1
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Gök C, Fuller W. Rise of palmitoylation: A new trick to tune NCX1 activity. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119719. [PMID: 38574822 DOI: 10.1016/j.bbamcr.2024.119719] [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: 12/22/2023] [Revised: 03/11/2024] [Accepted: 03/27/2024] [Indexed: 04/06/2024]
Abstract
The cardiac Na+/Ca2+ Exchanger (NCX1) controls transmembrane calcium flux in numerous tissues. The only reversible post-translational modification established to regulate NCX1 is palmitoylation, which alters the ability of the exchanger to inactivate. Palmitoylation creates a binding site for the endogenous XIP domain, a region of the NCX1 intracellular loop established to inactivate NCX1. The binding site created by NCX1 palmitoylation sensitizes the transporter to XIP. Herein we summarize our recent knowledge on NCX1 palmitoylation and its association with cardiac pathologies, and discuss these findings in the light of the recent cryo-EM structures of human NCX1.
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Affiliation(s)
- Caglar Gök
- School of Cardiovascular and Metabolic Health (SCMH), Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
| | - William Fuller
- School of Cardiovascular and Metabolic Health (SCMH), Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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2
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Giladi M, Fojtík L, Strauss T, Da'adoosh B, Hiller R, Man P, Khananshvili D. Structural dynamics of Na + and Ca 2+ interactions with full-size mammalian NCX. Commun Biol 2024; 7:463. [PMID: 38627576 PMCID: PMC11021524 DOI: 10.1038/s42003-024-06159-9] [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: 11/26/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Cytosolic Ca2+ and Na+ allosterically regulate Na+/Ca2+ exchanger (NCX) proteins to vary the NCX-mediated Ca2+ entry/exit rates in diverse cell types. To resolve the structure-based dynamic mechanisms underlying the ion-dependent allosteric regulation in mammalian NCXs, we analyze the apo, Ca2+, and Na+-bound species of the brain NCX1.4 variant using hydrogen-deuterium exchange mass spectrometry (HDX-MS) and molecular dynamics (MD) simulations. Ca2+ binding to the cytosolic regulatory domains (CBD1 and CBD2) rigidifies the intracellular regulatory loop (5L6) and promotes its interaction with the membrane domains. Either Na+ or Ca2+ stabilizes the intracellular portions of transmembrane helices TM3, TM4, TM9, TM10, and their connecting loops (3L4 and 9L10), thereby exposing previously unappreciated regulatory sites. Ca2+ or Na+ also rigidifies the palmitoylation domain (TMH2), and neighboring TM1/TM6 bundle, thereby uncovering a structural entity for modulating the ion transport rates. The present analysis provides new structure-dynamic clues underlying the regulatory diversity among tissue-specific NCX variants.
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Affiliation(s)
- Moshe Giladi
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel Aviv, 69978, Israel.
- Tel-Aviv Sourasky Medical Center, Tel Aviv, 6423906, Israel.
| | - Lukáš Fojtík
- Division BioCeV, Institute of Microbiology of the Czech Academy of Sciences, Prumyslova, 595, 252 50 Vestec, Prague, Czech Republic
- Department of Biochemistry, Faculty of Science, Charles University, 128 00, Prague, Czech Republic
| | - Tali Strauss
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - Benny Da'adoosh
- Blavatnik Center for Drug Discovery, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Reuben Hiller
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - Petr Man
- Division BioCeV, Institute of Microbiology of the Czech Academy of Sciences, Prumyslova, 595, 252 50 Vestec, Prague, Czech Republic.
- Department of Biochemistry, Faculty of Science, Charles University, 128 00, Prague, Czech Republic.
| | - Daniel Khananshvili
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel Aviv, 69978, Israel.
