1
|
Peterková L, Kmoníčková E, Ruml T, Rimpelová S. Sarco/Endoplasmic Reticulum Calcium ATPase Inhibitors: Beyond Anticancer Perspective. J Med Chem 2020; 63:1937-1963. [PMID: 32030976 DOI: 10.1021/acs.jmedchem.9b01509] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The sarco/endoplasmic reticulum calcium ATPase (SERCA), which plays a key role in the maintenance of Ca2+ ion homeostasis, is an extensively studied enzyme, the inhibition of which has a considerable impact on cell life and death decision. To date, several SERCA inhibitors have been thoroughly studied and the most notable one, a derivative of the sesquiterpene lactone thapsigargin, is gradually approaching a clinical application. Meanwhile, new compounds with SERCA-inhibiting properties of natural, synthetic, or semisynthetic origin are being discovered and/or developed; some of these might also be suitable for the development of new drugs with improved performance. This review brings an up-to-date comprehensive overview of recently discovered compounds with the potential of SERCA inhibition, discusses their mechanism of action, and highlights their potential clinical applications, such as cancer treatment.
Collapse
Affiliation(s)
- Lucie Peterková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Eva Kmoníčková
- Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Silvie Rimpelová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic.,Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| |
Collapse
|
2
|
Abstract
The SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) is probably the most extensively studied membrane protein transporter. There is a vast array of diverse inhibitors for the Ca2+ pump, and many have proved significant in helping to elucidate both the mechanism of transport and gaining conformational structures. Some SERCA inhibitors such as thapsigargin have been used extensively as pharmacological tools to probe the roles of Ca2+ stores in Ca2+ signalling processes. Furthermore, some inhibitors have been implicated in the cause of diseases associated with endocrine disruption by environmental pollutants, whereas others are being developed as potential anticancer agents. The present review therefore aims to highlight some of the wide range of chemically diverse inhibitors that are known, their mechanisms of action and their binding location on the Ca2+ ATPase. Additionally, some ideas for the future development of more useful isoform-specific inhibitors and anticancer drugs are presented.
Collapse
|
3
|
Vangheluwe P, Sepúlveda MR, Missiaen L, Raeymaekers L, Wuytack F, Vanoevelen J. Intracellular Ca2+- and Mn2+-Transport ATPases. Chem Rev 2009; 109:4733-59. [DOI: 10.1021/cr900013m] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Peter Vangheluwe
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - M. Rosario Sepúlveda
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Luc Raeymaekers
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Frank Wuytack
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jo Vanoevelen
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| |
Collapse
|
4
|
Dellen BK, Barber MJ, Ristig ML, Hescheler J, Sauer H, Wartenberg M. oscillations in a model of energy-dependent uptake by the endoplasmic reticulum. J Theor Biol 2005; 237:279-90. [PMID: 15975599 DOI: 10.1016/j.jtbi.2005.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 04/01/2005] [Accepted: 04/22/2005] [Indexed: 10/25/2022]
Abstract
Active Ca2+ transport in living cells necessitates controlled supply of metabolic energy. Direct coupling between sarco/endoplasmic reticulum (ER) Ca2+ ATPases (SERCA) and intracellular energy-generation sites has been well established experimentally. On the basis of these experimental findings we propose a pump-driven model to investigate complex dynamic properties of a cell system. The model describes the pump process both by the Ca2+ ATPase itself and by a suitable description of the glycolysis. The associated set of differential equations shows a rich behavior, the solutions ranging from simple periodic oscillations to complex patterns such as bursting and spiking. Recent experimental results on calcium oscillations in Xenopus laevis oocytes and on dynamic patterns of intracellular Ca2+ concentrations in electrically non-excitable cells are well described by corresponding theoretical results derived within the proposed model. The simulation results are further compared to spontaneous [Ca2+] oscillations in primitive endodermal cells.
Collapse
Affiliation(s)
- B K Dellen
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Köln, Germany.
| | | | | | | | | | | |
Collapse
|
5
|
Sepúlveda MR, Hidalgo-Sánchez M, Mata AM. A developmental profile of the levels of calcium pumps in chick cerebellum. J Neurochem 2005; 95:673-83. [PMID: 16104848 DOI: 10.1111/j.1471-4159.2005.03401.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The functional expression and distribution of intracellular ATPase (sarco(endo)plasmic reticulum Ca(2+)-ATPase: SERCA) and plasma membrane Ca(2+)-ATPase (PMCA) was analyzed in the developing chick cerebellum. The activity and Ca(2+) uptake increase with development for both ATPases. However, the protein content increases with the stage of development only for SERCA, remaining constant for PMCA. Immunohistochemical assays showed that the ontogenesis of these ATPases goes along with definite stages of cerebellum histogenesis, and is complete at hatching. The SERCA is mainly distributed in Purkinje neurons, whereas the PMCA seems to be expressed initially in climbing fibers, shifting to soma and spiny branchlets of Purkinje cells at late embryonic stages. Granule cells express both ATPases according to their degree of maturity, whereas only PMCA is present in cerebellar glomeruli. These pumps are present in deep nuclei and the choroid plexus, although in this latter tissue their expression declines with development. The spatio-temporal distribution of SERCA and PMCA must be closely related to their association with the development of specific cells and processes of the chick cerebellum.
Collapse
Affiliation(s)
- M Rosario Sepúlveda
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | | | | |
Collapse
|
6
|
Sepúlveda MR, Mata AM. Localization of intracellular and plasma membrane Ca2+-ATPases in the cerebellum. CEREBELLUM (LONDON, ENGLAND) 2005; 4:82-9. [PMID: 16035189 DOI: 10.1080/14734220410019075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The sarco-endoplasmic reticulum Ca2+-ATPase and the plasma membrane Ca2+-ATPase contribute to the regulation of the intracellular Ca2+ concentration. These proteins transport Ca2+ ions into the endoplasmic reticulum and to the extracellular medium, respectively. A different localization of the two families of Ca2+-ATPases has been shown in concrete subcellular areas of Purkinje cells and in other neuronal elements from cerebellum. In the light of the actual knowledge of Ca2+-ATPases, this strict distribution suggests the existence of different demands on Ca2+ homeostasis in these cerebellar and cellular subregions.
Collapse
Affiliation(s)
- M Rosario Sepúlveda
- Departamento de Bioquímica y Biologia Moleculary Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | | |
Collapse
|
7
|
Sepúlveda MR, Hidalgo-Sánchez M, Mata AM. Localization of endoplasmic reticulum and plasma membrane Ca2+-ATPases in subcellular fractions and sections of pig cerebellum. Eur J Neurosci 2004; 19:542-51. [PMID: 14984405 DOI: 10.1111/j.0953-816x.2003.03156.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Subcellular fractions and sections of the cerebellum were analysed to evaluate the relative activity and distribution of organellar and plasma membrane Ca2+-ATPases (SERCA and PMCA). Western blot analysis of the fractions with IID8 or Y/1F4 SERCA-specific antibodies or else with 5F10 or pbPMCA antibodies, specific to PMCA pump, revealed a major content of SERCA protein in microsomes and of PMCA protein in plasma membrane vesicles. The Ca2+-ATPase activity of microsomes was more sensitive to thapsigargin, a SERCA-specific inhibitor, whereas the activity of the plasma membrane vesicle fraction was inhibited more by vanadate, a blocker of PMCA activity. The SERCA and PMCA distribution analysed in cerebellar sections revealed IID8 antibody reactions in Purkinje cell cytoplasm, granule cells and cerebellar glomeruli. Y/1F4 gave immunostaining in Purkinje cells, molecular layer interneurons (basket and stellate cells) and glomeruli, but granule cells were not labelled. The 5F10 antibody reacted with Purkinje cells, including their dendritic spines, as well as cerebellar glomeruli, whereas the pbPMCA antibody labelled several processes in all three layers and some synaptic interaction sites. The differential content and localization of the two types of Ca2+ pumps in specific neuronal areas of pig cerebellum indicate precise Ca2+ requirements of specific cellular regions.
