1
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Bayley T, Hedwig B. Tonotopic Ca 2+ dynamics and sound processing in auditory interneurons of the bush-cricket Mecopoda elongata. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:353-369. [PMID: 37222786 PMCID: PMC11106180 DOI: 10.1007/s00359-023-01638-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/25/2023] [Accepted: 05/05/2023] [Indexed: 05/25/2023]
Abstract
Two auditory neurons, TN-1 and ON-1, in the bush-cricket, Mecopoda elongata, have large dendritic arborisations which receive excitatory synaptic inputs from tonotopically organised axonal terminals of auditory afferents in the prothoracic ganglion. By combining intracellular microelectrode recording with calcium imaging we demonstrate that the dendrites of both neurons show a clear Ca2+ signal in response to broad-frequency species-specific chirps. Due to the organisation of the afferents frequency specific auditory activation should lead to local Ca2+ increases in their dendrites. In response to 20 ms sound pulses the dendrites of both neurons showed tonotopically organised Ca2+ increases. In ON-1 we found no evidence for a tonotopic organisation of the Ca2+ signal related to axonal spike activity or for a Ca2+ response related to contralateral inhibition. The tonotopic organisation of the afferents may facilitate frequency-specific adaptation in these auditory neurons through localised Ca2+ increases in their dendrites. By combining 10 and 40 kHz test pulses and adaptation series, we provide evidence for frequency-specific adaptation in TN-1 and ON-1. By reversible deactivating of the auditory afferents and removing contralateral inhibition, we show that in ON-1 spike activity and Ca2+ responses increased but frequency-specific adaptation was not evident.
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Affiliation(s)
- T Bayley
- Department of Zoology, Cambridge, CB22 3EJ, UK
| | - B Hedwig
- Department of Zoology, Cambridge, CB22 3EJ, UK.
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2
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Davis MJ, Zawieja SD. Pacemaking in the lymphatic system. J Physiol 2024. [PMID: 38520402 DOI: 10.1113/jp284752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/08/2024] [Indexed: 03/25/2024] Open
Abstract
Lymphatic collecting vessels exhibit spontaneous phasic contractions that are critical for lymph propulsion and tissue fluid homeostasis. This rhythmic activity is driven by action potentials conducted across the lymphatic muscle cell (LMC) layer to produce entrained contractions. The contraction frequency of a lymphatic collecting vessel displays exquisite mechanosensitivity, with a dynamic range from <1 to >20 contractions per minute. A myogenic pacemaker mechanism intrinsic to the LMCs was initially postulated to account for pressure-dependent chronotropy. Further interrogation into the cellular constituents of the lymphatic vessel wall identified non-muscle cell populations that shared some characteristics with interstitial cells of Cajal, which have pacemaker functions in the gastrointestinal and lower urinary tracts, thus raising the possibility of a non-muscle cell pacemaker. However, recent genetic knockout studies in mice support LMCs and a myogenic origin of the pacemaker activity. LMCs exhibit stochastic, but pressure-sensitive, sarcoplasmic reticulum calcium release (puffs and waves) from IP3R1 receptors, which couple to the calcium-activated chloride channel Anoctamin 1, causing depolarisation. The resulting electrical activity integrates across the highly coupled lymphatic muscle electrical syncytia through connexin 45 to modulate diastolic depolarisation. However, multiple other cation channels may also contribute to the ionic pacemaking cycle. Upon reaching threshold, a voltage-gated calcium channel-dependent action potential fires, resulting in a nearly synchronous calcium global calcium flash within the LMC layer to drive an entrained contraction. This review summarizes the key ion channels potentially responsible for the pressure-dependent chronotropy of lymphatic collecting vessels and various mechanisms of IP3R1 regulation that could contribute to frequency tuning.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
| | - Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
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3
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Matveev VV. Close agreement between deterministic versus stochastic modeling of first-passage time to vesicle fusion. Biophys J 2022; 121:4569-4584. [PMID: 36815708 PMCID: PMC9748373 DOI: 10.1016/j.bpj.2022.10.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/13/2022] [Accepted: 10/24/2022] [Indexed: 11/22/2022] Open
Abstract
Ca2+-dependent cell processes, such as neurotransmitter or endocrine vesicle fusion, are inherently stochastic due to large fluctuations in Ca2+ channel gating, Ca2+ diffusion, and Ca2+ binding to buffers and target sensors. However, previous studies revealed closer-than-expected agreement between deterministic and stochastic simulations of Ca2+ diffusion, buffering, and sensing if Ca2+ channel gating is not Ca2+ dependent. To understand this result more fully, we present a comparative study complementing previous work, focusing on Ca2+ dynamics downstream of Ca2+ channel gating. Specifically, we compare deterministic (mean-field/mass-action) and stochastic simulations of vesicle exocytosis latency, quantified by the probability density of the first-passage time (FPT) to the Ca2+-bound state of a vesicle fusion sensor, following a brief Ca2+ current pulse. We show that under physiological constraints, the discrepancy between FPT densities obtained using the two approaches remains small even if as few as ∼50 Ca2+ ions enter per single channel-vesicle release unit. Using a reduced two-compartment model for ease of analysis, we illustrate how this close agreement arises from the smallness of correlations between fluctuations of the reactant molecule numbers, despite the large magnitude of fluctuation amplitudes. This holds if all relevant reactions are heteroreaction between molecules of different species, as is the case for bimolecular Ca2+ binding to buffers and downstream sensor targets. In this case, diffusion and buffering effectively decorrelate the state of the Ca2+ sensor from local Ca2+ fluctuations. Thus, fluctuations in the Ca2+ sensor's state underlying the FPT distribution are only weakly affected by the fluctuations in the local Ca2+ concentration around its average, deterministically computable value.
