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Missiaen L, Waelbroeck C, Pichat S, Jaccard SL, Eynaud F, Greenop R, Burke A. Improving North Atlantic Marine Core Chronologies Using 230Th Normalization. Paleoceanogr Paleoclimatol 2019; 34:1057-1073. [PMID: 31598586 PMCID: PMC6774303 DOI: 10.1029/2018pa003444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 06/10/2023]
Abstract
Producing independent and accurate chronologies for marine sediments is a prerequisite to understand the sequence of millennial-scale events and reveal potential temporal offsets between marine and continental records, or between different marine records, possibly from different regions. The last 40 ky is a generally well-constrained period since radiocarbon (14C) can be used as an absolute dating tool. However, in the northern North Atlantic, calendar ages cannot be directly derived from 14C ages, due to temporal and spatial variations of surface reservoir ages. Alternatively, chronologies can be derived by aligning Greenland ice-core time series with marine surface records. Yet this approach suffers from the lack of clearly defined climatic events between 14.7 and 23.3 cal ky BP (hereafter ka), a crucial period encompassing Heinrich Stadial 1 and the onset of the last deglaciation. In this study, (i) we assess the benefits of 230Th normalization to refine the sedimentation history between surface temperature alignment tie points and (ii) revisit the chronologies of three North Atlantic marine records. Our study supports the contention that the marked increase in the Greenland Ca2+ record at 17.48 ka ± 0.21 ky (1σ) occurred within dating uncertainty of sea surface temperature cooling in the North Atlantic at the onset of Heinrich Stadial 1. This sharp feature might be useful for future chronostratigraphic alignments to remedy the lack of chronological constraint between 14.7 and 23.3 ka for North Atlantic marine records that are subject to large changes in 14C surface reservoir age.
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Affiliation(s)
- L. Missiaen
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQ‐Université Paris SaclayGif‐sur‐YvetteFrance
- Climate Change Research CentreUniversity of New South WalesSydneyNew South WalesAustralia
| | - C. Waelbroeck
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQ‐Université Paris SaclayGif‐sur‐YvetteFrance
| | - S. Pichat
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQ‐Université Paris SaclayGif‐sur‐YvetteFrance
- Université de Lyon, ENS de Lyon, Laboratoire de Géologie de Lyon (LGL‐TPE)LyonFrance
- Climate Geochemistry DepartmentMax Planck Institute for ChemistryMainzGermany
| | - S. L. Jaccard
- Institute of Geological Sciences and Oeschger Center for Climate Change ResearchUniversity of BernBernSwitzerland
| | - F. Eynaud
- Université de Bordeaux, UMR EPOC 5805PessacFrance
| | - R. Greenop
- School of Earth and Environmental Science, Irvine BuildingUniversity of St AndrewsSt AndrewsUnited Kingdom
| | - A. Burke
- School of Earth and Environmental Science, Irvine BuildingUniversity of St AndrewsSt AndrewsUnited Kingdom
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Bijnens J, Missiaen L, Bultynck G, Parys JB. A critical appraisal of the role of intracellular Ca 2+-signaling pathways in Kawasaki disease. Cell Calcium 2018; 71:95-103. [PMID: 29604968 DOI: 10.1016/j.ceca.2018.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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: 01/08/2018] [Accepted: 01/20/2018] [Indexed: 12/31/2022]
Abstract
Kawasaki disease is a multi-systemic vasculitis that generally occurs in children and that can lead to coronary artery lesions. Recent studies showed that Kawasaki disease has an important genetic component. In this review, we discuss the single-nucleotide polymorphisms in the genes encoding proteins with a role in intracellular Ca2+ signaling: inositol 1,4,5-trisphosphate 3-kinase C, caspase-3, the store-operated Ca2+-entry channel ORAI1, the type-3 inositol 1,4,5-trisphosphate receptor, the Na+/Ca2+ exchanger 1, and phospholipase Cß4 and Cß1. An increase of the free cytosolic Ca2+ concentration is proposed to be a major factor in susceptibility to Kawasaki disease and disease outcome, but only for polymorphisms in the genes encoding the inositol 1,4,5-trisphosphate 3-kinase C and the Na+/Ca2+ exchanger 1, the free cytosolic Ca2+ concentration was actually measured and shown to be increased. Excessive cytosolic Ca2+ signaling can result in hyperactive calcineurin in T cells with an overstimulated nuclear factor of activated T cells pathway, in hypersecretion of interleukin-1ß and tumor necrosis factor-α by monocytes/macrophages, in increased urotensin-2 signaling, and in an overactivation of vascular endothelial cells.
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Affiliation(s)
- Jeroen Bijnens
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, B-3000 Leuven, Belgium.
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3
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Ivanova EA, Elmonem MA, Bongaerts I, Luyten T, Missiaen L, van den Heuvel LP, Levtchenko EN, Bultynck G. Ca(2+) signalling in human proximal tubular epithelial cells deficient for cystinosin. Cell Calcium 2016; 60:282-7. [PMID: 27451386 DOI: 10.1016/j.ceca.2016.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/03/2016] [Indexed: 11/17/2022]
Abstract
Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder caused by loss-of-function mutations in the CTNS gene coding for the lysosomal cystine transporter, cystinosin. Recent studies have demonstrated that, apart from cystine accumulation in the lysosomes, cystinosin-deficient cells, especially renal proximal tubular epithelial cells are characterized by abnormal vesicle trafficking and endocytosis, possible lysosomal dysfunction and perturbed intracellular signalling cascades. It is therefore possible that Ca(2+) signalling is disturbed in cystinosis, as it has been demonstrated for other disorders associated with lysosomal dysfunction, such as Gaucher, Niemann-Pick type C and Alzheimer's diseases. In this study we investigated ATP-induced, IP3-induced and lysosomal Ca(2+) release in human proximal tubular epithelial cells derived from control and cystinotic patients. No major dysregulation of intracellular Ca(2+) dynamics was found, although ATP-induced Ca(2+) release appeared slightly sensitized in cystinotic cells compared to control cells. Hence, these subtle changes in Ca(2+) signals elicited by agonists may contribute to the pathogenesis of the disease.
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Affiliation(s)
- Ekaterina A Ivanova
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Mohamed A Elmonem
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium; Cairo University, Faculty of Medicine, Department of Clinical and Chemical Pathology, Cairo, Egypt.
| | - Inge Bongaerts
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Tomas Luyten
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Lambertus P van den Heuvel
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium; Radboud University Medical Center, Department of Pediatric Nephrology, Nijmegen, The Netherlands
| | - Elena N Levtchenko
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
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Ivanova EA, van den Heuvel LP, Elmonem MA, De Smedt H, Missiaen L, Pastore A, Mekahli D, Bultynck G, Levtchenko EN. Altered mTOR signalling in nephropathic cystinosis. J Inherit Metab Dis 2016; 39:457-464. [PMID: 26909499 DOI: 10.1007/s10545-016-9919-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/22/2016] [Accepted: 02/02/2016] [Indexed: 11/27/2022]
Abstract
Lysosomes play a central role in regulating autophagy via activation of mammalian target of rapamycin complex 1 (mTORC1). We examined mTORC1 signalling in the lysosomal storage disease nephropathic cystinosis (MIM 219800), in which accumulation of autophagy markers has been previously demonstrated. Cystinosis is caused by mutations in the lysosomal cystine transporter cystinosin and initially affects kidney proximal tubules causing renal Fanconi syndrome, followed by a gradual development of end-stage renal disease and extrarenal complications. Using proximal tubular kidney cells obtained from healthy donors and from cystinotic patients, we demonstrate that cystinosin deficiency is associated with a perturbed mTORC1 signalling, delayed reactivation of mTORC1 after starvation and abnormal lysosomal retention of mTOR during starvation. These effects could not be reversed by treatment with cystine-depleting drug cysteamine. Altered mTORC1 signalling can contribute to the development of proximal tubular dysfunction in cystinosis and points to new possibilities in therapeutic intervention through modulation of mTORC-dependent signalling cascades.
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Affiliation(s)
- Ekaterina A Ivanova
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Lambertus P van den Heuvel
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Pediatric Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mohamed A Elmonem
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Anna Pastore
- Laboratory of Proteomics and Metabolomics, Children's Hospital and Research Institute "Bambino Gesù" IRCCS, Rome, Italy
| | - Djalila Mekahli
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Greet Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Elena N Levtchenko
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium.
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Ivanova H, Vervliet T, Missiaen L, Parys JB, De Smedt H, Bultynck G. Inositol 1,4,5-trisphosphate receptor-isoform diversity in cell death and survival. Biochim Biophys Acta 2014; 1843:2164-83. [PMID: 24642269 DOI: 10.1016/j.bbamcr.2014.03.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/06/2014] [Accepted: 03/09/2014] [Indexed: 01/22/2023]
Abstract
Cell-death and -survival decisions are critically controlled by intracellular Ca(2+) homeostasis and dynamics at the level of the endoplasmic reticulum (ER). Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) play a pivotal role in these processes by mediating Ca(2+) flux from the ER into the cytosol and mitochondria. Hence, it is clear that many pro-survival and pro-death signaling pathways and proteins affect Ca(2+) signaling by directly targeting IP3R channels, which can happen in an IP3R-isoform-dependent manner. In this review, we will focus on how the different IP3R isoforms (IP3R1, IP3R2 and IP3R3) control cell death and survival. First, we will present an overview of the isoform-specific regulation of IP3Rs by cellular factors like IP3, Ca(2+), Ca(2+)-binding proteins, adenosine triphosphate (ATP), thiol modification, phosphorylation and interacting proteins, and of IP3R-isoform specific expression patterns. Second, we will discuss the role of the ER as a Ca(2+) store in cell death and survival and how IP3Rs and pro-survival/pro-death proteins can modulate the basal ER Ca(2+) leak. Third, we will review the regulation of the Ca(2+)-flux properties of the IP3R isoforms by the ER-resident and by the cytoplasmic proteins involved in cell death and survival as well as by redox regulation. Hence, we aim to highlight the specific roles of the various IP3R isoforms in cell-death and -survival signaling. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Hristina Ivanova
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Tim Vervliet
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Geert Bultynck
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
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Luyten T, Bultynck G, Parys JB, De Smedt H, Missiaen L. Measurement of intracellular Ca2+ release in permeabilized cells using 45Ca2+. Cold Spring Harb Protoc 2014; 2014:289-294. [PMID: 24591686 DOI: 10.1101/pdb.prot073189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This protocol describes a technique to measure Ca(2+) release from the nonmitochondrial intracellular Ca(2+) stores in monolayers of saponin-permeabilized cells cultured in 12-well 4-cm(2) clusters. The (45)Ca(2+)-flux technique described here can only be applied to cell types that still adhere to the plastic after exposing them to saponin. We describe the permeabilization procedure, the loading of the nonmitochondrial Ca(2+) stores with (45)Ca(2+), and the subsequent (45)Ca(2+) efflux.