Collapse
Affiliation(s)
- M Rosario Sepúlveda
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | | | | |
Collapse
|
8
|
Dyer JL, Khan SZ, Bilmen JG, Hawtin SR, Wheatley M, Javed MUH, Michelangeli F. Curcumin: a new cell-permeant inhibitor of the inositol 1,4,5-trisphosphate receptor. Cell Calcium 2002; 31:45-52. [PMID: 11990299 DOI: 10.1054/ceca.2001.0259] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Curcumin (diferuoylmethane or 1,7-bis (4-hydroxy-3-methoxyphenol)-1,6-hepatadiene-3,5-dione) is the active ingredient of the spice turmeric. Curcumin has been shown to have a number of pharmacological and therapeutic uses. This study shows that curcumin is a potent inhibitor of the inositol 1,4,5-trisphosphate-sensitive Ca2+ channel (InsP3 receptor). In porcine cerebellar microsomes, the extent of InsP3-induced Ca2+ release (IICR) is almost completely inhibited by 50 microM curcumin (IC50 = 10 microM). As the extent of IICR cannot be restored back to control levels by the addition of excess InsP3 and since it has little effect on [3H]InsP3 binding to cerebellar microsomes, this inhibition is likely to be non-competitive in nature. IICR in cerebellar microsomes is biphasic consisting of a fast and slow component. The rate constants for the two components are both reduced by curcumin to similar extents (by about 70% of control values at 40 microM curcumin). In addition, curcumin also reduces agonist (ATP)-stimulated Ca2+ mobilization from intact HL-60 cells, indicating that curcumin is cell permeant. However, since it also affects intracellular Ca2+ pumps and possibly ryanodine receptors, it may lead to complex Ca2+ transient responses within cells, which may well explain some of its putative therapeutic properties.
Collapse
Affiliation(s)
- J L Dyer
- School of Biosciences, University of Birmingham, Edgbaston, UK
| | | | | | | | | | | | | |
Collapse
|
9
|
Khan SZ, Longland CL, Michelangeli F. The effects of phenothiazines and other calmodulin antagonists on the sarcoplasmic and endoplasmic reticulum Ca(2+) pumps. Biochem Pharmacol 2000; 60:1797-806. [PMID: 11108794 DOI: 10.1016/s0006-2952(00)00505-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effects of a number of phenothiazines and other calmodulin antagonists on the Ca(2+)-ATPase activity of sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) were investigated. The drugs used in this study were trifluoperazine, calmidazolium, fluphenazine, chlorpromazine, W-7, and calmodulin-binding peptide. Our results showed that calmidazolium and calmodulin-binding peptide were the most potent inhibitors of skeletal muscle SR Ca(2+)-ATPase activity (isoform SERCA 1) (IC(50) values of 0.5 and 7 microM, respectively), while W-7 was the least potent inhibitor (IC(50), 125 microM). All of the antagonists had little effect on the cerebellar ER Ca(2+)-ATPase activity (isoform SERCA 2b), except for trifluoperazine, which had a biphasic effect, causing stimulation at low concentrations and inhibition at higher concentrations. Our results suggest that the effects of these calmodulin antagonists are independent of calmodulin and that they inhibit the Ca(2+)-ATPase in an isoform-specific manner. It was found that these antagonists inhibit the skeletal muscle isoform of the Ca(2+) pump by altering the Ca(2+) affinity and the associated Ca(2+)-binding steps, as well as possibly stabilising the E1 conformational state of the enzyme.
Collapse
Affiliation(s)
- S Z Khan
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK
| | | | | |
Collapse
|
10
|
Hughes PJ, McLellan H, Lowes DA, Kahn SZ, Bilmen JG, Tovey SC, Godfrey RE, Michell RH, Kirk CJ, Michelangeli F. Estrogenic alkylphenols induce cell death by inhibiting testis endoplasmic reticulum Ca(2+) pumps. Biochem Biophys Res Commun 2000; 277:568-74. [PMID: 11061995 DOI: 10.1006/bbrc.2000.3710] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Industrial alkylphenols in the environment may act as "xenoestrogens" to disrupt testicular development and decrease male fertility. Amongst possible targets for these compounds are testicular Sertoli cells, which nurture the developing sperm cells. We demonstrate that SERCA 2 and 3 Ca(2+) pumps are relatively abundant in rat testis microsomal membranes, and also in Sertoli, myoid, and TM4 cells (a Sertoli cell line). A number of estrogenic alkylphenols such as nonylphenol, octylphenol, bisphenol A, and butylated hydroxytoluene all inhibit testicular Ca(2+) ATPase in the low micromolar concentration range. These agents also mobilize intracellular Ca(2+) in intact TM4 cells in a manner consistent with the inhibition of ER Ca(2+) pumps. Alkylphenols dramatically decrease the viability of TM4 cells, an effect that is reversed by either a caspase inhibitor or by BAPTA, and is therefore consistent with Ca(2+)-dependent cell death via apoptosis. We postulate that alkylphenols disrupt testicular development by inhibiting ER Ca(2+) pumps, thus disturbing testicular Ca(2+) homeostasis.
Collapse
Affiliation(s)
- P J Hughes
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Cadiou H, Sienaert I, Vanlingen S, Parys JB, Molle G, Duclohier H. Basic properties of an inositol 1,4,5-trisphosphate-gated channel in carp olfactory cilia. Eur J Neurosci 2000; 12:2805-11. [PMID: 10971622 DOI: 10.1046/j.1460-9568.2000.00166.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In addition to the activation of cAMP-dependent pathways, odorant binding to its receptor can lead to inositol 1,4,5-trisphosphate (InsP3) production that may induce the opening of plasma membrane channels. We therefore investigated the presence and nature of such channels in carp olfactory cilia. Functional analysis was performed by reconstitution of the olfactory cilia in planar lipid bilayers (tip-dip method). In the presence of InsP3 (10 microM) and Ca2+ (100 nM), a current of 1.6 +/- 0.1 pA (mean +/- SEM, n = 4) was measured, using Ba2+ as charge carrier. The I/V curve displayed a slope conductance of 45 +/- 5 pS and a reversal potential of -29 mV indicating a higher selectivity for divalent cations. This current was characterized by two mean open times (3.0 +/- 0.4 ms and 42.0 +/- 2.6 ms, n = 4) and was strongly inhibited by ruthenium red (30 microM) or heparin (10 microg/mL). Importantly, the channel activity was closely dependent on the Ca2+ concentration, with the highest open probability (Po) at 100 nM Ca2+ (Po = 0.50 +/- 0.02, n = 4). Po is lower at both higher and lower Ca2+ concentrations. A structural identification of the channel was attempted by using a large panel of antibodies, raised against several InsP3 receptor (InsP3R)/Ca2+ release channel isoforms. The type 1 InsP3R was detected in carp cerebellum and whole brain, while a lower molecular mass InsP3R, which may correspond to type 2 or 3, was detected in heart, whole brain and the soma of the olfactory neurons. None of the antibodies, however, cross-reacted with olfactory cilia. Taken together, these results indicate that in carp olfactory cilia an InsP3-dependent channel is present, distinct from the classical InsP3Rs localized on intracellular membranes.
