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Potokar M, Zorec R, Jorgačevski J. Astrocytes Are a Key Target for Neurotropic Viral Infection. Cells 2023; 12:2307. [PMID: 37759529 PMCID: PMC10528686 DOI: 10.3390/cells12182307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/28/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Astrocytes are increasingly recognized as important viral host cells in the central nervous system. These cells can produce relatively high quantities of new virions. In part, this can be attributed to the characteristics of astrocyte metabolism and its abundant and dynamic cytoskeleton network. Astrocytes are anatomically localized adjacent to interfaces between blood capillaries and brain parenchyma and between blood capillaries and brain ventricles. Moreover, astrocytes exhibit a larger membrane interface with the extracellular space than neurons. These properties, together with the expression of various and numerous viral entry receptors, a relatively high rate of endocytosis, and morphological plasticity of intracellular organelles, render astrocytes important target cells in neurotropic infections. In this review, we describe factors that mediate the high susceptibility of astrocytes to viral infection and replication, including the anatomic localization of astrocytes, morphology, expression of viral entry receptors, and various forms of autophagy.
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Affiliation(s)
- Maja Potokar
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
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2
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Terrar DA. Timing mechanisms to control heart rhythm and initiate arrhythmias: roles for intracellular organelles, signalling pathways and subsarcolemmal Ca 2. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220170. [PMID: 37122228 PMCID: PMC10150226 DOI: 10.1098/rstb.2022.0170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Rhythms of electrical activity in all regions of the heart can be influenced by a variety of intracellular membrane bound organelles. This is true both for normal pacemaker activity and for abnormal rhythms including those caused by early and delayed afterdepolarizations under pathological conditions. The influence of the sarcoplasmic reticulum (SR) on cardiac electrical activity is widely recognized, but other intracellular organelles including lysosomes and mitochondria also contribute. Intracellular organelles can provide a timing mechanism (such as an SR clock driven by cyclic uptake and release of Ca2+, with an important influence of intraluminal Ca2+), and/or can act as a Ca2+ store involved in signalling mechanisms. Ca2+ plays many diverse roles including carrying electric current, driving electrogenic sodium-calcium exchange (NCX) particularly when Ca2+ is extruded across the surface membrane causing depolarization, and activation of enzymes which target organelles and surface membrane proteins. Heart function is also influenced by Ca2+ mobilizing agents (cADP-ribose, nicotinic acid adenine dinucleotide phosphate and inositol trisphosphate) acting on intracellular organelles. Lysosomal Ca2+ release exerts its effects via calcium/calmodulin-dependent protein kinase II to promote SR Ca2+ uptake, and contributes to arrhythmias resulting from excessive beta-adrenoceptor stimulation. A separate arrhythmogenic mechanism involves lysosomes, mitochondria and SR. Interacting intracellular organelles, therefore, have profound effects on heart rhythms and NCX plays a central role. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Derek A Terrar
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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Wang Q, Zhu MX. NAADP-Dependent TPC Current. Handb Exp Pharmacol 2023; 278:35-56. [PMID: 35902437 DOI: 10.1007/164_2022_606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Two-pore channels, TPC1 and TPC2, are Ca2+- and Na+-permeable cation channels expressed on the membranes of endosomes and lysosomes in nearly all mammalian cells. These channels have been implicated in Ca2+ signaling initiated from the endolysosomes, vesicular trafficking, cellular metabolism, macropinocytosis, and viral infection. Although TPCs have been shown to mediate Ca2+ release from acidic organelles in response to NAADP (nicotinic acid adenine dinucleotide phosphate), the most potent Ca2+ mobilizing messenger, questions remain whether NAADP is a direct ligand of these channels. In whole-endolysosomal patch clamp recordings, it has been difficult to detect NAADP-evoked currents in vacuoles that expressed TPC1 or TPC2, while PI(3,5)P2 (phosphatidylinositol 3,5-bisphosphate) activated a highly Na+-selective current under the same experimental configuration. In this chapter, we summarize recent progress in this area and provide our observations on NAADP-elicited TPC2 currents from enlarged endolysosomes as well as their possible relationships with the currents evoked by PI(3,5)P2. We propose that TPCs are channels dually regulated by PI(3,5)P2 and NAADP in an interdependent manner and the two endogenous ligands may have both distinguished and cooperative roles.
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Affiliation(s)
- Qiaochu Wang
- Beijing Children's Hospital, Capital Medical University, Beijing, China
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA.
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Neuromasts and Olfactory Organs of Zebrafish Larvae Represent Possible Sites of SARS-CoV-2 Pseudovirus Host Cell Entry. J Virol 2022; 96:e0141822. [PMID: 36448804 PMCID: PMC9769390 DOI: 10.1128/jvi.01418-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the acute respiratory disease coronavirus disease 2019 (COVID-19), which has resulted in millions of deaths globally. Here, we explored the mechanism of host cell entry of a luciferase-ZsGreen spike (SARS-CoV-2)-pseudotyped lentivirus using zebrafish embryos/larvae as an in vivo model. Successful pseudovirus entry was demonstrated via the expression of the luciferase (luc) gene, which was validated by reverse transcription-PCR (RT-PCR). Treatment of larvae with chloroquine (a broad-spectrum viral inhibitor that blocks membrane fusion) or bafilomycin A1 (a specific inhibitor of vacuolar proton ATPases, which blocks endolysosomal trafficking) significantly reduced luc expression, indicating the possible involvement of the endolysosomal system in the viral entry mechanism. The pharmacological inhibition of two-pore channel (TPC) activity or use of the tpcn2dhkz1a mutant zebrafish line also led to diminished luc expression. The localized expression of ACE2 and TPC2 in the anterior neuromasts and the forming olfactory organs was demonstrated, and the occurrence of endocytosis in both locations was confirmed. Together, our data indicate that zebrafish embryos/larvae are a viable and tractable model to explore the mechanism of SARS-CoV-2 host cell entry, that the peripheral sense organs are a likely site for viral host cell entry, and that TPC2 plays a key role in the translocation of the virus through the endolysosomal system. IMPORTANCE Despite the development of effective vaccines to combat the COVID-19 pandemic, which help prevent the most life-threatening symptoms, full protection cannot be guaranteed, especially with the emergence of new viral variants. Moreover, some resistance to vaccination remains in certain age groups and cultures. As such, there is an urgent need for the development of new strategies and therapies to help combat this deadly disease. Here, we provide compelling evidence that the peripheral sensory organs of zebrafish possess several key components required for SARS-CoV-2 host cell entry. The nearly transparent larvae provide a most amenable complementary platform to investigate the key steps of viral entry into host cells, as well as its spread through the tissues and organs. This will help in the identification of key viral entry steps for therapeutic intervention, provide an inexpensive model for screening novel antiviral compounds, and assist in the development of new and more effective vaccines.
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Martucci LL, Cancela JM. Neurophysiological functions and pharmacological tools of acidic and non-acidic Ca2+ stores. Cell Calcium 2022; 104:102582. [DOI: 10.1016/j.ceca.2022.102582] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/07/2022] [Accepted: 03/23/2022] [Indexed: 02/08/2023]
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Abstract
It has previously been reported that in ex vivo planar explants prepared from Xenopus laevis embryos, the intracellular pH (pHi) increases in cells of the dorsal ectoderm from stage 10.5 to 11.5 (i.e. 11-12.5 hpf). It was proposed that such increases (potentially due to H+ being extruded, sequestered, or buffered in some manner), play a role in regulating neural induction. Here, we used an extracellular ion-selective electrode to non-invasively measure H+ fluxes at eight locations around the equatorial circumference of intact X. laevis embryos between stages 9-12 (˜7-13.25 hpf). We showed that at stages 9-11, there was a small H+ efflux recorded from all the measuring positions. At stage 12 there was a small, but significant, increase in the efflux of H+ from most locations, but the efflux from the dorsal side of the embryo was significantly greater than from the other positions. Embryos were also treated from stages 9-12 with bafilomycin A1, to block the activity of the ATP-driven H+ pump. By stage 22 (24 hpf), these embryos displayed retarded development, arresting before the end of gastrulation and therefore did not display the usual anterior and neural structures, which were observed in the solvent-control embryos. In addition, expression of the early neural gene, Zic3, was absent in treated embryos compared with the solvent controls. Together, our new in vivo data corroborated and extended the earlier explant-derived report describing changes in pHi that were suggested to play a role during neural induction in X. laevis embryos.
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Tong BCK, Wu AJ, Huang AS, Dong R, Malampati S, Iyaswamy A, Krishnamoorthi S, Sreenivasmurthy SG, Zhu Z, Su C, Liu J, Song J, Lu JH, Tan J, Pan W, Li M, Cheung KH. Lysosomal TPCN (two pore segment channel) inhibition ameliorates beta-amyloid pathology and mitigates memory impairment in Alzheimer disease. Autophagy 2021; 18:624-642. [PMID: 34313551 DOI: 10.1080/15548627.2021.1945220] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
ABBREVIATIONS Aβ: β-amyloid; AD: Alzheimer disease; AIF1/IBA1: allograft inflammatory factor 1; ALP: autophagy-lysosomal pathway; APP: amyloid beta precursor protein; ATP6V1B1/V-ATPase V1b1: ATPase H+ transporting V1 subunit B1; AVs: autophagy vacuoles; BAF: bafilomycin A1; CFC: contextual/cued fear conditioning assay; CHX: Ca2+/H+ exchanger; CTF-β: carboxy-terminal fragment derived from β-secretase; CTSD: cathepsin D; fAD: familial Alzheimer disease; GFAP: glial fibrillary acidic protein; LAMP1: lysosomal associated membrane protein 1; LTP: long-term potentiation; MCOLN1/TRPML1: mucolipin 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPT: microtubule associated protein tau; MWM: Morris water maze; NFT: neurofibrillary tangles; PFC: prefrontal cortex; PSEN1: presenilin 1; SQSTM1/p62: sequestosome 1; TBS: theta burst stimulation; TEM: transmission electronic microscopy; TPCN2/TPC2: two pore segment channel 2; WT: wild-type; V-ATPase: vacuolar type H+-ATPase.
