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Ismatullah H, Jabeen I, Kiani YS. Structural and functional insight into a new emerging target IP 3R in cancer. J Biomol Struct Dyn 2024; 42:2170-2196. [PMID: 37070253 DOI: 10.1080/07391102.2023.2201332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Calcium signaling has been identified as an important phenomenon in a plethora of cellular processes. Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ER-residing intracellular calcium (Ca2+) release channels responsible for cell bioenergetics by transferring calcium from the ER to the mitochondria. The recent availability of full-length IP3R channel structure has enabled the researchers to design the IP3 competitive ligands and reveal the channel gating mechanism by elucidating the conformational changes induced by ligands. However, limited knowledge is available for IP3R antagonists and the exact mechanism of action of these antagonists within a tumorigenic environment of a cell. Here in this review a summarized information about the role of IP3R in cell proliferation and apoptosis has been discussed. Moreover, structure and gating mechanism of IP3R in the presence of antagonists have been provided in this review. Additionally, compelling information about ligand-based studies (both agonists and antagonists) has been discussed. The shortcomings of these studies and the challenges toward the design of potent IP3R modulators have also been provided in this review. However, the conformational changes induced by antagonists for channel gating mechanism still display some major drawbacks that need to be addressed. However, the design, synthesis and availability of isoform-specific antagonists is a rather challenging one due to intra-structural similarity within the binding domain of each isoform. HighlightsThe intricate complexity of IP3R's in cellular processes declares them an important target whereby, the recently solved structure depicts the receptor's potential involvement in a complex network of processes spanning from cell proliferation to cell death.Pharmacological inhibition of IP3R attenuates the proliferation or invasiveness of cancers, thus inducing necrotic cell death.Despite significant advancements, there is a tremendous need to design new potential hits to target IP3R, based upon 3D structural features and pharmacophoric patterns.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Humaira Ismatullah
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Ishrat Jabeen
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Yusra Sajid Kiani
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
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Gao H, Liu L, Zaikin A, Chen S. An efficient reduced-lattice model of IP 3R for probing Ca 2+ dynamics. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184195. [PMID: 37353068 DOI: 10.1016/j.bbamem.2023.184195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Numerous cellular processes are regulated by Ca2+ signals, and the endoplasmic reticulum (ER) membrane's inositol triphosphate receptor (IP3R) is critical for modulating intracellular Ca2+ dynamics. The IP3Rs are seen to be clustered in a variety of cell types. The combination of IP3Rs clustering and IP3Rs-mediated Ca2+-induced Ca2+ release results in the hierarchical organization of the Ca2+ signals, which challenges the numerical simulation given the multiple spatial and temporal scales that must be covered. The previous methods rather ignore the spatial feature of IP3Rs or fail to coordinate the conflicts between the real biological relevance and the computational cost. In this work, a general and efficient reduced-lattice model is presented for the simulation of IP3Rs-mediated multiscale Ca2+ dynamics. The model highlights biological details that make up the majority of the calcium events, including IP3Rs clustering and calcium domains, and it reduces the complexity by approximating the minor details. The model's extensibility provides fresh insights into the function of IP3Rs in producing global Ca2+ events and supports the research under more physiological circumstances. Our work contributes to a novel toolkit for modeling multiscale Ca2+ dynamics and advances knowledge of Ca2+ signals.
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Affiliation(s)
- Huayi Gao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China; MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Langzhou Liu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China; MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Alexey Zaikin
- Institute for Women's Health and Department of Mathematics, University College London, Gower St., London, WC1E 6BT, UK; Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 7 Nizhniy Novgorod, 603022, Russia; Centre for Analysis of Complex Systems, Sechenov First Moscow State Medical University, Moscow, 119019, Russia
| | - Shangbin Chen
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China; MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.