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3
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Ashford F, Kuo CW, Dunning E, Brown E, Calagan S, Jayasinghe I, Henderson C, Fuller W, Wypijewski K. Cysteine post-translational modifications regulate protein interactions of caveolin-3. FASEB J 2024; 38:e23535. [PMID: 38466300 DOI: 10.1096/fj.202201497rr] [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: 09/15/2022] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 03/12/2024]
Abstract
Caveolae are small flask-shaped invaginations of the surface membrane which are proposed to recruit and co-localize signaling molecules. The distinctive caveolar shape is achieved by the oligomeric structural protein caveolin, of which three isoforms exist. Aside from the finding that caveolin-3 is specifically expressed in muscle, functional differences between the caveolin isoforms have not been rigorously investigated. Caveolin-3 is relatively cysteine-rich compared to caveolins 1 and 2, so we investigated its cysteine post-translational modifications. We find that caveolin-3 is palmitoylated at 6 cysteines and becomes glutathiolated following redox stress. We map the caveolin-3 palmitoylation sites to a cluster of cysteines in its C terminal membrane domain, and the glutathiolation site to an N terminal cysteine close to the region of caveolin-3 proposed to engage in protein interactions. Glutathiolation abolishes caveolin-3 interaction with heterotrimeric G protein alpha subunits. Our results indicate that a caveolin-3 oligomer contains up to 66 palmitates, compared to up to 33 for caveolin-1. The additional palmitoylation sites in caveolin-3 therefore provide a mechanistic basis by which caveolae in smooth and striated muscle can possess unique phospholipid and protein cargoes. These unique adaptations of the muscle-specific caveolin isoform have important implications for caveolar assembly and signaling.
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Affiliation(s)
- Fiona Ashford
- School of Medicine, University of Dundee, Dundee, UK
| | - Chien-Wen Kuo
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Emma Dunning
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Elaine Brown
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Sarah Calagan
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Izzy Jayasinghe
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | | | - William Fuller
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Krzysztof Wypijewski
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
- School of Life Sciences, University of Dundee, Dundee, UK
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4
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Néré R, Kouba S, Carreras-Sureda A, Demaurex N. S-acylation of Ca2+ transport proteins: molecular basis and functional consequences. Biochem Soc Trans 2024; 52:407-421. [PMID: 38348884 PMCID: PMC10903462 DOI: 10.1042/bst20230818] [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: 12/13/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 02/29/2024]
Abstract
Calcium (Ca2+) regulates a multitude of cellular processes during fertilization and throughout adult life by acting as an intracellular messenger to control effector functions in excitable and non-excitable cells. Changes in intracellular Ca2+ levels are driven by the co-ordinated action of Ca2+ channels, pumps, and exchangers, and the resulting signals are shaped and decoded by Ca2+-binding proteins to drive rapid and long-term cellular processes ranging from neurotransmission and cardiac contraction to gene transcription and cell death. S-acylation, a lipid post-translational modification, is emerging as a critical regulator of several important Ca2+-handling proteins. S-acylation is a reversible and dynamic process involving the attachment of long-chain fatty acids (most commonly palmitate) to cysteine residues of target proteins by a family of 23 proteins acyltransferases (zDHHC, or PATs). S-acylation modifies the conformation of proteins and their interactions with membrane lipids, thereby impacting intra- and intermolecular interactions, protein stability, and subcellular localization. Disruptions of S-acylation can alter Ca2+ signalling and have been implicated in the development of pathologies such as heart disease, neurodegenerative disorders, and cancer. Here, we review the recent literature on the S-acylation of Ca2+ transport proteins of organelles and of the plasma membrane and highlight the molecular basis and functional consequence of their S-acylation as well as the therapeutic potential of targeting this regulation for diseases caused by alterations in cellular Ca2+ fluxes.
