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Abstract
The discovery of NAADP-evoked Ca2+ release in sea urchin eggs and then as a ubiquitous Ca2+ mobilizing messenger has introduced several novel paradigms to our understanding of Ca2+ signalling, not least in providing a link between cell stimulation and Ca2+ release from lysosomes and other acidic Ca2+ storage organelles. In addition, the hallmark concentration-response relationship of NAADP-mediated Ca2+ release, shaped by striking activation/desensitization mechanisms, influences its actions as an intracellular messenger. There has been recent progress in our understanding of the molecular mechanisms underlying NAADP-evoked Ca2+ release, such as the identification of the endo-lysosomal two-pore channel family of cation channels (TPCs) as their principal target and the identity of NAADP-binding proteins that complex with them. The NAADP/TPC signalling axis has gained recent prominence in pathophysiology for their roles in such disease processes as neurodegeneration, tumorigenesis and cellular viral entry.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK.
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Lora L Martucci
- Department of Pharmacology, University of Oxford, Oxford, UK
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2
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Limatola N, Chun JT, Santella L. Regulation of the Actin Cytoskeleton-Linked Ca2+ Signaling by Intracellular pH in Fertilized Eggs of Sea Urchin. Cells 2022; 11:1496. [PMID: 35563801 PMCID: PMC9100012 DOI: 10.3390/cells11091496] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/19/2022] [Accepted: 04/26/2022] [Indexed: 01/27/2023] Open
Abstract
In sea urchin, the immediate contact of the acrosome-reacted sperm with the egg surface triggers a series of structural and ionic changes in the egg cortex. Within one minute after sperm fuses with the egg plasma membrane, the cell membrane potential changes with the concurrent increases in intracellular Ca2+ levels. The consequent exocytosis of the cortical granules induces separation of the vitelline layer from the egg plasma membrane. While these cortical changes are presumed to prevent the fusion of additional sperm, the subsequent late phase (between 1 and 4 min after fertilization) is characterized by reorganization of the egg cortex and microvilli (elongation) and by the metabolic shift to activate de novo protein and DNA syntheses. The latter biosynthetic events are crucial for embryonic development. Previous studies suggested that the early phase of fertilization was not a prerequisite for these changes in the second phase since the increase in the intracellular pH induced by the exposure of unfertilized sea urchin eggs to ammonia seawater could start metabolic egg activation in the absence of the cortical granule exocytosis. In the present study, we have demonstrated that the incubation of unfertilized eggs in ammonia seawater induced considerable elongations of microvilli (containing actin filaments) as a consequence of the intracellular pH increase, which increased the egg’s receptivity to sperm and made the eggs polyspermic at fertilization despite the elevation of the fertilization envelope (FE). These eggs also displayed compromised Ca2+ signals at fertilization, as the amplitude of the cortical flash was significantly reduced and the elevated intracellular Ca2+ level declined much faster. These results have also highlighted the importance of the increased internal pH in regulating Ca2+ signaling and the microvillar actin cytoskeleton during the late phase of the fertilization process.
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3
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Ramos I, Machado E, Masuda H, Gomes F. Open questions on the functional biology of the yolk granules during embryo development. Mol Reprod Dev 2022; 89:86-94. [PMID: 35020238 DOI: 10.1002/mrd.23555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 12/21/2022]
Abstract
Biogenesis and consumption of the yolk are well-conserved aspects of the reproductive biology in oviparous species. Most egg-laying animals accumulate yolk proteins within the oocytes thus creating the source of nutrients and energy that will feed embryo development. Yolk accumulation drives the generation of a highly specialized oocyte cytoplasm with maternal mRNAs, ribosomes, mitochondria, and, mainly, a set of organelles collectively referred to as yolk granules (Ygs). Following fertilization, the Ygs are involved in regulated mechanisms of yolk degradation to fuel the anabolic metabolism of the growing embryo. Thus, yolk accumulation and degradation are essential processes that allow successful development in many species. Nevertheless, the molecular machinery and mechanisms dedicated to the programmed yolk mobilization throughout development are still enigmatic and remain mostly unexplored. Moreover, while the Ygs functional biology as a nutritional source for the embryo has been acknowledged, several reports have suggested that Ygs cargoes and functions go far beyond yolk storage. Evidence of the role of Ygs in gene expression, microbiota harboring, and paracrine signaling has been proposed. In this study, we summarize the current knowledge of the Ygs functional biology pointing to open questions and where further investigation is needed.