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3
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Ramlow L, Falcke M, Lindner B. An integrate-and-fire approach to Ca 2+ signaling. Part I: Renewal model. Biophys J 2023; 122:713-736. [PMID: 36635961 PMCID: PMC9989887 DOI: 10.1016/j.bpj.2023.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/13/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023] Open
Abstract
In computational neuroscience integrate-and-fire models capture the spike generation by a subthreshold dynamics supplemented by a simple fire-and-reset rule; they allow for a numerically efficient and analytically tractable description of stochastic single cell as well as network dynamics. Stochastic spiking is also a prominent feature of Ca2+ signaling which suggests to adopt the integrate-and-fire approach for this fundamental biophysical process. The model introduced here consists of two components describing 1) activity of clusters of inositol-trisphosphate receptor channels and 2) dynamics of the global Ca2+ concentrations in the cytosol. The cluster dynamics is given in terms of a cyclic Markov chain, capturing the puff, i.e., the punctuated release of Ca2+ from intracellular stores. The cytosolic Ca2+ concentration is described by an integrate-and-fire dynamics driven by the puff current. For the cyclic Markov chain we derive expressions for the statistics of the interpuff interval, the single-puff strength and the puff current assuming constant cytosolic Ca2+. The latter condition is often well approximated because cytosolic Ca2+ varies much slower than the cluster activity does. Furthermore, because the detailed two-component model is numerically expensive to simulate and difficult to treat analytically, we develop an analytical framework to approximate the driving puff current of the stochastic cytosolic Ca2+ dynamics by a temporally uncorrelated Gaussian noise. This approximation reduces our two-component system to an integrate-and-fire model with a nonlinear drift function and a multiplicative Gaussian white noise, a model that is known to generate a renewal spike train, i.e., a point process with statistically independent interspike intervals. The model allows for fast numerical simulations, permits to derive analytical expressions for the rate of Ca2+ spiking and the coefficient of variation of the interspike interval, and to approximate the interspike interval density and the spike train power spectrum. Comparison of these statistics to experimental data is discussed.
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Affiliation(s)
- Lukas Ramlow
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Physics Department of Humboldt University Berlin, Berlin, Germany.
| | - Martin Falcke
- Physics Department of Humboldt University Berlin, Berlin, Germany; Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Benjamin Lindner
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Physics Department of Humboldt University Berlin, Berlin, Germany
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Smith HA, Taylor CW. Dissociation of inositol 1,4,5-trisphosphate from IP 3 receptors contributes to termination of Ca 2+ puffs. J Biol Chem 2023; 299:102871. [PMID: 36621623 PMCID: PMC9971896 DOI: 10.1016/j.jbc.2023.102871] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023] Open
Abstract
Ca2+ puffs are brief, localized Ca2+ signals evoked by physiological stimuli that arise from the coordinated opening of a few clustered inositol 1,4,5-trisphosphate receptors (IP3Rs). However, the mechanisms that control the amplitude and termination of Ca2+ puffs are unresolved. To address these issues, we expressed SNAP-tagged IP3R3 in HEK cells without endogenous IP3Rs and used total internal reflection fluorescence microscopy to visualize the subcellular distribution of IP3Rs and the Ca2+ puffs that they evoke. We first confirmed that SNAP-IP3R3 were reliably identified and that they evoked normal Ca2+ puffs after photolysis of a caged analog of IP3. We show that increased IP3R expression caused cells to assemble more IP3R clusters, each of which contained more IP3Rs, but the mean amplitude of Ca2+ puffs (indicative of the number of open IP3Rs) was unaltered. We thus suggest that functional interactions between IP3Rs constrain the number of active IP3Rs within a cluster. Furthermore, Ca2+ puffs evoked by IP3R with reduced affinity for IP3 had undiminished amplitude, but the puffs decayed more quickly. The selective effect of reducing IP3 affinity on the decay times of Ca2+ puffs was not mimicked by exposing normal IP3R to a lower concentration of IP3. We conclude that distinct mechanisms constrain recruitment of IP3Rs during the rising phase of a Ca2+ puff and closure of IP3Rs during the falling phase, and that only the latter is affected by the rate of IP3 dissociation.