Collapse
Affiliation(s)
- H Cadiou
- UMR 6522 CNRS, IFRMP 23,Université de Rouen, F-76821 Mont Saint Aignan, France
| | | | | | | | | | | |
Collapse
|
12
|
Ramos RC, de Meis L. Glucose 6-phosphate and fructose 1,6-bisphosphate can be used as ATP-regenerating systems by cerebellum Ca2+-transport ATPase. J Neurochem 1999; 72:81-6. [PMID: 9886057 DOI: 10.1046/j.1471-4159.1999.0720081.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this work, it is shown that the Ca2+-transport ATPase found in the microsomal fraction of the cerebellum can use both glucose 6-phosphate/hexokinase and fructose 1,6-bisphosphate/phosphofructokinase as ATP-regenerating systems. The vesicles derived from the cerebellum were able to accumulate Ca2+ in a medium containing ADP when either glucose 6-phosphate and hexokinase or fructose 1,6-bisphosphate and phosphofructokinase were added to the medium. There was no Ca2+ uptake if one of these components was omitted from the medium. The transport of Ca2+ was associated with the cleavage of sugar phosphate. The maximal amount of Ca2+ accumulated by the vesicles with the fructose 1,6-bisphosphate system was larger than that measured either with glucose 6-phosphate or with a low ATP concentration and phosphoenolpyruvate/pyruvate kinase. The Ca2+ uptake supported by glucose 6-phosphate was inhibited by glucose, but not by fructose 6-phosphate. In contrast, the Ca2+ uptake supported by fructose 1,6-bisphosphate was inhibited by fructose 6-phosphate, but not by glucose. Thapsigargin, a specific SERCA inhibitor, impaired the transport of Ca2+ sustained by either glucose 6-phosphate or fructose 1,6-bisphosphate. It is proposed that the use of glucose 6-phosphate and fructose 1,6-bisphosphate as an ATP-regenerating system by the cerebellum Ca2+-ATPase may represent a salvage route used at early stages of ischemia; this could be used to energize the Ca2+ transport, avoiding the deleterious effects derived from the cellular acidosis promoted by lactic acid.
Collapse
Affiliation(s)
- R C Ramos
- Instituto de Ciências Biomédicas, Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Brazil
| | | |
Collapse
|
13
|
Pinton P, Pozzan T, Rizzuto R. The Golgi apparatus is an inositol 1,4,5-trisphosphate-sensitive Ca2+ store, with functional properties distinct from those of the endoplasmic reticulum. EMBO J 1998; 17:5298-308. [PMID: 9736609 PMCID: PMC1170857 DOI: 10.1093/emboj/17.18.5298] [Citation(s) in RCA: 363] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the past few years, intracellular organelles, such as the endoplasmic reticulum, the nucleus and the mitochondria, have emerged as key determinants in the generation and transduction of Ca2+ signals of high spatio-temporal complexity. Little is known about the Golgi apparatus, despite the fact that Ca2+ within its lumen controls essential processes, such as protein processing and sorting. We report the direct monitoring of the [Ca2+] in the Golgi lumen ([Ca2+]Golgi) of living HeLa cells, using a specifically targeted Ca2+-sensitive photoprotein. With this probe, we show that, in resting cells, [Ca2+]Golgi is approximately 0.3 mM and that Ca2+ accumulation by the Golgi has properties distinct from those of the endoplasmic reticulum (as inferred by the sensitivity to specific inhibitors). Upon stimulation with histamine, an agonist coupled to the generation of inositol 1,4,5-trisphosphate (IP3), a large, rapid decrease in [Ca2+]Golgi is observed. The Golgi apparatus can thus be regarded as a bona fide IP3-sensitive intracellular Ca2+ store, a notion with major implications for the control of organelle function, as well as for the generation of local cytosolic Ca2+ signals.
Collapse
Affiliation(s)
- P Pinton
- Department of Biomedical Sciences and CNR Centre for the Study of Biomembranes, University of Padova, Via Colombo 3, 35121 Padova, Italy
| | | | | |
Collapse
|
14
|
Isoform Diversity and Regulation of Organellar-Type Ca2+-Transport ATPases. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1569-2558(08)60156-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
15
|
Wells KM, Abercrombie RF. Effects of the intraluminal Ca load on the kinetics of 45Ca uptake and efflux in brain microsomes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:C1472-9. [PMID: 8944629 DOI: 10.1152/ajpcell.1996.271.5.c1472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Effects of increasing intraluminal Ca ([Ca]i) on the kinetics of rat brain microsomal uptake and efflux are reported here. Isolated rat brain microsomes accumulated 45Ca in an extravesicular free Ca ([Ca]o)- and ATP-dependent manner. Increased microsomal Ca load resulted in a decreased initial rate of 45Ca uptake and an increased tau, time to reach 63% of steady-state accumulation. Isolated rate brain microsomes lost 45Ca in a temperature- and [Ca]i-dependent manner. Whether preloaded with tracer 45Ca and either < or = 0.5 or 25 microM [Ca]o, the time constant of efflux was larger at 4 degrees C as compared with 37 degrees C. Additionally, increased microsomal Ca load resulted in a decreased time constant of 45Ca efflux. This shorter efflux time constant cannot explain the effect of [Ca]i on tau during uptake which was in fact longer for preloaded microsomes. Rather, these data suggest that, as Ca accumulates into unloaded microsomes, a steadily increasing [Ca]i slows unidirectional Ca influx (presumably by inhibiting the endoplasmic reticulum Ca pump) and enhances unidirectional Ca efflux, and that these combined effects ultimately shorten the time needed to achieve steady-state luminal [Ca]i.
Collapse
Affiliation(s)
- K M Wells
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | |
Collapse
|
16
|
Genazzani AA, Galione A. Nicotinic acid-adenine dinucleotide phosphate mobilizes Ca2+ from a thapsigargin-insensitive pool. Biochem J 1996; 315 ( Pt 3):721-5. [PMID: 8645149 PMCID: PMC1217266 DOI: 10.1042/bj3150721] [Citation(s) in RCA: 150] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nicotinic acid-adenine dinucleotide phosphate (NAADP) is a novel intracellular Ca2+ releasing agent recently described in sea-urchin eggs and egg homogenates. Ca2+ release by NAADP is independent of that induced by either inositol trisphosphate (InsP3) or cyclic adenosine dinucleotide phosphate (cADPR). We now report that in sea urchin egg homogenates, NAADP releases Ca2+ from a Ca2+ pool that is distinct from those that are sensitive to InsP3 and cADPR. This organelle has distinct Ca2+ uptake characteristics: it is insensitive to thapsigargin and cyclopiazoic acid, but maintenance of the pool shows some requirement for ATP. Although the different Ca2+ pools have different characteristics, there appears to be some degree of overlap or cross-talk between the NAADP- and cADPR/InsP3-sensitive Ca2+ pools. Ca(2+)-induced Ca2+ release is unlikely to account for the apparent overlap between stores, since NAADP-induced Ca2+ release, in contrast with that stimulated by cADPR, is not potentiated by bivalent cations.