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Affiliation(s)
- Tomas Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven Campus Gasthuisberg O&N I, 3000 Leuven, Belgium
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Missiaen L, Luyten T, Bultynck G, Parys JB, De Smedt H. Measurement of intracellular Ca2+ release in intact and permeabilized cells using 45Ca2+. Cold Spring Harb Protoc 2014; 2014:263-270. [PMID: 24591684 DOI: 10.1101/pdb.top066126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ca(2+) is an important ion that controls almost every function in a cell. Activator Ca(2+) can be released from intracellular Ca(2+) stores, and there are various ways to study this release. Here, we introduce a technique that uses radioactive (45)Ca(2+) to quantitatively measure the unidirectional release of Ca(2+) from the nonmitochondrial Ca(2+) stores in monolayers of cultured cells. This technique can be used in cells with an intact plasma membrane as well as in cells in which the plasma membrane has been permeabilized.
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Affiliation(s)
- Ludwig Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven Campus Gasthuisberg O&N I, 3000 Leuven, Belgium
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Luyten T, Bultynck G, Parys JB, De Smedt H, Missiaen L. Measurement of intracellular Ca2+ release in intact cells using 45Ca2+. Cold Spring Harb Protoc 2014; 2014:284-8. [PMID: 24591687 DOI: 10.1101/pdb.prot073197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This protocol describes a technique using (45)Ca(2+) to measure the release of Ca(2+) from the intracellular stores in monolayers of intact cells cultured in 12-well 4-cm(2) clusters. The (45)Ca(2+)-flux technique described here can only be applied to cell types that adhere to plastic. We describe the loading of the stores with (45)Ca(2+), and the subsequent (45)Ca(2+) efflux.
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Affiliation(s)
- Tomas Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven Campus Gasthuisberg O&N I, 3000 Leuven, Belgium
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Vervliet T, Decrock E, Molgó J, Sorrentino V, Missiaen L, Leybaert L, De Smedt H, Kasri NN, Parys JB, Bultynck G. Bcl-2 binds to and inhibits ryanodine receptors. J Cell Sci 2014; 127:2782-92. [DOI: 10.1242/jcs.150011] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein not only counteracts apoptosis at the mitochondria by scaffolding pro-apoptotic Bcl-2-family members, but also acts at the endoplasmic reticulum, thereby controlling intracellular Ca2+ dynamics. Bcl-2 inhibits Ca2+ release by targeting the inositol 1,4,5-trisphosphate receptor (IP3R). Sequence analysis revealed that the Bcl-2-binding site on the IP3R displays strong homology with a conserved sequence present in all three ryanodine-receptor (RyR) isoforms. We now report that, Bcl-2 co-immunoprecipitated with RyRs in ectopic expression systems and in native rat hippocampi, indicating the existence of endogenous RyR/Bcl-2 complexes. Purified RyR domains containing the putative Bcl-2-binding site bound full-length Bcl-2 in pull-down experiments and interacted with Bcl-2's BH4 domain in surface-plasmon-resonance experiments, suggesting a direct interaction. Exogenous expression of full-length Bcl-2 or electroporation loading of Bcl-2's BH4-domain dampened RyR-mediated Ca2+ release in HEK293 cell models. Finally, introducing the BH4-domain peptide into hippocampal neurons via a patch pipette decreased RyR-mediated Ca2+ release. In conclusion, this study identifies Bcl-2 as a novel inhibitor of RyR-based intracellular Ca2+-release channels.
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Mekahli D, Decuypere JP, Sammels E, Welkenhuyzen K, Schoeber J, Audrezet MP, Corvelyn A, Dechênes G, Ong ACM, Wilmer MJ, van den Heuvel L, Bultynck G, Parys JB, Missiaen L, Levtchenko E, De Smedt H. Polycystin-1 but not polycystin-2 deficiency causes upregulation of the mTOR pathway and can be synergistically targeted with rapamycin and metformin. Pflugers Arch 2013; 466:1591-604. [PMID: 24193408 DOI: 10.1007/s00424-013-1394-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 09/30/2013] [Accepted: 10/21/2013] [Indexed: 12/22/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is caused by loss-of-function mutations in either PKD1 or PKD2 genes, which encode polycystin-1 (TRPP1) and polycystin-2 (TRPP2), respectively. Increased activity of the mammalian target of rapamycin (mTOR) pathway has been shown in PKD1 mutants but is less documented for PKD2 mutants. Clinical trials using mTOR inhibitors were disappointing, while the AMP-activated kinase (AMPK) activator, metformin is not yet tested in patients. Here, we studied the mTOR activity and its upstream pathways in several human and mouse renal cell models with either siRNA or stable knockdown and with overexpression of TRPP2. Our data reveal for the first time differences between TRPP1 and TRPP2 deficiency. In contrast to TRPP1 deficiency, TRPP2-deficient cells did neither display excessive activation of the mTOR-kinase complex nor inhibition of AMPK activity, while ERK1/2 and Akt activity were similarly affected among TRPP1- and TRPP2-deficient cells. Furthermore, cell proliferation was more pronounced in TRPP1 than in TRPP2-deficient cells. Interestingly, combining low concentrations of rapamycin and metformin was more effective for inhibiting mTOR complex 1 activity in TRPP1-deficient cells than either drug alone. Our results demonstrate a synergistic effect of a combination of low concentrations of drugs suppressing the increased mTOR activity in TRPP1-deficient cells. This novel insight can be exploited in future clinical trials to optimize the efficiency and avoiding side effects of drugs in the treatment of ADPKD patients with PKD1 mutations. Furthermore, as TRPP2 deficiency by itself did not affect mTOR signaling, this may underlie the differences in phenotype, and genetic testing has to be considered for selecting patients for the ongoing trials.
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Affiliation(s)
- Djalila Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O&N I, Leuven, Belgium,
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Monaco G, Decrock E, Nuyts K, Wagner II LE, Luyten T, Strelkov SV, Missiaen L, De Borggraeve WM, Leybaert L, Yule DI, De Smedt H, Parys JB, Bultynck G. Alpha-helical destabilization of the Bcl-2-BH4-domain peptide abolishes its ability to inhibit the IP3 receptor. PLoS One 2013; 8:e73386. [PMID: 24137498 PMCID: PMC3795776 DOI: 10.1371/journal.pone.0073386] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [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: 01/16/2013] [Accepted: 07/22/2013] [Indexed: 01/11/2023] Open
Abstract
The anti-apoptotic Bcl-2 protein is the founding member and namesake of the Bcl-2-protein family. It has recently been demonstrated that Bcl-2, apart from its anti-apoptotic role at mitochondrial membranes, can also directly interact with the inositol 1,4,5-trisphosphate receptor (IP3R), the primary Ca(2+)-release channel in the endoplasmic reticulum (ER). Bcl-2 can thereby reduce pro-apoptotic IP3R-mediated Ca(2+) release from the ER. Moreover, the Bcl-2 homology domain 4 (Bcl-2-BH4) has been identified as essential and sufficient for this IP3R-mediated anti-apoptotic activity. In the present study, we investigated whether the reported inhibitory effect of a Bcl-2-BH4 peptide on the IP 3R1 was related to the distinctive α-helical conformation of the BH4 domain peptide. We therefore designed a peptide with two glycine "hinges" replacing residues I14 and V15, of the wild-type Bcl-2-BH4 domain (Bcl-2-BH4-IV/GG). By comparing the structural and functional properties of the Bcl-2-BH4-IV/GG peptide with its native counterpart, we found that the variant contained reduced α-helicity, neither bound nor inhibited the IP 3R1 channel, and in turn lost its anti-apoptotic effect. Similar results were obtained with other substitutions in Bcl-2-BH4 that destabilized the α-helix with concomitant loss of IP3R inhibition. These results provide new insights for the further development of Bcl-2-BH4-derived peptides as specific inhibitors of the IP3R with significant pharmacological implications.
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Affiliation(s)
- Giovanni Monaco
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
- * E-mail: (GB); (GM)
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Koen Nuyts
- Section of Molecular Design and Synthesis, Department of Chemistry, Heverlee, Belgium
| | - Larry E. Wagner II
- Department of Pharmacology & Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Tomas Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Wim M. De Borggraeve
- Section of Molecular Design and Synthesis, Department of Chemistry, Heverlee, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - David I. Yule
- Department of Pharmacology & Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
- * E-mail: (GB); (GM)
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Akl H, Monaco G, La Rovere R, Welkenhuyzen K, Kiviluoto S, Vervliet T, Molgó J, Distelhorst CW, Missiaen L, Mikoshiba K, Parys JB, De Smedt H, Bultynck G. IP3R2 levels dictate the apoptotic sensitivity of diffuse large B-cell lymphoma cells to an IP3R-derived peptide targeting the BH4 domain of Bcl-2. Cell Death Dis 2013; 4:e632. [PMID: 23681227 PMCID: PMC3674349 DOI: 10.1038/cddis.2013.140] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [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] [Indexed: 01/01/2023]
Abstract
Disrupting inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)/B-cell lymphoma 2 (Bcl-2) complexes using a cell-permeable peptide (stabilized TAT-fused IP3R-derived peptide (TAT-IDPS)) that selectively targets the BH4 domain of Bcl-2 but not that of B-cell lymphoma 2-extra large (Bcl-Xl) potentiated pro-apoptotic Ca2+ signaling in chronic lymphocytic leukemia cells. However, the molecular mechanisms rendering cancer cells but not normal cells particularly sensitive to disrupting IP3R/Bcl-2 complexes are poorly understood. Therefore, we studied the effect of TAT-IDPS in a more heterogeneous Bcl-2-dependent cancer model using a set of ‘primed to death' diffuse large B-cell lymphoma (DL-BCL) cell lines containing elevated Bcl-2 levels. We discovered a large heterogeneity in the apoptotic responses of these cells to TAT-IDPS with SU-DHL-4 being most sensitive and OCI-LY-1 being most resistant. This sensitivity strongly correlated with the ability of TAT-IDPS to promote IP3R-mediated Ca2+ release. Although total IP3R-expression levels were very similar among SU-DHL-4 and OCI-LY-1, we discovered that the IP3R2-protein level was the highest for SU-DHL-4 and the lowest for OCI-LY-1. Strikingly, TAT-IDPS-induced Ca2+ rise and apoptosis in the different DL-BCL cell lines strongly correlated with their IP3R2-protein level, but not with IP3R1-, IP3R3- or total IP3R-expression levels. Inhibiting or knocking down IP3R2 activity in SU-DHL-4-reduced TAT-IDPS-induced apoptosis, which is compatible with its ability to dissociate Bcl-2 from IP3R2 and to promote IP3-induced pro-apoptotic Ca2+ signaling. Thus, certain chronically activated B-cell lymphoma cells are addicted to high Bcl-2 levels for their survival not only to neutralize pro-apoptotic Bcl-2-family members but also to suppress IP3R hyperactivity. In particular, cancer cells expressing high levels of IP3R2 are addicted to IP3R/Bcl-2 complex formation and disruption of these complexes using peptide tools results in pro-apoptotic Ca2+ signaling and cell death.