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Affiliation(s)
- Holly A Smith
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
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Arige V, Emrich SM, Yoast RE, Trebak M, Yule DI. A protocol for detecting elemental calcium signals (Ca 2+ puffs) in mammalian cells using total internal reflection fluorescence microscopy. STAR Protoc 2021; 2:100618. [PMID: 34195673 PMCID: PMC8225975 DOI: 10.1016/j.xpro.2021.100618] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This protocol outlines steps to visualize and detect Ca2+ puffs following photo-liberation of caged inositol-1,4,5-trisphosphate (IP3) from HEK-293 cells expressing only the native IP3R type 1 receptor using total internal reflection fluorescence (TIRF) microscopy. TIRF microscopy offers high axial resolution and allows imaging at high speed, with a higher signal-to-background ratio. Additionally, we shed light on commonly encountered pitfalls, which should be considered while recording Ca2+ puffs using TIRF microscopy. For complete details on the use and execution of this protocol, please refer to Emrich et al. (2021) and Lock et al. (2015a).
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Affiliation(s)
- Vikas Arige
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Scott M. Emrich
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Ryan E. Yoast
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - David I. Yule
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
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6
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KRAP tethers IP 3 receptors to actin and licenses them to evoke cytosolic Ca 2+ signals. Nat Commun 2021; 12:4514. [PMID: 34301929 PMCID: PMC8302619 DOI: 10.1038/s41467-021-24739-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/01/2021] [Indexed: 02/06/2023] Open
Abstract
Regulation of IP3 receptors (IP3Rs) by IP3 and Ca2+ allows regenerative Ca2+ signals, the smallest being Ca2+ puffs, which arise from coordinated openings of a few clustered IP3Rs. Cells express thousands of mostly mobile IP3Rs, yet Ca2+ puffs occur at a few immobile IP3R clusters. By imaging cells with endogenous IP3Rs tagged with EGFP, we show that KRas-induced actin-interacting protein (KRAP) tethers IP3Rs to actin beneath the plasma membrane. Loss of KRAP abolishes Ca2+ puffs and the global increases in cytosolic Ca2+ concentration evoked by more intense stimulation. Over-expressing KRAP immobilizes additional IP3R clusters and results in more Ca2+ puffs and larger global Ca2+ signals. Endogenous KRAP determines which IP3Rs will respond: it tethers IP3R clusters to actin alongside sites where store-operated Ca2+ entry occurs, licenses IP3Rs to evoke Ca2+ puffs and global cytosolic Ca2+ signals, implicates the actin cytoskeleton in IP3R regulation and may allow local activation of Ca2+ entry.
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7
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Gambardella J, Morelli MB, Wang X, Castellanos V, Mone P, Santulli G. The discovery and development of IP3 receptor modulators: an update. Expert Opin Drug Discov 2021; 16:709-718. [PMID: 33356639 DOI: 10.1080/17460441.2021.1858792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Introduction: Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular calcium (Ca2+) release channels located on the endoplasmic/sarcoplasmic reticulum. The availability of the structure of the ligand-binding domain of IP3Rs has enabled the design of compatible ligands, but the limiting step remains their actual effectiveness in a biological context.Areas covered: This article summarizes the compelling literature on both agonists and antagonists targeting IP3Rs, emphasizing their strengths and limitations. The main challenges toward the discovery and development of IP3 receptor modulators are also described.Expert opinion: Despite significant progress in recent years, the pharmacology of IP3R still has major drawbacks, especially concerning the availability of specific antag onists. Moreover, drugs specifically targeting the three different subtypes of IP3R are especially needed.
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Affiliation(s)
- Jessica Gambardella
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA.,Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy.,International Translational Research and Medical Education (ITME), Naples, Italy
| | - Marco B Morelli
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA
| | - Xujun Wang
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA
| | - Vanessa Castellanos
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA
| | - Pasquale Mone
- University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Gaetano Santulli
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA.,Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy.,International Translational Research and Medical Education (ITME), Naples, Italy
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8
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Atakpa-Adaji P, Thillaiappan NB, Taylor CW. IP3 receptors and their intimate liaisons. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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9
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Bartlett PJ, Cloete I, Sneyd J, Thomas AP. IP 3-Dependent Ca 2+ Oscillations Switch into a Dual Oscillator Mechanism in the Presence of PLC-Linked Hormones. iScience 2020; 23:101062. [PMID: 32353764 PMCID: PMC7191650 DOI: 10.1016/j.isci.2020.101062] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 12/11/2019] [Accepted: 04/09/2020] [Indexed: 11/28/2022] Open
Abstract
Ca2+ oscillations that depend on inositol-1,4,5-trisphosphate (IP3) have been ascribed to biphasic Ca2+ regulation of the IP3 receptor (IP3R) or feedback mechanisms controlling IP3 levels in different cell types. IP3 uncaging in hepatocytes elicits Ca2+ transients that are often localized at the subcellular level and increase in magnitude with stimulus strength. However, this does not reproduce the broad baseline-separated global Ca2+ oscillations elicited by vasopressin. Addition of hormone to cells activated by IP3 uncaging initiates a qualitative transition from high-frequency spatially disorganized Ca2+ transients, to low-frequency, oscillatory Ca2+ waves that propagate throughout the cell. A mathematical model with dual coupled oscillators that integrates Ca2+-induced Ca2+ release at the IP3R and mutual feedback mechanisms of cross-coupling between Ca2+ and IP3 reproduces this behavior. Thus, multiple Ca2+ oscillation modes can coexist in the same cell, and hormonal stimulation can switch from the simpler to the more complex to yield robust signaling.