Collapse
|
17
|
Mezna M, Patchick T, Tovey S, Michelangeli F. Inhibition of the cerebellar inositol 1,4,5-trisphosphate-sensitive Ca2+ channel by ethanol and other aliphatic alcohols. Biochem J 1996; 314 ( Pt 1):175-9. [PMID: 8660280 PMCID: PMC1217022 DOI: 10.1042/bj3140175] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effects of ethanol and other aliphatic alcohols on the endoplasmic reticulum Ca2+ pump and the inositol 1,4,5-trisphosphate (InsP3)-sensitive Ca2+ channel were studied in pig cerebellar microsomes. Methanol, ethanol and propanol all stimulated ATP-dependent Ca2+ uptake, whereas butanol inhibited this process. Ethanol inhibited InsP3-induced Ca2+ release [half-maximal inhibition at 3.5%, v/v (600 mM)]. However, ethanol affected only the amount of InsP3-releasable Ca2+, without affecting the concentration of InsP3 required to induce half-maximal release. Other alcohols of longer chain length were more potent than ethanol at inhibiting InsP3-induced Ca2+ release, but none of the alcohols tested affected [3H]InsP3 binding to its receptor. Using stopped-flow techniques, measurements of the rate of InsP3-induced Ca2+ release in the preparation of pig cerebellar microsomes used in this study showed the kinetics to be monophasic, with a rate constant of 0.93s-1 at 20 microM InsP3. This rate constant was dependent upon InsP3 concentration, decreasing to 0.38s-1 at 0.25 microM InsP3. Ethanol was shown to reduce the fractional amount of InsP3-induced Ca2+ release without significantly affecting the rate constant for this process.
Collapse
Affiliation(s)
- M Mezna
- School of Biochemistry, University of Birmingham, Edgbaston, U.K
| | | | | | | |
Collapse
|
18
|
|
19
|
Mezna M, Michelangeli F. Alkali metal ion dependence of inositol 1,4,5-trisphosphate-induced calcium release from rat cerebellar microsomes. J Biol Chem 1995; 270:28097-102. [PMID: 7499297 DOI: 10.1074/jbc.270.47.28097] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The effects of the alkali metal ions Na+, K+, Rb+, and Cs+ on ATP-dependent Ca2+ uptake, [3H]Inositol 1,4,5-trisphosphate (InsP3) binding, and quantal InsP3-induced Ca2+ release were investigated using rat cerebellar microsomes. Both the ion species and concentration affected the ability of the microsomes to support Ca2+ uptake with K+ being mot effective (3.8 nmol of Ca2+/min/mg at 100 mM K+). The order of efficacy of the other ions was as follows: K+ > Na+ > Rb+ = Cs+ >> Li+. The binding of [3H]InsP3 to cerebellar microsomes was, however, affected little by the presence of these ions. All these alkali metal ions (except Li+) supported InsP3-induced Ca2+ release at concentrations above 25 mM; however, the extent of Ca2+ release (expressed as a percent Ca2+ release compared with that released by the ionophore A23187) was dependent upon the ion species present. Again K+ was more potent than the other ions at facilitating InsP3-induced Ca2+ release (order of efficacy: K+ > Rb+ > Na+ > Cs+), although the concentration of InsP3 required to induce half-maximal Ca2+ release (IC50) was not significantly altered. Over the ion concentration range tested (25-100 mM), the extent of InsP3-induced Ca2+ release with both K+ and Rb+ increased in a linear fashion, while Na+ showed only a slight increase and Cs+ showed no increase over this range. The effect of K+ concentration on quantal Ca2+ release was to alter the extent of release rather than the IC50 InsP3 concentration. Using stopped-flow techniques, the effects of InsP3 and K+ concentrations on the kinetics of InsP3-induced Ca2+ release were shown to exhibit a monoexponential process in this microsomal preparation. The rate constants for Ca2+ release increased with InsP3 concentration (0.11 s-1 at 0.02 microM InsP3 to 0.5 s-1 at 40 microM InsP3); however, the relationship between the fractional extent of release and rate constants for release did not change in a similar way with InsP3 concentration. Although the fractional extent of Ca2+ release increased with K+ concentration, the rate constants for release over this K+ concentration range were unaffected. This observation leads us to question the role of K+ as a counter ion required for Ca2+ release, and we therefore postulate a role for K+ (and the other alkali metal ions) as a "co-factor" required for channel opening.
Collapse
Affiliation(s)
- M Mezna
- School of Biochemistry, University of Birmingham, Edgbaston, United Kingdom
| | | |
Collapse
|
20
|
Michelangeli F, Mezna M, Tovey S, Sayers LG. Pharmacological modulators of the inositol 1,4,5-trisphosphate receptor. Neuropharmacology 1995; 34:1111-22. [PMID: 8532181 DOI: 10.1016/0028-3908(95)00053-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Elevation of cytosolic calcium concentrations, induced by many neurotransmitters, plays a crucial role in neuronal function. Some neurotransmitters produce the second messenger InsP3 which activates an intracellular calcium channel (InsP3 receptor) usually located in the endoplasmic reticulum. This article undertakes a comprehensive survey of most pharmacological modulators of the InsP3 receptor so far reported. This review discusses in detail competitive antagonists, non-competitive antagonists and thiol reactive reagents, highlighting their modes of action and in some cases indicating drawbacks in their use.
Collapse
Affiliation(s)
- F Michelangeli
- School of Biochemistry, University of Birmingham, Edgbaston, UK
| | | | | | | |
Collapse
|
21
|
Poulsen JC, Caspersen C, Mathiasen D, East JM, Tunwell RE, Lai FA, Maeda N, Mikoshiba K, Treiman M. Thapsigargin-sensitive Ca(2+)-ATPases account for Ca2+ uptake to inositol 1,4,5-trisphosphate-sensitive and caffeine-sensitive Ca2+ stores in adrenal chromaffin cells. Biochem J 1995; 307 ( Pt 3):749-58. [PMID: 7741706 PMCID: PMC1136714 DOI: 10.1042/bj3070749] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In chromaffin cells of adrenal medulla, heterogeneity of Ca2+ stores has been suggested with respect to the mechanisms of Ca2+ uptake and release. We have examined Ca(2+)-ATPases responsible for loading of Ca2+ stores in these cells for their sensitivity to thapsigargin, a highly selective inhibitor of the SERCA [sarco(endo)plasmic reticulum calcium ATPase] family of intracellular Ca2+ pumps. Using immunostaining, we studied the distribution of Ca(2+)-ATPases, and of receptors for inositol 1,4,5-trisphosphate (InsP3) and ryanodine, in the density-gradient fractions of microsomes from bovine adrenal medulla. In parallel, we examined distribution profiles of ATP-dependent Ca2+ uptake in the same fractions, along with subcellular markers for plasma membranes and endoplasmic reticulum (ER). Two Ca(2+)-ATPase-like proteins (116 and 100 kDa) were detected, consistent with the presence of SERCA 2b and SERCA 3 isoenzymes of Ca2+ pumps. The distribution of these putative Ca(2+)-ATPase iso-enzymes paralleled that of InsP3 and ryanodine receptors. This distribution of ER Ca(2+)-ATPases, as determined immunologically, was consistent with that of thapsigargin-sensitive, but not of thapsigargin-insensitive, ATP-dependent Ca2+ uptake. In contrast, the distribution profile of the thapsigargin-insensitive Ca2+ uptake was strongly correlated to that of plasma membranes, and co-distributed with plasma membrane Ca(2+)-ATPase detected immunologically. In isolated, permeabilized chromaffin cells, InsP3 and caffeine induced Ca2+ release following an ATP-dependent Ca2+ accumulation to the stores. This accumulation was abolished by thapsigargin. Together, these data strongly indicate that the thapsigargin-sensitive, presumably SERCA-type Ca(2+)-ATPases account for Ca2+ uptake to InsP3-sensitive, as well as to caffeine-sensitive, Ca2+ stores in bovine adrenal chromaffin cells.
