor HiB5 cells. Mol Cells 2013; 36:527-33. [PMID: 24352699 PMCID: PMC3887960 DOI: 10.1007/s10059-013-0216-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/05/2013] [Accepted: 11/07/2013] [Indexed: 11/26/2022] Open
Abstract
Neural epidermal growth factor-like protein-like 2 (NELL2) is a secreted glycoprotein that is predominantly expressed in the nervous system, but little is known about the intracellular movement and secretion mechanism of this protein. By monitoring the localization and movements of enhanced green fluorescent protein (EGFP)-labeled NELL2 in living cultured hippocampal neuroprogenitor HiB5 cells, we determined the subcellular localization of NELL2 and its intracellular movement and secretion mechanism. Cterminal EGFP-fused NELL2 showed a typical expression pattern of secreted proteins, especially with respect to its localization in the endoplasmic reticulum, Golgi apparatus, and punctate structures. Vesicles containing NELL2 exhibited bidirectional movement in HiB5 cells. The majority of the vesicles (70.1%) moved in an anterograde direction with an average velocity of 0.454 μm/s, whereas some vesicles (28.7%) showed retrograde movement with an average velocity of 0.302 μm/s. The movement patterns of NELL2 vesicles were dependent upon the presence of microtubules in HiB5 cells. Anterograde movement of NELL2 did not lead to a detectable accumulation of NELL2 in the peripheral region of the cell, indicating that it was secreted into the culture medium. We also showed that the N-terminal 29 amino acids of NELL2 were important for secretion of this protein. Taken together, these results strongly suggest that the N-terminal region of NELL2 determines both the pattern of its intracellular expression and transport of NELL2 vesicles by high-velocity movement. Therefore, NELL2 may affect the cellular activity of cells in a paracrine or autocrine manner.
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Affiliation(s)
- Chang Man Ha
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-290,
Korea
- Convergence Brain Research Department, Korea Brain Research Institute (KBRI), Daegu 700-010,
Korea
| | - Eun Mi Hwang
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-290,
Korea
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791,
Korea
| | - Eunju Kim
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-290,
Korea
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791,
Korea
| | - Da Yong Lee
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791,
Korea
| | - Sunghoe Chang
- Department of Biomedical Sciences, Neuroscience Research Institute, Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799,
Korea
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan 680-749,
Korea
| | - Seong-Geun Hong
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-290,
Korea
| | - Jae-Yong Park
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-290,
Korea
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791,
Korea
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Kelemen O, Convertini P, Zhang Z, Wen Y, Shen M, Falaleeva M, Stamm S. Function of alternative splicing. Gene 2013; 514:1-30. [PMID: 22909801 PMCID: PMC5632952 DOI: 10.1016/j.gene.2012.07.083] [Citation(s) in RCA: 515] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/21/2012] [Accepted: 07/30/2012] [Indexed: 12/15/2022]
Abstract
Almost all polymerase II transcripts undergo alternative pre-mRNA splicing. Here, we review the functions of alternative splicing events that have been experimentally determined. The overall function of alternative splicing is to increase the diversity of mRNAs expressed from the genome. Alternative splicing changes proteins encoded by mRNAs, which has profound functional effects. Experimental analysis of these protein isoforms showed that alternative splicing regulates binding between proteins, between proteins and nucleic acids as well as between proteins and membranes. Alternative splicing regulates the localization of proteins, their enzymatic properties and their interaction with ligands. In most cases, changes caused by individual splicing isoforms are small. However, cells typically coordinate numerous changes in 'splicing programs', which can have strong effects on cell proliferation, cell survival and properties of the nervous system. Due to its widespread usage and molecular versatility, alternative splicing emerges as a central element in gene regulation that interferes with almost every biological function analyzed.