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Affiliation(s)
- Isabela Ramos
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil
| | - Ednildo Machado
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil.,Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hatisaburo Masuda
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil
| | - Fabio Gomes
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Vasilev F, Limatola N, Chun JT, Santella L. Contributions of suboolemmal acidic vesicles and microvilli to the intracellular Ca 2+ increase in the sea urchin eggs at fertilization. Int J Biol Sci 2019; 15:757-775. [PMID: 30906208 PMCID: PMC6429021 DOI: 10.7150/ijbs.28461] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 12/15/2018] [Indexed: 12/03/2022] Open
Abstract
The onset of fertilization in echinoderms is characterized by instantaneous increase of Ca2+ in the egg cortex, which is called 'cortical flash', and the subsequent Ca2+ wave. While the cortical flash is due to the ion influx through L-type Ca2+ channels in starfish eggs, its amplitude was shown to be affected by the integrity of the egg cortex. Here, we investigated the contribution of cortical granules (CG) and yolk granules (YG) to the sperm-induced Ca2+ signals in sea urchin eggs. To this end, prior to fertilization, Paracentrotus lividus eggs were treated with agents that disrupt or relocate CG beneath the plasma membrane: namely, glycyl-L-phenylalanine 2-naphthylamide (GPN), procaine, urethane, and NH4Cl. All these pretreatments consistently suppressed the cortical flash in the fertilized eggs, and accelerated the decay kinetics of the subsiding Ca2+ wave in most cases. By contrast, centrifugation of the eggs, which stratifies organelles but not the CG, did not exhibit such changes except that the CF was much enhanced in the centrifugal pole where YG are localized. Surprisingly, we noted that pretreatment of the eggs with these CG-disrupting agents or with the inhibitors of L-type Ca2+ channels all drastically reduced the density of the microvilli and their individual shapes on the egg surface. Taken together, our results suggest that the integrity of the egg cortex ensures successful generation of the Ca2+ responses at fertilization, and that modulation of microvilli shape and density may serve as a mechanism of controlling ion flux across the plasma membrane.
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Affiliation(s)
- F Vasilev
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - N Limatola
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - J T Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - L Santella
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Napoli, Italy
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Liu B, Cao W, Li J, Liu J. Lysosomal exocytosis of ATP is coupled to P2Y 2 receptor in marginal cells in the stria vascular in neonatal rats. Cell Calcium 2018; 76:62-71. [PMID: 30273839 DOI: 10.1016/j.ceca.2018.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/09/2018] [Accepted: 09/20/2018] [Indexed: 01/06/2023]
Abstract
Adenosine triphosphate (ATP) is stored as lysosomal vesicles in marginal cells of the stria vascular in neonatal rats, but the mechanisms of ATP release are unclear. Primary cultures of marginal cells from 1-day-old Sprague-Dawley rats were established. P2Y2 receptor and inositol 1,4,5-trisphosphate (IP3) receptor were immunolabelled in marginal cells of the stria vascular. We found that 30 μM ATP and 30 μM uridine triphosphate (UTP) evoked comparable significant increases in the intracellular Ca2+ concentration ([Ca2+]i) in the absence of extracellular Ca2+, whereas the response was suppressed by 100 μM suramin, 10 μM 1-(6-(17β-3-methoxyester-1,3,5(10)-trien-17-yl)amino)-hexyl)-1H-pyrrole-2,5-dione(U-73122), 100 μM 2-aminoethoxydiphenyl borate (2-APB) and 5 μM thapsigargin (TG), thus indicating that ATP coupled with the P2Y2R-PLC-IP3 pathway to evoke Ca2+ release from the endoplasmic reticulum (ER). Incubation with 200 μM Gly-Phe-β-naphthylamide (GPN) selectively disrupted lysosomes and caused significant increases in [Ca2+]I; this effect was partly inhibited by P2Y2R-PLC-IP3 pathway antagonists. After pre-treatment with 5 μM TG, [Ca2+]i was significantly lower than that after treatment with P2Y2R-PLC-IP3 pathway antagonists under the same conditions, thus indicating that lysosomal Ca2+ triggers Ca2+ release from ER Ca2+ stores. Baseline [Ca2+]i declined after treatment with the Ca2+ chelator 50 μM bis-(aminophenolxy) ethane-N,N,N',N'-tetra-acetic acid acetoxyme-thyl ester (BAPTA-AM) and 4 IU/ml apyrase. 30 μM ATP decrease of the number of quinacrine-positive vesicles via lysosome exocytosis, whereas the number of lysosomes did not change. However, lysosome exocytosis was significantly suppressed by pre-treatment with 5 μM vacuolin-1. Release of ATP and β-hexosaminidase both increased after treatment with 200 μM GPN and 5 μM TG, but decreased after incubation with 50 μM BAPTA-AM, 4 IU/ml apyrase and 5 μM vacuolin-1. We suggest that ATP triggers Ca2+ release from the ER, thereby contributing to secretion of lysosomal ATP via lysosomal exocytosis. Lysosomal stored Ca2+ triggers Ca2+ release from the ER directly though the IP3 receptors, and lysosomal ATP evokes Ca2+ signals indirectly via the P2Y2R-PLC-IP3 pathway.