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Affiliation(s)
- Paula J Bartlett
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Ielyaas Cloete
- Department of Mathematics, The University of Auckland, Auckland, New Zealand
| | - James Sneyd
- Department of Mathematics, The University of Auckland, Auckland, New Zealand
| | - Andrew P Thomas
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ 07103, USA.
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Lock JT, Parker I. IP 3 mediated global Ca 2+ signals arise through two temporally and spatially distinct modes of Ca 2+ release. eLife 2020; 9:e55008. [PMID: 32396066 PMCID: PMC7253181 DOI: 10.7554/elife.55008] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
The 'building-block' model of inositol trisphosphate (IP3)-mediated Ca2+ liberation posits that cell-wide cytosolic Ca2+ signals arise through coordinated activation of localized Ca2+ puffs generated by stationary clusters of IP3 receptors (IP3Rs). Here, we revise this hypothesis, applying fluctuation analysis to resolve Ca2+ signals otherwise obscured during large Ca2+ elevations. We find the rising phase of global Ca2+ signals is punctuated by a flurry of puffs, which terminate before the peak by a mechanism involving partial ER Ca2+ depletion. The continuing rise in Ca2+, and persistence of global signals even when puffs are absent, reveal a second mode of spatiotemporally diffuse Ca2+ signaling. Puffs make only small, transient contributions to global Ca2+ signals, which are sustained by diffuse release of Ca2+ through a functionally distinct process. These two modes of IP3-mediated Ca2+ liberation have important implications for downstream signaling, imparting spatial and kinetic specificity to Ca2+-dependent effector functions and Ca2+ transport.
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Affiliation(s)
- Jeffrey T Lock
- Department of Neurobiology & Behavior, UC IrvineIrvineUnited States
| | - Ian Parker
- Department of Neurobiology & Behavior, UC IrvineIrvineUnited States
- Department of Physiology & Biophysics, UC IrvineIrvineUnited States
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11
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Luo J, Chen L, Huang F, Gao P, Zhao H, Wang Y, Han S. Intraorganellar calcium imaging in Arabidopsis seedling roots using the GCaMP variants GCaMP6m and R-CEPIA1er. JOURNAL OF PLANT PHYSIOLOGY 2020; 246-247:153127. [PMID: 32007728 DOI: 10.1016/j.jplph.2020.153127] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 05/26/2023]
Abstract
Ca2+ acts as a universal second messenger in eukaryotes. In animals, a wide variety of environmental and developmental stimuli trigger Ca2+ dynamics in organelles, such as the cytoplasm, nucleus, and endoplasmic reticulum (ER). However, ER Ca2+ ([Ca2+]er) homeostasis and its contributions in cytosolic and/or nucleosolic Ca2+ dynamics in plants remain elusive. GCaMPs are comprised of a circularly permutated form of enhanced green fluorescent protein fused to calmodulin and myosin light-chain kinase M13 and used for monitoring Ca2+ dynamics in mammalian cells. Here, we targeted a high-affinity variant of GCaMP with nuclear export signal in the cytoplasm (NES-GCaMP6m), with a nuclear-localised signal in the nucleus (NLS-GCaMP6m), and a low-affinity variant of GCaMP, also known as calcium-measuring organelle-entrapped protein indicators (CEPIA), with a signal peptide sequence of the ER-localised protein Calreticulin 1a in the ER lumen (CRT1a-R-CEPIA1er) for intraorganellar Ca2+ imaging in Arabidopsis. We found that cytosolic Ca2+ ([Ca2+]cyt) increases induced by 250 mM sorbitol as an osmotic stress stimulus, 50 μM abscisic acid (ABA), or 1 mM carbachol (CCh) were mainly due to extracellular Ca2+ influx, whereas nucleosolic Ca2+ ([Ca2+]nuc) increases triggered by osmotic stress, ABA, or CCh were contributed by [Ca2+]er release. In addition, [Ca2+]er dynamics presented specific patterns in response to different stimuli such as osmotic stress, ABA, or CCh, indicating that Ca2+ signalling occurs in the ER in plants. These results provide valuable insights into subcellular Ca2+ dynamics in response to different stresses in Arabidopsis root cells and prove that GCaMP imaging is a useful tool for furthering our understanding of plant organelle functions.