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Affiliation(s)
- Victor V Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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4
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Subcellular partitioning of protein kinase activity revealed by functional kinome profiling. Sci Rep 2022; 12:17300. [PMID: 36243751 PMCID: PMC9569338 DOI: 10.1038/s41598-022-21026-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/21/2022] [Indexed: 01/10/2023] Open
Abstract
Protein kinases and their substrates form signaling networks partitioned across subcellular compartments to facilitate critical biological processes. While the subcellular roles of many individual kinases have been elucidated, a comprehensive assessment of the synaptic subkinome is lacking. Further, most studies of kinases focus on transcript, protein, and/or phospho-protein expression levels, providing an indirect measure of protein kinase activity. Prior work suggests that gene expression levels are not a good predictor of protein function. Thus, we assessed global serine/threonine protein kinase activity profiles in synaptosomal, nuclear, and cytosolic fractions from rat frontal cortex homogenate using peptide arrays. Comparisons made between fractions demonstrated differences in overall protein kinase activity. Upstream kinase analysis revealed a list of cognate kinases that were enriched in the synaptosomal fraction compared to the nuclear fraction. We identified many kinases in the synaptic fraction previously implicated in this compartment, while also identifying other kinases with little or no evidence for synaptic localization. Our results show the feasibility of assessing subcellular fractions with peptide activity arrays, as well as suggesting compartment specific activity profiles associated with established and novel kinases.
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5
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Parys JB, Van Coppenolle F. Sec61 complex/translocon: The role of an atypical ER Ca 2+-leak channel in health and disease. Front Physiol 2022; 13:991149. [PMID: 36277220 PMCID: PMC9582130 DOI: 10.3389/fphys.2022.991149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/20/2022] [Indexed: 11/02/2023] Open
Abstract
The heterotrimeric Sec61 protein complex forms the functional core of the so-called translocon that forms an aqueous channel in the endoplasmic reticulum (ER). The primary role of the Sec61 complex is to allow protein import in the ER during translation. Surprisingly, a completely different function in intracellular Ca2+ homeostasis has emerged for the Sec61 complex, and the latter is now accepted as one of the major Ca2+-leak pathways of the ER. In this review, we first discuss the structure of the Sec61 complex and focus on the pharmacology and regulation of the Sec61 complex as a Ca2+-leak channel. Subsequently, we will pay particular attention to pathologies that are linked to Sec61 mutations, such as plasma cell deficiency and congenital neutropenia. Finally, we will explore the relevance of the Sec61 complex as a Ca2+-leak channel in various pathophysiological (ER stress, apoptosis, ischemia-reperfusion) and pathological (type 2 diabetes, cancer) settings.
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Affiliation(s)
- Jan B. Parys
- Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Leuven, Belgium
| | - Fabien Van Coppenolle
- CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Groupement Hospitalier EST, Department of Cardiology, Hospices Civils de Lyon, Lyon, France
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6
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Shah KR, Guan X, Yan J. Diversity of two-pore channels and the accessory NAADP receptors in intracellular Ca 2+ signaling. Cell Calcium 2022; 104:102594. [PMID: 35561646 PMCID: PMC9645597 DOI: 10.1016/j.ceca.2022.102594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/10/2022] [Accepted: 05/04/2022] [Indexed: 02/03/2023]
Abstract
Intracellular Ca2+ signaling via changes or oscillation in cytosolic Ca2+ concentration controls almost every aspect of cellular function and physiological processes, such as gene transcription, cell motility and proliferation, muscle contraction, and learning and memory. Two-pore channels (TPCs) are a class of eukaryotic cation channels involved in intracellular Ca2+ signaling, likely present in a multitude of organisms from unicellular organisms to mammals. Accumulated evidence indicates that TPCs play a critical role in Ca2+ mobilization from intracellular stores mediated by the second messenger molecule, nicotinic acid adenine dinucleotide phosphate (NAADP). In recent years, significant progress has been made regarding our understanding of the structures and function of TPCs, including Cryo-EM structure determination of mammalian TPCs and characterization of a plastid TPC in a single-celled parasite.. The recent identification of Lsm12 and JPT2 as NAADP-binding proteins provides a new molecular basis for understanding NAADP-evoked Ca2+ signaling. In this review, we summarize basic structural and functional aspects of TPCs and highlight the most recent studies on the newly discovered TPC in a parasitic protozoan and the NAADP-binding proteins LSM12 and JPT2 as new key players in NAADP signaling.
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Affiliation(s)
- Kunal R. Shah
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xin Guan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jiusheng Yan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA,Neuroscience and Biochemistry and Cell Biology Programs, The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA,Corresponding author at: Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA., (J. Yan)
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7
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Erdemir S, Kocyigit O, Malkondu S. Optical and quantitative detection of Ca2+ ion by an calix[4]arene-isophorone incorporated fluorometric and colorimetric probe. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Chen Y, Matveev V. Stationary Ca 2+ nanodomains in the presence of buffers with two binding sites. Biophys J 2021; 120:1942-1956. [PMID: 33771472 DOI: 10.1016/j.bpj.2021.03.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 03/06/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022] Open
Abstract
We examine closed-form approximations for the equilibrium Ca2+ and buffer concentrations near a point Ca2+ source representing a Ca2+ channel, in the presence of a mobile buffer with two Ca2+ binding sites activated sequentially and possessing distinct binding affinities and kinetics. This allows us to model the impact on Ca2+ nanodomains of realistic endogenous Ca2+ buffers characterized by cooperative Ca2+ binding, such as calretinin. The approximations we present involve a combination or rational and exponential functions, whose parameters are constrained using the series interpolation method that we recently introduced for the case of simpler Ca2+ buffers with a single Ca2+ binding site. We conduct extensive parameter sensitivity analysis and show that the obtained closed-form approximations achieve reasonable qualitative accuracy for a wide range of buffer's Ca2+ binding properties and other relevant model parameters. In particular, the accuracy of the derived approximants exceeds that of the rapid buffering approximation in large portions of the relevant parameter space.