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Affiliation(s)
- Bin Liu
- Department of Otorhinolaryngology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Wanxin Cao
- Department of Otorhinolaryngology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Jiping Li
- Department of Otorhinolaryngology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
| | - Jun Liu
- Department of Otorhinolaryngology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
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Moundoyi H, Demouy J, Le Panse S, Morales J, Sarels B, Cormier P. Toward Multiscale Modeling of Molecular and Biochemical Events Occurring at Fertilization Time in Sea Urchins. Results Probl Cell Differ 2018; 65:69-89. [DOI: 10.1007/978-3-319-92486-1_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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Zhan Y, Hu W, Zhang W, Liu M, Duan L, Huang X, Chang Y, Li C. The impact of CO 2-driven ocean acidification on early development and calcification in the sea urchin Strongylocentrotus intermedius. Mar Pollut Bull 2016; 112:291-302. [PMID: 27522173 DOI: 10.1016/j.marpolbul.2016.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/21/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
The impact of CO2-driven ocean acidification(OA) on early development and calcification in the sea urchin Strongylocentrotus intermedius cultured in northern Yellow Sea was investigated by comparing fertilization success, early cleavage rate, hatching rate of blastulae, larvae survival rate at 70h post-fertilization, larval morphology and calcification under present natural seawater condition (pH=8.00±0.03) and three laboratory-controlled acidified conditions (OA1, △pH=-0.3units; OA2, △pH=-0.4units; OA3, △pH=-0.5units) projected by IPCC for 2100. Results showed that pH decline had no effect on the overall fertilization, however, with decreased pH, delayed early embryonic cleavage, reduced hatching rate of blastulae and four-armed larvae survival rate at 70h post-fertilization, impaired larval symmetry, shortened larval spicules, and corrosion spicule structure were observed in all OA-treated groups as compared to control, which indicated that CO2-driven OA affected early development and calcification in S. intermedius negatively.
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Affiliation(s)
- Yaoyao Zhan
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Wanbin Hu
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Weijie Zhang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Minbo Liu
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Lizhu Duan
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Xianya Huang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China
| | - Yaqing Chang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning 116023, China.
| | - Cong Li
- College of Basic Medical Science, Dalian Medical University, Dalian, Liaoning 116044, China
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Ronco V, Potenza DM, Denti F, Vullo S, Gagliano G, Tognolina M, Guerra G, Pinton P, Genazzani AA, Mapelli L, Lim D, Moccia F. A novel Ca²⁺-mediated cross-talk between endoplasmic reticulum and acidic organelles: implications for NAADP-dependent Ca²⁺ signalling. Cell Calcium 2015; 57:89-100. [PMID: 25655285 DOI: 10.1016/j.ceca.2015.01.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/01/2015] [Indexed: 12/31/2022]
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) serves as the ideal trigger of spatio-temporally complex intracellular Ca(2+) signals. However, the identity of the intracellular Ca(2+) store(s) recruited by NAADP, which may include either the endolysosomal (EL) or the endoplasmic reticulum (ER) Ca(2+) pools, is still elusive. Here, we show that the Ca(2+) response to NAADP was suppressed by interfering with either EL or ER Ca(2+) sequestration. The measurement of EL and ER Ca(2+) levels by using selectively targeted aequorin unveiled that the preventing ER Ca(2+) storage also affected ER Ca(2+) loading and vice versa. This indicates that a functional Ca(2+)-mediated cross-talk exists at the EL-ER interface and exerts profound implications for the study of NAADP-induced Ca(2+) signals. Extreme caution is warranted when dissecting NAADP targets by pharmacologically inhibiting EL and/or the ER Ca(2+) pools. Moreover, Ca(2+) transfer between these compartments might be essential to regulate vital Ca(2+)-dependent processes in both organelles.