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Affiliation(s)
- Raphaël Néré
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Sana Kouba
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Amado Carreras-Sureda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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5
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Essandoh K, Teuber JP, Brody MJ. Regulation of cardiomyocyte intracellular trafficking and signal transduction by protein palmitoylation. Biochem Soc Trans 2024; 52:41-53. [PMID: 38385554 PMCID: PMC10903464 DOI: 10.1042/bst20221296] [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: 12/18/2023] [Revised: 02/08/2024] [Accepted: 02/12/2024] [Indexed: 02/23/2024]
Abstract
Despite the well-established functions of protein palmitoylation in fundamental cellular processes, the roles of this reversible post-translational lipid modification in cardiomyocyte biology remain poorly studied. Palmitoylation is catalyzed by a family of 23 zinc finger and Asp-His-His-Cys domain-containing S-acyltransferases (zDHHC enzymes) and removed by select thioesterases of the lysophospholipase and α/β-hydroxylase domain (ABHD)-containing families of serine hydrolases. Recently, studies utilizing genetic manipulation of zDHHC enzymes in cardiomyocytes have begun to unveil essential functions for these enzymes in regulating cardiac development, homeostasis, and pathogenesis. Palmitoylation co-ordinates cardiac electrophysiology through direct modulation of ion channels and transporters to impact their trafficking or gating properties as well as indirectly through modification of regulators of channels, transporters, and calcium handling machinery. Not surprisingly, palmitoylation has roles in orchestrating the intracellular trafficking of proteins in cardiomyocytes, but also dynamically fine-tunes cardiomyocyte exocytosis and natriuretic peptide secretion. Palmitoylation has emerged as a potent regulator of intracellular signaling in cardiomyocytes, with recent studies uncovering palmitoylation-dependent regulation of small GTPases through direct modification and sarcolemmal targeting of the small GTPases themselves or by modification of regulators of the GTPase cycle. In addition to dynamic control of G protein signaling, cytosolic DNA is sensed and transduced into an inflammatory transcriptional output through palmitoylation-dependent activation of the cGAS-STING pathway, which has been targeted pharmacologically in preclinical models of heart disease. Further research is needed to fully understand the complex regulatory mechanisms governed by protein palmitoylation in cardiomyocytes and potential emerging therapeutic targets.
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Affiliation(s)
- Kobina Essandoh
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, U.S.A
| | - James P. Teuber
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, U.S.A
| | - Matthew J. Brody
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, U.S.A
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, U.S.A
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Deisl C, Moe OW, Hilgemann DW. Constitutive Plasma Membrane Turnover in T-REx293 cells via Ordered Membrane Domain Endocytosis under Mitochondrial Control. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.576124. [PMID: 38293164 PMCID: PMC10827192 DOI: 10.1101/2024.01.17.576124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Clathrin/dynamin-independent endocytosis of ordered plasma membrane domains (ordered membrane domain endocytosis, OMDE) can become massive in response to cytoplasmic Ca elevations, G protein activation by non-hydrolyzable GTP analogs, and enhanced oxidative metabolism. In patch-clamped murine bone marrow macrophages (BMMs), cytoplasmic succinate and pyruvate, but not β-hydroxybutyrate, induce OMDE of 75% of the plasma membrane within 2 min. The responses require palmitoylation of membrane proteins, being decreased by 70% in BMMs lacking the acyltransferase, DHHC5, by treatment with carnitine to shift long-chain acyl groups from cytoplasmic to mitochondrial acyl-CoAs, by bromopalmitate/albumin complexes to block DHHCs, and by the mitochondria-specific cyclosporin, NIM811, to block permeability transition pores that may release mitochondrial coenzyme A into the cytoplasm. Using T-REx293 cells, OMDE amounts to 40% with succinate, pyruvate, or GTPγS, and it is inhibited by actin cytoskeleton disruption. Pyruvate-induced OMDE is blocked by the hydrophobic antioxidant, edaravone, which prevents permeability transition pore openings. Using fluorescent 3kD dextrans to monitor endocytosis, OMDE appears to be constitutively active in T-REx293 cells but not in BMMs. After 1 h without substrates or bicarbonate, pyruvate and hydroxybutyrate inhibit constitutive OMDE, as expected for a shift of CoA from long-chain acyl-CoAs to other CoA metabolites. In the presence of bicarbonate, pyruvate strongly enhances OMDE, which is then blocked by β-hydroxybutyrate, bromopalmitate/albumin complexes, cyclosporines, or edaravone. After pyruvate responses, T-REx293 cells grow normally with no evidence for apoptosis. Fatty acid-free albumin (15 μM) inhibits basal OMDE in T-REx293 cells, as do cyclosporines, carnitine, and RhoA blockade. Surprisingly, OMDE in the absence of substrates and bicarbonate is not inhibited by siRNA knockdown of the acyltransferases, DHHC5 or DHHC2, which are required for activated OMDE in patch clamp experiments. We verify biochemically that small CoA metabolites decrease long-chain acyl-CoAs. We verify also that palmitoylations of many PM-associated proteins decrease and increase when OMDE is inhibited and stimulated, respectively, by different metabolites. STED microscopy reveals that vesicles formed during constitutive OMDE in T-REX293 cells have 90 to 130 nm diameters. In summary, OMDE is likely a major G-protein-dependent endocytic mechanism that can be constitutively active in some cell types, albeit not BMMs. OMDE depends on different DHHC acyltransferases in different circumstances and can be limited by local supplies of fatty acids, CoA, and long-chain acyl-CoAs.