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Affiliation(s)
- Benjamin Chun-Kit Tong
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Aston Jiaxi Wu
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Alexis Shiying Huang
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Rui Dong
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Sandeep Malampati
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Ashok Iyaswamy
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Senthilkumar Krishnamoorthi
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | | | - Zhou Zhu
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Chengfu Su
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Jia Liu
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - Juxian Song
- Medical College of Acupuncture-Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jia-Hong Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Jieqiong Tan
- Center for Medical Genetics and Hunan, Key Laboratory of Animal Model for Human Diseases, School of Life Sciences, Central South University, Changsha, Hunan 410078, China
| | - Weidong Pan
- Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guiyang, China
| | - Min Li
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
| | - King-Ho Cheung
- School of Chinese Medicine and Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, Hong Kong, China
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Wong NA, Saier MH. The SARS-Coronavirus Infection Cycle: A Survey of Viral Membrane Proteins, Their Functional Interactions and Pathogenesis. Int J Mol Sci 2021; 22:1308. [PMID: 33525632 PMCID: PMC7865831 DOI: 10.3390/ijms22031308] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a novel epidemic strain of Betacoronavirus that is responsible for the current viral pandemic, coronavirus disease 2019 (COVID-19), a global health crisis. Other epidemic Betacoronaviruses include the 2003 SARS-CoV-1 and the 2009 Middle East Respiratory Syndrome Coronavirus (MERS-CoV), the genomes of which, particularly that of SARS-CoV-1, are similar to that of the 2019 SARS-CoV-2. In this extensive review, we document the most recent information on Coronavirus proteins, with emphasis on the membrane proteins in the Coronaviridae family. We include information on their structures, functions, and participation in pathogenesis. While the shared proteins among the different coronaviruses may vary in structure and function, they all seem to be multifunctional, a common theme interconnecting these viruses. Many transmembrane proteins encoded within the SARS-CoV-2 genome play important roles in the infection cycle while others have functions yet to be understood. We compare the various structural and nonstructural proteins within the Coronaviridae family to elucidate potential overlaps and parallels in function, focusing primarily on the transmembrane proteins and their influences on host membrane arrangements, secretory pathways, cellular growth inhibition, cell death and immune responses during the viral replication cycle. We also offer bioinformatic analyses of potential viroporin activities of the membrane proteins and their sequence similarities to the Envelope (E) protein. In the last major part of the review, we discuss complement, stimulation of inflammation, and immune evasion/suppression that leads to CoV-derived severe disease and mortality. The overall pathogenesis and disease progression of CoVs is put into perspective by indicating several stages in the resulting infection process in which both host and antiviral therapies could be targeted to block the viral cycle. Lastly, we discuss the development of adaptive immunity against various structural proteins, indicating specific vulnerable regions in the proteins. We discuss current CoV vaccine development approaches with purified proteins, attenuated viruses and DNA vaccines.
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Affiliation(s)
- Nicholas A. Wong
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H. Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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Salazar E, Rodriguez-Acosta A, Lucena S, Gonzalez R, McLarty MC, Sanchez O, Suntravat M, Garcia E, Finol HJ, Giron ME, Fernandez I, Deba F, Bessac BF, Sánchez EE. Biological activities of a new crotamine-like peptide from Crotalus oreganus helleri on C2C12 and CHO cell lines, and ultrastructural changes on motor endplate and striated muscle. Toxicon 2020; 188:95-107. [PMID: 33065200 PMCID: PMC7720416 DOI: 10.1016/j.toxicon.2020.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/05/2020] [Accepted: 10/11/2020] [Indexed: 01/08/2023]
Abstract
Crotamine and crotamine-like peptides are non-enzymatic polypeptides, belonging to the family of myotoxins, which are found in high concentration in the venom of the Crotalus genus. Helleramine was isolated and purified from the venom of the Southern Pacific rattlesnake, Crotalus oreganus helleri. This peptide had a similar, but unique, identity to crotamine and crotamine-like proteins isolated from other rattlesnakes species. The variability of crotamine-like protein amino acid sequences may allow different toxic effects on biological targets or optimize the action against the same target of different prey. Helleramine was capable of increasing intracellular Ca2+ in Chinese Hamster Ovary (CHO) cell line. It inhibited cell migration as well as cell viability (IC50 = 11.44 μM) of C2C12, immortalized skeletal myoblasts, in a concentration dependent manner, and promoted early apoptosis and cell death under our experimental conditions. Skeletal muscle harvested from mice 24 h after helleramine injection showed contracted myofibrils and profound vacuolization that enlarged the subsarcolemmal space, along with loss of plasmatic and basal membrane integrity. The effects of helleramine provide further insights and evidence of myotoxic activities of crotamine-like peptides and their possible role in crotalid envenomings.
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Affiliation(s)
- Emelyn Salazar
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Alexis Rodriguez-Acosta
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico, Universidad Central de Venezuela, Caracas, Venezuela
| | - Sara Lucena
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Roschman Gonzalez
- Centro de Microscopía Electrónica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | - Morgan C McLarty
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Oscar Sanchez
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Montamas Suntravat
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Estefanie Garcia
- Centro de Microscopía Electrónica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | - Hector J Finol
- Centro de Microscopía Electrónica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | - Maria E Giron
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico, Universidad Central de Venezuela, Caracas, Venezuela
| | - Irma Fernandez
- Laboratorio de Inmunoquímica y Ultraestructura, Instituto Anatómico, Universidad Central de Venezuela, Caracas, Venezuela
| | - Farah Deba
- Texas A&M Rangel College of Pharmacy, Kingsville, TX, USA
| | - Bret F Bessac
- Texas A&M Rangel College of Pharmacy, Kingsville, TX, USA; Jerry H. Hodge School of Pharmacy, Texas Tech University HSC, Amarillo, TX, USA
| | - Elda E Sánchez
- National Natural Toxins Research Center (NNTRC), Texas A&M University-Kingsville, Kingsville, TX, USA; Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA.
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Nourbakhsh F, Read MI, Barreto GE, Sahebkar A. Boosting the autophagy-lysosomal pathway by phytochemicals: A potential therapeutic strategy against Alzheimer's disease. IUBMB Life 2020; 72:2360-2281. [PMID: 32894821 DOI: 10.1002/iub.2369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/20/2020] [Accepted: 07/31/2020] [Indexed: 01/14/2023]
Abstract
The lysosome is a membrane-enclosed organelle in eukaryotic cells, which has basic pattern recognition for nutrient-dependent signal transduction. In Alzheimer's disease, the already declining autophagy-lysosomal function is exacerbated by an increased need for clearance of damaged proteins and organelles in aged cells. Recent evidence suggests that numerous diseases are linked to impaired autophagy upstream of lysosomes. In this way, a comprehensive survey on the pathophysiology of the disease seems necessary. Hence, in the first section of this review, we will discuss the ultimate findings in lysosomal signaling functions and how they affect cellular metabolism and trafficking under neurodegenerative conditions, specifically Alzheimer's disease. In the second section, we focus on how natural products and their derivatives are involved in the regulation of inflammation and lysosomal dysfunction pathways, including how these should be considered a crucial target for Alzheimer's disease therapeutics.
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Affiliation(s)
- Fahimeh Nourbakhsh
- Medical Toxicology Research Centre, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morgayn I Read
- Department of Pharmacology, University of Otago School of Medical Sciences, Dunedin, New Zealand
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland.,Health Research Institute, University of Limerick, Limerick, Ireland
| | - Amirhossein Sahebkar
- Halal Research Center of IRI, FDA, Tehran, Iran.,Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
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11
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Filippini A, D'Amore A, D'Alessio A. Calcium Mobilization in Endothelial Cell Functions. Int J Mol Sci 2019; 20:ijms20184525. [PMID: 31547344 PMCID: PMC6769945 DOI: 10.3390/ijms20184525] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 09/02/2019] [Accepted: 09/06/2019] [Indexed: 02/07/2023] Open
Abstract
Endothelial cells (ECs) constitute the innermost layer that lines all blood vessels from the larger arteries and veins to the smallest capillaries, including the lymphatic vessels. Despite the histological classification of endothelium of a simple epithelium and its homogeneous morphological appearance throughout the vascular system, ECs, instead, are extremely heterogeneous both structurally and functionally. The different arrangement of cell junctions between ECs and the local organization of the basal membrane generate different type of endothelium with different permeability features and functions. Continuous, fenestrated and discontinuous endothelia are distributed based on the specific function carried out by the organs. It is thought that a large number ECs functions and their responses to extracellular cues depend on changes in intracellular concentrations of calcium ion ([Ca2+]i). The extremely complex calcium machinery includes plasma membrane bound channels as well as intracellular receptors distributed in distinct cytosolic compartments that act jointly to maintain a physiological [Ca2+]i, which is crucial for triggering many cellular mechanisms. Here, we first survey the overall notions related to intracellular Ca2+ mobilization and later highlight the involvement of this second messenger in crucial ECs functions with the aim at stimulating further investigation that link Ca2+ mobilization to ECs in health and disease.
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Affiliation(s)
- Antonio Filippini
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy.
| | - Antonella D'Amore
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy.
| | - Alessio D'Alessio
- Istituto di Istologia ed Embriologia, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "Agostino Gemelli", IRCCS, 00168 Rome, Italy.