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Affiliation(s)
- Virginia Ronco
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", 28100 Novara, Italy
| | - Duilio Michele Potenza
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Federico Denti
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Sabrina Vullo
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Giuseppe Gagliano
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Marialuisa Tognolina
- Laboratory of Neurophysiology, Department of Brain and Behavioural Sciences, University of Pavia, 27100 Pavia, Italy
| | - Germano Guerra
- Department of Medicine and Health Sciences, University of Molise, 86100 Campobasso, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, ItalyfCentro Fermi, 00184 Roma, Italy
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", 28100 Novara, Italy
| | - Lisa Mapelli
- Laboratory of Neurophysiology, Department of Brain and Behavioural Sciences, University of Pavia, 27100 Pavia, Italy; Centro Fermi, 00184 Roma, Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", 28100 Novara, Italy.
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy.
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Abstract
Egg activation at fertilization is an excellent process for studying calcium regulation. Nicotinic acid adenine dinucleotide-phosphate (NAADP), a potent calcium messenger, is able to trigger calcium release, likely through two-pore channels (TPCs). Concomitantly, a family of ectocellular enzymes, the ADP-ribosyl cyclases (ARCs), has emerged as being able to change their enzymatic mode from one of nucleotide cyclization in formation of cADPR to a base-exchange reaction in the generation of NAADP. Using sea star oocytes we gain insights into the functions of endogenously expressed TPCs and ARCs in the context of the global calcium signals at fertilization. Three TPCs and one ARC were found in the sea star (Patiria miniata) that were localized in the cortex of the oocytes and eggs. PmTPCs were localized in specialized secretory organelles called cortical granules, and PmARCs accumulated in a different, unknown, set of vesicles, closely apposed to the cortical granules in the egg cortex. Using morpholino knockdown of PmTPCs and PmARC in the oocytes, we found that both calcium regulators are essential for early embryo development, and that knockdown of PmTPCs leads to aberrant construction of the fertilization envelope at fertilization and changes in cortical granule pH. The calcium signals at fertilization are not significantly altered when individual PmTPCs are silenced, but the timing and shape of the cortical flash and calcium wave are slightly changed when the expression of all three PmTPCs is perturbed concomitantly, suggesting a cooperative activity among TPC isoforms in eliciting calcium signals that may influence localized physiological activities.
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Affiliation(s)
- Isabela Ramos
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, USA Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Adrian Reich
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Gary M Wessel
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
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Houel-Renault L, Philippe L, Piquemal M, Ciapa B. Autophagy is used as a survival program in unfertilized sea urchin eggs that are destined to die by apoptosis after inactivation of MAPK1/3 (ERK2/1). Autophagy 2014; 9:1527-39. [DOI: 10.4161/auto.25712] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Galione A, Chuang KT, Funnell TM, Davis LC, Morgan AJ, Ruas M, Parrington J, Churchill GC. Measurement of luminal pH of acidic stores as a readout for NAADP action. Cold Spring Harb Protoc 2014; 2014:pdb.prot076935. [PMID: 25275102 DOI: 10.1101/pdb.prot076935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In addition to mobilizing Ca²⁺, NAADP plays a role in modulating the luminal pH (pHL) of acidic stores of the endolysosomal system. The effects of NAADP on pHL have been most extensively studied in the sea urchin egg, both in the intact egg and in egg homogenates. Related observations have also been made in mammalian systems (e.g., guinea pig atrial myocytes and pancreatic acinar cells). Although the connection between Ca²⁺ mobilization and increase in pHL is not understood, pHL can be a useful parameter to measure when studying NAADP-mediated signaling. This protocol describes the fluorescent measurement of pHL of acidic stores. It relies on the use of acridine orange (AO), a standard dye for pHL. AO selectively accumulates to high concentrations in the lumen of organelles as a function of acidity; at these high concentrations it self-quenches. When pHL increases, some AO is lost from the vesicle. As a result, the lower luminal AO concentration relieves the quenching and fluorescence increases in the lumen.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Tim M Funnell
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Margarida Ruas
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Grant C Churchill
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Abstract
Much excitement surrounded the proposal that a family of endo-lysosomal channels, the two-pore channels (TPCs) were the long sought after targets of the Ca(2+) -mobilising messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). However, the role of TPCs in NAADP signalling may be more complex than originally envisaged. First, NAADP may not bind directly to TPCs but via an accessory protein. Second, two papers recently challenged the notion that TPCs are NAADP-regulated Ca(2+) channels by suggesting that they are highly selective Na(+) channels regulated by the lipid phosphatidylinositol 3,5-bisphosphate and by ATP. This paper aims critically to evaluate the evidence for TPCs as NAADP targets and to discuss how the new findings fit in with what we know about endo-lysosomal Ca(2+) stores.
