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Greene D, Shiferaw Y. A structure-based computational model of IP 3R1 incorporating Ca and IP3 regulation. Biophys J 2024; 123:1274-1288. [PMID: 38627970 PMCID: PMC11140470 DOI: 10.1016/j.bpj.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/20/2024] [Accepted: 04/12/2024] [Indexed: 05/02/2024] Open
Abstract
The inositol 1,4,5-triphosphate receptor (IP3R) mediates Ca release in many cell types and is pivotal to a wide range of cellular processes. High-resolution cryoelectron microscopy studies have provided new structural details of IP3R type 1 (IP3R1), showing that channel function is determined by the movement of various domains within and between each of its four subunits. Channel properties are regulated by ligands, such as Ca and IP3, which bind at specific sites and control the interactions between these domains. However, it is not known how the various ligand-binding sites on IP3R1 interact to control the opening of the channel. In this study, we present a coarse-grained model of IP3R1 that accounts for the channel architecture and the location of specific Ca- and IP3-binding sites. This computational model accounts for the domain-domain interactions within and between the four subunits that form IP3R1, and it also describes how ligand binding regulates these interactions. Using a kinetic model, we explore how two Ca-binding sites on the cytosolic side of the channel interact with the IP3-binding site to regulate the channel open probability. Our primary finding is that the bell-shaped open probability of IP3R1 provides constraints on the relative strength of these regulatory binding sites. In particular, we argue that a specific Ca-binding site, whose function has not yet been established, is very likely a channel antagonist. Additionally, we apply our model to show that domain-domain interactions between neighboring subunits exert control over channel cooperativity and dictate the nonlinear response of the channel to Ca concentration. This suggests that specific domain-domain interactions play a pivotal role in maintaining the channel's stability, and a disruption of these interactions may underlie disease states associated with Ca dysregulation.
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Affiliation(s)
- D'Artagnan Greene
- Department of Physics & Astronomy, California State University, Northridge, California
| | - Yohannes Shiferaw
- Department of Physics & Astronomy, California State University, Northridge, California.
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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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Yuan Y, Arige V, Saito R, Mu Q, Brailoiu GC, Pereira GJS, Bolsover SR, Keller M, Bracher F, Grimm C, Brailoiu E, Marchant JS, Yule DI, Patel S. Two-pore channel-2 and inositol trisphosphate receptors coordinate Ca 2+ signals between lysosomes and the endoplasmic reticulum. Cell Rep 2024; 43:113628. [PMID: 38160394 PMCID: PMC10931537 DOI: 10.1016/j.celrep.2023.113628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/13/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024] Open
Abstract
Lysosomes and the endoplasmic reticulum (ER) are Ca2+ stores mobilized by the second messengers NAADP and IP3, respectively. Here, we establish Ca2+ signals between the two sources as fundamental building blocks that couple local release to global changes in Ca2+. Cell-wide Ca2+ signals evoked by activation of endogenous NAADP-sensitive channels on lysosomes comprise both local and global components and exhibit a major dependence on ER Ca2+ despite their lysosomal origin. Knockout of ER IP3 receptor channels delays these signals, whereas expression of lysosomal TPC2 channels accelerates them. High-resolution Ca2+ imaging reveals elementary events upon TPC2 opening and signals coupled to IP3 receptors. Biasing TPC2 activation to a Ca2+-permeable state sensitizes local Ca2+ signals to IP3. This increases the potency of a physiological agonist to evoke global Ca2+ signals and activate a downstream target. Our data provide a conceptual framework to understand how Ca2+ release from physically separated stores is coordinated.
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Affiliation(s)
- Yu Yuan
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK
| | - Vikas Arige
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Ryo Saito
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK; Department of Dermatology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Qianru Mu
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK
| | - Gabriela C Brailoiu
- Department of Pharmaceutical Sciences, Jefferson College of Pharmacy, Thomas Jefferson University, 901 Walnut Street, Philadelphia, PA 19107, USA
| | - Gustavo J S Pereira
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK; Department of Pharmacology, Federal University of São Paulo (UNIFESP), São Paulo 04044-020, Brazil
| | - Stephen R Bolsover
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK
| | - Marco Keller
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilian University, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - Franz Bracher
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilian University, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilian University, Nussbaumstrasse 26, 80336 Munich, Germany; Immunology, Infection and Pandemic Research IIP, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, 60596 Frankfurt, Germany
| | - Eugen Brailoiu
- Department of Neural Sciences and Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK.
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Parys JB, Lemos FO. The interplay between associated proteins, redox state and Ca 2+ in the intraluminal ER compartment regulates the IP 3 receptor. Cell Calcium 2024; 117:102823. [PMID: 37976974 DOI: 10.1016/j.ceca.2023.102823] [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: 10/09/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
There have been in the last three decades repeated publications indicating that the inositol 1,4,5-trisphosphate receptor (IP3R) is regulated not only by cytosolic Ca2+ but also by intraluminal Ca2+. Although most studies indicated that a decreasing intraluminal Ca2+ level led to an inhibition of the IP3R, a number of publications reported exactly the opposite effect, i.e. an inhibition of the IP3R by high intraluminal Ca2+ levels. Although intraluminal Ca2+-binding sites on the IP3Rs were reported, a regulatory role for them was not demonstrated. It is also well known that the IP3R is regulated by a vast array of associated proteins, but only relatively recently proteins were identified that can be linked to the regulation of the IP3R by intraluminal Ca2+. The first to be reported was annexin A1 that is proposed to associate with the second intraluminal loop of the IP3R at high intraluminal Ca2+ levels and to inhibit the IP3R. More recently, ERdj5/PDIA19 reductase was described to reduce an intraluminal disulfide bridge of IP3R1 only at low intraluminal Ca2+ levels and thereby to inhibit the IP3R. Annexin A1 and ERdj5/PDIA19 can therefore explain most of the experimental results on the regulation of the IP3R by intraluminal Ca2+. Further studies are needed to provide a fuller understanding of the regulation of the IP3R from the intraluminal side. These findings underscore the importance of the state of the endoplasmic reticulum in the control of IP3R activity.