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Affiliation(s)
- H Akl
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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Tsuchiya K, Shiohira S, Sugiura H, Suzuki M, Okano K, Nitta K, Kaesler N, Immendorf S, Ouyang C, Carmeliet P, Floege J, Kruger T, Schlieper G, Georgescu A, Kalucka J, Olbrich S, Baumgartl J, Hackenbeck T, Eckardt KU, Weidemann A, Chmielewski S, Olejnik A, Sikorski K, Heemann U, Wesoly J, Bluyssen H, Baumann M, Mekahli D, Decuypere JP, Missiaen L, Levtchenko E, De Smedt H, Stasi A, Castellano G, Gigante M, Intini A, Pontrelli P, Divella C, Curci C, Grandaliano G, Gesualdo L, Vizza D, Perri A, Lofaro D, Toteda P, Lupinacci S, Leone F, Gigliotti P, Papalia T, Bonofiglio R, Vatazin AV, Astakhov PV, Zulkarnaev AB, Parodi E, Verzola D, D'Amato E, Viazzi F, Gonnella A, Garneri D, Pontremoli R, Garibotto G, Chen TH, Chen CH, Chen YC, Sue YM, Cheng CY, Guiying L, Ying L, Pozzoli S, Lino M, Delli Carpini S, Ferrandi M, Zerbini G, Simonini M, Zagato L, Molinari I, Citterio L, Manunta P, Feng X, Pan X, Wang W, Chen N, Chen YX, Wang WM, Chen N, Tanaka S, Yano S, Sugimoto T, Noh H, Yu MR, Kim HJ, Woo SA, Cho YJ, Kwon SH, Jeon JS, Han DC, Shimizu H, Yisireyili M, Nishijima F, Niwa T, Koh ES, Chung S, Kim SJ, Kim SJ, Yoon HE, Park CW, Chang YS, Shin SJ, Seong EY, Rhee H, Shin MJ, Yang BY, Jung YS, Lee DW, Lee SB, Kwak IS, Kim IY, Sancho-Martinez SM, Prieto-Garcia L, Lopez-Hernandez FJ, Lopez-Novoa JM, Bae EH, Choi HS, Joo SY, Kim IJ, Kim CS, Choi JS, Ma SK, Lee J, Kim SW, Humanes B, Sonia C, Jado J, Mojena M, Lara J, Alvarez-Sala L, Tejedor A, Lazaro A, Wada Y, Iyoda M, Matsumoto K, Shindo-Hirai Y, Kuno Y, Yamamoto Y, Suzuki T, Shibata T, Akizawa T, Lee DW, Kwak IS, Lee SB, Seong EY, Faubel S, Edelstein CL, Cano Penalver JL, de Frutos Garcia S, Griera Merino M, Luengo Rodriguez A, Garcia Jerez A, Bohorquez Magro L, Medrano D, Calleros Basilio L, Rodriguez Puyol M, Prieto-Garcia L, Sancho-Martinez SM, Lopez-Hernandez FJ, Lopez-Novoa JM, Thilo F, Liu Y, Tepel M, Hsu HH, Chen KH, Hung CC, Yang CW, Endlich N, Lin JL, Pavenstadt H, Rodrigues Diez RR, Mezzano S, Ruiz-Ortega M, Rodrigues Diez R, Lavoz C, Nakayama Y, Fukami K, Yamagishi SI, Obara N, Yokoro M, Ando R, Kaida Y, Toyonaga M, Kaifu K, Takeuchi M, Ueda S, Okuda S, Daenen K, Hoylaerts MF, Bammens B, Liu J, Zhong F, Dai Q, Xu L, Wang W, Chen N, Zaravinos A, Deltas CC. Cell signalling. Nephrol Dial Transplant 2013. [DOI: 10.1093/ndt/gft125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Decuypere JP, Kindt D, Luyten T, Welkenhuyzen K, Missiaen L, De Smedt H, Bultynck G, Parys JB. mTOR-Controlled Autophagy Requires Intracellular Ca(2+) Signaling. PLoS One 2013; 8:e61020. [PMID: 23565295 PMCID: PMC3614970 DOI: 10.1371/journal.pone.0061020] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [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: 11/22/2012] [Accepted: 03/05/2013] [Indexed: 11/17/2022] Open
Abstract
Autophagy is a lysosomal degradation pathway important for cellular homeostasis and survival. Inhibition of the mammalian target of rapamycin (mTOR) is the best known trigger for autophagy stimulation. In addition, intracellular Ca2+ regulates autophagy, but its exact role remains ambiguous. Here, we report that the mTOR inhibitor rapamycin, while enhancing autophagy, also remodeled the intracellular Ca2+-signaling machinery. These alterations include a) an increase in the endoplasmic-reticulum (ER) Ca2+-store content, b) a decrease in the ER Ca2+-leak rate, and c) an increased Ca2+ release through the inositol 1,4,5-trisphosphate receptors (IP3Rs), the main ER-resident Ca2+-release channels. Importantly, buffering cytosolic Ca2+ with BAPTA impeded rapamycin-induced autophagy. These results reveal intracellular Ca2+ signaling as a crucial component in the canonical mTOR-dependent autophagy pathway.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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Monaco G, Beckers M, Ivanova H, Missiaen L, Parys JB, De Smedt H, Bultynck G. Profiling of the Bcl-2/Bcl-XL-binding sites on type 1 IP3 receptor. Biochem Biophys Res Commun 2012; 428:31-5. [DOI: 10.1016/j.bbrc.2012.10.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/01/2012] [Indexed: 02/04/2023]
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Mekahli D, Parys JB, Bultynck G, Missiaen L, De Smedt H. Polycystins and cellular Ca2+ signaling. Cell Mol Life Sci 2012; 70:2697-712. [PMID: 23076254 PMCID: PMC3708286 DOI: 10.1007/s00018-012-1188-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [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: 08/22/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022]
Abstract
The cystic phenotype in autosomal dominant polycystic kidney disease is characterized by a profound dysfunction of many cellular signaling patterns, ultimately leading to an increase in both cell proliferation and apoptotic cell death. Disturbance of normal cellular Ca2+ signaling seems to be a primary event and is clearly involved in many pathways that may lead to both types of cellular responses. In this review, we summarize the current knowledge about the molecular and functional interactions between polycystins and multiple components of the cellular Ca2+-signaling machinery. In addition, we discuss the relevant downstream responses of the changed Ca2+ signaling that ultimately lead to increased proliferation and increased apoptosis as observed in many cystic cell types.
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Affiliation(s)
- D. Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - G. Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - L. Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
| | - H. De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, B-802, Herestraat 49, 3000 Leuven, Belgium
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Kiviluoto S, Schneider L, Luyten T, Vervliet T, Missiaen L, De Smedt H, Parys JB, Methner A, Bultynck G. Bax inhibitor-1 is a novel IP₃ receptor-interacting and -sensitizing protein. Cell Death Dis 2012; 3:e367. [PMID: 22875004 PMCID: PMC3434651 DOI: 10.1038/cddis.2012.103] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Decuypere JP, Welkenhuyzen K, Luyten T, Ponsaerts R, Dewaele M, Molgó J, Agostinis P, Missiaen L, De Smedt H, Parys JB, Bultynck G. Ins(1,4,5)P3 receptor-mediated Ca2+ signaling and autophagy induction are interrelated. Autophagy 2012; 7:1472-89. [PMID: 22082873 DOI: 10.4161/auto.7.12.17909] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The role of intracellular Ca2+ signaling in starvation-induced autophagy remains unclear. Here, we examined Ca2+ dynamics during starvation-induced autophagy and the underlying molecular mechanisms. Tightly correlating with autophagy stimulation, we observed a remodeling of the Ca2+ signalosome. First, short periods of starvation (1 to 3 h) caused a prominent increase of the ER Ca2+-store content and enhanced agonist-induced Ca2+ release. The mechanism involved the upregulation of intralumenal ER Ca2+-binding proteins, calreticulin and Grp78/BiP, which increased the ER Ca2+-buffering capacity and reduced the ER Ca2+ leak. Second, starvation led to Ins(1,4,5)P3R sensitization. Immunoprecipitation experiments showed that during starvation Beclin 1, released from Bcl-2, first bound with increasing efficiency to Ins(1,4,5)P3Rs; after reaching a maximal binding after 3 h, binding, however, decreased again. The interaction site of Beclin 1 was determined to be present in the N-terminal Ins(1,4,5)P3-binding domain of the Ins(1,4,5)P3R. The starvation-induced Ins(1,4,5)P3R sensitization was abolished in cells treated with BECN1 siRNA, but not with ATG5 siRNA, pointing toward an essential role of Beclin 1 in this process. Moreover, recombinant Beclin 1 sensitized Ins(1,4,5)P3Rs in 45Ca2+-flux assays, indicating a direct regulation of Ins(1,4,5)P3R activity by Beclin 1. Finally, we found that Ins(1,4,5)P3R-mediated Ca2+ signaling was critical for starvation-induced autophagy stimulation, since the Ca2+ chelator BAPTA-AM as well as the Ins(1,4,5)P3R inhibitor xestospongin B abolished the increase in LC3 lipidation and GFP-LC3-puncta formation. Hence, our results indicate a tight and essential interrelation between intracellular Ca2+ signaling and autophagy stimulation as a proximal event in response to starvation.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signaling, Department Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, Leuven, Belgium
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Mekahli D, Sammels E, Luyten T, Welkenhuyzen K, van den Heuvel LP, Levtchenko EN, Gijsbers R, Bultynck G, Parys JB, De Smedt H, Missiaen L. Polycystin-1 and polycystin-2 are both required to amplify inositol-trisphosphate-induced Ca2+ release. Cell Calcium 2012; 51:452-8. [PMID: 22456092 DOI: 10.1016/j.ceca.2012.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/27/2012] [Accepted: 03/02/2012] [Indexed: 12/31/2022]
Abstract
Autosomal dominant polycystic kidney disease is caused by loss-of-function mutations in the PKD1 or PKD2 genes encoding respectively polycystin-1 and polycystin-2. Polycystin-2 stimulates the inositol trisphosphate (IP(3)) receptor (IP(3)R), a Ca(2+)-release channel in the endoplasmic reticulum (ER). The effect of ER-located polycystin-1 is less clear. Polycystin-1 has been reported both to stimulate and to inhibit the IP(3)R. We now studied the effect of polycystin-1 and of polycystin-2 on the IP(3)R activity under conditions where the cytosolic Ca(2+) concentration was kept constant and the reuptake of released Ca(2+) was prevented. We also studied the interdependence of the interaction of polycystin-1 and polycystin-2 with the IP(3)R. The experiments were done in conditionally immortalized human proximal-tubule epithelial cells in which one or both polycystins were knocked down using lentiviral vectors containing miRNA-based short hairpins. The Ca(2+) release was induced in plasma membrane-permeabilized cells by various IP(3) concentrations at a fixed Ca(2+) concentration under unidirectional (45)Ca(2+)-efflux conditions. We now report that knock down of polycystin-1 or of polycystin-2 inhibited the IP(3)-induced Ca(2+) release. The simultaneous presence of the two polycystins was required to fully amplify the IP(3)-induced Ca(2+) release, since the presence of polycystin-1 alone or of polycystin-2 alone did not result in an increased Ca(2+) release. These novel findings indicate that ER-located polycystin-1 and polycystin-2 operate as a functional complex. They are compatible with the view that loss-of-function mutations in PKD1 and in PKD2 both cause autosomal dominant polycystic kidney disease.