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Affiliation(s)
- Olga Kelemen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Paolo Convertini
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Zhaiyi Zhang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Yuan Wen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Manli Shen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Marina Falaleeva
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Stefan Stamm
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
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Munemasa Y, Chang CS, Kwong JMK, Kyung H, Kitaoka Y, Caprioli J, Piri N. The neuronal EGF-related gene Nell2 interacts with Macf1 and supports survival of retinal ganglion cells after optic nerve injury. PLoS One 2012; 7:e34810. [PMID: 22496866 PMCID: PMC3319615 DOI: 10.1371/journal.pone.0034810] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 03/05/2012] [Indexed: 12/20/2022] Open
Abstract
Nell2 is a neuron-specific protein containing six epidermal growth factor-like domains. We have identified Nell2 as a retinal ganglion cell (RGC)-expressed gene by comparing mRNA profiles of control and RGC-deficient rat retinas. The aim of this study was to analyze Nell2 expression in wild-type and optic nerve axotomized retinas and evaluate its potential role in RGCs. Nell2-positive in situ and immunohistochemical signals were localized to irregularly shaped cells in the ganglion cell layer (GCL) and colocalized with retrogradely-labeled RGCs. No Nell2-positive cells were detected in 2 weeks optic nerve transected (ONT) retinas characterized with approximately 90% RGC loss. RT-PCR analysis showed a dramatic decrease in the Nell2 mRNA level after ONT compared to the controls. Immunoblot analysis of the Nell2 expression in the retina revealed the presence of two proteins with approximate MW of 140 and 90 kDa representing glycosylated and non-glycosylated Nell2, respectively. Both products were almost undetectable in retinal protein extracts two weeks after ONT. Proteome analysis of Nell2-interacting proteins carried out with MALDI-TOF MS (MS) identified microtubule-actin crosslinking factor 1 (Macf1), known to be critical in CNS development. Strong Macf1 expression was observed in the inner plexiform layer and GCL where it was colocalizied with Thy-1 staining. Since Nell2 has been reported to increase neuronal survival of the hippocampus and cerebral cortex, we evaluated the effect of Nell2 overexpression on RGC survival. RGCs in the nasal retina were consistently more efficiently transfected than in other areas (49% vs. 13%; n = 5, p<0.05). In non-transfected or pEGFP-transfected ONT retinas, the loss of RGCs was approximately 90% compared to the untreated control. In the nasal region, Nell2 transfection led to the preservation of approximately 58% more cells damaged by axotomy compared to non-transfected (n = 5, p<0.01) or pEGFP-transfected controls (n = 5, p<0.01).
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Affiliation(s)
- Yasunari Munemasa
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Department Ophthalmology, St Marianna University School of Medicine, Kawasaki, Japan
| | - Chang-Sheng Chang
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jacky M. K. Kwong
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Haksu Kyung
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yasushi Kitaoka
- Department Ophthalmology, St Marianna University School of Medicine, Kawasaki, Japan
| | - Joseph Caprioli
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Natik Piri
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Nakamura R, Nakamoto C, Obama H, Durward E, Nakamoto M. Structure-function analysis of Nel, a thrombospondin-1-like glycoprotein involved in neural development and functions. J Biol Chem 2011; 287:3282-91. [PMID: 22157752 DOI: 10.1074/jbc.m111.281485] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nel (neural epidermal growth factor (EGF)-like molecule) is a multimeric, multimodular extracellular glycoprotein with heparin-binding activity and structural similarities to thrombospondin-1. Nel is predominantly expressed in the nervous system and has been implicated in neuronal proliferation and differentiation, retinal axon guidance, synaptic functions, and spatial learning. The Nel protein contains an N-terminal thrombospondin-1 (TSP-N) domain, five cysteine-rich domains, and six EGF-like domains. However, little is known about the functions of specific domains of the Nel protein. In this study, we have performed structure-function analysis of Nel, by using a series of expression constructs for different regions of the Nel protein. Our studies demonstrate that the TSP-N domain is responsible for homo-multimer formation of Nel and its heparin-binding activity. In vivo, Nel and related Nell1 are expressed in several regions of the mouse central nervous system with partly overlapping patterns. When they are expressed in the same cells in vitro, Nel and Nell1 can form hetero-multimers through the TSP-N domain, but they do not hetero-oligomerize with thrombospondin-1. Whereas both the TSP-N domain and cysteine-rich domains can bind to retinal axons in vivo, only the latter causes growth cone collapse in cultured retinal axons, suggesting that cysteine-rich domains interact with and activate an inhibitory axon guidance receptor. These results suggest that Nel interacts with a range of molecules through its different domains and exerts distinct functions.