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Affiliation(s)
- Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), Campus Gasthuisberg O&N1 - Box 802, Herestraat 49, B-3000, Leuven, Belgium.
| | - Fernanda O Lemos
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut (LKI), Campus Gasthuisberg O&N1 - Box 802, Herestraat 49, B-3000, Leuven, Belgium
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Gao X, Keller KR, Bonzerato CG, Li P, Laemmerhofer M, Wojcikiewicz RJH. The ubiquitin-proteasome pathway inhibitor TAK-243 has major effects on calcium handling in mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119618. [PMID: 37907195 DOI: 10.1016/j.bbamcr.2023.119618] [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: 08/11/2023] [Revised: 10/17/2023] [Accepted: 10/22/2023] [Indexed: 11/02/2023]
Abstract
The ubiquitin-proteasome pathway (UPP) is a major route for protein degradation and a key regulatory mechanism in mammalian cells. UPP inhibitors, including TAK-243, a first-in-class inhibitor of the E1 ubiquitin-activating enzyme, are currently being used and tested for treatment of a range of diseases, particularly cancer. Here, we reveal that TAK-243 has major effects on Ca2+ handling in a range of cultured mammalian cells (αT3, HeLa and SH-SY5Y). Effects were seen on agonist-induced Ca2+ mobilization, basal cytosolic Ca2+ levels, Ca2+ leak from the endoplasmic reticulum (ER), store-operated Ca2+ entry and mitochondrial Ca2+ uptake. These effects correlated with induction of ER stress, as measured by PERK activation / eIF2α phosphorylation, and most seemed to be underpinned by enhanced Ca2+ leak from the ER. Overall, these data indicate that TAK-243 reprograms the Ca2+-handling properties of mammalian cells and that these effects should be considered when UPP inhibitors are employed as therapeutic agents.
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Affiliation(s)
- Xiaokong Gao
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Katherine R Keller
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Caden G Bonzerato
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Peng Li
- Institute of Pharmaceutical Sciences, University of Tuebingen, Tuebingen 72076, Germany
| | - Michael Laemmerhofer
- Institute of Pharmaceutical Sciences, University of Tuebingen, Tuebingen 72076, Germany
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Albalawi SS, Aljabri A, Alshibani M, Al-Gayyar MM. The Involvement of Calcium Channels in the Endoplasmic Reticulum Membrane in Nonalcoholic Fatty Liver Disease Pathogenesis. Cureus 2023; 15:e49150. [PMID: 38024063 PMCID: PMC10663096 DOI: 10.7759/cureus.49150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2023] [Indexed: 12/01/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a prevalent and complex condition that affects millions of people globally. It occurs when fat, primarily triglycerides, accumulates in liver cells, leading to inflammation and damage. Calcium, an essential mineral, is involved in various physiological processes, including the regeneration process following liver injury. The endoplasmic reticulum (ER), a complex organelle involved in protein synthesis and lipid metabolism, regulates intracellular calcium levels. Dysregulation of this process can lead to calcium overload, oxidative stress, and cellular damage, all of which are hallmarks of NAFLD. Inositol 1,4,5-trisphosphate receptor (IP3R), a type of calcium ion channel, is found throughout the body, including the liver. IP3R is classified into three subtypes: IP3R1, IP3R2, and IP3R3, and it plays a critical role in regulating intracellular calcium levels. However, excessive calcium accumulation in the mitochondria due to an overload of calcium ions or increased IP3R activity can lead to NAFLD. Therefore, targeting calcium channels in the ER membrane may represent a promising therapeutic strategy for preventing and treating this increasingly prevalent metabolic disorder. It may help prevent mitochondrial calcium accumulation and reduce the risk of hepatic damage. This review article aimed to review the relationship between IP3R modulation and the pathogenicity of NAFLD, providing valuable insights to help researchers develop more effective treatments for the condition.
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Affiliation(s)
- Sarah S Albalawi
- PharmD Program, Faculty of Pharmacy, University of Tabuk, Tabuk, SAU
| | - Ahmed Aljabri
- Pharmacy Practice, Faculty of Pharmacy, King Abdulaziz University, Jeddah, SAU
- Pharmacy Practice, Faculty of Pharmacy, University of Tabuk, Tabuk, SAU
| | - Mohannad Alshibani
- Pharmacy Practice, Faculty of Pharmacy, King Abdulaziz University, Jeddah, SAU
| | - Mohammed M Al-Gayyar
- Pharmaceutical Chemistry, Faculty of Pharmacy, University of Tabuk, Tabuk, SAU
- Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, EGY
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