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Affiliation(s)
- Christine Deisl
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Orson W Moe
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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7
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Xue J, Zeng W, Han Y, John S, Ottolia M, Jiang Y. Structural mechanisms of the human cardiac sodium-calcium exchanger NCX1. Nat Commun 2023; 14:6181. [PMID: 37794011 PMCID: PMC10550945 DOI: 10.1038/s41467-023-41885-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/22/2023] [Indexed: 10/06/2023] Open
Abstract
Na+/Ca2+ exchangers (NCX) transport Ca2+ in or out of cells in exchange for Na+. They are ubiquitously expressed and play an essential role in maintaining cytosolic Ca2+ homeostasis. Although extensively studied, little is known about the global structural arrangement of eukaryotic NCXs and the structural mechanisms underlying their regulation by various cellular cues including cytosolic Na+ and Ca2+. Here we present the cryo-EM structures of human cardiac NCX1 in both inactivated and activated states, elucidating key structural elements important for NCX ion exchange function and its modulation by cytosolic Ca2+ and Na+. We demonstrate that the interactions between the ion-transporting transmembrane (TM) domain and the cytosolic regulatory domain define the activity of NCX. In the inward-facing state with low cytosolic [Ca2+], a TM-associated four-stranded β-hub mediates a tight packing between the TM and cytosolic domains, resulting in the formation of a stable inactivation assembly that blocks the TM movement required for ion exchange function. Ca2+ binding to the cytosolic second Ca2+-binding domain (CBD2) disrupts this inactivation assembly which releases its constraint on the TM domain, yielding an active exchanger. Thus, the current NCX1 structures provide an essential framework for the mechanistic understanding of the ion transport and cellular regulation of NCX family proteins.
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Affiliation(s)
- Jing Xue
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Weizhong Zeng
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yan Han
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Scott John
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Youxing Jiang
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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8
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Villanueva CE, Hagenbuch B. Palmitoylation of solute carriers. Biochem Pharmacol 2023; 215:115695. [PMID: 37481134 PMCID: PMC10530500 DOI: 10.1016/j.bcp.2023.115695] [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: 05/06/2023] [Revised: 07/05/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
Post-translational modifications are an important mechanism in the regulation of protein expression, function, and degradation. Well-known post-translational modifications are phosphorylation, glycosylation, and ubiquitination. However, lipid modifications, including myristoylation, prenylation, and palmitoylation, are poorly studied. Since the early 2000s, researchers have become more interested in lipid modifications, especially palmitoylation. The number of articles in PubMed increased from about 350 between 2000 and 2005 to more than 600 annually during the past ten years. S-palmitoylation, where the 16-carbon saturated (C16:0) palmitic acid is added to free cysteine residues of proteins, is a reversible protein modification that can affect the expression, membrane localization, and function of the modified proteins. Various diseases like Huntington's and Alzheimer's disease have been linked to changes in protein palmitoylation. In humans, the addition of palmitic acid is mediated by 23 palmitoyl acyltransferases, also called DHHC proteins. The modification can be reversed by a few thioesterases or hydrolases. Numerous soluble and membrane-attached proteins are known to be palmitoylated, but among the approximately 400 solute carriers that are classified in 66 families, only 15 found in 8 families have so far been documented to be palmitoylated. Among the best-characterized transporters are the glucose transporters GLUT1 (SLC2A1) and GLUT4 (SLC2A4), the three monoamine transporters norepinephrine transporter (NET; SLC6A2), dopamine transporter (DAT; SLC6A3), and serotonin transporter (SERT; SLC6A4), and the sodium-calcium exchanger NCX1 (SLC8A1). While there is evidence from recent proteomics experiments that numerous solute carriers are palmitoylated, no details beyond the 15 transporters covered in this review are available.