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Affiliation(s)
- Jin Luo
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Lvli Chen
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Feifei Huang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Ping Gao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Heping Zhao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yingdian Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Shengcheng Han
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
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12
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Wilson C, Zhang X, Buckley C, Heathcote HR, Lee MD, McCarron JG. Increased Vascular Contractility in Hypertension Results From Impaired Endothelial Calcium Signaling. Hypertension 2019; 74:1200-1214. [PMID: 31542964 PMCID: PMC6791503 DOI: 10.1161/hypertensionaha.119.13791] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Supplemental Digital Content is available in the text. Endothelial cells line all blood vessels and are critical regulators of vascular tone. In hypertension, disruption of endothelial function alters the release of endothelial-derived vasoactive factors and results in increased vascular tone. Although the release of endothelial-derived vasodilators occurs in a Ca2+-dependent manner, little is known on how Ca2+ signaling is altered in hypertension. A key element to endothelial control of vascular tone is Ca2+ signals at specialized regions (myoendothelial projections) that connect endothelial cells and smooth muscle cells. This work describes disruption in the operation of this key Ca2+ signaling pathway in hypertension. We show that vascular reactivity to phenylephrine is increased in hypertensive (spontaneously hypertensive rat) when compared with normotensive (Wistar Kyoto) rats. Basal endothelial Ca2+ activity limits vascular contraction, but that Ca2+-dependent control is impaired in hypertension. When changes in endothelial Ca2+ levels are buffered, vascular contraction to phenylephrine increased, resulting in similar responses in normotension and hypertension. Local endothelial IP3(inositol trisphosphate)-mediated Ca2+ signals are smaller in amplitude, shorter in duration, occur less frequently, and arise from fewer sites in hypertension. Spatial control of endothelial Ca2+ signaling is also disrupted in hypertension: local Ca2+ signals occur further from myoendothelial projections in hypertension. The results demonstrate that the organization of local Ca2+ signaling circuits occurring at myoendothelial projections is disrupted in hypertension, giving rise to increased contractile responses.