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Affiliation(s)
- D Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven Campus Gasthuisberg O&N I, Belgium
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Monaco G, Decrock E, Akl H, Ponsaerts R, Vervliet T, Luyten T, De Maeyer M, Missiaen L, Distelhorst CW, De Smedt H, Parys JB, Leybaert L, Bultynck G. Selective regulation of IP3-receptor-mediated Ca2+ signaling and apoptosis by the BH4 domain of Bcl-2 versus Bcl-Xl. Cell Death Differ 2012; 19:295-309. [PMID: 21818117 PMCID: PMC3263504 DOI: 10.1038/cdd.2011.97] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 05/02/2011] [Accepted: 06/13/2011] [Indexed: 12/11/2022] Open
Abstract
Antiapoptotic B-cell lymphoma 2 (Bcl-2) targets the inositol 1,4,5-trisphosphate receptor (IP(3)R) via its BH4 domain, thereby suppressing IP(3)R Ca(2+)-flux properties and protecting against Ca(2+)-dependent apoptosis. Here, we directly compared IP(3)R inhibition by BH4-Bcl-2 and BH4-Bcl-Xl. In contrast to BH4-Bcl-2, BH4-Bcl-Xl neither bound the modulatory domain of IP(3)R nor inhibited IP(3)-induced Ca(2+) release (IICR) in permeabilized and intact cells. We identified a critical residue in BH4-Bcl-2 (Lys17) not conserved in BH4-Bcl-Xl (Asp11). Changing Lys17 into Asp in BH4-Bcl-2 completely abolished its IP(3)R-binding and -inhibitory properties, whereas changing Asp11 into Lys in BH4-Bcl-Xl induced IP(3)R binding and inhibition. This difference in IP(3)R regulation between BH4-Bcl-2 and BH4-Bcl-Xl controls their antiapoptotic action. Although both BH4-Bcl-2 and BH4-Bcl-Xl had antiapoptotic activity, BH4-Bcl-2 was more potent than BH4-Bcl-Xl. The effect of BH4-Bcl-2, but not of BH4-Bcl-Xl, depended on its binding to IP(3)Rs. In agreement with the IP(3)R-binding properties, the antiapoptotic activity of BH4-Bcl-2 and BH4-Bcl-Xl was modulated by the Lys/Asp substitutions. Changing Lys17 into Asp in full-length Bcl-2 significantly decreased its binding to the IP(3)R, its ability to inhibit IICR and its protection against apoptotic stimuli. A single amino-acid difference between BH4-Bcl-2 and BH4-Bcl-Xl therefore underlies differential regulation of IP(3)Rs and Ca(2+)-driven apoptosis by these functional domains. Mutating this residue affects the function of Bcl-2 in Ca(2+) signaling and apoptosis.
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Affiliation(s)
- G Monaco
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - E Decrock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, BE-9000 Gent, Belgium
| | - H Akl
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - R Ponsaerts
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - T Vervliet
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - T Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - M De Maeyer
- Biomolecular Modelling, Biochemistry, Molecular and Structural Biology Section, Department of Chemistry, Celestijnenlaan 200G bus 2403, BE-3001 Heverlee, Belgium
| | - L Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - C W Distelhorst
- Departments of Medicine and Pharmacology, Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
| | - H De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - J B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - L Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, BE-9000 Gent, Belgium
| | - G Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
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Kiviluoto S, Akl H, Vervliet T, Bultynck G, Parys JB, Missiaen L, De Smedt H. IP3 receptor-binding partners in cell-death mechanisms. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/wmts.5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Szlufcik K, Missiaen L, Parys JB, Callewaert G, De Smedt H. Uncoupled IP3 receptor can function as a Ca2+-leak channel: cell biological and pathological consequences. Biol Cell 2012; 98:1-14. [PMID: 16354157 DOI: 10.1042/bc20050031] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ca(2+) release via intracellular release channels, IP(3)Rs (inositol 1,4,5-trisphosphate receptors) and RyRs (ryanodine receptors), is perhaps the most ubiquitous and versatile cellular signalling mechanism, and is involved in a vast number of cellular processes. In addition to this classical release pathway there is limited, but yet persistent, information about less well-defined Ca(2+)-leak pathways that may play an important role in the control of the Ca(2+) load of the endo(sarco)plasmic reticulum. The mechanisms responsible for this 'basal' leak are not known, but recent data suggest that both IP(3)Rs and RyRs may also operate as Ca(2+)-leak channels, particularly in pathological conditions. Proteolytic cleavage or biochemical modification (such as hyperphosphorylation or nitrosylation), for example, occurring during conditions of cell stress or apoptosis, can functionally uncouple the cytoplasmic control domains from the channel domain of the receptor. Highly significant information has been obtained from studies of malfunctioning channels in various disorders; for example, RyRs in cardiac malfunction or genetic muscle diseases and IP(3)Rs in neurodegenerative diseases. In this review we aim to summarize the existing information about functionally uncoupled IP(3)R and RyR channels, and to discuss the concept that those channels can participate in Ca(2+)-leak pathways.
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Bultynck G, Kiviluoto S, Henke N, Ivanova H, Schneider L, Rybalchenko V, Luyten T, Nuyts K, De Borggraeve W, Bezprozvanny I, Parys JB, De Smedt H, Missiaen L, Methner A. The C terminus of Bax inhibitor-1 forms a Ca2+-permeable channel pore. J Biol Chem 2011; 287:2544-57. [PMID: 22128171 DOI: 10.1074/jbc.m111.275354] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Bax inhibitor-1 (BI-1) is a multitransmembrane domain-spanning endoplasmic reticulum (ER)-located protein that is evolutionarily conserved and protects against apoptosis and ER stress. Furthermore, BI-1 is proposed to modulate ER Ca(2+) homeostasis by acting as a Ca(2+)-leak channel. Based on experimental determination of the BI-1 topology, we propose that its C terminus forms a Ca(2+) pore responsible for its Ca(2+)-leak properties. We utilized a set of C-terminal peptides to screen for Ca(2+) leak activity in unidirectional (45)Ca(2+)-flux experiments and identified an α-helical 20-amino acid peptide causing Ca(2+) leak from the ER. The Ca(2+) leak was independent of endogenous ER Ca(2+)-release channels or other Ca(2+)-leak mechanisms, namely translocons and presenilins. The Ca(2+)-permeating property of the peptide was confirmed in lipid-bilayer experiments. Using mutant peptides, we identified critical residues responsible for the Ca(2+)-leak properties of this BI-1 peptide, including a series of critical negatively charged aspartate residues. Using peptides corresponding to the equivalent BI-1 domain from various organisms, we found that the Ca(2+)-leak properties were conserved among animal, but not plant and yeast orthologs. By mutating one of the critical aspartate residues in the proposed Ca(2+)-channel pore in full-length BI-1, we found that Asp-213 was essential for BI-1-dependent ER Ca(2+) leak. Thus, we elucidated residues critically important for BI-1-mediated Ca(2+) leak and its potential channel pore. Remarkably, one of these residues was not conserved among plant and yeast BI-1 orthologs, indicating that the ER Ca(2+)-leak properties of BI-1 are an added function during evolution.
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Affiliation(s)
- Geert Bultynck
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, K.U. Leuven, B-3000 Leuven, Belgium.
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Temmerman F, Missiaen L, Bammens B, Laleman W, Cassiman D, Verslype C, van Pelt J, Nevens F. Systematic review: the pathophysiology and management of polycystic liver disease. Aliment Pharmacol Ther 2011; 34:702-13. [PMID: 21790682 DOI: 10.1111/j.1365-2036.2011.04783.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Polycystic liver diseases (PCLD) represent a group of genetic disorders in which cysts occur solely in the liver, or together with renal cysts. Most of the patients with PCLD are asymptomatic, however, in some patients, expansion of liver cysts causes invalidating abdominal symptoms. AIM To provide a systemic review on the pathophysiology and management of PCLD. METHODS A PubMed search was undertaken to identify relevant literature using search terms including polycystic liver disease, pathophysiology, surgical and medical management. RESULTS The most common complication in patients with PCLD is extensive hepatomegaly, which may lead to malnutrition and can be lethal. Conservative surgical approaches are only partially effective and do not change the natural course of the disease. Liver transplantation has been successfully performed in PCLD, however, in an era of organ shortage, medical management needs to be evaluated. A better understanding of the pathophysiology and the availability of animal models have already identified promising drugs. Abnormalities in cholangiocyte proliferation/apoptosis and enhanced fluid secretion are key factors in the pathophysiology. It has been demonstrated in rodents and in humans that somatostatin analogues diminish liver volume. The role of the inhibitors of the mammalian target of rapamycin (mTOR) in the management of PCLD is still under investigation. CONCLUSIONS The exact pathophysiology of polycystic liver disease still remains unclear. In symptomatic patients, none of the currently available surgical options except liver transplantation have been shown to change the natural course of the disease. The use of somatostatin analogues has been shown to diminish liver volume.