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Affiliation(s)
- Cecilia E Villanueva
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States.
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9
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Kadam A, Jadiya P, Tomar D. Post-translational modifications and protein quality control of mitochondrial channels and transporters. Front Cell Dev Biol 2023; 11:1196466. [PMID: 37601094 PMCID: PMC10434574 DOI: 10.3389/fcell.2023.1196466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Mitochondria play a critical role in energy metabolism and signal transduction, which is tightly regulated by proteins, metabolites, and ion fluxes. Metabolites and ion homeostasis are mainly mediated by channels and transporters present on mitochondrial membranes. Mitochondria comprise two distinct compartments, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM), which have differing permeabilities to ions and metabolites. The OMM is semipermeable due to the presence of non-selective molecular pores, while the IMM is highly selective and impermeable due to the presence of specialized channels and transporters which regulate ion and metabolite fluxes. These channels and transporters are modulated by various post-translational modifications (PTMs), including phosphorylation, oxidative modifications, ions, and metabolites binding, glycosylation, acetylation, and others. Additionally, the mitochondrial protein quality control (MPQC) system plays a crucial role in ensuring efficient molecular flux through the mitochondrial membranes by selectively removing mistargeted or defective proteins. Inefficient functioning of the transporters and channels in mitochondria can disrupt cellular homeostasis, leading to the onset of various pathological conditions. In this review, we provide a comprehensive overview of the current understanding of mitochondrial channels and transporters in terms of their functions, PTMs, and quality control mechanisms.
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Affiliation(s)
- Ashlesha Kadam
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Pooja Jadiya
- Department of Internal Medicine, Section of Gerontology and Geriatric Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Dhanendra Tomar
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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10
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Takei GL, Ogura Y, Ujihara Y, Toyama F, Hayashi K, Fujita T. Hamster Sperm Possess Functional Na +/Ca 2+-Exchanger 1: Its Implication in Hyperactivation. Int J Mol Sci 2023; 24:ijms24108905. [PMID: 37240252 DOI: 10.3390/ijms24108905] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Previous studies demonstrated that hamster sperm hyperactivation is suppressed by extracellular Na+ by lowering intracellular Ca2+ levels, and Na+/Ca2+-exchanger (NCX) specific inhibitors canceled the suppressive effects of extracellular Na+. These results suggest the involvement of NCX in the regulation of hyperactivation. However, direct evidence of the presence and functionality of NCX in hamster spermatozoa is still lacking. This study aimed to reveal that NCX is present and is functional in hamster spermatozoa. First, NCX1 and NCX2 transcripts were detected via RNA-seq analyses of hamster testis mRNAs, but only the NCX1 protein was detected. Next, NCX activity was determined by measuring the Na+-dependent Ca2+ influx using the Ca2+ indicator Fura-2. The Na+-dependent Ca2+ influx was detected in hamster spermatozoa, notably in the tail region. The Na+-dependent Ca2+ influx was inhibited by the NCX inhibitor SEA0400 at NCX1-specific concentrations. NCX1 activity was reduced after 3 h of incubation in capacitating conditions. These results, together with authors' previous study, showed that hamster spermatozoa possesses functional NCX1 and that its activity was downregulated upon capacitation to trigger hyperactivation. This is the first study to successfully reveal the presence of NCX1 and its physiological function as a hyperactivation brake.