Collapse
Affiliation(s)
- J C Poulsen
- Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Brown GR, Benyon SL, Kirk CJ, Wictome M, East JM, Lee AG, Michelangeli F. Characterisation of a novel Ca2+ pump inhibitor (bis-phenol) and its effects on intracellular Ca2+ mobilization. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1195:252-8. [PMID: 7947918 DOI: 10.1016/0005-2736(94)90264-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Bis-phenol, a phenolic antioxidant, is an inhibitor of sarcoplasmic reticulum (SR), endoplasmic reticulum (ER) and plasma membrane Ca2+ ATPases. The concentration of bis-phenol giving half-maximal inhibition of the SR Ca(2+)-ATPase is 2 microM. On binding to the SR Ca(2+)-ATPase it shifts the E2 to E1 transition towards the E2 state and slows the transition between E2 to E1. Bis-phenol completely inhibits Ca(2+)-dependent ATP hydrolysis and Ca2+ uptake by rat cerebellar microsomes at a concentration of 30 microM. The plasma membrane Ca(2+)-ATPase is also completely inhibited at similar concentrations, however, the Na+/K(+)-ATPase is only marginally affected. Other inhibitors of the ER Ca(2+)-ATPases, thapsigargin and 2,5-di-(tert-butyl)-1,4-benzohydroquinone (BHQ), inhibit Ca2+ uptake by approximately 75%. Bis-phenol therefore inhibits all types of ER Ca(2+)-ATPases present in cerebellum. This inhibitor is also able to mobilize Ca2+ from intracellular Ca2+ stores, including those sensitive to InsP3, in intact HL-60 cells.
Collapse
Affiliation(s)
- G R Brown
- School of Biochemistry, University of Birmingham, Edgbaston, UK
| | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
Over the past years, a concept for creatine kinase function, the 'PCr-circuit' model, has evolved. Based on this concept, multiple functions for the CK/PCr-system have been proposed, such as an energy buffering function, regulatory functions, as well as an energy transport function, mostly based on studies with muscle. While the temporal energy buffering and metabolic regulatory roles of CK are widely accepted, the spatial buffering or energy transport function, that is, the shuttling of PCr and Cr between sites of energy utilization and energy demand, is still being debated. There is, however, much circumstantial evidence, that supports the latter role of CK including the distinct, isoenzyme-specific subcellular localization of CK isoenzymes, the isolation and characterization of functionally coupled in vitro microcompartments of CK with a variety of cellular ATPases, and the observed functional coupling of mitochondrial oxidative phosphorylation with mitochondrial CK. New insight concerning the functions of the CK/PCr-system has been gained from recent M-CK null-mutant transgenic mice and by the investigation of CK localization and function in certain highly specialized non-muscle tissues and cells, such as electrocytes, retina photoreceptor cells, brain cells, kidney, salt glands, myometrium, placenta, pancreas, thymus, thyroid, intestinal brush-border epithelial cells, endothelial cells, cartilage and bone cells, macrophages, blood platelets, tumor and cancer cells. Studies with electric organ, including in vivo 31P-NMR, clearly reveal the buffer function of the CK/PCr-system in electrocytes and additionally corroborate a direct functional coupling of membrane-bound CK to the Na+/K(+)-ATPase. On the other hand, experiments with live sperm and recent in vivo 31P-NMR measurements on brain provide convincing evidence for the transport function of the CK/PCr-system. We report on new findings concerning the isoenzyme-specific cellular localization and subcellular compartmentation of CK isoenzymes in photoreceptor cells, in glial and neuronal cells of the cerebellum and in spermatozoa. Finally, the regulation of CK expression by hormones is discussed, and new developments concerning a connection of CK with malignancy and cancer are illuminated. Most interesting in this respect is the observed upregulation of CK expression by adenoviral oncogenes.
Collapse
Affiliation(s)
- T Wallimann
- Institute for Cell Biology, Swiss Federal Institute of Technology, ETH-Hönggerberg, Zürich
| | | |
Collapse
|
24
|
Hemmer W, Zanolla E, Furter-Graves EM, Eppenberger HM, Wallimann T. Creatine kinase isoenzymes in chicken cerebellum: specific localization of brain-type creatine kinase in Bergmann glial cells and muscle-type creatine kinase in Purkinje neurons. Eur J Neurosci 1994; 6:538-49. [PMID: 8025709 DOI: 10.1111/j.1460-9568.1994.tb00298.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Creatine kinase isoenzymes were localized in the chicken cerebellum by the use of isoenzyme-specific anti-chicken creatine kinase antibodies. Brain-type creatine kinase was found in high amounts in the molecular layer, particularly in Bergmann glial cells but also in other cells of the cerebellar cortex, e.g. in astrocytes and in the glomerular structures, as well as in cells of the deeper nuclei. A mitochondrial creatine kinase isoform was primarily localized to the glomerular structures in the granule cell layer and was also identified in Purkinje neurons. Surprisingly, a small amount of the muscle-type creatine kinase isoform was identified in cerebellar extracts by immunoprecipitation, immunoblotting and native enzyme electrophoresis, and was shown to be localized exclusively in Purkinje neurons. Cell type-specific expression of brain- and muscle-type creatine kinase in Bergmann glial cells and Purkinje neurons, respectively, may serve to adapt cellular ATP regeneration to the different energy requirements in these specialized cell types. The presence of brain-type creatine kinase in Bergmann glial cells and astrocytes is discussed within the context of the energy requirements for ion homeostasis (K+ resorption), as well as for metabolite and neurotransmitter trafficking. In addition, the presence of muscle-type creatine kinase in Purkinje neurons, which also express other muscle-specific proteins, is discussed with respect to the unique calcium metabolism of these neurons and their role in cerebellar motor learning.
Collapse
Affiliation(s)
- W Hemmer
- Institute for Cell Biology, Swiss Federal Institute of Technology, Zürich
| | | | | | | | | |
Collapse
|
25
|
Meldolesi J, Villa A, Podini P, Clementi E, Zacchetti D, D'Andrea P, Lorenzon P, Grohovaz F. Intracellular Ca2+ stores in neurons. Identification and functional aspects. ACTA ACUST UNITED AC 1994; 86:23-30. [PMID: 1343593 DOI: 10.1016/s0928-4257(05)80004-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Various aspects of the rapidly exchanging intracellular Ca2+ stores of neurons and nerve cells are reviewed: their multiplicity, with separate sensitivity to either the second messenger, inositol 1,4,5-trisphosphate, or ryanodine-caffeine (the latter stores are probably activated via Ca(2+)-induced Ca2+ release); their control of the plasma membrane Ca2+ permeability, via the activation of a peculiar type of cation channels; their ability to sustain localized heterogeneities of the [Ca2+]i that could be of physiological key-importance. Finally, the molecular composition of these stores is discussed. They are shown (by high resolution immunocytochemistry and subcellular fractionation) to express: i) a Ca2+ ATPase responsible for the accumulation of the cation; ii) Ca2+ binding protein(s) of low affinity and high capacity to keep Ca2+ stored; and iii) a Ca2+ channel, activated by either one of the mechanisms mentioned above, to release Ca2+ to the cytosol. Results obtained in Purkinje neurons document the heterogeneity of the stores and the strategical distribution of the corresponding organelles (calciosomes; specialized portions of the ER) within the cell body, dendrites and dendritic spines.