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Affiliation(s)
- F Temmerman
- Department of Hepatology, UZ Gasthuisberg, K.U. Leuven, Leuven, Belgium
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Decuypere JP, Monaco G, Kiviluoto S, Oh-hora M, Luyten T, De Smedt H, Parys JB, Missiaen L, Bultynck G. STIM1, but not STIM2, is required for proper agonist-induced Ca2+ signaling. Cell Calcium 2011; 48:161-7. [PMID: 20801505 DOI: 10.1016/j.ceca.2010.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 08/02/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
The stromal interaction molecules STIM1 and STIM2 sense a decreasing Ca(2+) concentration in the lumen of the endoplasmic reticulum and activate Ca(2+) channels in the plasma membrane. In addition, at least 2 reports suggested that STIM1 may also interact with the inositol 1,4,5-trisphosphate (IP(3)) receptor. Using embryonic fibroblasts from Stim1(-/-), Stim2(-/-) and wild-type mice, we now tested the hypothesis that STIM1 and STIM2 would also regulate the IP(3) receptor. We investigated whether STIM1 or STIM2 would be the luminal Ca(2+) sensor that controls the loading dependence of the IP(3)-induced Ca(2+) release. Partial emptying of the stores in plasma-membrane permeabilized cells resulted in an increased EC(50) and a decreased Hill coefficient for IP(3)-induced Ca(2+) release. This effect occurred both in the presence and absence of STIM proteins, indicating that these proteins were not the luminal Ca(2+) sensor for the IP(3) receptor. Although Stim1(-/-) cells displayed a normal IP(3)-receptor function, agonist-induced Ca(2+) release was reduced. This finding suggests that the presence of STIM1 is required for proper agonist-induced Ca(2+) signaling. Our data do not provide experimental evidence for the suggestion that STIM proteins would directly control the function of the IP(3) receptor.
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Abstract
The endoplasmic reticulum (ER) as an intracellular Ca(2+) store not only sets up cytosolic Ca(2+) signals, but, among other functions, also assembles and folds newly synthesized proteins. Alterations in ER homeostasis, including severe Ca(2+) depletion, are an upstream event in the pathophysiology of many diseases. On the one hand, insufficient release of activator Ca(2+) may no longer sustain essential cell functions. On the other hand, loss of luminal Ca(2+) causes ER stress and activates an unfolded protein response, which, depending on the duration and severity of the stress, can reestablish normal ER function or lead to cell death. We will review these various diseases by mainly focusing on the mechanisms that cause ER Ca(2+) depletion.
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Affiliation(s)
- Djalila Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven Campus Gasthuisberg O&N I, Belgium
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Kiviluoto S, Decuypere JP, De Smedt H, Missiaen L, Parys JB, Bultynck G. STIM1 as a key regulator for Ca2+ homeostasis in skeletal-muscle development and function. Skelet Muscle 2011; 1:16. [PMID: 21798093 PMCID: PMC3156639 DOI: 10.1186/2044-5040-1-16] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [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: 12/13/2010] [Accepted: 04/04/2011] [Indexed: 12/17/2022] Open
Abstract
Stromal interaction molecules (STIM) were identified as the endoplasmic-reticulum (ER) Ca2+ sensor controlling store-operated Ca2+ entry (SOCE) and Ca2+-release-activated Ca2+ (CRAC) channels in non-excitable cells. STIM proteins target Orai1-3, tetrameric Ca2+-permeable channels in the plasma membrane. Structure-function analysis revealed the molecular determinants and the key steps in the activation process of Orai by STIM. Recently, STIM1 was found to be expressed at high levels in skeletal muscle controlling muscle function and properties. Novel STIM targets besides Orai channels are emerging.Here, we will focus on the role of STIM1 in skeletal-muscle structure, development and function. The molecular mechanism underpinning skeletal-muscle physiology points toward an essential role for STIM1-controlled SOCE to drive Ca2+/calcineurin/nuclear factor of activated T cells (NFAT)-dependent morphogenetic remodeling programs and to support adequate sarcoplasmic-reticulum (SR) Ca2+-store filling. Also in our hands, STIM1 is transiently up-regulated during the initial phase of in vitro myogenesis of C2C12 cells. The molecular targets of STIM1 in these cells likely involve Orai channels and canonical transient receptor potential (TRPC) channels TRPC1 and TRPC3. The fast kinetics of SOCE activation in skeletal muscle seem to depend on the triad-junction formation, favoring a pre-localization and/or pre-formation of STIM1-protein complexes with the plasma-membrane Ca2+-influx channels. Moreover, Orai1-mediated Ca2+ influx seems to be essential for controlling the resting Ca2+ concentration and for proper SR Ca2+ filling. Hence, Ca2+ influx through STIM1-dependent activation of SOCE from the T-tubule system may recycle extracellular Ca2+ losses during muscle stimulation, thereby maintaining proper filling of the SR Ca2+ stores and muscle function. Importantly, mouse models for dystrophic pathologies, like Duchenne muscular dystrophy, point towards an enhanced Ca2+ influx through Orai1 and/or TRPC channels, leading to Ca2+-dependent apoptosis and muscle degeneration. In addition, human myopathies have been associated with dysfunctional SOCE. Immunodeficient patients harboring loss-of-function Orai1 mutations develop myopathies, while patients suffering from Duchenne muscular dystrophy display alterations in their Ca2+-handling proteins, including STIM proteins. In any case, the molecular determinants responsible for SOCE in human skeletal muscle and for dysregulated SOCE in patients of muscular dystrophy require further examination.
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Affiliation(s)
- Santeri Kiviluoto
- Laboratory of Molecular and Cellular Signaling, Department Molecular Cell Biology, K,U, Leuven, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
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Decuypere JP, Monaco G, Missiaen L, De Smedt H, Parys JB, Bultynck G. IP(3) Receptors, Mitochondria, and Ca Signaling: Implications for Aging. J Aging Res 2011; 2011:920178. [PMID: 21423550 PMCID: PMC3056293 DOI: 10.4061/2011/920178] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [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: 10/15/2010] [Revised: 12/23/2010] [Accepted: 01/05/2011] [Indexed: 12/21/2022] Open
Abstract
The tight interplay between endoplasmic-reticulum-(ER-) and mitochondria-mediated Ca(2+) signaling is a key determinant of cellular health and cellular fate through the control of apoptosis and autophagy. Proteins that prevent or promote apoptosis and autophagy can affect intracellular Ca(2+) dynamics and homeostasis through binding and modulation of the intracellular Ca(2+)-release and Ca(2+)-uptake mechanisms. During aging, oxidative stress becomes an additional factor that affects ER and mitochondrial function and thus their role in Ca(2+) signaling. Importantly, mitochondrial dysfunction and sustained mitochondrial damage are likely to underlie part of the aging process. In this paper, we will discuss the different mechanisms that control intracellular Ca(2+) signaling with respect to apoptosis and autophagy and review how these processes are affected during aging through accumulation of reactive oxygen species.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Biology, K.U.Leuven, Campus Gasthuisberg O/N-1, Herestraat 49, Bus 802, 3000 Leuven, Belgium
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Decuypere JP, Monaco G, Bultynck G, Missiaen L, De Smedt H, Parys JB. The IP(3) receptor-mitochondria connection in apoptosis and autophagy. Biochim Biophys Acta 2010; 1813:1003-13. [PMID: 21146562 DOI: 10.1016/j.bbamcr.2010.11.023] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/24/2010] [Accepted: 11/25/2010] [Indexed: 01/08/2023]
Abstract
The amount of Ca(2+) taken up in the mitochondrial matrix is a crucial determinant of cell fate; it plays a decisive role in the choice of the cell between life and death. The Ca(2+) ions mainly originate from the inositol 1,4,5-trisphosphate (IP(3))-sensitive Ca(2+) stores of the endoplasmic reticulum (ER). The uptake of these Ca(2+) ions in the mitochondria depends on the functional properties and the subcellular localization of the IP(3) receptor (IP(3)R) in discrete domains near the mitochondria. To allow for an efficient transfer of the Ca(2+) ions from the ER to the mitochondria, structural interactions between IP(3)Rs and mitochondria are needed. This review will focus on the key proteins involved in these interactions, how they are regulated, and what are their physiological roles in apoptosis, necrosis and autophagy. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Jean-Paul Decuypere
- Laboratory of Molecular and Cellular Signalling, Dept. Molecular and Cellular, campus Gasthuisberg O/N1 K.U.Leuven, Bus 802, B-3000 Leuven, Belgium
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Sammels E, Devogelaere B, Mekahli D, Bultynck G, Missiaen L, Parys JB, De Smedt H. Unraveling the role of polycystin-2/inositol 1,4,5-trisphosphate receptor interaction in Ca signaling. Commun Integr Biol 2010; 3:530-2. [PMID: 21331231 DOI: 10.4161/cib.3.6.12751] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [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: 06/18/2010] [Accepted: 06/18/2010] [Indexed: 01/04/2023] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) arises as a consequence of mutations of the genes PKD1 and PKD2, encoding respectively the integral membrane proteins polycystin-1 and polycystin-2 (TRPP2), resulting in a disturbance in intracellular Ca(2+) signaling. Previously we investigated the interaction between TRPP2 and the inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R), an intracellular Ca(2+) channel in the endoplasmic reticulum (ER). We identified the molecular determinants of this interaction and observed an enhanced IP(3)-induced Ca(2+) release (IICR). Since we found that TRPP2 strongly bound to a cluster of positively charged amino acids in the N-terminal ligand-binding domain (LBD) of the IP(3)R, we now investigated whether TRPP2 would interfere with the binding of IP(3) to the IP(3)R. In in vitro experiments we observed that TRPP2 partially inhibited the binding of IP(3) to the LBD of the IP(3)R with an IC(50) of ∼350 nM. The suppressor domain, i.e., the N-terminal 225 amino acids of the LBD of the IP(3)R, mediated this inhibitory effect of TRPP2 on IP(3) binding. The observation that the interaction between the IP(3)R and TRPP2 decreased IP(3) binding is in apparent contrast to the increased IICR. The data can be explained however by a subsequent activation of Ca(2+)-induced Ca(2+) release (CICR) via TRPP2. Implications of this mechanism for cellular Ca(2+) signaling are discussed in this addendum.