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Affiliation(s)
- Yinbo Chen
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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9
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Chen Y, Muratov CB, Matveev V. Efficient Approximations for Stationary Single-Channel Ca 2+ Nanodomains across Length Scales. Biophys J 2020; 119:1239-1254. [PMID: 32877663 DOI: 10.1016/j.bpj.2020.06.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 06/06/2020] [Accepted: 06/10/2020] [Indexed: 10/23/2022] Open
Abstract
We consider the stationary solution for the Ca2+ concentration near a point Ca2+ source describing a single-channel Ca2+ nanodomain in the presence of a single mobile Ca2+ buffer with 1:1 Ca2+ binding. We present computationally efficient approximants that estimate stationary single-channel Ca2+ nanodomains with great accuracy in broad regions of parameter space. The presented approximants have a functional form that combines rational and exponential functions, which is similar to that of the well-known excess buffer approximation and the linear approximation but with parameters estimated using two novel, to our knowledge, methods. One of the methods involves interpolation between the short-range Taylor series of the free buffer concentration and its long-range asymptotic series in inverse powers of distance from the channel. Although this method has already been used to find Padé (rational-function) approximants to single-channel Ca2+ and buffer concentrations, extending this method to interpolants combining exponential and rational functions improves accuracy in a significant fraction of the relevant parameter space. A second method is based on the variational approach and involves a global minimization of an appropriate functional with respect to parameters of the chosen approximations. An extensive parameter-sensitivity analysis is presented, comparing these two methods with previously developed approximants. Apart from increased accuracy, the strength of these approximants is that they can be extended to more realistic buffers with multiple binding sites characterized by cooperative Ca2+ binding, such as calmodulin and calretinin.
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Affiliation(s)
- Yinbo Chen
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Cyrill B Muratov
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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10
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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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Powell J, Falcke M, Skupin A, Bellamy TC, Kypraios T, Thul R. A Statistical View on Calcium Oscillations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:799-826. [PMID: 31646535 DOI: 10.1007/978-3-030-12457-1_32] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Transient rises and falls of the intracellular calcium concentration have been observed in numerous cell types and under a plethora of conditions. There is now a growing body of evidence that these whole-cell calcium oscillations are stochastic, which poses a significant challenge for modelling. In this review, we take a closer look at recently developed statistical approaches to calcium oscillations. These models describe the timing of whole-cell calcium spikes, yet their parametrisations reflect subcellular processes. We show how non-stationary calcium spike sequences, which e.g. occur during slow depletion of intracellular calcium stores or in the presence of time-dependent stimulation, can be analysed with the help of so-called intensity functions. By utilising Bayesian concepts, we demonstrate how values of key parameters of the statistical model can be inferred from single cell calcium spike sequences and illustrate what information whole-cell statistical models can provide about the subcellular mechanistic processes that drive calcium oscillations. In particular, we find that the interspike interval distribution of HEK293 cells under constant stimulation is captured by a Gamma distribution.
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Affiliation(s)
- Jake Powell
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - Martin Falcke
- Max Delbrück Centre for Molecular Medicine, Berlin, Germany.,Department of Physics, Humboldt University, Berlin, Germany
| | - Alexander Skupin
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belval, Luxembourg.,National Biomedical Computation Resource, University California San Diego, La Jolla, CA, USA
| | - Tomas C Bellamy
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Theodore Kypraios
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - Rüdiger Thul
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK.
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12
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Du F, Bai L, He M, Zhang WY, Gu YY, Yin H, Liu YJ. Design, synthesis and biological evaluation of iridium(III) complexes as potential antitumor agents. J Inorg Biochem 2019; 201:110822. [DOI: 10.1016/j.jinorgbio.2019.110822] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/02/2019] [Accepted: 09/02/2019] [Indexed: 12/11/2022]
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13
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Uwada J, Yazawa T, Nakazawa H, Mikami D, Krug SM, Fromm M, Sada K, Muramatsu I, Taniguchi T. Store-operated calcium entry (SOCE) contributes to phosphorylation of p38 MAPK and suppression of TNF-α signalling in the intestinal epithelial cells. Cell Signal 2019; 63:109358. [PMID: 31295519 DOI: 10.1016/j.cellsig.2019.109358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/25/2019] [Accepted: 07/06/2019] [Indexed: 01/31/2023]
Abstract
Calcium influx via store-operated calcium entry (SOCE) has an important role for regulation of vast majority of cellular physiological events. MAPK signalling is also another pivotal modulator of many cellular functions. However, the relationship between SOCE and MAPK is not well understood. In this study, we elucidated the involvement of SOCE in Gαq/11 protein-mediated activation of p38 MAPK in an intestinal epithelial cell line HT-29/B6. In this cell line, we previously showed that the stimulation of M3 muscarinic acetylcholine receptor (M3-mAChR) but not histamine H1 receptor (H1R) led to phosphorylation of p38 MAPK which suppressed tumor necrosis factor-α (TNF-α)-induced NF-κB signalling through ADAM17 protease-mediated shedding of TNF receptor-1 (TNFR1). First, we found that stimulation of M3-mAChR and protease-activated receptor-2 (PAR-2) but not H1R induced persistent upregulation of cytosolic Ca2+ concentration through SOCE. Activation of M3-mAChR or PAR-2 also suppressed TNF-α-induced NF-κB phosphorylation, which was dependent on the p38 MAPK activity. Time course experiments revealed that M3-mAChR stimulation evoked intracellular Ca2+-dependent early phase p38 MAPK phosphorylation and extracellular Ca2+-dependent later phase p38 MAPK phosphorylation. This later phase p38 MAPK phosphorylation, evoked by M3-mAChRs or PAR-2, was abolished by inhibition of SOCE. Thapsigargin or ionomycin also phosphorylate p38 MAPK by Ca2+ influx through SOCE, leading to suppression of TNF-α-induced NF-κB phosphorylation. Finally, we showed that p38 MAPK was essential for thapsigargin-induced cleavage of TNFR1 and suppression of TNF-α-induced NF-κB phosphorylation. In conclusion, SOCE is important for p38 MAPK phosphorylation and is involved in TNF-α signalling suppression.