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16
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Kashir J, Deguchi R, Jones C, Coward K, Stricker SA. Comparative biology of sperm factors and fertilization-induced calcium signals across the animal kingdom. Mol Reprod Dev 2013; 80:787-815. [PMID: 23900730 DOI: 10.1002/mrd.22222] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/23/2013] [Indexed: 11/08/2022]
Abstract
Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca²⁺) in all animals that have been examined, and such Ca²⁺ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca²⁺ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca²⁺ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca²⁺ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca²⁺ signals are typically propagated as global waves that depend on Ca²⁺ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP₃). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca²⁺ transients are also examined. In addition, the importance of fertilization-induced Ca²⁺ signals for activating development is underscored by noting some major downstream effects of these signals in various animals.
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Affiliation(s)
- Junaid Kashir
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Level 3, Women's Centre, John Radcliffe Hospital, Headington, Oxford, UK
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Abbineni PS, Hibbert JE, Coorssen JR. Critical role of cortical vesicles in dissecting regulated exocytosis: overview of insights into fundamental molecular mechanisms. Biol Bull 2013; 224:200-217. [PMID: 23995744 DOI: 10.1086/bblv224n3p200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Regulated exocytosis is one of the defining features of eukaryotic cells, underlying many conserved and essential functions. Definitively assigning specific roles to proteins and lipids in this fundamental mechanism is most effectively accomplished using a model system in which distinct stages of exocytosis can be effectively separated. Here we discuss the establishment of sea urchin cortical vesicle fusion as a model to study regulated exocytosis-a system in which the docked, release-ready, and late Ca(2+)-triggered steps of exocytosis are isolated and can be quantitatively assessed using the rigorous coupling of functional and molecular assays. We provide an overview of the insights this has provided into conserved molecular mechanisms and how these have led to and integrate with findings from other regulated exocytotic cells.
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Affiliation(s)
- Prabhodh S Abbineni
- Department of Molecular Physiology, School of Medicine, University of Western Sydney, NSW, Australia
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18
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Morgan AJ, Davis LC, Wagner SKTY, Lewis AM, Parrington J, Churchill GC, Galione A. Bidirectional Ca²⁺ signaling occurs between the endoplasmic reticulum and acidic organelles. ACTA ACUST UNITED AC 2013; 200:789-805. [PMID: 23479744 PMCID: PMC3601362 DOI: 10.1083/jcb.201204078] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
After acidic organelles induce signaling to activate ER calcium ion release, local microdomains of high calcium at ER–acidic organelle junctions feed back to activate further acidic organelle calcium release. The endoplasmic reticulum (ER) and acidic organelles (endo-lysosomes) act as separate Ca2+ stores that release Ca2+ in response to the second messengers IP3 and cADPR (ER) or NAADP (acidic organelles). Typically, trigger Ca2+ released from acidic organelles by NAADP subsequently recruits IP3 or ryanodine receptors on the ER, an anterograde signal important for amplification and Ca2+ oscillations/waves. We therefore investigated whether the ER can signal back to acidic organelles, using organelle pH as a reporter of NAADP action. We show that Ca2+ released from the ER can activate the NAADP pathway in two ways: first, by stimulating Ca2+-dependent NAADP synthesis; second, by activating NAADP-regulated channels. Moreover, the differential effects of EGTA and BAPTA (slow and fast Ca2+ chelators, respectively) suggest that the acidic organelles are preferentially activated by local microdomains of high Ca2+ at junctions between the ER and acidic organelles. Bidirectional organelle communication may have wider implications for endo-lysosomal function as well as the generation of Ca2+ oscillations and waves.
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Affiliation(s)
- Anthony J Morgan
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, England, UK.