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12
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Bouillot S, Reboud E, Huber P. Functional Consequences of Calcium Influx Promoted by Bacterial Pore-Forming Toxins. Toxins (Basel) 2018; 10:toxins10100387. [PMID: 30257425 PMCID: PMC6215193 DOI: 10.3390/toxins10100387] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 09/14/2018] [Accepted: 09/20/2018] [Indexed: 02/06/2023] Open
Abstract
Bacterial pore-forming toxins induce a rapid and massive increase in cytosolic Ca2+ concentration due to the formation of pores in the plasma membrane and/or activation of Ca2+-channels. As Ca2+ is an essential messenger in cellular signaling, a sustained increase in Ca2+ concentration has dramatic consequences on cellular behavior, eventually leading to cell death. However, host cells have adapted mechanisms to protect against Ca2+ intoxication, such as Ca2+ efflux and membrane repair. The final outcome depends upon the nature and concentration of the toxin and on the cell type. This review highlights the repercussions of Ca2+ overload on the induction of cell death, repair mechanisms, cellular adhesive properties, and the inflammatory response.
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Affiliation(s)
- Stéphanie Bouillot
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
| | - Emeline Reboud
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
| | - Philippe Huber
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
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13
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Tong BCK, Wu AJ, Li M, Cheung KH. Calcium signaling in Alzheimer's disease & therapies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1745-1760. [PMID: 30059692 DOI: 10.1016/j.bbamcr.2018.07.018] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/12/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is the most common type of dementia and is characterized by the accumulation of amyloid (Aβ) plaques and neurofibrillary tangles in the brain. Much attention has been given to develop AD treatments based on the amyloid cascade hypothesis; however, none of these drugs had good efficacy at improving cognitive functions in AD patients suggesting that Aβ might not be the disease origin. Thus, there are urgent needs for the development of new therapies that target on the proximal cause of AD. Cellular calcium (Ca2+) signals regulate important facets of neuronal physiology. An increasing body of evidence suggests that age-related dysregulation of neuronal Ca2+ homeostasis may play a proximal role in the pathogenesis of AD as disrupted Ca2+ could induce synaptic deficits and promote the accumulation of Aβ plaques and neurofibrillary tangles. Given that Ca2+ disruption is ubiquitously involved in all AD pathologies, it is likely that using chemical agents or small molecules specific to Ca2+ channels or handling proteins on the plasma membrane and membranes of intracellular organelles to correct neuronal Ca2+ dysregulation could open up a new approach to AD prevention and treatment. This review summarizes current knowledge on the molecular mechanisms linking Ca2+ dysregulation with AD pathologies and discusses the possibility of correcting neuronal Ca2+ disruption as a therapeutic approach for AD.
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Affiliation(s)
- Benjamin Chun-Kit Tong
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Aston Jiaxi Wu
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Min Li
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - King-Ho Cheung
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.
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14
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Veklich TO, Nikonishyna YV, Kosterin SO. Pathways and mechanisms of transmembrane calcium ions exchange in the cell nucleus. UKRAINIAN BIOCHEMICAL JOURNAL 2018. [DOI: 10.15407/ubj90.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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15
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Notomi T, Kuno M, Hiyama A, Nozaki T, Ohura K, Ezura Y, Noda M. Role of lysosomal channel protein TPC2 in osteoclast differentiation and bone remodeling under normal and low-magnesium conditions. J Biol Chem 2017; 292:20998-21010. [PMID: 29084844 DOI: 10.1074/jbc.m117.780072] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 09/25/2017] [Indexed: 11/06/2022] Open
Abstract
The bone is the main storage site for Ca2+ and Mg2+ ions in the mammalian body. Although investigations into Ca2+ signaling have progressed rapidly and led to better understanding of bone biology, the Mg2+ signaling pathway and associated molecules remain to be elucidated. Here, we investigated the role of a potential Mg2+ signaling-related lysosomal molecule, two-pore channel subtype 2 (TPC2), in osteoclast differentiation and bone remodeling. Previously, we found that under normal Mg2+ conditions, TPC2 promotes osteoclastogenesis. We observed that under low-Mg2+ conditions, TPC2 inhibited, rather than promoted, the osteoclast differentiation and that the phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) signaling pathway played a role in the TPC2 activation under low-Mg2+ conditions. Furthermore, PI(3,5)P2 depolarized the membrane potential by increasing the intracellular Na+ levels. To investigate how membrane depolarization affects osteoclast differentiation, we generated a light-sensitive cell line and developed a system for the light-stimulated depolarization of the membrane potential. The light-induced depolarization inhibited the osteoclast differentiation. We then tested the effect of myo-inositol supplementation, which increased the PI(3,5)P2 levels in mice fed a low-Mg2+ diet. The myo-inositol supplementation rescued the low-Mg2+ diet-induced trabecular bone loss, which was accompanied by the inhibition of osteoclastogenesis. These results indicate that low-Mg2+-induced osteoclastogenesis involves changes in the role of TPC2, which are mediated through the PI(3,5)P2 pathway. Our findings also suggest that myo-inositol consumption might provide beneficial effects in Mg2+ deficiency-induced skeletal diseases.
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Affiliation(s)
- Takuya Notomi
- From the Department of Molecular Pharmacology, Medical Research Institute and .,the Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, Bunkyo 113-8510, Tokyo, Japan.,the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Miyuki Kuno
- the Department of Physiology, Graduate School of Medicine, Osaka City University, Abeno, Osaka 545-8585, Japan, and
| | - Akiko Hiyama
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Tadashige Nozaki
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Kiyoshi Ohura
- the Department of Pharmacology, Osaka Dental University, Hirakata, Osaka 573-1121, Japan
| | - Yoichi Ezura
- From the Department of Molecular Pharmacology, Medical Research Institute and
| | - Masaki Noda
- From the Department of Molecular Pharmacology, Medical Research Institute and .,the Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, Bunkyo 113-8510, Tokyo, Japan.,the Yokohama City Minato Red Cross Hospital, Yokohama, Kanagawa 231-8682, Japan
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16
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Castonguay J, Orth JHC, Müller T, Sleman F, Grimm C, Wahl-Schott C, Biel M, Mallmann RT, Bildl W, Schulte U, Klugbauer N. The two-pore channel TPC1 is required for efficient protein processing through early and recycling endosomes. Sci Rep 2017; 7:10038. [PMID: 28855648 PMCID: PMC5577145 DOI: 10.1038/s41598-017-10607-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/11/2017] [Indexed: 02/06/2023] Open
Abstract
Two-pore channels (TPCs) are localized in endo-lysosomal compartments and assumed to play an important role for vesicular fusion and endosomal trafficking. Recently, it has been shown that both TPC1 and 2 were required for host cell entry and pathogenicity of Ebola viruses. Here, we investigate the cellular function of TPC1 using protein toxins as model substrates for distinct endosomal processing routes. Toxin uptake and activation through early endosomes but not processing through other compartments were reduced in TPC1 knockout cells. Detailed co-localization studies with subcellular markers confirmed predominant localization of TPC1 to early and recycling endosomes. Proteomic analysis of native TPC1 channels finally identified direct interaction with a distinct set of syntaxins involved in fusion of intracellular vesicles. Together, our results demonstrate a general role of TPC1 for uptake and processing of proteins in early and recycling endosomes, likely by providing high local Ca2+ concentrations required for SNARE-mediated vesicle fusion.
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Affiliation(s)
- Jan Castonguay
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany
| | - Joachim H C Orth
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany
| | - Thomas Müller
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany
| | - Faten Sleman
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany
| | - Christian Grimm
- Department of Pharmacy, Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-University, Munich, Germany
| | - Christian Wahl-Schott
- Department of Pharmacy, Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-University, Munich, Germany
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-University, Munich, Germany
| | - Robert Theodor Mallmann
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany
| | - Wolfgang Bildl
- Institute of Physiology II, Faculty of Medicine, Albert-Ludwigs-University, Hermann-Herder-Strasse 7, 79104, Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology II, Faculty of Medicine, Albert-Ludwigs-University, Hermann-Herder-Strasse 7, 79104, Freiburg, Germany.,Logopharm GmbH, Schlossstrasse 14, 79232, March-Buchheim, Germany.,Center for Biological Signaling Studies (BIOSS), Schänzlestrasse 18, 79104, Freiburg, Germany
| | - Norbert Klugbauer
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University, Albertstrasse 25, 79104, Freiburg, Germany.
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17
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Fernández B, Fdez E, Gómez-Suaga P, Gil F, Molina-Villalba I, Ferrer I, Patel S, Churchill GC, Hilfiker S. Iron overload causes endolysosomal deficits modulated by NAADP-regulated 2-pore channels and RAB7A. Autophagy 2016; 12:1487-506. [PMID: 27383256 PMCID: PMC5082776 DOI: 10.1080/15548627.2016.1190072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 05/05/2016] [Accepted: 05/11/2016] [Indexed: 12/19/2022] Open
Abstract
Various neurodegenerative disorders are associated with increased brain iron content. Iron is known to cause oxidative stress, which concomitantly promotes cell death. Whereas endolysosomes are known to serve as intracellular iron storage organelles, the consequences of increased iron on endolysosomal functioning, and effects on cell viability upon modulation of endolysosomal iron release remain largely unknown. Here, we show that increasing intracellular iron causes endolysosomal alterations associated with impaired autophagic clearance of intracellular protein aggregates, increased cytosolic oxidative stress and increased cell death. These effects are subject to regulation by NAADP, a potent second messenger reported to target endolysosomal TPCNs (2-pore channels). Consistent with endolysosomal iron storage, cytosolic iron levels are modulated by NAADP, and increased cytosolic iron is detected when overexpressing active, but not inactive TPCNs, indicating that these channels can modulate endolysosomal iron release. Cell death triggered by altered intralysosomal iron handling is abrogated in the presence of an NAADP antagonist or when inhibiting RAB7A activity. Taken together, our results suggest that increased endolysosomal iron causes cell death associated with increased cytosolic oxidative stress as well as autophagic impairments, and these effects are subject to modulation by endolysosomal ion channel activity in a RAB7A-dependent manner. These data highlight alternative therapeutic strategies for neurodegenerative disorders associated with increased intracellular iron load.