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Affiliation(s)
- Junsuke Uwada
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan.
| | - Takashi Yazawa
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Hitomi Nakazawa
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Daisuke Mikami
- Department of Nephrology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Susanne M Krug
- Institute of Clinical Physiology, Charité - Universitätsmedizin Berlin, 12203 Berlin, Germany
| | - Michael Fromm
- Institute of Clinical Physiology, Charité - Universitätsmedizin Berlin, 12203 Berlin, Germany
| | - Kiyonao Sada
- Department of Genome Science and Microbiology, University of Fukui, Fukui 910-1193, Japan
| | - Ikunobu Muramatsu
- Department of Pharmacology, Kanazawa Medical University, Kanazawa 920-0293, Japan
| | - Takanobu Taniguchi
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
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14
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Wang L, Yao Y, Wang J, Dong C, Han H. Selective sensing Ca
2+
with a spiropyran‐based fluorometric probe. LUMINESCENCE 2019; 34:707-714. [DOI: 10.1002/bio.3656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Li Wang
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
| | - Yuanjun Yao
- School of Chemistry and Chemical EngineeringShanxi University Taiyuan 030006 China
| | - Jiao Wang
- School of Chemistry and Chemical EngineeringShanxi University Taiyuan 030006 China
| | - Chuan Dong
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
| | - Hui Han
- Institute of Environmental ScienceShanxi University Taiyuan 030006 China
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15
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Liu H, Cui S, Shi F, Pu S. A highly selective fluorescent sensor for Ca2+ and Sr2+ based on diarylethene with a furan-carbohydrazide unit. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.05.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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16
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Prole DL, Taylor CW. A genetically encoded toolkit of functionalized nanobodies against fluorescent proteins for visualizing and manipulating intracellular signalling. BMC Biol 2019; 17:41. [PMID: 31122229 PMCID: PMC6533734 DOI: 10.1186/s12915-019-0662-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Intrabodies enable targeting of proteins in live cells, but generating specific intrabodies against the thousands of proteins in a proteome poses a challenge. We leverage the widespread availability of fluorescently labelled proteins to visualize and manipulate intracellular signalling pathways in live cells by using nanobodies targeting fluorescent protein tags. RESULTS We generated a toolkit of plasmids encoding nanobodies against red and green fluorescent proteins (RFP and GFP variants), fused to functional modules. These include fluorescent sensors for visualization of Ca2+, H+ and ATP/ADP dynamics; oligomerising or heterodimerising modules that allow recruitment or sequestration of proteins and identification of membrane contact sites between organelles; SNAP tags that allow labelling with fluorescent dyes and targeted chromophore-assisted light inactivation; and nanobodies targeted to lumenal sub-compartments of the secretory pathway. We also developed two methods for crosslinking tagged proteins: a dimeric nanobody, and RFP-targeting and GFP-targeting nanobodies fused to complementary hetero-dimerizing domains. We show various applications of the toolkit and demonstrate, for example, that IP3 receptors deliver Ca2+ to the outer membrane of only a subset of mitochondria and that only one or two sites on a mitochondrion form membrane contacts with the plasma membrane. CONCLUSIONS This toolkit greatly expands the utility of intrabodies and will enable a range of approaches for studying and manipulating cell signalling in live cells.
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Affiliation(s)
- David L Prole
- 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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17
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Abstract
Fundamental cell processes such as synaptic neurotransmitter release, endocrine hormone secretion, and myocyte contraction are controlled by highly localized calcium (Ca2+) signals resulting from brief openings of trans-membrane Ca2+ channels. On short temporal and spatial scales, the corresponding local Ca2+ nanodomains formed in the vicinity of a single or several open Ca2+ channels can be effectively approximated by quasi-stationary solutions. The rapid buffering approximation (RBA) is one of the most powerful of such approximations, and is based on the assumption of instantaneous equilibration of the bimolecular Ca2+ buffering reaction, combined with the conservation condition for the total Ca2+ and buffer molecule numbers. Previously, RBA has been generalized to an arbitrary arrangement of Ca2+ channels on a flat membrane, in the presence of any number of simple Ca2+ buffers with one-to-one Ca2+ binding stoichiometry. However, many biological buffers have multiple binding sites. For example, buffers and sensors phylogenetically related to calmodulin consist of two Ca2+-binding domains (lobes), with each domain binding two Ca2+ ions in a cooperative manner. Here we consider an extension of RBA to such buffers with two interdependent Ca2+ binding sites. We show that in the presence of such buffers, RBA solution is given by the solution to a cubic equation, analogous to the quadratic equation describing RBA in the case of a simple, one-to-one Ca2+ buffer. We examine in detail the dependence of RBA accuracy on buffering parameters, to reveal conditions under which RBA provides sufficient precision.