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Affiliation(s)
- Calum Wilson
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Xun Zhang
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Charlotte Buckley
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Helen R Heathcote
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Matthew D Lee
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - John G McCarron
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
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13
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Taylor CW, Machaca K. IP3 receptors and store-operated Ca2+ entry: a license to fill. Curr Opin Cell Biol 2019; 57:1-7. [DOI: 10.1016/j.ceb.2018.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/05/2018] [Indexed: 10/28/2022]
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14
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Prole DL, Taylor CW. Structure and Function of IP 3 Receptors. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035063. [PMID: 30745293 DOI: 10.1101/cshperspect.a035063] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs), by releasing Ca2+ from the endoplasmic reticulum (ER) of animal cells, allow Ca2+ to be redistributed from the ER to the cytosol or other organelles, and they initiate store-operated Ca2+ entry (SOCE). For all three IP3R subtypes, binding of IP3 primes them to bind Ca2+, which then triggers channel opening. We are now close to understanding the structural basis of IP3R activation. Ca2+-induced Ca2+ release regulated by IP3 allows IP3Rs to regeneratively propagate Ca2+ signals. The smallest of these regenerative events is a Ca2+ puff, which arises from the nearly simultaneous opening of a small cluster of IP3Rs. Ca2+ puffs are the basic building blocks for all IP3-evoked Ca2+ signals, but only some IP3 clusters, namely those parked alongside the ER-plasma membrane junctions where SOCE occurs, are licensed to respond. The location of these licensed IP3Rs may allow them to selectively regulate SOCE.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
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15
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Voorsluijs V, Dawson SP, De Decker Y, Dupont G. Deterministic Limit of Intracellular Calcium Spikes. PHYSICAL REVIEW LETTERS 2019; 122:088101. [PMID: 30932600 DOI: 10.1103/physrevlett.122.088101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/09/2019] [Indexed: 06/09/2023]
Abstract
In nonexcitable cells, global Ca^{2+} spikes emerge from the collective dynamics of clusters of Ca^{2+} channels that are coupled by diffusion. Current modeling approaches have opposed stochastic descriptions of these systems to purely deterministic models, while both paradoxically appear compatible with experimental data. Combining fully stochastic simulations and mean-field analyses, we demonstrate that these two approaches can be reconciled. Our fully stochastic model generates spike sequences that can be seen as noise-perturbed oscillations of deterministic origin, while displaying statistical properties in agreement with experimental data. These underlying deterministic oscillations arise from a phenomenological spike nucleation mechanism.
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Affiliation(s)
- V Voorsluijs
- Nonlinear Physical Chemistry Unit and Center for Nonlinear Phenomena and Complex Systems (CENOLI), Université libre de Bruxelles, Boulevard du Triomphe, C.P. 231, B-1050 Brussels, Belgium
| | - S Ponce Dawson
- Departamento de Física, FCEN-UBA and IFIBA, UBA-CONICET, Ciudad Universitaria, Pabellón I, 1428 Buenos Aires, Argentina
| | - Y De Decker
- Nonlinear Physical Chemistry Unit and Center for Nonlinear Phenomena and Complex Systems (CENOLI), Université libre de Bruxelles, Boulevard du Triomphe, C.P. 231, B-1050 Brussels, Belgium
| | - G Dupont
- Unité de Chronobiologie Théorique, Université libre de Bruxelles, Boulevard du Triomphe, C.P. 231, B-1050 Brussels, Belgium
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16
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Lock JT, Smith IF, Parker I. Spatial-temporal patterning of Ca 2+ signals by the subcellular distribution of IP 3 and IP 3 receptors. Semin Cell Dev Biol 2019; 94:3-10. [PMID: 30703557 DOI: 10.1016/j.semcdb.2019.01.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/17/2019] [Accepted: 01/22/2019] [Indexed: 12/25/2022]
Abstract
The patterning of cytosolic Ca2+ signals in space and time underlies their ubiquitous ability to specifically regulate numerous cellular processes. Signals mediated by liberation of Ca2+ sequestered in the endoplasmic reticulum (ER) through inositol trisphosphate receptor (IP3R) channels constitute a hierarchy of events; ranging from openings of individual IP3 channels, through the concerted openings of several clustered IP3Rs to generate local Ca2+ puffs, to global Ca2+ waves and oscillations that engulf the entire cell. Here, we review recent progress in elucidating how this hierarchy is shaped by an interplay between the functional gating properties of IP3Rs and their spatial distribution within the cell. We focus in particular on the subset of IP3Rs that are organized in stationary clusters and are endowed with the ability to preferentially liberate Ca2+.
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Affiliation(s)
- Jeffrey T Lock
- Department of Neurobiology & Behavior, UC Irvine, Irvine, CA, USA.