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Affiliation(s)
- Belén Fernández
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Elena Fdez
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Patricia Gómez-Suaga
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Fernando Gil
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada, Granada, Spain
| | - Isabel Molina-Villalba
- Department of Legal Medicine and Toxicology, School of Medicine, University of Granada, Granada, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, IDIBELL-University Hospital Bellvitge, University of Barcelona, Llobregat, Spain
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Sabine Hilfiker
- Institute of Parasitology and Biomedicine “López-Neyra,” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
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18
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Larisch N, Kirsch SA, Schambony A, Studtrucker T, Böckmann RA, Dietrich P. The function of the two-pore channel TPC1 depends on dimerization of its carboxy-terminal helix. Cell Mol Life Sci 2016; 73:2565-81. [PMID: 26781468 PMCID: PMC4894940 DOI: 10.1007/s00018-016-2131-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/07/2015] [Accepted: 01/04/2016] [Indexed: 12/12/2022]
Abstract
Two-pore channels (TPCs) constitute a family of intracellular cation channels with diverse permeation properties and functions in animals and plants. In the model plant Arabidopsis, the vacuolar cation channel TPC1 is involved in propagation of calcium waves and in cation homeostasis. Here, we discovered that the dimerization of a predicted helix within the carboxyl-terminus (CTH) is essential for the activity of TPC1. Bimolecular fluorescence complementation and co-immunoprecipitation demonstrated the interaction of the two C-termini and pointed towards the involvement of the CTH in this process. Synthetic CTH peptides dimerized with a dissociation constant of 3.9 µM. Disruption of this domain in TPC1 either by deletion or point mutations impeded the dimerization and cation transport. The homo-dimerization of the CTH was analyzed in silico using coarse-grained molecular dynamics (MD) simulations for the study of aggregation, followed by atomistic MD simulations. The simulations revealed that the helical region of the wild type, but not a mutated CTH forms a highly stable, antiparallel dimer with characteristics of a coiled-coil. We propose that the voltage- and Ca(2+)-sensitive conformation of TPC1 depends on C-terminal dimerization, adding an additional layer to the complex regulation of two-pore cation channels.
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Affiliation(s)
- Nina Larisch
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Sonja A Kirsch
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Alexandra Schambony
- Developmental Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Tanja Studtrucker
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Petra Dietrich
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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19
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Wu JS, Li WM, Chen YN, Zhao Q, Chen QF. Endoplasmic reticulum stress is activated in acute pancreatitis. J Dig Dis 2016; 17:295-303. [PMID: 27059531 DOI: 10.1111/1751-2980.12347] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/21/2016] [Accepted: 03/31/2016] [Indexed: 12/11/2022]
Abstract
Endoplasmic reticulum (ER) is one of the most important cell organelles in the body, regulating protein synthesis, folding and aggregation. Endoplasmic reticulum stress (ERS) is a particular subcellular pathological process involving an imbalance of homeostasis and ER disorder. In the early stage of ERS, cells show a protective unfolded protein response that changes the cellular transcriptional and translational programs to alleviate the process. Therefore, a certain degree of ERS can activate the protective adaptation of cells, whereas sustained severe ERS triggers an apoptotic signal and leads to apoptosis. Acute pancreatitis is a disease caused by trypsin digestion of the pancreas, although the pathogenesis is not completely understood. However, a close association has been suggested between pancreatitis and ERS. This article reviewed relevant research advances and discussed the effect of ERS on the development and progression of acute pancreatitis.
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Affiliation(s)
- Jian Sheng Wu
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Wei Min Li
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yi Na Chen
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Qian Zhao
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Qin Fen Chen
- Department of Gastroenterology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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20
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Pitt SJ, Reilly-O'Donnell B, Sitsapesan R. Exploring the biophysical evidence that mammalian two-pore channels are NAADP-activated calcium-permeable channels. J Physiol 2016; 594:4171-9. [PMID: 26872338 DOI: 10.1113/jp270936] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/15/2016] [Indexed: 01/15/2023] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) potently releases Ca(2+) from acidic intracellular endolysosomal Ca(2+) stores. It is widely accepted that two types of two-pore channels, termed TPC1 and TPC2, are responsible for the NAADP-mediated Ca(2+) release but the underlying mechanisms regulating their gating appear to be different. For example, although both TPC1 and TPC2 are activated by NAADP, TPC1 appears to be additionally regulated by cytosolic Ca(2+) . Ion conduction and permeability also differ markedly. TPC1 and TPC2 are permeable to a range of cations although biophysical experiments suggest that TPC2 is slightly more selective for Ca(2+) over K(+) than TPC1 and hence capable of releasing greater quantities of Ca(2+) from acidic stores. TPC1 is also permeable to H(+) and therefore may play a role in regulating lysosomal and cytosolic pH, possibly creating localised acidic domains. The significantly different gating and ion conducting properties of TPC1 and TPC2 suggest that these two ion channels may play complementary physiological roles as Ca(2+) -release channels of the endolysosomal system.
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Affiliation(s)
- Samantha J Pitt
- School of Medicine, University of St Andrews, St Andrews, KY16 9TF, UK
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21
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Evolution of acidic Ca2+ stores and their resident Ca2+-permeable channels. Cell Calcium 2015; 57:222-30. [DOI: 10.1016/j.ceca.2014.12.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022]
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22
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Ezeani M, Omabe M. A New Perspective of Lysosomal Cation Channel-Dependent Homeostasis in Alzheimer's Disease. Mol Neurobiol 2015; 53:1672-1678. [PMID: 25691454 DOI: 10.1007/s12035-015-9108-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 01/20/2015] [Indexed: 01/08/2023]
Abstract
Studies have reported typically biophysical lysosomal cation channels including TPCs. Their plausible biological roles are being elucidated by pharmacological, genetic and conventional patch clamp procedures. The best characterized so far among these channels is the ML1 isoform of TRP. The reported TRPs and TPCs are bypass for cation fluxes and are strategic for homeostasis of ionic milieu of the acidic organelles they confine to. Ca(2+) homeostasis and adequate acidic pHL are critically influential for the regulation of a plethora of biological functions these intracellular cation channels perform. In lysosomal ion channel biology, we review: ML1 and TPC2 in Ca(2+) signaling, ML1 and TPC2 in pH(L) regulation. Using Aβ42 and tau proteins found along clathrin endolysosomal internalization pathway (Fig. 3), we proffer a mechanism of abnormal pH(L) and ML1/TPC2-dependent cation homeostasis in AD.
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Affiliation(s)
- Martin Ezeani
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, B3H 4R2, Nova Scotia, Canada.
| | - Maxwell Omabe
- Cancer Research Unit, Saskatchewan Cancer Agency, Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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23
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Ogunbayo OA, Zhu Y, Shen B, Agbani E, Li J, Ma J, Zhu MX, Evans AM. Organelle-specific subunit interactions of the vertebrate two-pore channel family. J Biol Chem 2014; 290:1086-95. [PMID: 25451935 DOI: 10.1074/jbc.m114.610493] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The organellar targeting of two-pore channels (TPCs) and their capacity to associate as homo- and heterodimers may be critical to endolysosomal signaling. A more detailed understanding of the functional association of vertebrate TPC1-3 is therefore necessary. We report here that when stably expressed in HEK293 cells, human (h) TPC1 and chicken (c) TPC3 were specifically targeted to different subpopulations of endosomes, hTPC2 was specifically targeted to lysosomes, and rabbit (r) TPC3 was specifically targeted to both endosomes and lysosomes. Intracellular dialysis of NAADP evoked a Ca(2+) transient in HEK293 cells that stably overexpressed hTPC1, hTPC2, and rTPC3, but not in cells that stably expressed cTPC3. The Ca(2+) transients induced in cells that overexpressed endosome-targeted hTPC1 were abolished upon depletion of acidic Ca(2+) stores by bafilomycin A1, but remained unaffected following depletion of endoplasmic reticulum stores by thapsigargin. In contrast, Ca(2+) transients induced via lysosome-targeted hTPC2 and endolysosome-targeted rTPC3 were abolished by bafilomycin A1 and markedly attenuated by thapsigargin. NAADP induced marked Ca(2+) transients in HEK293 cells that stably coexpressed hTPC2 with hTPC1 or cTPC3, but failed to evoke any such response in cells that coexpressed interacting hTPC2 and rTPC3 subunits. We therefore conclude that 1) all three TPC subtypes may support Ca(2+) signaling from their designate acidic stores, and 2) lysosome-targeted (but not endosome-targeted) TPCs support coupling to the endoplasmic reticulum.
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Affiliation(s)
- Oluseye A Ogunbayo
- From the Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9XD, Scotland, United Kingdom
| | - Yingmin Zhu
- the Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Bing Shen
- the Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77030, the Department of Physiology, Anhui Medical University, Hefei, Anhui 230032, China, and
| | - Ejaife Agbani
- From the Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9XD, Scotland, United Kingdom
| | - Jie Li
- the Department of Physiology, Anhui Medical University, Hefei, Anhui 230032, China, and
| | - Jianjie Ma
- the Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210
| | - Michael X Zhu
- the Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77030,
| | - A Mark Evans
- From the Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9XD, Scotland, United Kingdom,
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24
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Boccaccio A, Scholz-Starke J, Hamamoto S, Larisch N, Festa M, Gutla PVK, Costa A, Dietrich P, Uozumi N, Carpaneto A. The phosphoinositide PI(3,5)P₂ mediates activation of mammalian but not plant TPC proteins: functional expression of endolysosomal channels in yeast and plant cells. Cell Mol Life Sci 2014; 71:4275-83. [PMID: 24770793 PMCID: PMC11113638 DOI: 10.1007/s00018-014-1623-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/18/2014] [Accepted: 03/31/2014] [Indexed: 11/29/2022]
Abstract
Two-pore channel proteins (TPC) encode intracellular ion channels in both animals and plants. In mammalian cells, the two isoforms (TPC1 and TPC2) localize to the endo-lysosomal compartment, whereas the plant TPC1 protein is targeted to the membrane surrounding the large lytic vacuole. Although it is well established that plant TPC1 channels activate in a voltage- and calcium-dependent manner in vitro, there is still debate on their activation under physiological conditions. Likewise, the mode of animal TPC activation is heavily disputed between two camps favoring as activator either nicotinic acid adenine dinucleotide phosphate (NAADP) or the phosphoinositide PI(3,5)P₂. Here, we investigated TPC current responses to either of these second messengers by whole-vacuole patch-clamp experiments on isolated vacuoles of Arabidopsis thaliana. After expression in mesophyll protoplasts from Arabidopsis tpc1 knock-out plants, we detected the Arabidopsis TPC1-EGFP and human TPC2-EGFP fusion proteins at the membrane of the large central vacuole. Bath (cytosolic) application of either NAADP or PI(3,5)P₂ did not affect the voltage- and calcium-dependent characteristics of AtTPC1-EGFP. By contrast, PI(3,5)P₂ elicited large sodium currents in hTPC2-EGFP-containing vacuoles, while NAADP had no such effect. Analogous results were obtained when PI(3,5)P₂ was applied to hTPC2 expressed in baker's yeast giant vacuoles. Our results underscore the fundamental differences in the mode of current activation and ion selectivity between animal and plant TPC proteins and corroborate the PI(3,5)P₂-mediated activation and Na(+) selectivity of mammalian TPC2.