Collapse
Affiliation(s)
- J Meldolesi
- Department of Pharmacology, CNR Cytopharmacology, Milan, Italy
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Sah P, Dulhunty A, Junankar P, Stanhope C. Subcellular distribution of ryanodine receptor-like and calcium ATPase-like immunoreactivity in brainstem and cerebellar neurones of rat and guinea pig. Neurosci Lett 1994; 166:143-8. [PMID: 8177490 DOI: 10.1016/0304-3940(94)90471-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Monoclonal antibodies against ryanodine receptor (5C3) and calcium ATPase (D12) of skeletal muscle sarcoplasmic reticulum were used in an immunoelectron microscopic study of cerebellar Purkinje cells and neurons of the hypoglossal and dorsal motor nuclei of the vagus (DMV) from rat and guinea-pig. All neurones were labelled with D12 and all, except rat DMV, labelled with 5C3. Most labelling was on smooth endoplasmic reticulum within 500 nm of the plasmalemma where Ca(2+)-activated Ca2+ release would rapidly increase cytosolic calcium following a small Ca2+ influx across the plasmalemma.
Collapse
Affiliation(s)
- P Sah
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra
| | | | | | | |
Collapse
|
27
|
Rodrigo J, Uttenthal O, Bentura ML, Maeda N, Mikoshiba K, Martinez-Murillo R, Polak JM. Subcellular localization of the inositol 1,4,5-trisphosphate receptor, P400, in the vestibular complex and dorsal cochlear nucleus of the rat. Brain Res 1994; 634:191-202. [PMID: 8131069 DOI: 10.1016/0006-8993(94)91922-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The subcellular localization of the inositol 1,4,5-trisphosphate receptor protein, P400, was studied in the vestibular complex, an area to which Purkinje cells project, as well as in neurons of the dorsal cochlear nucleus and in ectopic Purkinje cells of adult rat brain. The receptor was demonstrated by electron microscopical immunocytochemistry using the avidin-biotin peroxidase complex procedure, with the monoclonal antibody 4C11 raised against mouse cerebellar inositol 1,4,5-trisphosphate receptor protein. Immunoreactivity was found in preterminal fibres and terminal boutons in the nuclei of the vestibular complex, generally associated with the subsurface systems and stacks or fragments of smooth endoplasmic reticulum. Ectopic Purkinje cells and cartwheel cells of the dorsal cochlear nucleus also displayed immunoreactivity, but this was much less intense in the latter. The results of the present study suggest that this receptor protein, involved in the release of Ca2+, is located in sites that enable it to influence the synthesis, transport and release of neurotransmitters.
Collapse
Affiliation(s)
- J Rodrigo
- Unidad de Neuroanatomía Funcional, Instituto Cajal, C.S.I.C., Madrid, Spain
| | | | | | | | | | | | | |
Collapse
|
28
|
Christensen SB, Andersen A, Poulsen JC, Treiman M. Derivatives of thapsigargin as probes of its binding site on endoplasmic reticulum Ca2+ ATPase. Stereoselectivity and important functional groups. FEBS Lett 1993; 335:345-8. [PMID: 8262181 DOI: 10.1016/0014-5793(93)80416-r] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The naturally occurring sesquiterpene lactone thapsigargin is a potent and selective inhibitor of SERCA ATPases, a family of Ca(2+)-pumping ATPases present in the endoplasmic reticulum of all mammalian cells. We have studied some of the molecular features of thapsigargin responsible for its inhibitory action towards these Ca2+ ATPases. A series of thapsigargin analogues were synthesised and their inhibitory potencies determined using the uptake of 45Ca2+ in bovine cerebellar microsomes as a sensitive marker of Ca2+ ATPase activity. An attenuation of the inhibitory potency relative to the parent compound was found ranging from slight to over 3 orders of magnitude. The inhibitory activity showed a very strong configuration dependence, a major contribution from the ester groups at C3 and C10, and an apparently minor contribution from the lactone ring substituents. The data are consistent with thapsigargin fitting to a sterically discriminating cleft involving the hydrophobic transmembrane region of the ATPase, and is compatible with available kinetic evidence of thapsigargin-mediated inhibition.
Collapse
Affiliation(s)
- S B Christensen
- Department of Organic Chemistry, Royal Danish School of Pharmacy, University of Copenhagen, Denmark
| | | | | | | |
Collapse
|
29
|
Sayers LG, Michelangeli F. The effects of tetrahexyl ammonium cations (THA+) on inositol 1,4,5-trisphosphate-induced calcium release from porcine cerebellar microsomes: THA+ can induce calcium release selectively from the InsP3-sensitive calcium stores. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1152:177-83. [PMID: 8399297 DOI: 10.1016/0005-2736(93)90245-u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this study we show that the potassium-channel blocker tetrahexyl ammonium chloride (THA+) is able to inhibit inositol 1,4,5-trisphosphate (InsP3)-induced calcium release in an apparently biphasic fashion with a IC50 of 3 microM. This inhibition was not alleviated by valinomycin and, therefore, is not consistent with the blocking of K+ counter-ion movement, an observation initially made by Palade et al. (Palade, P., Dettbarn, C., Volpe, P., Alderson, B. and Otero, A.S (1989) Mol. Pharmacol. 36, 664-672). THA+ affected quantal calcium release by reducing the amount of calcium released by InsP3, but did not greatly affect the concentration of InsP3 required to cause half-maximal calcium release. THA+ did not affect the metabolism of InsP3 or its binding to porcine cerebellar microsomes. THA+ could also itself induce calcium release. At concentrations below 100 microM, THA+ appears to release Ca2+ selectively from the InsP3-sensitive calcium stores, since prior depletion of these stores with supramaximal doses of InsP3 abolishes this response. At higher THA+ concentrations (above 100 microM) Ca2+ is released non-selectively from all stores. THA+ has no effect on the Ca(2+)-ATPase activity at concentrations below 100 microM, indicating that selective THA(+)-induced Ca2+ release is not due to non-specific inhibition of the microsomal Ca2+ pumps and does not affect Ca2+ leakage. A number of pharmacological modulators of intracellular calcium channels were also tested on THA(+)-induced calcium release with little effect, except for spermidine which reduced this release by up to 50%. Our observations are consistent with the view that THA+, at concentrations below 100 microM, selectively releases calcium from the InsP3-sensitive calcium stores.