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Affiliation(s)
- Ritsuko Nakamura
- Aberdeen Developmental Biology Group, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, United Kingdom
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Neacsu CD, Grosch M, Tejada M, Winterpacht A, Paulsson M, Wagener R, Tagariello A. Ucmaa (Grp-2) is required for zebrafish skeletal development. Evidence for a functional role of its glutamate γ-carboxylation. Matrix Biol 2011; 30:369-78. [PMID: 21839171 DOI: 10.1016/j.matbio.2011.07.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/22/2011] [Accepted: 07/25/2011] [Indexed: 01/20/2023]
Abstract
UCMA (alternatively named GRP) is a novel member of the family of γ-carboxyglutamate (Gla) containing proteins that is mainly expressed in cartilage. We have used the zebrafish as a model organism to study UCMA function. Due to the whole genome duplication two Ucma genes are present in zebrafish, ucmaa and ucmab, located on chromosomes 25 and 4, respectively. UCMA gene structure, alternative splicing and protein sequence are highly conserved between mammals and zebrafish and Ucmaa and Ucmab are expressed in zebrafish skeletal tissues. Ucmaa is first detected in the notochord at 18 hpf and expression continues during notochord development. In addition, it is widely present in the developing craniofacial cartilage. In contrast, the weakly expressed Ucmab can be first detected at specific sites in the craniofacial cartilage at 96 hpf, but not in notochord. Knockdown of ucmaa leads to severe growth retardation and perturbance of skeletal development. The cartilage of the morphants has a decreased aggrecan and collagen II content. Similar malformations were observed when glutamate γ-carboxylation was inhibited by warfarin treatment, indicating that glutamate γ-carboxylation is crucial for Ucma function and pointing to a role of UCMA in the pathogenesis of "warfarin embryopathies" and other human skeletal diseases.
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13
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NELL-1 binds to APR3 affecting human osteoblast proliferation and differentiation. FEBS Lett 2011; 585:2410-8. [PMID: 21723284 DOI: 10.1016/j.febslet.2011.06.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 06/11/2011] [Accepted: 06/17/2011] [Indexed: 11/23/2022]
Abstract
Nel-like protein 1 (NELL-1) is an osteoinductive molecule associated with premature calvarial suture closure. Here we identified apoptosis related protein 3 (APR3), a membrane protein known as a proliferation suppressor, as a binding protein of NELL-1 by biopanning. NELL-1 and APR3 colocalized on the nuclear envelope of human osteoblasts. NELL-1 significantly inhibited proliferation of osteoblasts co-transfected with APR3 through further down-regulation of Cyclin D1. The co-expression of NELL-1 and APR3 enhanced Ocn and Bsp expression and mineralization. RNAi of APR3 significantly reduced the differentiation effect of NELL-1. These findings suggest that the effects of NELL-1 on osteoblastic differentiation and proliferation are partly through binding to APR3.
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Zhang X, Zara J, Siu RK, Ting K, Soo C. The role of NELL-1, a growth factor associated with craniosynostosis, in promoting bone regeneration. J Dent Res 2010; 89:865-78. [PMID: 20647499 DOI: 10.1177/0022034510376401] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Efforts to enhance bone regeneration in orthopedic and dental cases have grown steadily for the past decade, in line with increasingly sophisticated regenerative medicine. To meet the unprecedented demand for novel osteospecific growth factors with fewer adverse effects compared with those of existing adjuncts such as BMPs, our group has identified a craniosynostosis-associated secreted molecule, NELL-1, which is a potent growth factor that is highly specific to the osteochondral lineage, and has demonstrated robust induction of bone in multiple in vivo models from rodents to pre-clinical large animals. NELL-1 is preferentially expressed in osteoblasts under direct transcriptional control of Runx2, and is well-regulated during skeletal development. NELL-1/Nell-1 can promote orthotopic bone regeneration via either intramembranous or endochondral ossification, both within and outside of the craniofacial complex. Unlike BMP-2, Nell-1 cannot initiate ectopic bone formation in muscle, but can induce bone marrow stromal cells (BMSCs) to form bone in a mouse muscle pouch model, exhibiting specificity that BMPs lack. In addition, synergistic osteogenic effects of Nell-1 and BMP combotherapy have been observed, and are likely due to distinct differences in their signaling pathways. NELL-1's unique role as a novel osteoinductive growth factor makes it an attractive alternative with promise for future clinical applications. [Note: NELL-1 and NELL-1 indicate the human gene and protein, respectively; Nell-1 and Nell-1 indicate the mouse gene and protein, respectively.]