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Romancino DP, Anello L, Morici G, d'Azzo A, Bongiovanni A, Di Bernardo M. Identification and characterization of PlAlix, the Alix homologue from the Mediterranean sea urchin Paracentrotus lividus. Dev Growth Differ 2013; 55:237-46. [PMID: 23302023 DOI: 10.1111/dgd.12023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/11/2012] [Accepted: 10/31/2012] [Indexed: 12/13/2022]
Abstract
The sea urchin provides a relatively simple and tractable system for analyzing the early stages of embryo development. Here, we use the sea urchin species, Paracentrotus lividus, to investigate the role of Alix in key stages of embryogenesis, namely the egg fertilization and the first cleavage division. Alix is a multifunctional protein involved in different cellular processes including endocytic membrane trafficking, filamentous (F)-actin remodeling, and cytokinesis. Alix homologues have been identified in different metazoans; in these organisms, Alix is involved in oogenesis and in determination/differentiation events during embryo development. Herein, we describe the identification of the sea urchin homologue of Alix, PlAlix. The deduced amino acid sequence shows that Alix is highly conserved in sea urchins. Accordingly, we detect the PlAlix protein cross-reacting with monoclonal Alix antibodies in extracts from P. lividus, at different developmental stages. Focusing on the role of PlAlix during early embryogenesis we found that PlAlix is a maternal protein that is expressed at increasingly higher levels from fertilization to the 2-cell stage embryo. In sea urchin eggs, PlAlix localizes throughout the cytoplasm with a punctuated pattern and, soon after fertilization, accumulates in larger puncta in the cytosol, and in microvilli-like protrusions. Together our data show that PlAlix is structurally conserved from sea urchin to mammals and may open new lines of inquiry into the role of Alix during the early stages of embryo development.
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Affiliation(s)
- Daniele P Romancino
- Institute of Biomedicine and Molecular Immunology, National Research Council, via Ugo La Malfa, 153-90100, Palermo, Italy
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20
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Ramos I, Wessel GM. Calcium pathway machinery at fertilization in echinoderms. Cell Calcium 2012; 53:16-23. [PMID: 23218671 DOI: 10.1016/j.ceca.2012.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/07/2012] [Accepted: 11/09/2012] [Indexed: 01/01/2023]
Abstract
Calcium signaling in cells directs diverse physiological processes. The calcium waves triggered by fertilization is a highly conserved calcium signaling event essential for egg activation, and has been documented in every egg tested. This activity is one of the few highly conserved events of egg activation through the course of evolution. Echinoderm eggs, as well as many other cell types, have three main intracellular Ca(2+) mobilizing messengers - IP3, cADPR and NAADP. Both cADPR and NAADP were identified as Ca(2+) mobilizing messengers using the sea urchin egg homogenate, and this experimental system, along with the intact urchin and starfish oocyte/egg, continues to be a vital tool for investigating the mechanism of action of calcium signals. While many of the major regulatory steps of the IP3 pathway are well resolved, both cADPR and NAADP remain understudied in terms of our understanding of the fundamental process of egg activation at fertilization. Recently, NAADP has been shown to trigger Ca(2+) release from acidic vesicles, separately from the ER, and a new class of calcium channels, the two-pore channels (TPCs), was identified as the likely targets for this messenger. Moreover, it was found that both cADPR and NAADP can be synthesized by the same family of enzymes, the ADP-rybosyl cyclases (ARCs). In this context of increasing amount of information, the potential coupling and functional roles of different messengers, intracellular stores and channels in the formation of the fertilization calcium wave in echinoderms will be critically evaluated.
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Affiliation(s)
- Isabela Ramos
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
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Morgan AJ, Parrington J, Galione A. The luminal Ca(2+) chelator, TPEN, inhibits NAADP-induced Ca(2+) release. Cell Calcium 2012; 52:481-7. [PMID: 23099186 PMCID: PMC3526783 DOI: 10.1016/j.ceca.2012.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 08/06/2012] [Accepted: 09/19/2012] [Indexed: 10/31/2022]
Abstract
The regulation of Ca(2+) release by luminal Ca(2+) has been well studied for the ryanodine and IP(3) receptors but has been less clear for the NAADP-regulated channel. In view of conflicting reports, we have re-examined the issue by manipulating luminal Ca(2+) with the membrane-permeant, low affinity Ca(2+) buffer, TPEN, and monitoring NAADP-induced Ca(2+) release in sea urchin egg homogenate. NAADP-induced Ca(2+) release was almost entirely blocked by TPEN (IC(50) 17-25μM) which suppressed the maximal extent of Ca(2+) release without altering NAADP sensitivity. In contrast, Ca(2+) release via IP(3) receptors was 3- to 30-fold less sensitive to TPEN whereas that evoked by ionomycin was essentially unaffected. The effect of TPEN on NAADP-induced Ca(2+) release was not due to an increase in the luminal pH or chelation of trace metals since it could not be mimicked by NH(4)Cl or phenanthroline. The fact that TPEN had no effect upon ionophore-induced Ca(2+) release also argued against a substantial reduction in the driving force for Ca(2+) efflux. We propose that, in the sea urchin egg, luminal Ca(2+) is important for gating native NAADP-regulated two-pore channels.