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Affiliation(s)
- Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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18
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Distelhorst CW. Targeting Bcl-2-IP 3 receptor interaction to treat cancer: A novel approach inspired by nearly a century treating cancer with adrenal corticosteroid hormones. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1795-1804. [PMID: 30053503 DOI: 10.1016/j.bbamcr.2018.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/12/2022]
Abstract
Bcl-2 inhibits cell death by at least two different mechanisms. On the one hand, its BH3 domain binds to pro-apoptotic proteins such as Bim and prevents apoptosis induction. On the other hand, the BH4 domain of Bcl-2 binds to the inositol 1,4,5-trisphosphate receptor (IP3R), preventing Ca2+ signals that mediate cell death. In normal T-cells, Bcl-2 levels increase during the immune response, protecting against cell death, and then decline as apoptosis ensues and the immune response dissipates. But in many cancers Bcl-2 is aberrantly expressed and exploited to prevent cell death by inhibiting IP3R-mediated Ca2+ elevation. This review summarizes what is known about the mechanism of Bcl-2's control over IP3R-mediated Ca2+ release and cell death induction. Early insights into the role of Ca2+ elevation in corticosteroid-mediated cell death serves as a model for how targeting IP3R-mediated Ca2+ elevation can be a highly effective therapeutic approach for different types of cancer. Moreover, the successful development of ABT-199 (Venetoclax), a small molecule targeting the BH3 domain of Bcl-2 but without effects on Ca2+, serves as proof of principle that targeting Bcl-2 can be an effective therapeutic approach. BIRD-2, a synthetic peptide that inhibits Bcl-2-IP3R interaction, induces cell death induction in ABT-199 (Venetoclax)-resistant cancer models, attesting to the value of developing therapeutic agents that selectively target Bcl-2-IP3R interaction, inducing Ca2+-mediated cell death.
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Affiliation(s)
- Clark W Distelhorst
- Case Western University School of Medicine, Case Comprehensive Cancer Center, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, United States of America.
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Cyclic AMP Recruits a Discrete Intracellular Ca 2+ Store by Unmasking Hypersensitive IP 3 Receptors. Cell Rep 2017; 18:711-722. [PMID: 28099849 PMCID: PMC5276804 DOI: 10.1016/j.celrep.2016.12.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/17/2016] [Accepted: 12/19/2016] [Indexed: 12/12/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) stimulates Ca2+ release from the endoplasmic reticulum (ER), and the response is potentiated by 3′,5′-cyclic AMP (cAMP). We investigated this interaction in HEK293 cells using carbachol and parathyroid hormone (PTH) to stimulate formation of IP3 and cAMP, respectively. PTH alone had no effect on the cytosolic Ca2+ concentration, but it potentiated the Ca2+ signals evoked by carbachol. Surprisingly, however, the intracellular Ca2+ stores that respond to carbachol alone could be both emptied and refilled without affecting the subsequent response to PTH. We provide evidence that PTH unmasks high-affinity IP3 receptors within a discrete Ca2+ store. We conclude that Ca2+ stores within the ER that dynamically exchange Ca2+ with the cytosol maintain a functional independence that allows one store to be released by carbachol and another to be released by carbachol with PTH. Compartmentalization of ER Ca2+ stores adds versatility to IP3-evoked Ca2+ signals. Cyclic AMP directly potentiates IP3-evoked Ca2+ release The Ca2+ stores released by IP3 alone or IP3 with cAMP are functionally independent Cyclic AMP unmasks high-affinity IP3 receptors in a discrete ER Ca2+ store Independent regulation of discrete Ca2+ stores increases signaling versatility
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20
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Matveev V. Padé Approximation of a Stationary Single-Channel Ca 2+ Nanodomain. Biophys J 2017; 111:2062-2074. [PMID: 27806286 DOI: 10.1016/j.bpj.2016.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/09/2016] [Accepted: 09/14/2016] [Indexed: 11/30/2022] Open
Abstract
We consider the stationary solution for the Ca2+ concentration near a point Ca2+ source describing a single-channel Ca2+ nanodomain, in the presence of a single mobile buffer with one-to-one Ca2+ binding stoichiometry. Previously, a number of Ca2+ nanodomains approximations have been developed, for instance the excess buffer approximation (EBA), the rapid buffering approximation (RBA), and the linear approximation (LIN), each valid for appropriate buffering conditions. Apart from providing a simple method of estimating Ca2+ and buffer concentrations without resorting to computationally expensive numerical solution of reaction-diffusion equations, such approximations proved useful in revealing the dependence of nanodomain Ca2+ distribution on crucial parameters such as buffer mobility and its Ca2+ binding properties. In this study, we present a different form of analytic approximation, which is based on matching the short-range Taylor series of the nanodomain concentration with the long-range asymptotic series expressed in inverse powers of distance from channel location. Namely, we use a "dual" Padé rational function approximation to simultaneously match terms in the short- and the long-range series, and we show that this provides an accurate approximation to the nanodomain Ca2+ and buffer concentrations. We compare this approximation with the previously obtained approximations and show that it yields a better estimate of the free buffer concentration for a wide range of buffering conditions. The drawback of our method is that it has a complex algebraic form for any order higher than the lowest bilinear order, and cannot be readily extended to multiple Ca2+ channels. However, it may be possible to extend the Padé method to estimate Ca2+ nanodomains in the presence of cooperative Ca2+ buffers with two Ca2+ binding sites, the case that existing methods do not address.
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Affiliation(s)
- V Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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21
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Calcium spikes, waves and oscillations in a large, patterned epithelial tissue. Sci Rep 2017; 7:42786. [PMID: 28218282 PMCID: PMC5317010 DOI: 10.1038/srep42786] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 01/17/2017] [Indexed: 12/31/2022] Open
Abstract
While calcium signaling in excitable cells, such as muscle or neurons, is extensively characterized, calcium signaling in epithelial tissues is little understood. Specifically, the range of intercellular calcium signaling patterns elicited by tightly coupled epithelial cells and their function in the regulation of epithelial characteristics are little explored. We found that in Drosophila imaginal discs, a widely studied epithelial model organ, complex spatiotemporal calcium dynamics occur. We describe patterns that include intercellular waves traversing large tissue domains in striking oscillatory patterns as well as spikes confined to local domains of neighboring cells. The spatiotemporal characteristics of intercellular waves and oscillations arise as emergent properties of calcium mobilization within a sheet of gap-junction coupled cells and are influenced by cell size and environmental history. While the in vivo function of spikes, waves and oscillations requires further characterization, our genetic experiments suggest that core calcium signaling components guide actomyosin organization. Our study thus suggests a possible role for calcium signaling in epithelia but importantly, introduces a model epithelium enabling the dissection of cellular mechanisms supporting the initiation, transmission and regeneration of long-range intercellular calcium waves and the emergence of oscillations in a highly coupled multicellular sheet.