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Affiliation(s)
- Anna Boccaccio
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149 Genoa, Italy
| | - Joachim Scholz-Starke
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149 Genoa, Italy
| | - Shin Hamamoto
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama, Sendai, 980-8579 Japan
| | - Nina Larisch
- Department of Biology, Molecular Plant Physiology and Erlangen Center of Plant Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Margherita Festa
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149 Genoa, Italy
| | | | - Alex Costa
- Department of Biology, Università degli Studi di Milano, Via G. Celoria 26, 20133 Milan, Italy
- Milan Division, Institute of Biophysics, National Research Council, Via G. Celoria 26, 20133 Milan, Italy
| | - Petra Dietrich
- Department of Biology, Molecular Plant Physiology and Erlangen Center of Plant Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama, Sendai, 980-8579 Japan
| | - Armando Carpaneto
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149 Genoa, Italy
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25
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A non-inactivating high-voltage-activated two-pore Na⁺ channel that supports ultra-long action potentials and membrane bistability. Nat Commun 2014; 5:5015. [PMID: 25256615 PMCID: PMC4224019 DOI: 10.1038/ncomms6015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/19/2014] [Indexed: 01/11/2023] Open
Abstract
Action potentials (APs) are fundamental cellular electrical signals. The genesis of short APs lasting milliseconds is well understood. Ultra-long APs (ulAPs) lasting seconds to minutes also occur in eukaryotic organisms, but their biological functions and mechanisms of generation are largely unknown. Here, we identify TPC3, a previously uncharacterized member of the two-pore channel protein family, as a new voltage-gated Na+ channel (NaV) that generates ulAPs, and that establishes membrane potential bistability. Unlike the rapidly inactivating NaVs that generate short APs in neurons, TPC3 has a high activation threshold, activates slowly, and does not inactivate—three properties that help generate long-lasting APs and guard the membrane against unintended perturbation. In amphibian oocytes, TPC3 forms a channel similar to channels induced by depolarization and sperm entry into eggs. TPC3 homologs are present in plants and animals, and they may be important for cellular processes and behaviors associated with prolonged membrane depolarization.
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26
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Parrington J, Tunn R. Ca(2+) signals, NAADP and two-pore channels: role in cellular differentiation. Acta Physiol (Oxf) 2014; 211:285-96. [PMID: 24702694 DOI: 10.1111/apha.12298] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/13/2014] [Accepted: 03/27/2014] [Indexed: 02/06/2023]
Abstract
Ca(2+) signals regulate a wide range of physiological processes. Intracellular Ca(2+) stores can be mobilized in response to extracellular stimuli via a range of signal transduction mechanisms, often involving recruitment of diffusible second messenger molecules. The Ca(2+) -mobilizing messengers InsP3 and cADPR release Ca(2+) from the endoplasmic reticulum via the InsP3 and ryanodine receptors, respectively, while a third messenger, NAADP, releases Ca(2+) from acidic endosomes and lysosomes. Bidirectional communication between the endoplasmic reticulum (ER) and acidic organelles may have functional relevance for endolysosomal function as well as for the generation of Ca(2+) signals. The two-pore channels (TPCs) are currently strong candidates for being key components of NAADP-regulated Ca(2+) channels. Ca(2+) signals have been shown to play important roles in differentiation; however, much remains to be established about the exact signalling mechanisms involved. The investigation of the role of NAADP and TPCs in differentiation is still at an early stage, but recent studies have suggested that they are important mediators of differentiation of neurones, skeletal muscle cells and osteoclasts. NAADP signals and TPCs have also been implicated in autophagy, an important process in differentiation. Further studies will be required to identify the precise mechanism of TPC action and their link with NAADP signalling, as well as relating this to their roles in differentiation and other key processes in the cell and organism.
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Affiliation(s)
- J. Parrington
- Department of Pharmacology; University of Oxford; Oxford UK
| | - R. Tunn
- Department of Pharmacology; University of Oxford; Oxford UK
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Pitt SJ, Lam AKM, Rietdorf K, Galione A, Sitsapesan R. Reconstituted human TPC1 is a proton-permeable ion channel and is activated by NAADP or Ca2+. Sci Signal 2014; 7:ra46. [PMID: 24847115 DOI: 10.1126/scisignal.2004854] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
NAADP potently triggers Ca2+ release from acidic lysosomal and endolysosomal Ca2+ stores. Human two-pore channels (TPC1 and TPC2), which are located on these stores, are involved in this process, but there is controversy over whether TPC1 and TPC2 constitute the Ca2+ release channels. We therefore examined the single-channel properties of human TPC1 after reconstitution into bilayers of controlled composition. We found that TPC1 was permeable not only to Ca2+ but also to monovalent cations and that permeability to protons was the highest (relative permeability sequence: H+ >> K+ > Na(+) ≥ Ca2+). NAADP or Ca2+ activated TPC1, and the presence of one of these ligands was required for channel activation. The endolysosome-located lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] had no effect on TPC1 open probability but significantly increased the relative permeability of Na+ to Ca2+ and of H+ to Ca2+. Furthermore, our data showed that, although both TPC1 and TPC2 are stimulated by NAADP, these channels differ in ion selectivity and modulation by Ca2+ and pH. We propose that NAADP triggers H+ release from lysosomes and endolysomes through activation of TPC1, but that the Ca2+ -releasing ability of TPC1 will depend on the ionic composition of the acidic stores and may be influenced by other regulators that affect TPC1 ion permeation.
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Affiliation(s)
- Samantha J Pitt
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, UK
| | - Andy K M Lam
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Katja Rietdorf
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Rebecca Sitsapesan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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Pereira GJS, Hirata H, do Carmo LG, Stilhano RS, Ureshino RP, Medaglia NC, Han SW, Churchill G, Bincoletto C, Patel S, Smaili SS. NAADP-sensitive two-pore channels are present and functional in gastric smooth muscle cells. Cell Calcium 2014; 56:51-8. [PMID: 24882212 DOI: 10.1016/j.ceca.2014.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 04/11/2014] [Accepted: 04/21/2014] [Indexed: 01/06/2023]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) has been identified as an important modulator of Ca(2+) release from the endo-lysosomal system in a variety of cells by a new and ubiquitous class of endo-lysosomal ion channels known as the two-pore channels (TPCs). However, the role of TPCs in NAADP action in smooth muscle is not known. In the present work, we investigated the effects of NAADP in gastric smooth muscle cells and its ability to release Ca(2+) by TPCs. We show that Ca(2+) signals mediated by NAADP were inhibited by disrupting Ca(2+) handling by either acidic organelles (using bafilomycin A1) or the Endoplasmic Reticulum (using thapsigargin, ryanodine or 2-APB). Transcripts for endogenous TPC1 and TPC2 were readily detected and recombinant TPCs localized to the endosomes and/or lysosomes. Overexpression of wild-type TPCs but not pore mutants enhanced NAADP-mediated cytosolic Ca(2+) signals. Desensitizing the NAADP pathway inhibited Ca(2+)-responses to extracellular stimulation with carbachol but not ATP. Taken together, these results indicate that NAADP likely induces Ca(2+) release from the endolysosomal system through TPCs which is subsequently amplified via the ER in an agonist-specific manner. Thus, we suggest a second messenger role for NAADP in smooth muscle cells.