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Affiliation(s)
- Gen L Takei
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
| | - Yuhei Ogura
- Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yoshihiro Ujihara
- Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Fubito Toyama
- School of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya 321-8585, Japan
| | - Keitaro Hayashi
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
| | - Tomoe Fujita
- Department of Pharmacology and Toxicology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
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11
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Congreve SD, Main A, Butler AS, Gao X, Brown E, Du C, Choisy SC, Cheng H, Hancox JC, Fuller W. Palmitoylation regulates the magnitude of HCN4-mediated currents in mammalian cells. Front Physiol 2023; 14:1163339. [PMID: 37123274 PMCID: PMC10133559 DOI: 10.3389/fphys.2023.1163339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
The sinoatrial node (SAN) and subsidiary pacemakers in the cardiac conduction system generate spontaneous electrical activity which is indispensable for electrical and therefore contractile function of the heart. The hyperpolarisation-activated cyclic nucleotide-gated channel HCN4 is responsible for genesis of the pacemaker "funny" current during diastolic depolarisation. S-palmitoylation, the reversible conjugation of the fatty acid palmitate to protein cysteine sulfhydryls, regulates the activity of key cardiac Na+ and Ca2+ handling proteins, influencing their membrane microdomain localisation and function. We investigated HCN4 palmitoylation and its functional consequences in engineered human embryonic kidney 293T cells as well as endogenous HCN4 in neonatal rat ventricular myocytes. HCN4 was palmitoylated in all experimental systems investigated. We mapped the HCN4 palmitoylation sites to a pair of cysteines in the HCN4 intracellular amino terminus. A double cysteine-to-alanine mutation CC93A/179AA of full length HCN4 caused a ∼67% reduction in palmitoylation in comparison to wild type HCN4. We used whole-cell patch clamp to evaluate HCN4 current (IHCN4) in stably transfected 293T cells. Removal of the two N-terminal palmitoylation sites did not significantly alter half maximal activation voltage of IHCN4 or the activation slope factor. IHCN4 was significantly larger in cells expressing wild type compared to non-palmitoylated HCN4 across a range of voltages. Phylogenetic analysis revealed that although cysteine 93 is widely conserved across all classes of HCN4 vertebrate orthologs, conservation of cysteine 179 is restricted to placental mammals. Collectively, we provide evidence for functional regulation of HCN4 via palmitoylation of its amino terminus in vertebrates. We suggest that by recruiting the amino terminus to the bilayer, palmitoylation enhances the magnitude of HCN4-mediated currents, but does not significantly affect the kinetics.
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Affiliation(s)
- Samitha Dilini Congreve
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Alice Main
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Andrew S. Butler
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Xing Gao
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Elaine Brown
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Stephanié C. Choisy
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Hongwei Cheng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - William Fuller
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
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12
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Kuo CWS, Dobi S, Gök C, Da Silva Costa A, Main A, Robertson-Gray O, Baptista-Hon D, Wypijewski KJ, Costello H, Hales TG, MacQuaide N, Smith GL, Fuller W. Palmitoylation of the pore-forming subunit of Ca(v)1.2 controls channel voltage sensitivity and calcium transients in cardiac myocytes. Proc Natl Acad Sci U S A 2023; 120:e2207887120. [PMID: 36745790 PMCID: PMC9963536 DOI: 10.1073/pnas.2207887120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 12/07/2022] [Indexed: 02/08/2023] Open
Abstract
Mammalian voltage-activated L-type Ca2+ channels, such as Ca(v)1.2, control transmembrane Ca2+ fluxes in numerous excitable tissues. Here, we report that the pore-forming α1C subunit of Ca(v)1.2 is reversibly palmitoylated in rat, rabbit, and human ventricular myocytes. We map the palmitoylation sites to two regions of the channel: The N terminus and the linker between domains I and II. Whole-cell voltage clamping revealed a rightward shift of the Ca(v)1.2 current-voltage relationship when α1C was not palmitoylated. To examine function, we expressed dihydropyridine-resistant α1C in human induced pluripotent stem cell-derived cardiomyocytes and measured Ca2+ transients in the presence of nifedipine to block the endogenous channels. The transients generated by unpalmitoylatable channels displayed a similar activation time course but significantly reduced amplitude compared to those generated by wild-type channels. We thus conclude that palmitoylation controls the voltage sensitivity of Ca(v)1.2. Given that the identified Ca(v)1.2 palmitoylation sites are also conserved in most Ca(v)1 isoforms, we propose that palmitoylation of the pore-forming α1C subunit provides a means to regulate the voltage sensitivity of voltage-activated Ca2+ channels in excitable cells.