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Dickinson GD, Ellefsen KL, Dawson SP, Pearson JE, Parker I. Hindered cytoplasmic diffusion of inositol trisphosphate restricts its cellular range of action. Sci Signal 2016; 9:ra108. [PMID: 27919026 DOI: 10.1126/scisignal.aag1625] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The range of action of intracellular messengers is determined by their rates of diffusion and degradation. Previous measurements in oocyte cytoplasmic extracts indicated that the Ca2+-liberating second messenger inositol trisphosphate (IP3) diffuses with a coefficient (~280 μm2 s-1) similar to that in water, corresponding to a range of action of ~25 μm. Consequently, IP3 is generally considered a "global" cellular messenger. We reexamined this issue by measuring local IP3-evoked Ca2+ puffs to monitor IP3 diffusing from spot photorelease in neuroblastoma cells. Fitting these data by numerical simulations yielded a diffusion coefficient (≤10 μm2 s-1) about 30-fold slower than that previously reported. We propose that diffusion of IP3 in mammalian cells is hindered by binding to immobile, functionally inactive receptors that were diluted in oocyte extracts. The predicted range of action of IP3 (<5 μm) is thus smaller than the size of typical mammalian cells, indicating that IP3 should better be considered as a local rather than a global cellular messenger.
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Affiliation(s)
- George D Dickinson
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA.
| | - Kyle L Ellefsen
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | | | - John E Pearson
- Theoretical Biology and Biophysics, T-10 MS K710, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA.,Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA
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23
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Determining the Roles of Inositol Trisphosphate Receptors in Neurodegeneration: Interdisciplinary Perspectives on a Complex Topic. Mol Neurobiol 2016; 54:6870-6884. [PMID: 27771899 DOI: 10.1007/s12035-016-0205-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023]
Abstract
It is well known that calcium (Ca2+) is involved in the triggering of neuronal death. Ca2+ cytosolic levels are regulated by Ca2+ release from internal stores located in organelles, such as the endoplasmic reticulum. Indeed, Ca2+ transit from distinct cell compartments follows complex dynamics that are mediated by specific receptors, notably inositol trisphosphate receptors (IP3Rs). Ca2+ release by IP3Rs plays essential roles in several neurological disorders; however, details of these processes are poorly understood. Moreover, recent studies have shown that subcellular location, molecular identity, and density of IP3Rs profoundly affect Ca2+ transit in neurons. Therefore, regulation of IP3R gene products in specific cellular vicinities seems to be crucial in a wide range of cellular processes from neuroprotection to neurodegeneration. In this regard, microRNAs seem to govern not only IP3Rs translation levels but also subcellular accumulation. Combining new data from molecular cell biology with mathematical modelling, we were able to summarize the state of the art on this topic. In addition to presenting how Ca2+ dynamics mediated by IP3R activation follow a stochastic regimen, we integrated a theoretical approach in an easy-to-apply, cell biology-coherent fashion. Following the presented premises and in contrast to previously tested hypotheses, Ca2+ released by IP3Rs may play different roles in specific neurological diseases, including Alzheimer's disease and Parkinson's disease.
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Imperatore R, Palomba L, Morello G, Spiezio AD, Piscitelli F, Marzo VD, Cristino L. Formation of OX-1R/CB 1 R heteromeric complexes in embryonic mouse hypothalamic cells: Effect on intracellular calcium, 2-arachidonoyl-glycerol biosynthesis and ERK phosphorylation. Pharmacol Res 2016; 111:600-609. [DOI: 10.1016/j.phrs.2016.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/27/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022]
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25
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Prole DL, Taylor CW. Inositol 1,4,5-trisphosphate receptors and their protein partners as signalling hubs. J Physiol 2016; 594:2849-66. [PMID: 26830355 PMCID: PMC4887697 DOI: 10.1113/jp271139] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/06/2015] [Indexed: 01/26/2023] Open
Abstract
Inositol 1,4,5‐trisphosphate receptors (IP3Rs) are expressed in nearly all animal cells, where they mediate the release of Ca2+ from intracellular stores. The complex spatial and temporal organization of the ensuing intracellular Ca2+ signals allows selective regulation of diverse physiological responses. Interactions of IP3Rs with other proteins contribute to the specificity and speed of Ca2+ signalling pathways, and to their capacity to integrate information from other signalling pathways. In this review, we provide a comprehensive survey of the proteins proposed to interact with IP3Rs and the functional effects that these interactions produce. Interacting proteins can determine the activity of IP3Rs, facilitate their regulation by multiple signalling pathways and direct the Ca2+ that they release to specific targets. We suggest that IP3Rs function as signalling hubs through which diverse inputs are processed and then emerge as cytosolic Ca2+ signals.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
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26
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Fluorescence methods for analysis of interactions between Ca(2+) signaling, lysosomes, and endoplasmic reticulum. Methods Cell Biol 2015. [PMID: 25665449 DOI: 10.1016/bs.mcb.2014.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The endoplasmic reticulum (ER) is both the major source of intracellular Ca(2+) for cell signaling and the organelle that forms the most extensive contacts with the plasma membrane and other organelles. Lysosomes fulfill important roles in degrading cellular materials and in cholesterol handling, but they also contribute to Ca(2+) signaling by both releasing and sequestering Ca(2+). Interactions between ER and other Ca(2+)-transporting membranes, notably mitochondria and the plasma membrane, often occur at sites where the two membranes are closely apposed, allowing local Ca(2+) signaling between them. These interactions are often facilitated by scaffold proteins. Recent evidence suggests similar local interactions between ER and lysosomes. We describe simple fluorescence-based methods that allow the interplay between Ca(2+) signals, the ER, and lysosomes to be examined.