Collapse
Affiliation(s)
- L G Sayers
- School of Biochemistry, University of Birmingham, Edgbaston, UK
| | | |
Collapse
|
30
|
Ouyang Y, Deerinck TJ, Walton PD, Airey JA, Sutko JL, Ellisman MH. Distribution of ryanodine receptors in the chicken central nervous system. Brain Res 1993; 620:269-80. [PMID: 8369958 DOI: 10.1016/0006-8993(93)90165-j] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ryanodine receptor (RR), an intracellular calcium release channel, has been identified in the nervous system but its contributions to neuronal function are unknown. We have utilized immunohistochemical techniques to establish the distribution of RRs in the central nervous system (CNS) of the chick as a step toward elucidating the function of RRs in this system. RR immunoreactivity is observed throughout the brain, most prominently in large neurons. The strongest immunoreactivity is found in cerebellar Purkinje neurons, but nuclei in the motor, visual and vestibular systems are also intensely labeled, and immunoreactive neurons are observed the olfactory bulb and the hippocampus. In these neurons, labeling is prominent in cell bodies, dendrites and axons, but is not observed in the dendritic spines or in plasma membranes. The neuronal RRs bind [3H]ryanodine with high affinity and this activity is regulated by calcium, caffeine, MgCl2/ATP and ionic strength. Multiple forms of the RRs are found in the chicken CNS. Immunoprecipitation and localization studies using RR isoform specific monoclonal antibodies reveal major differences in their distribution. The predominant species in the cerebellum is similar to the skeletal muscle isoform while there is a lower level of expression of either the cardiac or beta skeletal isoforms. In the remainder of the brain, the predominant isoform is similar to the cardiac or beta skeletal muscle isoforms. The broad distribution of RRs in the CNS suggests that calcium release events mediated by these proteins may have a functional role in a diverse array of neurons. Moreover within the populations of neurons expressing RR's, the presence of specific RR isoforms may correlate with specialization in the calcium release events mediated by these proteins.
Collapse
Affiliation(s)
- Y Ouyang
- Department of Neurosciences, University of California San Diego, La Jolla 92093-0608
| | | | | | | | | | | |
Collapse
|
31
|
Sah P, Francis K, McLachlan EM, Junankar P. Distribution of ryanodine receptor-like immunoreactivity in mammalian central nervous system is consistent with its role in calcium-induced calcium release. Neuroscience 1993; 54:157-65. [PMID: 8390624 DOI: 10.1016/0306-4522(93)90391-r] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The distributions of ryanodine receptor-like immunoreactivity and Ca-ATPase-like immunoreactivity were identified in the guinea-pig and rat central nervous system using antibodies raised against the rabbit skeletal muscle ryanodine receptor and Ca-ATPase. In both guinea-pig and rat cerebellum, the ryanodine receptor-like immunoreactivity was restricted to the soma and dendrites of Purkinje cells. In the medulla, neuron somata in the hypoglossal nucleus were stained in both species, but in the dorsal motor nucleus of the vagus somata were stained in guinea-pigs but not in rats. This species difference in ryanodine receptor-like immunoreactivity is consistent with the species difference in expression of a ryanodine sensitive, calcium activated potassium conductance in neurons of the dorsal motor nucleus of the vagus. Immunoreactivity to Ca-ATPase was present in vagal motoneurons in both species with denser staining in the guinea-pig. The data further support the idea that, in neurons of the dorsal motor nucleus of the vagus, release of intracellular calcium stores via a ryanodine receptor activates a specific class of potassium channels, thereby modulating cell excitability.
Collapse
Affiliation(s)
- P Sah
- Department of Physiology and Pharmacology, University of Queensland, Australia
| | | | | | | |
Collapse
|
32
|
Sayers LG, Brown GR, Michell RH, Michelangeli F. The effects of thimerosal on calcium uptake and inositol 1,4,5-trisphosphate-induced calcium release in cerebellar microsomes. Biochem J 1993; 289 ( Pt 3):883-7. [PMID: 8435083 PMCID: PMC1132258 DOI: 10.1042/bj2890883] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Thimerosal inhibits calcium uptake in skeletal muscle sarcoplasmic reticulum and rat cerebellar microsomes by inhibiting the Ca(2+)-ATPase. In the presence of 5 mM dithiothreitol (DTT), Ca2+ uptake and ATPase activity were not inhibited by thimerosal, indicating that thimerosal modifies cysteine residues of the Ca(2+)-ATPase. Low thimerosal concentrations (2 microM) sensitize the inositol 1,4,5-trisphosphate (InsP3)-sensitive Ca2+ channel, making it open at lower InsP3 concentrations. Higher concentrations of thimerosal, however, cause inhibition of InsP3-induced Ca2+ release. Both sensitization and inhibition of the InsP3 receptor by thimerosal can be prevented by DTT. The binding and metabolism of InsP3 by cerebellar microsomes is not affected by thimerosal. The amount of InsP3-induced Ca2+ release is co-operatively linked to the InsP3 concentration with a Hill coefficient of 2.0 +/- 0.3. This is decreased to 1.0 +/- 0.2 at inhibitory concentrations of thimerosal. Under our experimental conditions, we observed no dependence of quantal Ca2+ release on intraluminal Ca2+ concentration.
Collapse
Affiliation(s)
- L G Sayers
- School of Biochemistry, University of Birmingham, Edgbaston, UK
| | | | | | | |
Collapse
|
33
|
Michelangeli F. The effects of amino acid-reactive reagents on the functioning of the inositol 1,4,5-trisphosphate-sensitive calcium channel from rat cerebellum. Cell Signal 1993; 5:33-9. [PMID: 7680878 DOI: 10.1016/0898-6568(93)90005-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Covalent modification of arginine residues with phenylglyoxal and lysine residues with 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene (DIDS) was carried out in preparations of rat cerebellar microsomes, as was the interaction of silver ions (silver nitrate) with cysteine residues. The effects of these amino acid-reactive agents on [3H]inositol 1,4,5-trisphosphate (InsP3) binding and InsP3-induced calcium release were assessed. Both phenylglyoxal and DIDS inhibited [3H]InsP3 binding and InsP3-induced calcium release (IC50 = 2.0 mM and 18 microM, respectively). Silver ions inhibited InsP3-induced Ca2+ release alone (IC50 approximately 1 microM). These results suggest that arginine and lysine residues may be located at or close to the InsP3 binding site of the InsP3 receptor, while cysteine residues are important in channel opening.
Collapse
Affiliation(s)
- F Michelangeli
- School of Biochemistry, University of Birmingham, Edgbaston, U.K
| |
Collapse
|
34
|
Johnson RJ, Pyun HY, Lytton J, Fine RE. Differences in the subcellular localization of calreticulin and organellar Ca(2+)-ATPase in neurons. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1993; 17:9-16. [PMID: 8381914 DOI: 10.1016/0169-328x(93)90066-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
It has become clear that calcium is an important mediator in the transduction of signals due to ligand binding to cell surface receptors. Cytosolic calcium is typically maintained at low levels in both muscle and non-muscle cells and intracellular sequestering of calcium appears to be important in this process. The identification of intracellular calcium pools has been the subject of much recent study, and it has been proposed that such pools would contain three components: a calcium-activated pump or Ca(2+)-ATPase, a calcium channel such as the inositol trisphosphate receptor or ryanodine receptor, and a high-capacity calcium-binding protein such as calsequestrin or calreticulin. We report here on the localization of two components, the organellar Ca(2+)-ATPase (SERCA) and calreticulin, in neuronal tissues. Using immunofluorescence and subcellular fractionation, we have found that for the most part, these two proteins do not co-localize in neuron cell bodies, dendrites, or axons; but may co-localize at the axon terminal.