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Affiliation(s)
- X Zhang
- Dental and Craniofacial Research Institute, University of California, Los Angeles, 10833 Le Conte Avenue, CHS 73-060, Los Angeles, CA 90095, USA.
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15
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Magnetic nanoparticle-based isolation of endocytic vesicles reveals a role of the heat shock protein GRP75 in macromolecular delivery. Proc Natl Acad Sci U S A 2010; 107:13342-7. [PMID: 20624969 DOI: 10.1073/pnas.1002622107] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
An increased understanding of cellular uptake mechanisms of macromolecules remains an important challenge in cell biology with implications for viral infection and macromolecular drug delivery. Here, we report a strategy based on antibody-conjugated magnetic nanoparticles for the isolation of endocytic vesicles induced by heparan sulfate proteoglycans (HSPGs), key cell-surface receptors of macromolecular delivery. We provide evidence for a role of the glucose-regulated protein (GRP)75/PBP74/mtHSP70/mortalin (hereafter termed "GRP75") in HSPG-mediated endocytosis of macromolecules. GRP75 was found to be a functional constituent of intracellular vesicles of a nonclathrin-, noncaveolin-dependent pathway that was sensitive to membrane cholesterol depletion and that showed colocalization with the membrane raft marker cholera toxin subunit B. We further demonstrate a functional role of the RhoA GTPase family member CDC42 in this transport pathway; however, the small GTPase dynamin appeared not to be involved. Interestingly, we provide evidence of a functional role of GRP75 using RNAi-mediated down-regulation of GRP75 and GRP75-blocking antibodies, both of which inhibited macromolecular endocytosis. We conclude that GRP75, a chaperone protein classically found in the endoplasmic reticulum and mitochondria, is a functional constituent of noncaveolar, membrane raft-associated endocytic vesicles. Our data provide proof of principle of a strategy that should be generally applicable in the molecular characterization of selected endocytic pathways involved in macromolecular uptake by mammalian cells.
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Identification and characterization of a truncated isoform of NELL2. Biochem Biophys Res Commun 2010; 391:529-34. [DOI: 10.1016/j.bbrc.2009.11.092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 11/13/2009] [Indexed: 11/20/2022]
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17
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Avidan A, Perlmutter M, Tal S, Oraki O, Kapp T, Krelin Y, Elkabets M, Dotan S, Apte RN, Lichtenstein RG. Differences in the sialylation patterns of membrane stress proteins in chemical carcinogen-induced tumors developed in BALB/c and IL-1α deficient mice. Glycoconj J 2009; 26:1181-95. [DOI: 10.1007/s10719-009-9238-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 03/06/2009] [Accepted: 04/06/2009] [Indexed: 11/29/2022]
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Kwon H, Jeong K, Hwang EM, Park JY, Hong SG, Choi WS, Pak Y. Caveolin-2 regulation of STAT3 transcriptional activation in response to insulin. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1325-33. [PMID: 19427337 DOI: 10.1016/j.bbamcr.2009.04.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2009] [Revised: 04/01/2009] [Accepted: 04/29/2009] [Indexed: 11/26/2022]
Abstract
The regulatory function of caveolin-2 in signal transducer and activator of transcription 3 (STAT3) signaling by insulin was investigated. Insulin-induced increase in phosphorylation of STAT3 was reduced by caveolin-2 siRNA. Mutagenesis studies identified that phosphorylation of tyrosines 19 and 27 on caveolin-2 is required for the STAT3 activation. Caveolin-2 Y27A mutation decreased insulin-induced phosphorylation of STAT3 interacting with caveolin-2. pY27-Caveolin-2 was required for nuclear translocation of pY705-STAT3 in response to insulin. In contrast, caveolin-2 Y19A mutation influenced neither the phosphorylation of STAT3 nor nuclear translocation of pY705-STAT3. pY19-Caveolin-2, however, was essential for insulin-induced DNA binding of pS727-STAT3 and STAT3-targeted gene induction in the nucleus. Finally, insulin-induced transcriptional activation of STAT3 depended on phosphorylation of both 19 and 27 tyrosines. Together, our data reveal that phosphotyrosine-caveolin-2 is a novel regulator for transcriptional activation of STAT3 in response to insulin.