| | - Ian F Smith
- Department of Neurobiology & Behavior, UC Irvine, Irvine, CA, USA
| | - Ian Parker
- Department of Neurobiology & Behavior, UC Irvine, Irvine, CA, USA; Department of Physiology & Biophysics, UC Irvine, Irvine, CA, USA
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17
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Lock JT, Alzayady KJ, Yule DI, Parker I. All three IP 3 receptor isoforms generate Ca 2+ puffs that display similar characteristics. Sci Signal 2018; 11:11/561/eaau0344. [PMID: 30563861 DOI: 10.1126/scisignal.aau0344] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inositol 1,4,5-trisphosphate (IP3) evokes Ca2+ release through IP3 receptors (IP3Rs) to generate both local Ca2+ puffs arising from concerted openings of clustered IP3Rs and cell-wide Ca2+ waves. Imaging Ca2+ puffs with single-channel resolution yields information on the localization and properties of native IP3Rs in intact cells, but interpretation has been complicated because cells express varying proportions of three structurally and functionally distinct isoforms of IP3Rs. Here, we used TIRF and light-sheet microscopy to image Ca2+ puffs in HEK-293 cell lines generated by CRISPR-Cas9 technology to express exclusively IP3R type 1, 2, or 3. Photorelease of the IP3 analog i-IP3 in all three cell lines evoked puffs with largely similar mean amplitudes, temporal characteristics, and spatial extents. Moreover, the single-channel Ca2+ flux was similar among isoforms, indicating that clusters of different IP3R isoforms contain comparable numbers of active channels. Our results show that all three IP3R isoforms cluster to generate local Ca2+ puffs and, contrary to findings of divergent properties from in vitro electrophysiological studies, display similar conductances and gating kinetics in intact cells.
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Affiliation(s)
- Jeffrey T Lock
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
| | - Kamil J Alzayady
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642, USA
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642, USA
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.,Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
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18
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Applications of FLIKA, a Python-based image processing and analysis platform, for studying local events of cellular calcium signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1171-1179. [PMID: 30500432 DOI: 10.1016/j.bbamcr.2018.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/20/2018] [Accepted: 11/22/2018] [Indexed: 11/21/2022]
Abstract
The patterning of cytosolic Ca2+ signals underlies their ubiquitous ability to specifically regulate numerous cellular processes. Advances in fluorescence microscopy have made it possible to image these signals with unprecedented temporal and spatial resolution. However, this is a double-edged sword, as the resulting enormous data sets necessitate development of software to automate image processing and analysis. Here, we describe Flika, an open source, graphical user interface program written in the Python environment that contains a suite of built-in image processing tools to enable intuitive visualization of image data and analysis. We illustrate the utility and power of Flika by three applications for studying cellular Ca2+ signaling: a script for measuring single-cell global Ca2+ signals; a plugin for the detection, localization and analysis of subcellular Ca2+ puffs; and a script that implements a novel approach for fluctuation analysis of transient, local Ca2+ fluorescence signals. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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19
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Thillaiappan NB, Chakraborty P, Hasan G, Taylor CW. IP 3 receptors and Ca 2+ entry. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1092-1100. [PMID: 30448464 DOI: 10.1016/j.bbamcr.2018.11.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 12/23/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3R) are the most widely expressed intracellular Ca2+ release channels. Their activation by IP3 and Ca2+ allows Ca2+ to pass rapidly from the ER lumen to the cytosol. The resulting increase in cytosolic [Ca2+] may directly regulate cytosolic effectors or fuel Ca2+ uptake by other organelles, while the decrease in ER luminal [Ca2+] stimulates store-operated Ca2+ entry (SOCE). We are close to understanding the structural basis of both IP3R activation, and the interactions between the ER Ca2+-sensor, STIM, and the plasma membrane Ca2+ channel, Orai, that lead to SOCE. IP3Rs are the usual means through which extracellular stimuli, through ER Ca2+ release, stimulate SOCE. Here, we review evidence that the IP3Rs most likely to respond to IP3 are optimally placed to allow regulation of SOCE. We also consider evidence that IP3Rs may regulate SOCE downstream of their ability to deplete ER Ca2+ stores. Finally, we review evidence that IP3Rs in the plasma membrane can also directly mediate Ca2+ entry in some cells.