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Affiliation(s)
- Gustavo J S Pereira
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Hanako Hirata
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Lúcia G do Carmo
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Roberta S Stilhano
- Interdisciplinary Center for Gene Therapy, Federal University of São Paulo, São Paulo, Brazil
| | - Rodrigo P Ureshino
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Natalia C Medaglia
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Sang W Han
- Interdisciplinary Center for Gene Therapy, Federal University of São Paulo, São Paulo, Brazil
| | - Grant Churchill
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Claudia Bincoletto
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Soraya S Smaili
- Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
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Webb SE, Miller AL. Calcium signaling in extraembryonic domains during early teleost development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 304:369-418. [PMID: 23809440 DOI: 10.1016/b978-0-12-407696-9.00007-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
It is becoming recognized that the extraembryonic domains of developing vertebrates, that is, those that make no cellular contribution to the embryo proper, act as important signaling centers that induce and pattern the germ layers and help establish the key embryonic axes. In the embryos of teleost fish, in particular, significant progress has been made in understanding how signaling activity in extraembryonic domains, such as the enveloping layer, the yolk syncytial layer, and the yolk cell, might help regulate development via a combination of inductive interactions, cellular dynamics, and localized gene expression. Ca(2+) signaling in a variety of forms that include propagating waves and standing gradients is a feature found in all three teleostean extraembryonic domains. This leads us to propose that in addition to their other well-characterized signaling activities, extraembryonic domains are well suited (due to their relative stability and continuity) to act as Ca(2+) signaling centers and conduits.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
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30
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Arndt L, Castonguay J, Arlt E, Meyer D, Hassan S, Borth H, Zierler S, Wennemuth G, Breit A, Biel M, Wahl-Schott C, Gudermann T, Klugbauer N, Boekhoff I. NAADP and the two-pore channel protein 1 participate in the acrosome reaction in mammalian spermatozoa. Mol Biol Cell 2014; 25:948-64. [PMID: 24451262 PMCID: PMC3952862 DOI: 10.1091/mbc.e13-09-0523] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A TPCN1 gene–deficient mouse strain is used to show that two convergent working NAADP-dependent pathways with nonoverlapping activation and self-inactivation profiles for distinct NAADP concentrations drive acrosomal exocytosis, by which TPC1 is central for the pathway activated by low-micromolar NAADP concentrations. The functional relationship between the formation of hundreds of fusion pores during the acrosome reaction in spermatozoa and the mobilization of calcium from the acrosome has been determined only partially. Hence, the second messenger NAADP, promoting efflux of calcium from lysosome-like compartments and one of its potential molecular targets, the two-pore channel 1 (TPC1), were analyzed for its involvement in triggering the acrosome reaction using a TPCN1 gene–deficient mouse strain. The present study documents that TPC1 and NAADP-binding sites showed a colocalization at the acrosomal region and that treatment of spermatozoa with NAADP resulted in a loss of the acrosomal vesicle that showed typical properties described for TPCs: Registered responses were not detectable for its chemical analogue NADP and were blocked by the NAADP antagonist trans-Ned-19. In addition, two narrow bell-shaped dose-response curves were identified with maxima in either the nanomolar or low micromolar NAADP concentration range, where TPC1 was found to be responsible for activating the low affinity pathway. Our finding that two convergent NAADP-dependent pathways are operative in driving acrosomal exocytosis supports the concept that both NAADP-gated cascades match local NAADP concentrations with the efflux of acrosomal calcium, thereby ensuring complete fusion of the large acrosomal vesicle.
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Affiliation(s)
- Lilli Arndt
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians University, 81377 München, Germany Department of Pharmacy, Ludwig-Maximilians University, 81377 München, Germany Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University, 79104 Freiburg, Germany Institute for Anatomy, University of Duisburg-Essen, 45141 Essen, Germany
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Dadacz-Narloch B, Kimura S, Kurusu T, Farmer EE, Becker D, Kuchitsu K, Hedrich R. On the cellular site of two-pore channel TPC1 action in the Poaceae. THE NEW PHYTOLOGIST 2013; 200:663-674. [PMID: 23845012 DOI: 10.1111/nph.12402] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 06/02/2013] [Indexed: 06/02/2023]
Abstract
The slow vacuolar (SV) channel has been characterized in different dicots by patch-clamp recordings. This channel represents the major cation conductance of the largest organelle in most plant cells. Studies with the tpc1-2 mutant of the model dicot plant Arabidopsis thaliana identified the SV channel as the product of the TPC1 gene. By contrast, research on rice and wheat TPC1 suggested that the monocot gene encodes a plasma membrane calcium-permeable channel. To explore the site of action of grass TPC1 channels, we expressed OsTPC1 from rice (Oryza sativa) and TaTPC1 from wheat (Triticum aestivum) in the background of the Arabidopsis tpc1-2 mutant. Cross-species tpc1 complementation and patch-clamping of vacuoles using Arabidopsis and rice tpc1 null mutants documented that both monocot TPC1 genes were capable of rescuing the SV channel deficit. Vacuoles from wild-type rice but not the tpc1 loss-of-function mutant harbor SV channels exhibiting the hallmark properties of dicot TPC1/SV channels. When expressed in human embryonic kidney (HEK293) cells OsTPC1 was targeted to Lysotracker-Red-positive organelles. The finding that the rice TPC1, just like those from the model plant Arabidopsis and even animal cells, is localized and active in lyso-vacuolar membranes associates this cation channel species with endomembrane function.
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Affiliation(s)
- Beata Dadacz-Narloch
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, D-97082, Wuerzburg, Germany
| | - Sachie Kimura
- Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan
| | - Takamitsu Kurusu
- Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan
- School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, 192-0982, Japan
| | - Edward E Farmer
- Department of Plant Molecular Biology, University of Lausanne, Biophore, 1015, Lausanne, Switzerland
| | - Dirk Becker
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, D-97082, Wuerzburg, Germany
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, D-97082, Wuerzburg, Germany
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Schönknecht G. Calcium Signals from the Vacuole. PLANTS (BASEL, SWITZERLAND) 2013; 2:589-614. [PMID: 27137394 PMCID: PMC4844392 DOI: 10.3390/plants2040589] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 01/13/2023]
Abstract
The vacuole is by far the largest intracellular Ca(2+) store in most plant cells. Here, the current knowledge about the molecular mechanisms of vacuolar Ca(2+) release and Ca(2+) uptake is summarized, and how different vacuolar Ca(2+) channels and Ca(2+) pumps may contribute to Ca(2+) signaling in plant cells is discussed. To provide a phylogenetic perspective, the distribution of potential vacuolar Ca(2+) transporters is compared for different clades of photosynthetic eukaryotes. There are several candidates for vacuolar Ca(2+) channels that could elicit cytosolic [Ca(2+)] transients. Typical second messengers, such as InsP₃ and cADPR, seem to trigger vacuolar Ca(2+) release, but the molecular mechanism of this Ca(2+) release still awaits elucidation. Some vacuolar Ca(2+) channels have been identified on a molecular level, the voltage-dependent SV/TPC1 channel, and recently two cyclic-nucleotide-gated cation channels. However, their function in Ca(2+) signaling still has to be demonstrated. Ca(2+) pumps in addition to establishing long-term Ca(2+) homeostasis can shape cytosolic [Ca(2+)] transients by limiting their amplitude and duration, and may thus affect Ca(2+) signaling.
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Affiliation(s)
- Gerald Schönknecht
- Department of Botany, Oklahoma State University, Stillwater, OK 74078, USA.
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33
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The N-terminal region of two-pore channel 1 regulates trafficking and activation by NAADP. Biochem J 2013; 453:147-51. [PMID: 23634879 DOI: 10.1042/bj20130474] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
TPCs (two-pore channels) are NAADP (nicotinic acid-adenine dinucleotide phosphate)-sensitive Ca2+-permeable ion channels expressed on acidic organelles. In the present study we show that deletion of the N-terminal region redirects TPC1 to the ER (endoplasmic reticulum). The introduction of fluorophores at the N-terminus of TPC1 does not affect its subcellular location, but does reversibly abolish NAADP sensitivity. Our results reveal a dual role for the N-terminus in localization and function of TPC1.
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Kawano T, Bouteau F. Crosstalk between intracellular and extracellular salicylic acid signaling events leading to long-distance spread of signals. PLANT CELL REPORTS 2013; 32:1125-38. [PMID: 23689257 DOI: 10.1007/s00299-013-1451-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 05/08/2023]
Abstract
It is well recognized that salicylic acid (SA) acts as a natural signaling molecule involved in both local and systemic plant defense responses upon attacks by pathogens. Recently, cellular SA receptors and a number of SA-related phloem-mobile signals were identified. Here, we compare the old and up-to-date concepts of plant defense signaling events involving SA. Finally, the crosstalk between intracellular and extracellular SA signaling events leading to long-distance spread of signals was outlined by focusing on the modes of both the short- and long-distance signaling events involving the actions of SA. For the above purpose, two distinct conceptual models for local SA perception and signaling mechanisms in the intracellular and extracellular paths (referred to as models i and ii, respectively) were proposed. In addition to two local SA perception models, we propose that the long-distance SA action could be attributed to three different modes, namely, (iii) local increase in SA followed by transport of SA and SA intermediates, (iv) systemic propagation of SA-derived signals with both chemical and electrical natures without direct movement of SA, and (v) integrated crosstalk allowing alternately repeated secondary signal propagation and biosynthesis of SA and/or conversion of inert SA intermediates to free SA finally contributing to the systemic spread of SA-derived signals. We review here that the long-distance SA signaling events (models iii-v), inevitably involve the mechanisms described in the local signaling models (models i and ii) as the key pieces of the crosstalk.
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Affiliation(s)
- Tomonori Kawano
- Faculty and Graduate School of Environmental Engineering, The University of Kitakyushu, Kitakyushu, Japan.
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Li PL, Zhang Y, Abais JM, Ritter JK, Zhang F. Cyclic ADP-Ribose and NAADP in Vascular Regulation and Diseases. ACTA ACUST UNITED AC 2013; 2:63-85. [PMID: 24749015 DOI: 10.1166/msr.2013.1022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP), two intracellular Ca2+ mobilizing second messengers, have been recognized as a fundamental signaling mechanism regulating a variety of cell or organ functions in different biological systems. Here we reviewed the literature regarding these ADP-ribosylcyclase products in vascular cells with a major focus on their production, physiological roles, and related underlying mechanisms mediating their actions. In particular, several hot topics in this area of research are comprehensively discussed, which may help understand some of the controversial evidence provided by different studies. For example, some new models are emerging for the agonist receptor coupling of CD38 or ADP-ribosylcyclase and for the formation of an acidic microenvironment to facilitate the production of NAADP in vascular cells. We also summarized the evidence regarding the NAADP-mediated two-phase Ca2+ release with a slow Ca2+-induced Ca2+ release (CICR) and corresponding physiological relevance. The possibility of a permanent structural space between lysosomes and sarcoplasmic reticulum (SR), as well as the critical role of lysosome trafficking in phase 2 Ca2+ release in response to some agonists are also explored. With respect to the molecular targets of NAADP within cells, several possible candidates including SR ryanodine receptors (RyRs), lysosomal transient receptor potential-mucolipin 1 (TRP-ML1) and two pore channels (TPCs) are presented with supporting and opposing evidence. Finally, the possible role of NAADP-mediated regulation of lysosome function in autophagy and atherogenesis is discussed, which may indicate a new direction for further studies on the pathological roles of cADPR and NAADP in the vascular system.