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27
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Putula J, Pihlajamaa T, Kukkonen JP. Calcium affects OX1 orexin (hypocretin) receptor responses by modifying both orexin binding and the signal transduction machinery. Br J Pharmacol 2014; 171:5816-28. [PMID: 25132134 DOI: 10.1111/bph.12883] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 08/05/2014] [Accepted: 08/12/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE One of the major responses upon orexin receptor activation is Ca(2+) influx, and this influx seems to amplify the other responses mediated by orexin receptors. However, the reduction in Ca(2+) , often used to assess the importance of Ca(2+) influx, might affect other properties, like ligand-receptor interactions, as suggested for some GPCR systems. Hence, we investigated the role of the ligand-receptor interaction and Ca(2+) signal cascades in the apparent Ca(2+) requirement of orexin-A signalling. EXPERIMENTAL APPROACH Receptor binding was assessed in CHO cells expressing human OX1 receptors with [(125) I]-orexin-A by conventional ligand binding as well as scintillation proximity assays. PLC activity was determined by chromatography. KEY RESULTS Both orexin receptor binding and PLC activation were strongly dependent on the extracellular Ca(2+) concentration. The relationship between Ca(2+) concentration and receptor binding was the same as that for PLC activation. However, when Ca(2+) entry was reduced by depolarizing the cells or by inhibiting the receptor-operated Ca(2+) channels, orexin-A-stimulated PLC activity was much more strongly inhibited than orexin-A binding. CONCLUSIONS AND IMPLICATIONS Ca(2+) plays a dual role in orexin signalling by being a prerequisite for both ligand-receptor interaction and amplifying orexin signals via Ca(2+) influx. Some previous results obtained utilizing Ca(2+) chelators have to be re-evaluated based on the results of the current study. From a drug discovery perspective, further experiments need to identify the target for Ca(2+) in orexin-A-OX1 receptor interaction and its mechanism of action.
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Affiliation(s)
- Jaana Putula
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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28
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Kukkonen JP, Leonard CS. Orexin/hypocretin receptor signalling cascades. Br J Pharmacol 2014; 171:314-31. [PMID: 23902572 DOI: 10.1111/bph.12324] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 07/18/2013] [Accepted: 07/28/2013] [Indexed: 12/16/2022] Open
Abstract
Orexin (hypocretin) peptides and their two known G-protein-coupled receptors play essential roles in sleep-wake control and powerfully influence other systems regulating appetite/metabolism, stress and reward. Consequently, drugs that influence signalling by these receptors may provide novel therapeutic opportunities for treating sleep disorders, obesity and addiction. It is therefore critical to understand how these receptors operate, the nature of the signalling cascades they engage and their physiological targets. In this review, we evaluate what is currently known about orexin receptor signalling cascades, while a sister review (Leonard & Kukkonen, this issue) focuses on tissue-specific responses. The evidence suggests that orexin receptor signalling is multifaceted and is substantially more diverse than originally thought. Indeed, orexin receptors are able to couple to members of at least three G-protein families and possibly other proteins, through which they regulate non-selective cation channels, phospholipases, adenylyl cyclase, and protein and lipid kinases. In the central nervous system, orexin receptors produce neuroexcitation by postsynaptic depolarization via activation of non-selective cation channels, inhibition of K⁺ channels and activation of Na⁺/Ca²⁺ exchange, but they also can stimulate the release of neurotransmitters by presynaptic actions and modulate synaptic plasticity. Ca²⁺ signalling is also prominently influenced by these receptors, both via the classical phospholipase C-Ca²⁺ release pathway and via Ca²⁺ influx, mediated by several pathways. Upon longer-lasting stimulation, plastic effects are observed in some cell types, while others, especially cancer cells, are stimulated to die. Thus, orexin receptor signals appear highly tunable, depending on the milieu in which they are operating.
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Affiliation(s)
- J P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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29
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Liu Q, Du H, Ren X, Bian W, Fan L, Shuang S, Dong C, Hu Q, Choi MMF. Design of ratiometric emission probe with visible light excitation for determination of Ca2+ in living cells. Anal Chem 2014; 86:8025-30. [PMID: 25054689 DOI: 10.1021/ac5022002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An organic salt as a fluorescent probe based on intramolecular charge transfer for Ca(2+) determination is developed. Ca(2+) can be detected by ratiometric emission at 490 and 594 nm with an excitation wavelength of 405 nm. This probe is highly selective for Ca(2+) over other divalent metal cations and displays a large Stokes shift of 189 nm that can avoid interference of the excitation light beam and autofluorescence of biological samples. The dissociation constant for Ca(2+) is 2.25 ± 0.47 μM and pertinent to Ca(2+) detection in cellular resting and dynamic states. The probe demonstrates its application in monitoring Ca(2+) in living cells under confocal microscopic imaging.