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23
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Vasilev F, Chun JT, Gragnaniello G, Garante E, Santella L. Effects of ionomycin on egg activation and early development in starfish. PLoS One 2012; 7:e39231. [PMID: 22723970 PMCID: PMC3377674 DOI: 10.1371/journal.pone.0039231] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/21/2012] [Indexed: 11/21/2022] Open
Abstract
Ionomycin is a Ca2+-selective ionophore that is widely used to increase intracellular Ca2+ levels in cell biology laboratories. It is also occasionally used to activate eggs in the clinics practicing in vitro fertilization. However, neither the precise molecular action of ionomycin nor its secondary effects on the eggs' structure and function is well known. In this communication we have studied the effects of ionomycin on starfish oocytes and zygotes. By use of confocal microscopy, calcium imaging, as well as light and transmission electron microscopy, we have demonstrated that immature oocytes exposed to ionomycin instantly increase intracellular Ca2+ levels and undergo structural changes in the cortex. Surprisingly, when microinjected into the cells, ionomycin produced no Ca2+ increase. The ionomycin-induced Ca2+ rise was followed by fast alteration of the actin cytoskeleton displaying conspicuous depolymerization at the oocyte surface and in microvilli with concomitant polymerization in the cytoplasm. In addition, cortical granules were disrupted or fused with white vesicles few minutes after the addition of ionomycin. These structural changes prevented cortical maturation of the eggs despite the normal progression of nuclear envelope breakdown. At fertilization, the ionomycin-pretreated eggs displayed reduced Ca2+ response, no elevation of the fertilization envelope, and the lack of orderly centripetal translocation of actin fibers. These alterations led to difficulties in cell cleavage in the monospermic zygotes and eventually to a higher rate of abnormal development. In conclusion, ionomycin has various deleterious impacts on egg activation and the subsequent embryonic development in starfish. Although direct comparison is difficult to make between our findings and the use of the ionophore in the in vitro fertilization clinics, our results call for more defining investigations on the issue of a potential risk in artificial egg activation.
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Affiliation(s)
- Filip Vasilev
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Jong T. Chun
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Giovanni Gragnaniello
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Ezio Garante
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
| | - Luigia Santella
- Laboratory of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, Italy
- * E-mail:
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Morgan AJ, Platt FM, Lloyd-Evans E, Galione A. 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] [What about the content of this article? (0)] [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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25
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Abstract
Changes in the concentration of cytosolic Ca(2+) form the basis of a ubiquitous signal transduction pathway. Accumulating evidence implicates acidic organelles in the control of Ca(2+) dynamics in organisms across phyla. In this special issue, we discuss Ca(2+) signalling by these "acidic Ca(2+) stores" which include acidocalcisomes, vacuoles, the endo-lysosomal system, lysosome-related organelles, secretory vesicles and the Golgi complex. Ca(2+) release from these morphologically very different organelles is mediated by members of the TRP channel superfamily and two-pore channels. Inositol trisphosphate and ryanodine receptors which are traditionally viewed as endoplasmic reticulum Ca(2+) release channels can also mobilize acidic Ca(2+) stores. Ca(2+) uptake into acidic Ca(2+) stores is driven by Ca(2+) ATPases and Ca(2+)/H(+) exchangers. In animal cells, the Ca(2+)-mobilizing messenger NAADP plays a central role in mediating Ca(2+) signals from acidic Ca(2+) stores through activation of two-pore channels. These signals are important for several physiological processes including muscle contraction and differentiation. Dysfunctional acidic Ca(2+) stores have been implicated in diseases such as acute pancreatitis and lysosomal storage disorders. Acidic Ca(2+) stores are therefore emerging as essential components of the Ca(2+) signalling network and merit extensive further study.
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