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Affiliation(s)
- Pin-Lan Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Yang Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Justine M Abais
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Fan Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
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Jiang YL, Lin AHY, Xia Y, Lee S, Paudel O, Sun H, Yang XR, Ran P, Sham JSK. Nicotinic acid adenine dinucleotide phosphate (NAADP) activates global and heterogeneous local Ca2+ signals from NAADP- and ryanodine receptor-gated Ca2+ stores in pulmonary arterial myocytes. J Biol Chem 2013; 288:10381-94. [PMID: 23443655 PMCID: PMC3624421 DOI: 10.1074/jbc.m112.423053] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 02/08/2013] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca(2+)-mobilizing messenger that releases Ca(2+) from endolysosomal organelles. Recent studies showed that NAADP-induced Ca(2+) release is mediated by the two-pore channels (TPCs) TPC1 and TPC2. However, the expression of TPCs and the NAADP-induced local Ca(2+) signals have not been examined in vascular smooth muscle. Here, we found that both TPC1 and TPC2 are expressed in rat pulmonary arterial smooth muscle cells (PASMCs), with TPC1 being the major subtype. Application of membrane-permeant NAADP acetoxymethyl ester to PASMCs elicited a biphasic increase in global [Ca(2+)]i, which was independent of extracellular Ca(2+) and blocked by the NAADP antagonist Ned-19 or the vacuolar H(+)-ATPase inhibitor bafilomycin A1, indicating Ca(2+) release from acidic endolysosomal Ca(2+) stores. The Ca(2+) response was unaffected by xestospongin C but was partially blocked by ryanodine or thapsigargin. NAADP triggered heterogeneous local Ca(2+) signals, including a diffuse increase in cytosolic [Ca(2+)], Ca(2+) sparks, Ca(2+) bursts, and regenerative Ca(2+) release. The diffuse Ca(2+) increase and Ca(2+) bursts were ryanodine-insensitive, presumably arising from different endolysosomal sources. Ca(2+) sparks and regenerative Ca(2+) release were inhibited by ryanodine, consistent with cross-activation of loosely coupled ryanodine receptors. Moreover, Ca(2+) release stimulated by endothelin-1 was inhibited by Ned-19, ryanodine, or xestospongin C, suggesting that NAADP-mediated Ca(2+) signals interact with both ryanodine and inositol 1,4,5-trisphosphate receptors during agonist stimulation. Our results show that NAADP mediates complex global and local Ca(2+) signals. Depending on the physiological stimuli, these diverse Ca(2+) signals may serve to regulate different cellular functions in PASMCs.
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Affiliation(s)
- Yong-Liang Jiang
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
- the State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical University, 510120 Guangzhou, China
| | - Amanda H. Y. Lin
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Yang Xia
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Suengwon Lee
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Omkar Paudel
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Hui Sun
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Xiao-Ru Yang
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
| | - Pixin Ran
- the State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital, Guangzhou Medical University, 510120 Guangzhou, China
| | - James S. K. Sham
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224 and
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38
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Kurusu T, Hamada H, Koyano T, Kuchitsu K. Intracellular localization and physiological function of a rice Ca²⁺-permeable channel OsTPC1. PLANT SIGNALING & BEHAVIOR 2012; 7:1428-30. [PMID: 22990444 PMCID: PMC3548864 DOI: 10.4161/psb.22086] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Two-pore channels (TPCs) are cation channels with a voltage-sensor domain conserved in plants and animals. Rice OsTPC1 is predominantly localized to the plasma membrane (PM), and assumed to play an important role as a Ca²⁺-permeable cation channel in the regulation of cytosolic Ca²⁺ rise and innate immune responses including hypersensitive cell death and phytoalexin biosynthesis in cultured rice cells triggered by a fungal elicitor, xylanase from Trichoderma viride. In contrast, Arabidopsis AtTPC1 is localized to the vacuolar membrane (VM). To gain further insights into the intracellular localization of OsTPC1, we stably expressed OsTPC1-GFP in tobacco BY-2 cells. Confocal imaging and membrane fractionation revealed that, unlike in rice cells, the majority of OsTPC1-GFP fusion protein was targeted to the VM in tobacco BY-2 cells. Intracellular localization and functions of the plant TPC family is discussed.
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Affiliation(s)
- Takamitsu Kurusu
- Department of Applied Biological Science; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
| | - Haruyasu Hamada
- Department of Applied Biological Science; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
| | - Tomoko Koyano
- Department of Applied Biological Science; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; 2641 Yamazaki, Noda, Chiba, Japan
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Abstract
PURPOSE OF REVIEW In this article, recent advances in the pathogenesis of acute pancreatitis have been reviewed. RECENT FINDINGS Pathologic intra-acinar trypsinogen activation had been hypothesized to be the central mechanism of pancreatitis for over a century. This hypothesis could be explored for the first time with the development of a novel mouse model lacking pathologic intra-acinar trypsinogen activation. It became clear that intra-acinar trypsinogen activation contributes to early acinar injury, but local and systemic inflammation progress independently during pancreatitis. Early intra-acinar nuclear factor kappa B (NFκB) activation, which occurs parallel to but independent of trypsinogen activation, may be crucial in pancreatitis. Although the mechanism of NFκB and trypsinogen activation is not entirely clear, further insights have been made into key pathogenic cellular events such as calcium signaling, mitochondrial dysfunction, endoplasmic reticulum (ER) stress, autophagy and impaired trafficking, and lysosomal and secretory responses. Cellular intrinsic damage-sensing mechanisms that lead to activation of the inflammatory response aimed at repair, but lead to disease when overwhelmed, are beginning to be understood. SUMMARY New findings necessitate a paradigm shift in our understanding of acute pancreatitis. Intra-acinar trypsinogen activation leads to early pancreatic injury, but the inflammatory response of acute pancreatitis develops independently, driven by early activation of inflammatory pathways.
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Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
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Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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41
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Notomi T, Ezura Y, Noda M. Identification of two-pore channel 2 as a novel regulator of osteoclastogenesis. J Biol Chem 2012; 287:35057-35064. [PMID: 22833668 DOI: 10.1074/jbc.m111.328930] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Osteoclast differentiation is one of the critical steps that control bone mass levels in osteoporosis, but the molecules involved in osteoclastogenesis are still incompletely understood. Here, we show that two-pore channel 2 (TPC2) is expressed in osteoclast precursor cells, and its knockdown (TPC2-KD) in these cells suppressed RANKL-induced key events including multinucleation, enhancement of tartrate-resistant acid phosphatase (TRAP) activities, and TRAP mRNA expression levels. With respect to intracellular signaling, TPC2-KD reduced the levels of the RANKL-induced dynamic waving of Ca(2+) in RAW cells. The search for the target of TPC2 identified that nuclear localization of NFATc1 is retarded in TPC2-KD cells. Finally, TPC2-KD suppressed osteoclastic pit formation in cultures. We conclude that TPC2 is a novel critical molecule for osteoclastogenesis.
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Affiliation(s)
- Takuya Notomi
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
| | - Yoichi Ezura
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Masaki Noda
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
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42
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Marchant JS, Lin-Moshier Y, Walseth TF, Patel S. The Molecular Basis for Ca 2+ Signalling by NAADP: Two-Pore Channels in a Complex? ACTA ACUST UNITED AC 2012; 1:63-76. [PMID: 25309835 DOI: 10.1166/msr.2012.1003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
NAADP is a potent Ca2+ mobilizing messenger in a variety of cells but its molecular mechanism of action is incompletely understood. Accumulating evidence indicates that the poorly characterized two-pore channels (TPCs) in animals are NAADP sensitive Ca2+-permeable channels. TPCs localize to the endo-lysosomal system but are functionally coupled to the better characterized endoplasmic reticulum Ca2+ channels to generate physiologically relevant complex Ca2+ signals. Whether TPCs directly bind NAADP is not clear. Here we discuss the idea based on recent studies that TPCs are the pore-forming subunits of a protein complex that includes tightly associated, low molecular weight NAADP-binding proteins.
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Affiliation(s)
- Jonathan S Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Yaping Lin-Moshier
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK
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43
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Verkhratsky A, Rodríguez JJ, Parpura V. Calcium signalling in astroglia. Mol Cell Endocrinol 2012; 353:45-56. [PMID: 21945602 DOI: 10.1016/j.mce.2011.08.039] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 08/28/2011] [Accepted: 08/31/2011] [Indexed: 12/15/2022]
Abstract
Astroglia possess excitability based on movements of Ca(2+) ions between intracellular compartments and plasmalemmal Ca(2+) fluxes. This "Ca(2+) excitability" is controlled by several families of proteins located in the plasma membrane, within the cytosol and in the intracellular organelles, most notably in the endoplasmic reticulum (ER) and mitochondria. Accumulation of cytosolic Ca(2+) can be caused by the entry of Ca(2+) from the extracellular space through ionotropic receptors and store-operated channels expressed in astrocytes. Plasmalemmal Ca(2+) ATP-ase and sodium-calcium exchanger extrude cytosolic Ca(2+) to the extracellular space; the exchanger can also operate in reverse, depending of the intercellular Na(+) concentration, to deliver Ca(2+) to the cytosol. The ER internal store possesses inositol 1,4,5-trisphosphate receptors which can be activated upon stimulation of astrocytes through a multiple plasma membrane metabotropic G-protein coupled receptors. This leads to release of Ca(2+) from the ER and its elevation in the cytosol, the level of which can be modulated by mitochondria. The mitochondrial uniporter takes up Ca(2+) into the matrix, while free Ca(2+) exits the matrix through the mitochondrial Na(+)/Ca(2+) exchanger as well as via transient openings of the mitochondrial permeability transition pore. One of the prominent consequences of astroglial Ca(2+) excitability is gliotransmission, a release of transmitters from astroglia which can lead to signalling to adjacent neurones.