Collapse
Affiliation(s)
- R J Johnson
- Biochemistry Department, Boston University School of Medicine, MA 02118
| | | | | | | |
Collapse
|
35
|
Kuwajima G, Futatsugi A, Niinobe M, Nakanishi S, Mikoshiba K. Two types of ryanodine receptors in mouse brain: skeletal muscle type exclusively in Purkinje cells and cardiac muscle type in various neurons. Neuron 1992; 9:1133-42. [PMID: 1334420 DOI: 10.1016/0896-6273(92)90071-k] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two types of ryanodine receptors, channels for Ca2+ release from intracellular stores, are known. We detected the skeletal muscle type only in cerebellum by immunoblot analysis of microsomes and partially purified proteins. The cardiac muscle type was found in all parts of the mouse brain. Immunohistochemical study showed that the cardiac muscle type was localized mainly at the somata of most neurons. Analysis of mutant cerebella suggested that the skeletal muscle type was present exclusively in Purkinje cells. These results suggest that Ca(2+)-induced Ca2+ release, probably mediated by the cardiac muscle receptor, functions generally in various neurons, whereas depolarization-induced Ca2+ release, probably mediated by the skeletal muscle receptor, functions specifically in Purkinje cells.
Collapse
Affiliation(s)
- G Kuwajima
- Shionogi Institute for Medical Science, Osaka, Japan
| | | | | | | | | |
Collapse
|
36
|
Cataldi de Flombaum MA, Stoppani AO. High-affinity calcium-stimulated, magnesium-dependent adenosine triphosphatase in Trypanosoma cruzi. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1992; 103:933-7. [PMID: 1478071 DOI: 10.1016/0305-0491(92)90218-g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. A high-affinity (Ca2+ + Mg2+)-ATPase and a low-affinity Mg(2+)-ATPase were identified in the 105,000 g fraction from epimastigote forms of Trypanosoma cruzi, the agent of Chagas' disease (Tulahuen strain). 2. Activities were conserved after enzyme solubilization with deoxycholate. 3. The Ca(2+)-stimulated ATPase activity was (a) lower than that of the Mg(2+)-ATPase; (b) inhibited by p-chloromercurobenzoate and orthovanadate and (c) insensitive to oligomycin. 4. Optimal stimulation by Ca2+ was observed at pH 6.5-6.8 in the presence of 1 mM MgCl2 and 0.1 M KCl. 5. The Mg(2+)-ATPase was insensitive to p-chloromercurobenzoate and orthovanadate and did not require KCl for activity. 6. Kinetic analysis of the (Ca2+ + Mg2+)-ATPase yielded a half-maximal stimulating concentration of 1.1 microM for Ca2+ and a Km of 66 microM for ATP. 7. The (Ca2+ + Mg2+)-ATPase clearly differed from the Ca(2+)- or Mg(2+)-ATPases previously characterized in the same strain of T. cruzi (Frasch et al., 1978; Comp. Biochem. Physiol. 60B, 271-275).
Collapse
|
37
|
Villa A, Sharp AH, Racchetti G, Podini P, Bole DG, Dunn WA, Pozzan T, Snyder SH, Meldolesi J. The endoplasmic reticulum of Purkinje neuron body and dendrites: molecular identity and specializations for Ca2+ transport. Neuroscience 1992; 49:467-77. [PMID: 1331857 DOI: 10.1016/0306-4522(92)90111-e] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Immunofluorescence and immunogold labeling, together with sucrose gradient separation and Western blot analysis of microsomal subfractions, were employed in parallel to probe the endoplasmic reticulum in the cell body and dendrites of rat cerebellar Purkinje neurons. Two markers, previously investigated in non-nerve cells, the membrane protein p91 (calnexin) and the lumenal protein BiP, were found to be highly expressed and widely distributed to the various endoplasmic reticulum sections of Purkinje neurons, from the cell body to dendrites and dendritic spines. An antibody (denominated anti-rough-surfaced endoplasmic reticulum), which recognized two membrane proteins, p14 and p40, revealed a similar immunogold labeling pattern. However, centrifugation results consistent with a widespread distribution were obtained for p14 only, while p40 was concentrated in the rough microsome-enriched subfractions. The areas enriched in the inositol 1,4,5-triphosphate receptor and thus presumably specialized in Ca2+ transport (stacks of multiple smooth-surfaced cisternae; the dendritic spine apparatus) also exhibited labeling for BiP and p91, and were positive for the anti-rough-surfaced endoplasmic reticulum antibody (presumably via the p14 antigen). Additional antibodies, that yielded inadequate immunocytochemical signals, were employed only by Western blotting of the microsomal subfractions, while the ryanodine receptor was studied by specific binding. The latter receptor and the Ca2+ ATPase, known in other species to be concentrated in Purkinje neurons, exhibited bimodal distributions with a peak in the light and another in the heavy subfractions. A similar distribution was also observed with another lumenal protein, protein disulfide isomerase. Taken as a whole, the results that we have obtained suggest the existence in the endoplasmic reticulum of Purkinje neurons of two levels of organization; the first identified by widespread, probably general markers (BiP, p91, possibly p14 and others), the second by specialization markers, such as the inositol 1,4,5-triphosphate receptor and, possibly, p40, which appear restricted to areas where specific functions appear to be localized.
Collapse
Affiliation(s)
- A Villa
- Department of Pharmacology, CNR Cytopharmacology and B. Ceccarelli Centers, S. Raffaele Scientific Institute, Milano, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Brown GR, Sayers LG, Kirk CJ, Michell RH, Michelangeli F. The opening of the inositol 1,4,5-trisphosphate-sensitive Ca2+ channel in rat cerebellum is inhibited by caffeine. Biochem J 1992; 282 ( Pt 2):309-12. [PMID: 1312323 PMCID: PMC1130779 DOI: 10.1042/bj2820309] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ins(1,4,5)P3(InsP3)-induced Ca2+ release and [3H]InsP3 binding were measured in rat cerebellar microsomes in the presence or absence of caffeine. The quantal Ca2+ release was shown to occur in an apparently co-operative fashion with a Hill coefficient (h) of 2.2. Half-maximal Ca2+ release was observed at 900 nM-InsP3. Addition of caffeine caused changes both to the concentration of InsP3 required to cause half-maximal Ca2+ release (3.9 microM at 50 mM-caffeine) and to the apparent co-operativity (h = 1.0 at 50 mM-caffeine). Under standard conditions for [3H]InsP3 binding, caffeine had no effect, and it had no effect on InsP3 metabolism. Cyclic AMP also had no effect on the quantal release induced by InsP3. These results are consistent with the view that caffeine affects the opening (Ca2+ release) events rather than the ligand-binding events in the operation of the InsP3-sensitive Ca2+ channel.
Collapse
Affiliation(s)
- G R Brown
- School of Biochemistry, University of Birmingham, Edgbaston, U.K
| | | | | | | | | |
Collapse
|
39
|
Measuring calcium uptake and inositol 1,4,5-trisphosphate-induced calcium release in cerebellum microsomes using Fluo-3. J Fluoresc 1991; 1:203-6. [DOI: 10.1007/bf00865367] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/1991] [Accepted: 10/14/1991] [Indexed: 10/26/2022]
|