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Affiliation(s)
- Qiaoling Liu
- Institute of Environmental Science, and School of Chemistry and Chemical Engineering, Shanxi University , Taiyuan 030006, China
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30
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Fedorenko OA, Popugaeva E, Enomoto M, Stathopulos PB, Ikura M, Bezprozvanny I. Intracellular calcium channels: inositol-1,4,5-trisphosphate receptors. Eur J Pharmacol 2013; 739:39-48. [PMID: 24300389 DOI: 10.1016/j.ejphar.2013.10.074] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 09/28/2013] [Accepted: 10/17/2013] [Indexed: 01/13/2023]
Abstract
The inositol-1,4,5-trisphosphate receptors (InsP3Rs) are the major intracellular Ca(2+)-release channels in cells. Activity of InsP3Rs is essential for elementary and global Ca(2+) events in the cell. There are three InsP3Rs isoforms that are present in mammalian cells. In this review we will focus primarily on InsP3R type 1. The InsP3R1 is a predominant isoform in neurons and it is the most extensively studied isoform. Combination of biophysical and structural methods revealed key mechanisms of InsP3R function and modulation. Cell biological and biochemical studies lead to identification of a large number of InsP3R-binding proteins. InsP3Rs are involved in the regulation of numerous physiological processes, including learning and memory, proliferation, differentiation, development and cell death. Malfunction of InsP3R1 play a role in a number of neurodegenerative disorders and other disease states. InsP3Rs represent a potentially valuable drug target for treatment of these disorders and for modulating activity of neurons and other cells. Future studies will provide better understanding of physiological functions of InsP3Rs in health and disease.
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Affiliation(s)
- Olena A Fedorenko
- Department of Brain Physiology, Bogomoletz Institute of Physiology, 01024 Kiev, Ukraine; State Key Laboratory of Molecular and Cellular Biology, 01024 Kiev, Ukraine
| | - Elena Popugaeva
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, St. Petersburg State Polytechnical University, 195251 St. Petersburg, Russia
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Peter B Stathopulos
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, St. Petersburg State Polytechnical University, 195251 St. Petersburg, Russia; Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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31
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Taylor CW, Tovey SC, Rossi AM. High-throughput analyses of IP3 receptor behavior. Cold Spring Harb Protoc 2013; 2013:914-7. [PMID: 24086047 DOI: 10.1101/pdb.top066100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca(2+) channels. They are expressed in most animal cells and mediate release of Ca(2+) from the endoplasmic reticulum (ER) in response to the many stimuli that evoke formation of inositol 1,4,5-trisphosphate (IP3). The opening of individual IP3Rs causes small, transient, local increases in cytosolic Ca(2+) concentration, and these events are the fundamental units of Ca(2+) signaling. These openings allow Ca(2+) signals to be selectively delivered by individual channels to the specific Ca(2+) sensors that evoke cellular responses. Stimulation of IP3Rs by the Ca(2+) they release allows these tiny events to grow into much larger ones by recruitment of neighboring IP3Rs. Understanding how Ca(2+) effectively and specifically regulates so many cellular processes demands an understanding of the interplay between IP3 and Ca(2+) in controlling IP3R gating. Here, we briefly set the scene before introducing high-throughput methods that seek to address this issue.
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Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
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32
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Redweik S, Cianciulli C, Hara M, Xu Y, Wätzig H. Precise, fast and flexible determination of protein interactions by affinity capillary electrophoresis. Part 2: Cations. Electrophoresis 2013; 34:1812-9. [DOI: 10.1002/elps.201300050] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/21/2013] [Accepted: 02/21/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Sabine Redweik
- Institute of Medicinal and Pharmaceutical Chemistry; TU Braunschweig; Braunschweig; Germany
| | - Claudia Cianciulli
- Institute of Medicinal and Pharmaceutical Chemistry; TU Braunschweig; Braunschweig; Germany
| | - Masakazu Hara
- Department of Applied Biological Chemistry; Shizuoka University; Shizuoka; Japan
| | | | - Hermann Wätzig
- Institute of Medicinal and Pharmaceutical Chemistry; TU Braunschweig; Braunschweig; Germany
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33
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Pilla AA. Nonthermal electromagnetic fields: From first messenger to therapeutic applications. Electromagn Biol Med 2013; 32:123-36. [DOI: 10.3109/15368378.2013.776335] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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CaBP1, a neuronal Ca2+ sensor protein, inhibits inositol trisphosphate receptors by clamping intersubunit interactions. Proc Natl Acad Sci U S A 2013; 110:8507-12. [PMID: 23650371 DOI: 10.1073/pnas.1220847110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcium-binding protein 1 (CaBP1) is a neuron-specific member of the calmodulin superfamily that regulates several Ca(2+) channels, including inositol 1,4,5-trisphosphate receptors (InsP3Rs). CaBP1 alone does not affect InsP3R activity, but it inhibits InsP3-evoked Ca(2+) release by slowing the rate of InsP3R opening. The inhibition is enhanced by Ca(2+) binding to both the InsP3R and CaBP1. CaBP1 binds via its C lobe to the cytosolic N-terminal region (NT; residues 1-604) of InsP3R1. NMR paramagnetic relaxation enhancement analysis demonstrates that a cluster of hydrophobic residues (V101, L104, and V162) within the C lobe of CaBP1 that are exposed after Ca(2+) binding interact with a complementary cluster of hydrophobic residues (L302, I364, and L393) in the β-domain of the InsP3-binding core. These residues are essential for CaBP1 binding to the NT and for inhibition of InsP3R activity by CaBP1. Docking analyses and paramagnetic relaxation enhancement structural restraints suggest that CaBP1 forms an extended tetrameric turret attached by the tetrameric NT to the cytosolic vestibule of the InsP3R pore. InsP3 activates InsP3Rs by initiating conformational changes that lead to disruption of an intersubunit interaction between a "hot-spot" loop in the suppressor domain (residues 1-223) and the InsP3-binding core β-domain. Targeted cross-linking of residues that contribute to this interface show that InsP3 attenuates cross-linking, whereas CaBP1 promotes it. We conclude that CaBP1 inhibits InsP3R activity by restricting the intersubunit movements that initiate gating.
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35
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Wang Y, Jin Y. Perfluorooctane sulfonate (PFOS) and calcium channel downstream signaling molecules. Toxicol Res (Camb) 2012. [DOI: 10.1039/c2tx20017a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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