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Affiliation(s)
- Eva Sammels
- Laboratory of Molecular and Cellular Signaling; Department of Molecular Cell Biology; K.U. Leuven, Leuven Belgium
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Sammels E, Devogelaere B, Mekahli D, Bultynck G, Missiaen L, Parys JB, Cai Y, Somlo S, De Smedt H. Polycystin-2 activation by inositol 1,4,5-trisphosphate-induced Ca2+ release requires its direct association with the inositol 1,4,5-trisphosphate receptor in a signaling microdomain. J Biol Chem 2010; 285:18794-805. [PMID: 20375013 DOI: 10.1074/jbc.m109.090662] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Autosomal dominant polycystic kidney disease is characterized by the loss-of-function of a signaling complex involving polycystin-1 and polycystin-2 (TRPP2, an ion channel of the TRP superfamily), resulting in a disturbance in intracellular Ca(2+) signaling. Here, we identified the molecular determinants of the interaction between TRPP2 and the inositol 1,4,5-trisphosphate receptor (IP(3)R), an intracellular Ca(2+) channel in the endoplasmic reticulum. Glutathione S-transferase pulldown experiments combined with mutational analysis led to the identification of an acidic cluster in the C-terminal cytoplasmic tail of TRPP2 and a cluster of positively charged residues in the N-terminal ligand-binding domain of the IP(3)R as directly responsible for the interaction. To investigate the functional relevance of TRPP2 in the endoplasmic reticulum, we re-introduced the protein in TRPP2(-/-) mouse renal epithelial cells using an adenoviral expression system. The presence of TRPP2 resulted in an increased agonist-induced intracellular Ca(2+) release in intact cells and IP(3)-induced Ca(2+) release in permeabilized cells. Using pathological mutants of TRPP2, R740X and D509V, and competing peptides, we demonstrated that TRPP2 amplified the Ca(2+) signal by a local Ca(2+)-induced Ca(2+)-release mechanism, which only occurred in the presence of the TRPP2-IP(3)R interaction, and not via altered IP(3)R channel activity. Moreover, our results indicate that this interaction was instrumental in the formation of Ca(2+) microdomains necessary for initiating Ca(2+)-induced Ca(2+) release. The data strongly suggest that defects in this mechanism may account for the altered Ca(2+) signaling associated with pathological TRPP2 mutations and therefore contribute to the development of autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Eva Sammels
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49 bus 802, B-3000 Leuven, Belgium
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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] [What about the content of this article? (0)] [Affiliation(s)] [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
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Vanderheyden V, Devogelaere B, Missiaen L, De Smedt H, Bultynck G, Parys JB. Regulation of inositol 1,4,5-trisphosphate-induced Ca2+ release by reversible phosphorylation and dephosphorylation. Biochim Biophys Acta 2008; 1793:959-70. [PMID: 19133301 DOI: 10.1016/j.bbamcr.2008.12.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 11/27/2008] [Accepted: 12/03/2008] [Indexed: 12/12/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is a universal intracellular Ca2+-release channel. It is activated after cell stimulation and plays a crucial role in the initiation and propagation of the complex spatio-temporal Ca2+ signals that control cellular processes as different as fertilization, cell division, cell migration, differentiation, metabolism, muscle contraction, secretion, neuronal processing, and ultimately cell death. To achieve these various functions, often in a single cell, exquisite control of the Ca2+ release is needed. This review aims to highlight how protein kinases and protein phosphatases can interact with the IP3R or with associated proteins and so provide a large potential for fine tuning the Ca2+-release activity and for creating efficient Ca2+ signals in subcellular microdomains.
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Affiliation(s)
- Veerle Vanderheyden
- Laboratory of Molecular and Cellular Signalling, Department Molecular and Cellular Biology, Campus Gasthuisberg O/N1-K. U. Leuven, Herestraat 49-Bus 802, B-3000 Leuven, Belgium
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Baron S, Struyf S, Wuytack F, Van Damme J, Missiaen L, Raeymaekers L, Vanoevelen J. Contribution of intracellular Ca2+ stores to Ca2+ signaling during chemokinesis of human neutrophil granulocytes. Biochim Biophys Acta 2008; 1793:1041-9. [PMID: 19095014 DOI: 10.1016/j.bbamcr.2008.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/06/2008] [Accepted: 11/16/2008] [Indexed: 10/21/2022]
Abstract
Extracellular agonists increase the cytosolic free Ca2+ concentration ([Ca2+]c) by Ca2+ influx and by stimulating Ca2+ release from intracellular stores, mainly the endoplasmic reticulum and to a lesser extent also later compartments of the secretory pathway, particularly the Golgi. The Golgi takes up Ca2+ via Sarco/Endoplasmic Reticulum Ca2+ATPases (SERCAs) and the Secretory-Pathway Ca2+ATPases (SPCAs). The endogenous expression of SERCAs and SPCAs neutrophils was demonstrated by Western blotting and immunocytochemistry. Up till now, all cytosolic Ca2+ transients due to intracellular Ca2+ release have been found to originate from SERCA-dependent stores. We found that human neutrophils also present Ca2+ release from a SERCA-independent store. Changes in [Ca2+]c of neutrophils were investigated during chemokinesis induced by chemotactic factors in Ca2+-free solution with and without the SERCA-specific inhibitor thapsigargin. Using N-formyl-methionyl-leucyl-phenylalanine or interleukin-8 as agonists, Ca2+ release from intracellular stores was observed in respectively about 40% and 20% of the neutrophils pre-treated with Ca2+-free solution and thapsigargin. In the latter condition, 20-30% of the cells preserved migratory behaviour. These results indicate that both SERCA-dependent and SERCA-independent (presumably SPCA-dependent) intracellular Ca2+ stores contribute to Ca2+ signaling during chemokinesis of human neutrophil granulocytes.
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Affiliation(s)
- Szilvia Baron
- Laboratory of Ca2+-transport ATPases, Department of Molecular Cell Biology, KULeuven Campus Gasthuisberg, Leuven, Belgium
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Verbert L, Lee B, Kocks SL, Assefa Z, Parys JB, Missiaen L, Callewaert G, Fissore RA, De Smedt H, Bultynck G. Caspase-3-truncated type 1 inositol 1,4,5-trisphosphate receptor enhances intracellular Ca2+ leak and disturbs Ca2+ signalling. Biol Cell 2008; 100:39-49. [PMID: 17868032 PMCID: PMC2909191 DOI: 10.1042/bc20070086] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION The IP(3)R (inositol 1,4,5-trisphosphate receptor) is a tetrameric channel that accounts for a large part of the intracellular Ca(2+) release in virtually all cell types. We have previously demonstrated that caspase-3-mediated cleavage of IP(3)R1 during cell death generates a C-terminal fragment of 95 kDa comprising the complete channel domain. Expression of this truncated IP(3)R increases the cellular sensitivity to apoptotic stimuli, and it was postulated to be a constitutively active channel. RESULTS In the present study, we demonstrate that expression of the caspase-3-cleaved C-terminus of IP(3)R1 increased the rate of thapsigargin-mediated Ca(2+) leak and decreased the rate of Ca(2+) uptake into the ER (endoplasmic reticulum), although it was not sufficient by itself to deplete intracellular Ca(2+) stores. We detected the truncated IP(3)R1 in different cell types after a challenge with apoptotic stimuli, as well as in aged mouse oocytes. Injection of mRNA corresponding to the truncated IP(3)R1 blocked sperm factor-induced Ca(2+) oscillations and induced an apoptotic phenotype. CONCLUSIONS In the present study, we show that caspase-3-mediated truncation of IP(3)R1 enhanced the Ca(2+) leak from the ER. We suggest a model in which, in normal conditions, the increased Ca(2+) leak is largely compensated by enhanced Ca(2+)-uptake activity, whereas in situations where the cellular metabolism is compromised, as occurring in aging oocytes, the Ca(2+) leak acts as a feed-forward mechanism to divert the cell into apoptosis.
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Affiliation(s)
- Leen Verbert
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Bora Lee
- Program and Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01002, U.S.A
| | - Sarah L. Kocks
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Zerihun Assefa
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Geert Callewaert
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Rafael A. Fissore
- Program and Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01002, U.S.A
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
- To whom correspondence should be addressed ()
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Devogelaere B, Beullens M, Sammels E, Derua R, Waelkens E, vanLint J, Parys J, Missiaen L, Bollen M, DeSmedt H. Protein phosphatase-1 is a novel regulator of the interaction between IRBIT and the inositol 1,4,5-trisphosphate receptor. Biochem J 2008; 407:303-11. [PMID: 17635105 PMCID: PMC2049018 DOI: 10.1042/bj20070361] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
IRBIT is an IP3R [IP3 (inositol 1,4,5-trisphosphate) receptor]-binding protein that competes with IP3 for binding to the IP3R. Phosphorylation of IRBIT is essential for the interaction with the IP3R. The unique N-terminal region of IRBIT, residues 1-104 for mouse IRBIT, contains a PEST (Pro-Glu-Ser-Thr) domain with many putative phosphorylation sites. In the present study, we have identified a well-conserved PP1 (protein phosphatase-1)-binding site preceeding this PEST domain which enabled the binding of PP1 to IRBIT both in vitro and in vivo. IRBIT emerged as a mediator of its own dephosphorylation by associated PP1 and, hence, as a novel substrate specifier for PP1. Moreover, IRBIT-associated PP1 specifically dephosphorylated Ser68 of IRBIT. Phosphorylation of Ser68 was required for subsequent phosphorylation of Ser71 and Ser74, but the latter two sites were not targeted by PP1. We found that phosphorylation of Ser71 and Ser74 were sufficient to enable inhibition of IP3 binding to the IP3R by IRBIT. Finally, we have shown that mutational inactivation of the docking site for PP1 on IRBIT increased the affinity of IRBIT for the IP3R. This pinpoints PP1 as a key player in the regulation of IP3R-controlled Ca2+ signals.
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Affiliation(s)
- Benoit Devogelaere
- *Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Monique Beullens
- †Laboratory of Biosignalling and Therapeutics, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Eva Sammels
- *Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Rita Derua
- ‡Laboratory of Protein Phosphorylation and Proteomics, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Etienne Waelkens
- ‡Laboratory of Protein Phosphorylation and Proteomics, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Johan vanLint
- §Laboratory of Molecular Medicine of Protein Kinases, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Jan B. Parys
- *Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Ludwig Missiaen
- *Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- †Laboratory of Biosignalling and Therapeutics, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
| | - Humbert DeSmedt
- *Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1, B-3000 Leuven, Belgium
- To whom correspondence should be sent (email )
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Devogelaere B, Verbert L, Parys JB, Missiaen L, De Smedt H. The complex regulatory function of the ligand-binding domain of the inositol 1,4,5-trisphosphate receptor. Cell Calcium 2007; 43:17-27. [PMID: 17499849 DOI: 10.1016/j.ceca.2007.04.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/23/2007] [Indexed: 11/21/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) can be divided in three functionally distinct regions: a ligand-binding domain, a modulatory domain and a channel domain. Numerous regulatory mechanisms including inter- and intra-molecular protein-protein interactions and phosphorylation events act via these domains to regulate the function of the IP(3)R. Regulation at the level of the ligand-binding domain primarily affects the affinity for IP(3). The extent of IP(3)-induced Ca(2+) release (IICR) is, however, not only determined by the affinity for IP(3) but also by the effectiveness of the coupling between ligand binding and channel opening. As a result, regulation as well as malfunction of IICR may be affected by both steps in the activation mechanism. The 3D structures of the two subdomains of the ligand-binding domain have recently been determined by X-ray diffraction analysis. This allows a more detailed molecular explanation of the regulatory events situated at the ligand-binding domain of the IP(3)R. In this review, we will focus on recent structural and functional data on the ligand-binding domain that have extended and clarified the view on the molecular mechanisms of IP(3)R regulation.