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44
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Rybalchenko V, Ahuja M, Coblentz J, Churamani D, Patel S, Kiselyov K, Muallem S. Membrane potential regulates nicotinic acid adenine dinucleotide phosphate (NAADP) dependence of the pH- and Ca2+-sensitive organellar two-pore channel TPC1. J Biol Chem 2012; 287:20407-16. [PMID: 22500018 DOI: 10.1074/jbc.m112.359612] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent second messenger that mobilizes Ca(2+) from the acidic endolysosomes by activation of the two-pore channels TPC1 and TPC2. The channel properties of human TPC1 have not been studied before, and its cellular function is not known. In the present study, we characterized TPC1 incorporated into lipid bilayers. The native and recombinant TPC1 channels are activated by NAADP. TPC1 activity requires acidic luminal pH and high luminal Ca(2+). With Ba(2+) as the permeable ion, luminal Ca(2+) activates TPC1 with an apparent K(m) of 180 μm. TPC1 operates in two tightly coupled conductance states of 47 ± 8 and 200 ± 9 picosiemens. Importantly, opening of the large conductance markedly increases the small conductance mean open time. Changes in membrane potential from 0 to -60 mV increased linearly both the small and the large conductances and NP(o), indicating that TPC1 is regulated by voltage. Intriguingly, the apparent affinity for activation of TPC1 by its ligand NAADP is not constant. Rather, hyperpolarization increases the apparent affinity of TPC1 for NAADP by 10 nm/mV. The concerted regulation of TPC1 activity by luminal Ca(2+) and by membrane potential thus provides a potential mechanism to explain NAADP-induced Ca(2+) oscillations. These findings reveal unique properties of TPC1 to explain its role in Ca(2+) oscillations and cell function.
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Affiliation(s)
- Volodymyr Rybalchenko
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA
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45
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Zampese E, Pizzo P. Intracellular organelles in the saga of Ca2+ homeostasis: different molecules for different purposes? Cell Mol Life Sci 2012; 69:1077-104. [PMID: 21968921 PMCID: PMC11114864 DOI: 10.1007/s00018-011-0845-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/15/2011] [Accepted: 09/19/2011] [Indexed: 11/28/2022]
Abstract
An increase in the concentration of cytosolic free Ca(2+) is a key component regulating different cellular processes ranging from egg fertilization, active secretion and movement, to cell differentiation and death. The multitude of phenomena modulated by Ca(2+), however, do not simply rely on increases/decreases in its concentration, but also on specific timing, shape and sub-cellular localization of its signals that, combined together, provide a huge versatility in Ca(2+) signaling. Intracellular organelles and their Ca(2+) handling machineries exert key roles in this complex and precise mechanism, and this review will try to depict a map of Ca(2+) routes inside cells, highlighting the uniqueness of the different Ca(2+) toolkit components and the complexity of the interactions between them.
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Affiliation(s)
- Enrico Zampese
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
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46
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Kang J, Park KH, Kim JJ, Jo EK, Han MK, Kim UH. The role of CD38 in Fcγ receptor (FcγR)-mediated phagocytosis in murine macrophages. J Biol Chem 2012; 287:14502-14. [PMID: 22396532 DOI: 10.1074/jbc.m111.329003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Phagocytosis is a crucial event in the immune system that allows cells to engulf and eliminate pathogens. This is mediated through the action of immunoglobulin (IgG)-opsonized microbes acting on Fcγ receptors (FcγR) on macrophages, which results in sustained levels of intracellular Ca(2+) through the mobilization of Ca(2+) second messengers. It is known that the ADP-ribosyl cyclase is responsible for the rise in Ca(2+) levels after FcγR activation. However, it is unclear whether and how CD38 is involved in FcγR-mediated phagocytosis. Here we show that CD38 is recruited to the forming phagosomes during phagocytosis of IgG-opsonized particles and produces cyclic-ADP-ribose, which acts on ER Ca(2+) stores, thus allowing an increase in FcγR activation-mediated phagocytosis. Ca(2+) data show that pretreatment of J774A.1 macrophages with 8-bromo-cADPR, ryanodine, blebbistatin, and various store-operated Ca(2+) inhibitors prevented the long-lasting Ca(2+) signal, which significantly reduced the number of ingested opsonized particles. Ex vivo data with macrophages extracted from CD38(-/-) mice also shows a reduced Ca(2+) signaling and phagocytic index. Furthermore, a significantly reduced phagocytic index of Mycobacterium bovis BCG was shown in macrophages from CD38(-/-) mice in vivo. This study suggests a crucial role of CD38 in FcγR-mediated phagocytosis through its recruitment to the phagosome and mobilization of cADPR-induced intracellular Ca(2+) and store-operated extracellular Ca(2+) influx.
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Affiliation(s)
- John Kang
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, 561-180, Korea
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47
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Plattner H, Sehring IM, Mohamed IK, Miranda K, De Souza W, Billington R, Genazzani A, Ladenburger EM. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma). Cell Calcium 2012; 51:351-82. [PMID: 22387010 DOI: 10.1016/j.ceca.2012.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 12/20/2022]
Abstract
The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section.
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Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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48
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Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent intracellular Ca(2+)-mobilising messenger. Much evidence indicates that NAADP targets novel Ca(2+) channels located on acidic organelles but the identity of these channels has remained obscure. Recent studies have converged on a novel class of ion channels, the two-pore channels (TPCs) as likely molecular targets. The location of these channels to the endo-lysosomal system and their sensitivity to NAADP match closely those of endogenous NAADP-sensitive channels in both mammalian cells and sea urchin eggs, where the effects of NAADP were discovered. Moreover, the functional coupling of TPCs to archetypal endoplasmic reticulum (ER) Ca(2+) channels is also matched. Biophysical analysis in conjunction with site-directed mutagenesis demonstrates that TPCs are pore-forming subunits of NAADP-gated ion channels. TPCs have a unique two-repeat structure, are regulated by N-linked glycosylation and harbor an endo-lysosomal targeting motif in their N-terminus. Knockdown studies have shown TPCs to regulate smooth muscle contraction, differentiation and endothelial cell activation consistent with previous studies implicating NAADP in these processes. Thus multiple lines of evidence indicate that TPCs are the likely long sought targets for NAADP.
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Affiliation(s)
- Robert Hooper
- Department of Cell and Developmental Biology, University College London, UK.
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49
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Nascimento FD, Sancey L, Pereira A, Rome C, Oliveira V, Oliveira EB, Nader HB, Yamane T, Kerkis I, Tersariol ILS, Coll JL, Hayashi MAF. The Natural Cell-Penetrating Peptide Crotamine Targets Tumor Tissue in Vivo and Triggers a Lethal Calcium-Dependent Pathway in Cultured Cells. Mol Pharm 2011; 9:211-21. [DOI: 10.1021/mp2000605] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fabio D. Nascimento
- Grupo de Estudos em Odontologia, Universidade Bandeirante de São Paulo (UNIBAN), São Paulo, SP,
Brazil
| | - Lucie Sancey
- INSERM U823, Institut Albert Bonniot, Grenoble, France
- University Joseph Fourier, Grenoble, France
| | | | - Claire Rome
- INSERM U823, Institut Albert Bonniot, Grenoble, France
- University Joseph Fourier, Grenoble, France
| | - Vitor Oliveira
- Departamento
de Biofísica, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Eduardo B. Oliveira
- Departamento de Bioquímica
e Imunologia, Universidade de São Paulo (USP), Ribeirão Preto, Brazil
| | - Helena B. Nader
- Departamento de Bioquímica, Universidade Federal de São Paulo (UNIFESP), São Paulo,
Brazil
| | - Tetsuo Yamane
- Laboratório
de Bioquímica e Biologia Molecular, Centro de Biotecnologia da Amazônia (CBA), Manaus, AM,
Brazil
| | - Irina Kerkis
- Laboratório
de Genética, Instituto Butantan,
São Paulo, SP, Brasil
| | - Ivarne L. S. Tersariol
- Centro Interdisciplinar
de Investigação Bioquímica (CIIB), Universidade de Mogi das Cruzes, Mogi das Cruzes, SP,
Brazil
| | - Jean-Luc Coll
- INSERM U823, Institut Albert Bonniot, Grenoble, France
- University Joseph Fourier, Grenoble, France
| | - Mirian A. F. Hayashi
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP),
São Paulo, SP, Brazil
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50
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Molecular mechanisms of endolysosomal Ca2+ signalling in health and disease. Biochem J 2011; 439:349-74. [PMID: 21992097 DOI: 10.1042/bj20110949] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Endosomes, lysosomes and lysosome-related organelles are emerging as important Ca2+ storage cellular compartments with a central role in intracellular Ca2+ signalling. Endocytosis at the plasma membrane forms endosomal vesicles which mature to late endosomes and culminate in lysosomal biogenesis. During this process, acquisition of different ion channels and transporters progressively changes the endolysosomal luminal ionic environment (e.g. pH and Ca2+) to regulate enzyme activities, membrane fusion/fission and organellar ion fluxes, and defects in these can result in disease. In the present review we focus on the physiology of the inter-related transport mechanisms of Ca2+ and H+ across endolysosomal membranes. In particular, we discuss the role of the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) as a major regulator of Ca2+ release from endolysosomes, and the recent discovery of an endolysosomal channel family, the TPCs (two-pore channels), as its principal intracellular targets. Recent molecular studies of endolysosomal Ca2+ physiology and its regulation by NAADP-gated TPCs are providing exciting new insights into the mechanisms of Ca2+-signal initiation that control a wide range of cellular processes and play a role in disease. These developments underscore a new central role for the endolysosomal system in cellular Ca2+ regulation and signalling.
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