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Affiliation(s)
- Hayeong Kwon
- Department of Biochemistry, Gyeongsang National University, Jinju 660-701, Republic of Korea
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Jeong JK, Ryu BJ, Choi J, Kim DH, Choi EJ, Park JW, Park JJ, Lee BJ. NELL2 participates in formation of the sexually dimorphic nucleus of the pre-optic area in rats. J Neurochem 2008; 106:1604-13. [PMID: 18513367 DOI: 10.1111/j.1471-4159.2008.05505.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Formation of the sexually dimorphic nucleus of the pre-optic area (SDN-POA) in the rat hypothalamus shows a sexually differential development of neurons. Volume of the SDN-POA in males is much bigger than that in females which is because of a neuroprotective effect of estradiol converted from circulating testosterone during a critical period of brain development. We found that neural epidermal growth factor-like like-2 (NELL2), a neural tissue-enriched protein, is a potential downstream target of estrogen. In this study, we examined a possible role of NELL2 in the development of the SDN-POA and in the normalcy of sexual behavior in the male rats. NELL2 was expressed and co-localized with estrogen receptor alpha in the SDN-POA. A blockade of NELL2 synthesis in the brain during postnatal day 0 (d0) to d4 by an intracerebroventricular injection of an antisense NELL2 oligodeoxynucleotide, resulted in a decrease in volume of the SDN-POA in males. Interestingly, it reduced some components of the male sexual behavior such as mounting and intromission, but not the sexual partner preference in adulthood. In vitro study using the hippocampal neuroprecursor HiB5 cells showed that NELL2 has a protective effect from a cell death condition. These data suggest that a relevant expression of NELL2 in the neonatal brain is important for the estrogen-induced normal development of the SDN-POA and the normalcy of sexual behavior in male rats.
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Affiliation(s)
- Jin Kwon Jeong
- Department of Biological Sciences, University of Ulsan, Ulsan, South Korea
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20
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Park JY, Hwang EM, Yarishkin O, Seo JH, Kim E, Yoo J, Yi GS, Kim DG, Park N, Ha CM, La JH, Kang D, Han J, Oh U, Hong SG. TRPM4b channel suppresses store-operated Ca2+ entry by a novel protein-protein interaction with the TRPC3 channel. Biochem Biophys Res Commun 2008; 368:677-83. [PMID: 18262493 DOI: 10.1016/j.bbrc.2008.01.153] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 01/26/2008] [Indexed: 11/18/2022]
Abstract
We identified human TRPC3 protein by yeast two-hybrid screening of a human brain cDNA library with human TRPM4b as a bait. Immunoprecipitation and confocal microscopic analyses confirmed the protein-protein interaction between TRPM4b and TRPC3, and these two TRPs were found to be highly colocalized at the plasma membrane of HEK293T cells. Overexpression of TRPM4b suppressed TRPC3-mediated whole cell currents by more than 90% compared to those in TRPC3-expressed HEK293T cells. Furthermore, HEK293T cells stably overexpressing red fluorescent protein (RFP)-TRPM4b exhibited an almost complete abolition of UTP-induced store-operated Ca(2+) entry, which is known to take place via endogenous TRPC channels in HEK293T cells. This study is believed to provide the first clear evidence that TRPM4b interacts physically with TRPC3, a member of a different TRP subfamily, and regulates negatively the channel activity, in turn suppressing store-operated Ca(2+) entry through the TRPC3 channel.
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Affiliation(s)
- Jae-Yong Park
- Department of Physiology, Institute of Health Science, and Medical Research Center for Neural Dysfunction, Gyeongsang National University School of Medicine, Jinju 660-751, Republic of Korea
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