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Affiliation(s)
- Benoit Devogelaere
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
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38
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Abstract
The secretory-pathway Ca2+-ATPases (SPCAs) represent a recently recognized family of phosphorylation-type ATPases that supply the lumen of the Golgi apparatus with Ca2+ and Mn2+ needed for the normal functioning of this structure. Mutations of the human SPCA1 gene (ATP2C1) cause Hailey-Hailey disease, an autosomal dominant skin disorder in which keratinocytes in the suprabasal layer of the epidermis detach. We will first review the physiology of the SPCAs and then discuss how mutated SPCA1 proteins can lead to an epidermal disorder.
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Affiliation(s)
- Ludwig Missiaen
- Afdeling Fysiologie, Departement Moleculaire Celbiologie, KULeuven Campus Gasthuisberg O/N, Herestraat 49 bus 802, B-3000 Leuven, Belgium.
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39
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Vandeput F, Combettes L, Mills SJ, Backers K, Wohlkönig A, Parys JB, De Smedt H, Missiaen L, Dupont G, Potter BVL, Erneux C. Biphenyl 2,3′,4,5′,6‐pentakisphosphate, a novel inositol polyphosphate surrogate, modulates Ca2+responses in rat hepatocytes. FASEB J 2007; 21:1481-91. [PMID: 17264160 DOI: 10.1096/fj.06-7691com] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Benzene polyphosphates containing phosphate groups on one ring are Ins(1,4,5)P3 5-phosphatase inhibitors when evaluated against type-I Ins(1,4,5)P3 5-phosphatase. A novel biphenyl derivative, biphenyl 2,3',4,5',6-pentakisphosphate, with five phosphate groups on two rings was synthesized: It inhibited the activity of two inositol 5-phosphatases: type I and SHIP2 with Ins(1,3,4,5)P4 as substrate. The inhibition was competitive with respect to the substrate. IC50 value measured in rat hepatocytes, which contains the native Ins(1,4,5)P3 5-phosphatase, was in the micromolar range at 1.0 microM Ins(1,4,5)P3 as substrate. Biphenyl 2,3',4,5',6-pentakisphosphate did not affect the activity of Ins(1,4,5)P3 3-kinase A in the 5-100 microM range. Surprisingly, experimental evidence supports an effect of biphenyl 2,3',4,5',6-pentakisphosphate at the level of the Ins(1,4,5)P3 receptor. Finally, when injected into rat hepatocytes, the analog affected the frequency of Ca2+ oscillations in a positive or negative way depending on its concentration. At very high concentrations of the analog, Ca2+ oscillations were even suppressed. These data were interpreted as a dual effect of the biphenyl 2,3',4,5',6-pentakisphosphate on cytosolic [Ca2+] increases: an activation effect through an increase in Ins(1,4,5)P3 level via Ins(1,4,5)P3 5-phosphatase inhibition and an inhibitory effect, which was exerted directly on the Ins(1,4,5)P3 receptor. Thus, our data show for the first time that the frequency of Ca2+ oscillations in response to a Ca2+-mobilizing agonist can be controlled by inhibitors of type-I Ins(1,4,5)P3 5-phosphatase.
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Affiliation(s)
- Fabrice Vandeput
- Institut de Recherche Interdisciplinaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070 Brussels, Belgium
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40
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Abstract
Secretory-pathway Ca2(+)-transport ATPases (SPCA) provide the Golgi apparatus with Ca2+ and Mn2+ needed for the normal functioning of this organelle. Loss of one functional copy of the human SPCA1 gene (ATP2C1) causes Hailey-Hailey disease, a rare skin disorder characterized by recurrent blisters and erosions in the flexural areas. Here, we will review the properties and functional role of the SPCAs. The relationship between Hailey-Hailey disease and its defective gene (ATP2C1) will be adressed as well.
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Affiliation(s)
- J Vanoevelen
- Laboratory of Physiology, KULeuven Campus Gasthuisberg O&N1, Herestraat 49 bus 802, B-3000 Leuven, Belgium
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41
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Kasri NN, Kocks SL, Verbert L, Hébert SS, Callewaert G, Parys JB, Missiaen L, De Smedt H. Up-regulation of inositol 1,4,5-trisphosphate receptor type 1 is responsible for a decreased endoplasmic-reticulum Ca2+ content in presenilin double knock-out cells. Cell Calcium 2006; 40:41-51. [PMID: 16675011 DOI: 10.1016/j.ceca.2006.03.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/12/2006] [Accepted: 03/16/2006] [Indexed: 11/27/2022]
Abstract
Presenilins (PS) are proteins involved in the pathogenesis of autosomal-dominant familial cases of Alzheimer's disease. Mutations in PS are known to induce specific alterations in cellular Ca2+ signaling which might be involved in the pathogenesis of neurodegenerative diseases. Mouse embryonic fibroblasts (MEF) deficient in PS1 and PS2 (PS DKO) as well as the latter rescued with PS1 (Rescue), were used to investigate the underlying mechanism of these alterations in Ca2+ signaling. PS DKO cells were characterized by a decrease in the [Ca2+]ER as measured by ER-targeted aequorin luminescence and an increased level of type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). The lower [Ca2+]ER was associated with an increase in a Ca2+ leak from the ER. The increased IP3R1 expression and the concomitant changes in ER Ca2+ handling were reversed in the Rescue cells. Moreover using RNA-interference mediated reduction of IP3R1 we could demonstrate that the up-regulation of this isoform was responsible for the increased Ca2+ leak and the lowered [Ca2+]ER PS DKO cells. Finally, we show that the decreased [Ca2+]ER in PS DKO cells was protective against apoptosis.
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Affiliation(s)
- Nael Nadif Kasri
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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42
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Szlufcik K, Bultynck G, Callewaert G, Missiaen L, Parys JB, De Smedt H. The suppressor domain of inositol 1,4,5-trisphosphate receptor plays an essential role in the protection against apoptosis. Cell Calcium 2006; 39:325-36. [PMID: 16458354 DOI: 10.1016/j.ceca.2005.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 11/24/2005] [Accepted: 11/28/2005] [Indexed: 12/12/2022]
Abstract
The N-terminal 1-225 amino acids (aa) of the type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R1) function as a suppressor/coupling domain. In this study we used IP(3)R-deficient B-lymphocytes to investigate the effects of modifications in this domain on IP(3) binding and Ca(2+)-release activity. Although the N-terminal 1-225 aa of IP(3)R3 had the same role as in IP(3)R1, the suppression of IP(3) binding for IP(3)R1 was lost when the suppressor/coupling domains were exchanged between the two isoforms. Resulting chimeric receptors showed a higher sensitivity to IP(3)-induced activation (IICR). Deletion of 11 aa in IP(3)R1 ([Delta76-86]-IP(3)R1) or replacing aa 76-86 of the IP(3)R1 in the suppressor/coupling domain by 13 aa of IP(3)R3 ([75-87 T3]-IP(3)R1) also resulted in increased IP(3) binding and sensitivity of IICR. These residues constitute the only part of the suppressor/coupling domain that is strikingly different between the two isoforms. Expression of [Delta76-86]-IP(3)R1 and of [75-87 T3]-IP(3)R1 increased the propensity of cells to undergo staurosporine-induced apoptosis, but had no effect on the Ca(2+) content in the endoplasmic reticulum. In the cell model used, our observations suggest that the sensitivity of the Ca(2+)-release activity of IP(3)R1 to IP(3) influences the sensitivity of the cells to apoptotic stimuli and that the suppressor/coupling domain may have an anti-apoptotic function by attenuating the sensitivity of IICR.
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Affiliation(s)
- Karolina Szlufcik
- Laboratorium voor Fysiologie, KU Leuven Campus Gasthuisberg O/N, Belgium
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43
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Devogelaere B, Nadif Kasri N, Derua R, Waelkens E, Callewaert G, Missiaen L, Parys JB, De Smedt H. Binding of IRBIT to the IP3 receptor: Determinants and functional effects. Biochem Biophys Res Commun 2006; 343:49-56. [PMID: 16527252 DOI: 10.1016/j.bbrc.2006.02.119] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Accepted: 02/21/2006] [Indexed: 11/26/2022]
Abstract
IRBIT has previously been shown to interact with the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) in an IP3-sensitive way. So far it remained to be elucidated whether this interaction was direct or indirect, and whether it was functionally relevant. We now show that IRBIT can directly interact with the IP3R, and that both the suppressor domain and the IP3-binding core of the IP3R are essential for a strong interaction. Moreover, we identified a PEST motif and a PDZ-ligand on IRBIT which were critical for the interaction with the IP3R. Furthermore, we identified Asp-73 as a critical residue for this interaction. Finally, we demonstrated that this interaction functionally affects the IP3R: IRBIT inhibits both IP3 binding and IP3-induced Ca2+ release.
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Affiliation(s)
- Benoit Devogelaere
- Laboratorium voor Fysiologie, Katholieke Universiteit Leuven Campus Gasthuisberg O/N1, Leuven, Belgium
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Kasri NN, Török K, Galione A, Garnham C, Callewaert G, Missiaen L, Parys JB, De Smedt H. Endogenously Bound Calmodulin Is Essential for the Function of the Inositol 1,4,5-Trisphosphate Receptor. J Biol Chem 2006; 281:8332-8. [PMID: 16410249 DOI: 10.1074/jbc.m510971200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) is a ubiquitous Ca2+ sensor protein that plays an important role in regulating a large number of Ca2+ channels, including the inositol 1,4,5-trisphosphate receptor (IP3R). Despite many efforts, the exact mechanism by which CaM regulates the IP3R still remains elusive. Here we show, using unidirectional 45Ca2+ flux experiments on permeabilized L15 fibroblasts and COS-1 cells, that endogenously bound CaM is essential for the proper activation of the IP3R. Removing endogenously bound CaM by titration with a high affinity (pM) CaM-binding peptide derived from smooth muscle myosin light-chain kinase (MLCK peptide) strongly inhibited IP3-induced Ca2+ release. This inhibition was concentration- and time-dependent. Removing endogenously bound CaM affected the maximum release capacity but not its sensitivity to IP3. A mutant peptide with a strongly reduced affinity for CaM did not affect inhibited IP3-induced Ca2+ release. Furthermore, the inhibition by the MLCK peptide was fully reversible. Re-adding exogenous CaM, but not CaM1234, reactivated the IP3R. These data suggest that, by using a specific CaM-binding peptide, we removed endogenously bound CaM from a high affinity CaM-binding site on the IP3R, and this resulted in a complete loss of the IP3R activity. Our data support a new model whereby CaM is constitutively associated with the IP3R and functions as an essential subunit for proper functioning of the IP3R.