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Affiliation(s)
| | - Pragnya Chakraborty
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, United Kingdom; National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Colin W Taylor
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
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Keebler MV, Taylor CW. Endogenous signalling pathways and caged IP 3 evoke Ca 2+ puffs at the same abundant immobile intracellular sites. J Cell Sci 2017; 130:3728-3739. [PMID: 28893841 PMCID: PMC5702060 DOI: 10.1242/jcs.208520] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/04/2017] [Indexed: 12/18/2022] Open
Abstract
The building blocks of intracellular Ca2+ signals evoked by inositol 1,4,5-trisphosphate receptors (IP3Rs) are Ca2+ puffs, transient focal increases in Ca2+ concentration that reflect the opening of small clusters of IP3Rs. We use total internal reflection fluorescence microscopy and automated analyses to detect Ca2+ puffs evoked by photolysis of caged IP3 or activation of endogenous muscarinic receptors with carbachol in human embryonic kidney 293 cells. Ca2+ puffs evoked by carbachol initiated at an estimated 65±7 sites/cell, and the sites remained immobile for many minutes. Photolysis of caged IP3 evoked Ca2+ puffs at a similar number of sites (100±35). Increasing the carbachol concentration increased the frequency of Ca2+ puffs without unmasking additional Ca2+ release sites. By measuring responses to sequential stimulation with carbachol or photolysed caged IP3, we established that the two stimuli evoked Ca2+ puffs at the same sites. We conclude that IP3-evoked Ca2+ puffs initiate at numerous immobile sites and the sites become more likely to fire as the IP3 concentration increases; there is no evidence that endogenous signalling pathways selectively deliver IP3 to specific sites. Summary: Ca2+ puffs are the building blocks for IP3-evoked Ca2+ signals. Ca2+ puffs evoked by caged IP3 or via endogenous signalling pathways initiate at the same fixed intracellular sites.
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Affiliation(s)
- Michael V Keebler
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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21
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De Loof A. Calcitox-aging counterbalanced by endogenous farnesol-like sesquiterpenoids: An undervalued evolutionarily ancient key signaling pathway. Commun Integr Biol 2017; 10:e1341024. [PMID: 28919940 PMCID: PMC5595427 DOI: 10.1080/19420889.2017.1341024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/07/2017] [Indexed: 02/08/2023] Open
Abstract
Cells are powerful miniature electrophoresis chambers, at least during part of their life cycle. They die at the moment the voltage gradient over their plasma membrane, and their ability to drive a self-generated electric current carried by inorganic ions through themselves irreversibly collapses. Senescence is likely due to the progressive, multifactorial damage to the cell's electrical system. This is the essence of the "Fading electricity theory of aging" (De Loof et al., Aging Res. Rev. 2013;12:58-66). "Biologic electric current" is not carried by electrons, but by inorganic ions. The major ones are H+, Na+, K+, Ca2+, Mg2+, Cl- and HCO3-. Ca2+ and H+ in particular are toxic to cells. At rising concentrations, they can alter the 3D-conformation of chromatin and some (e.g. cytoskeletal) proteins: Calcitox and Protontox. This paper only focuses on Calcitox and endogenous sesquiterpenoids. pH-control and Ca2+-homeostasis have been shaped to near perfection during billions of years of evolution. The role of Ca2+ in some aspects of aging, e.g., as causal to neurodegenerative diseases is still debated. The main anti-Calcitox mechanism is to keep free cytoplasmic Ca2+ as low as possible. This can be achieved by restricting the passive influx of Ca2+ through channels in the plasma membrane, and by maximizing the active extrusion of excess Ca2+ e.g., by means of different types of Ca2+-ATPases. Like there are mechanisms that antagonize the toxic effects of Reactive Oxygen Species (ROS), there must also exist endogenous tools to counteract Calcitox. During a re-evaluation of which mechanism(s) exactly initiates the fast aging that accompanies induction of metamorphosis in insects, a causal relationship between absence of an endogenous sesquiterpenoid, namely the farnesol ester named "juvenile hormone," and disturbed Ca2+-homeostasis was suggested. In this paper, this line of thinking is further explored and extended to vertebrate physiology. A novel concept emerges: horseshoe-shaped sesquiterpenoids seem to act as "inbrome" agonists with the function of a "chemical valve" or "spring" in some types of multi-helix transmembrane proteins (intramolecular prenylation), from bacterial rhodopsins to some types of GPCRs and ion pumps, in particular the SERCA-Ca2+-pump. This further underpins the Fading Electricity Theory of Aging.
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Affiliation(s)
- Arnold De Loof
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven-University of Leuven, Leuven, Belgium
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