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Affiliation(s)
- Nael Nadif Kasri
- Laboratorium voor Fysiologie, K. U. Leuven Campus Gasthuisberg, O/N Herestraat 49/802, B-3000 Leuven, Belgium
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45
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Buytaert E, Callewaert G, Hendrickx N, Scorrano L, Hartmann D, Missiaen L, Vandenheede JR, Heirman I, Grooten J, Agostinis P. Role of endoplasmic reticulum depletion and multidomain proapoptotic BAX and BAK proteins in shaping cell death after hypericin-mediated photodynamic therapy. FASEB J 2006; 20:756-8. [PMID: 16455754 DOI: 10.1096/fj.05-4305fje] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Both the commitment event and the modality of cell death in photodynamic therapy (PDT) remain poorly defined. We report that PDT with endoplasmic reticulum (ER)-associating hypericin leads to an immediate loss of SERCA2 protein levels, causing disruption of Ca2+ homeostasis and cell death. Protection of SERCA2 protein rescues ER-Ca2+ levels and prevents cell death, suggesting that SERCA2 photodestruction with consequent incapability of the ER to maintain intracellular Ca2+ homeostasis is causal to cell killing. Apoptosis is rapidly initiated after ER-Ca2+ depletion and strictly requires the BAX/BAK gateway at the mitochondria. Bax-/-Bak-/- double-knockout (DKO) cells are protected from apoptosis but undergo autophagy-associated cell death as revealed by electron microscopy and biochemical analysis. Autophagy inhibitors, but not caspase antagonists, significantly reduce death of DKO cells, suggesting that sustained autophagy is lethal. Thus, following ER photodamage and consequent disruption of Ca2+ homeostasis, BAX and BAK proteins model PDT-mediated cell killing, which is executed through apoptosis in their presence or via an autophagic pathway in their absence.
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Affiliation(s)
- Esther Buytaert
- Department of Molecular and Cell Biology, Faculty of Medicine, Catholic University of Leuven, Leuven, Belgium
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46
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Dode L, Andersen JP, Vanoevelen J, Raeymaekers L, Missiaen L, Vilsen B, Wuytack F. Dissection of the Functional Differences between Human Secretory Pathway Ca2+/Mn2+-ATPase (SPCA) 1 and 2 Isoenzymes by Steady-state and Transient Kinetic Analyses. J Biol Chem 2006; 281:3182-9. [PMID: 16332677 DOI: 10.1074/jbc.m511547200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human secretory pathway Ca2+/Mn2+-ATPase (SPCA) 2 encoded by ATP2C2 is only expressed in a limited number of tissues, unlike the ubiquitously expressed SPCA1 pump (encoded by ATP2C1, the gene defective in Hailey-Hailey disease). It has not been determined whether there are significant functional differences between SPCA1 and SPCA2 pump enzymes. Therefore, steady-state and transient kinetic approaches were used to characterize the overall and partial reactions of the Ca2+ transport cycle mediated by the human SPCA2 enzyme upon heterologous expression in HEK-293 cells. The catalytic turnover rate of SPCA2 was found enhanced relative to SPCA1 pumps. SPCA2 displayed a very high apparent affinity for cytosolic Ca2+ (K0.5 = 0.025 microm) in activation of the phosphorylation activity but still 2.5-fold lower than that of SPCA1d. Our kinetic analysis traced both differences to the increased rate characterizing the E1 approximately PCa to E2-P transition of SPCA2. Moreover, the reduced rate of the E2 to E1 transition seems to contribute in determining the lower apparent Ca2+ affinity and the increased sensitivity to thapsigargin inhibition, relative to SPCA1d. SPCA2 also displayed a reduced apparent affinity for inorganic phosphate, which could be explained by the observed enhanced rate of the E2-P dephosphorylation. The insensitivity to modulation by pH and K+ concentration of the constitutively enhanced E2-P dephosphorylation of SPCA2 is similar to SPCA1d and possibly represents a novel SPCA-specific feature, which is not shared by sarco(endo)plasmic reticulum Ca2+-ATPases.
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Affiliation(s)
- Leonard Dode
- Laboratory of Physiology, Catholic University of Leuven, Campus Gasthuisberg O/N, Herestraat 49, Bus 802, B-3000 Leuven, Belgium
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47
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Vanoevelen J, Raeymaekers L, Dode L, Parys JB, De Smedt H, Callewaert G, Wuytack F, Missiaen L. Cytosolic Ca2+ signals depending on the functional state of the Golgi in HeLa cells. Cell Calcium 2005; 38:489-95. [PMID: 16122795 DOI: 10.1016/j.ceca.2005.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 05/30/2005] [Accepted: 07/05/2005] [Indexed: 10/25/2022]
Abstract
The Golgi apparatus is, like the endoplasmic reticulum, an inositol-1,4,5-trisphosphate-sensitive Ca2+ store, but its role in setting up Ca2+ signals is not well understood. We have now measured histamine-induced Ca2+ signals in HeLa cells pretreated with brefeldin A, a fungal metabolite that leads to the fragmentation and subsequent disappearance of the Golgi apparatus by its reabsorption within the endoplasmic reticulum. Ca2+ responses in which the free cytoplasmic Ca2+ concentration returned to resting levels during the histamine stimulation (mainly baseline Ca2+ oscillations or a single Ca2+ peak) occurred more often in brefeldin A pretreated cells, resulting in a lower Ca2+ plateau in population measurements. The latencies before the onset of the Ca2+ signals were longer after brefeldin A pretreatment. These results suggest that the integrity of the Golgi apparatus contributes to the shaping of intracellular Ca2+ signals.
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Affiliation(s)
- J Vanoevelen
- Afdeling Fysiologie, K.U. Leuven Campus Gasthuisberg O/N-802, Herestraat 49, B-3000 Leuven, Belgium.
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48
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Pesesse X, Leyman A, Luyten T, Missiaen L, Erneux C. Hyperosmotic stress stimulates inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate formation independently of bis-diphosphoinositol tetrakisphosphate modulation. Biochem Biophys Res Commun 2005; 336:157-62. [PMID: 16139247 DOI: 10.1016/j.bbrc.2005.08.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 08/03/2005] [Indexed: 10/25/2022]
Abstract
Hyperosmotic stress induces water diffusion out of the cell, resulting in cell shrinkage, and leading to DNA damage, cell cycle arrest, and cytoskeletal reorganization. A previous report showed that low concentrations of sorbitol (200mM) could increase up to 25-fold the concentration of InsP(8) in animal cells. Here, we investigate the effect of sorbitol (200mM) on the inositol 1,4,5-trisphosphate (InsP(3)) and inositol 1,3,4,5-tetrakisphosphate (InsP(4)) pathway. A 3- to 4-fold increase in InsP(3) and InsP(4) levels after sorbitol challenge was observed. It was prevented by the phospholipase C inhibitor U-73122 but was insensitive to the MAP kinase inhibitor U0126. We also observed an increase in the free intracellular [Ca(2+)] and the occurrence of Ca(2+) oscillations in response to sorbitol. A hyperosmotic stress could therefore affect the levels of both hyperphosphorylated inositol phosphates and InsP(3)/InsP(4)-signalling molecules.
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Affiliation(s)
- Xavier Pesesse
- Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070 Bruxelles, Belgium.
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49
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Abstract
Calmodulin (CaM) is a ubiquitous cytosolic protein that plays a critical role in regulating cellular functions by altering the activity of a large number of ion channels. There are many examples for CaM directly mediating the feedback effects of Ca2+ on Ca2+ channels. Recently the molecular mechanisms by which CaM interacts with voltage-gated Ca2+ channels, Ca(2+)-activated K+ channels and ryanodine receptors have been clarified. CaM plays an important role in regulating these ion channels through lobe-specific Ca2+ detection. CaM seems to behave as a channel subunit. It binds at low [Ca2+] and undergoes conformational changes upon binding of Ca2+, leading to an interaction with another part of the channel to regulate its gating. Here we focus on the mechanism by which CaM regulates the inositol 1,4,5-trisphosphate receptor (IP3R). Although the IP3R is inhibited by CaM and by other CaM-like proteins in the presence of Ca2+, we conclude that CaM does not act as the Ca2+ sensor for IP3R function. Furthermore we discuss a novel Ca(2+)-induced Ca(2+)-release mechanism found in A7r5 (embryonic rat aorta) and 16HBE14o- (human bronchial mucosa) cells for which CaM acts as a Ca2+ sensor.
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Affiliation(s)
- Nael Nadif Kasri
- Laboratorium voor Fysiologie, K.U. Leuven Campus Gasthuisberg O/N, Herestraat 49, B-3000 Leuven, Belgium
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50
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Dode L, Andersen JP, Raeymaekers L, Missiaen L, Vilsen B, Wuytack F. Functional comparison between secretory pathway Ca2+/Mn2+-ATPase (SPCA) 1 and sarcoplasmic reticulum Ca2+-ATPase (SERCA) 1 isoforms by steady-state and transient kinetic analyses. J Biol Chem 2005; 280:39124-34. [PMID: 16192278 DOI: 10.1074/jbc.m506181200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Steady-state and transient kinetic studies were performed to functionally analyze the overall and partial reactions of the Ca(2+) transport cycle of the human secretory pathway Ca(2+)/Mn(2+)-ATPase 1 (SPCA1) isoforms: SPCA1a, SPCA1b, SPCA1c, and SPCA1d (encoded by ATP2C1, the gene defective in Hailey-Hailey disease) upon heterologous expression in mammalian cells. The expression levels of SPCA1 isoforms were 200-350-fold higher than in control cells except for SPCA1c, whose low expression level appears to be the effect of rapid degradation because of protein misfolding. Relative to SERCA1a, the active SPCA1a, SPCA1b, and SPCA1d enzymes displayed extremely high apparent affinities for cytosolic Ca(2+) in activation of the overall ATPase and phosphorylation activities. The maximal turnover rates of the ATPase activity for SPCA1 isoforms were 4.7-6.4-fold lower than that of SERCA1a (lowest for the shortest SPCA1a isoform). The kinetic analysis traced these differences to a decreased rate of the E(1) approximately P(Ca) to E(2)-P transition. The apparent affinity for inorganic phosphate was reduced in the SPCA1 enzymes. This could be accounted for by an enhanced rate of the E(2)-P hydrolysis, which showed constitutive activation, lacking the SERCA1a-specific dependence on pH and K(+).
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Affiliation(s)
- Leonard Dode
- Laboratory of Physiology, Catholic University of Leuven, Campus Gasthuisberg O/N, Herestraat 49, Bus 802, B-3000 Leuven, Belgium.
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