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Affiliation(s)
- Chien-Wen S. Kuo
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Sara Dobi
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Caglar Gök
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Ana Da Silva Costa
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Alice Main
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Olivia Robertson-Gray
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Daniel Baptista-Hon
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
- Center for Biomedicine and Innovations, Faculty of Medicine, Macau University of Science and Technology, Macau SAR, 999078China
| | | | - Hannah Costello
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Tim G. Hales
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Niall MacQuaide
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Godfrey L. Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - William Fuller
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
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13
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Structure-Based Function and Regulation of NCX Variants: Updates and Challenges. Int J Mol Sci 2022; 24:ijms24010061. [PMID: 36613523 PMCID: PMC9820601 DOI: 10.3390/ijms24010061] [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] [Received: 10/09/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
The plasma-membrane homeostasis Na+/Ca2+ exchangers (NCXs) mediate Ca2+ extrusion/entry to dynamically shape Ca2+ signaling/in biological systems ranging from bacteria to humans. The NCX gene orthologs, isoforms, and their splice variants are expressed in a tissue-specific manner and exhibit nearly 104-fold differences in the transport rates and regulatory specificities to match the cell-specific requirements. Selective pharmacological targeting of NCX variants could benefit many clinical applications, although this intervention remains challenging, mainly because a full-size structure of eukaryotic NCX is unavailable. The crystal structure of the archaeal NCX_Mj, in conjunction with biophysical, computational, and functional analyses, provided a breakthrough in resolving the ion transport mechanisms. However, NCX_Mj (whose size is nearly three times smaller than that of mammalian NCXs) cannot serve as a structure-dynamic model for imitating high transport rates and regulatory modules possessed by eukaryotic NCXs. The crystal structures of isolated regulatory domains (obtained from eukaryotic NCXs) and their biophysical analyses by SAXS, NMR, FRET, and HDX-MS approaches revealed structure-based variances of regulatory modules. Despite these achievements, it remains unclear how multi-domain interactions can decode and integrate diverse allosteric signals, thereby yielding distinct regulatory outcomes in a given ortholog/isoform/splice variant. This article summarizes the relevant issues from the perspective of future developments.
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14
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Gao X, Kuo CW, Main A, Brown E, Rios FJ, Camargo LDL, Mary S, Wypijewski K, Gök C, Touyz RM, Fuller W. Palmitoylation regulates cellular distribution of and transmembrane Ca flux through TrpM7. Cell Calcium 2022; 106:102639. [PMID: 36027648 DOI: 10.1016/j.ceca.2022.102639] [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: 05/24/2022] [Revised: 08/03/2022] [Accepted: 08/14/2022] [Indexed: 11/19/2022]
Abstract
The bifunctional cation channel/kinase TrpM7 is ubiquitously expressed and regulates embryonic development and pathogenesis of several common diseases. The TrpM7 integral membrane ion channel domain regulates transmembrane movement of divalent cations, and its kinase domain controls gene expression via histone phosphorylation. Mechanisms regulating TrpM7 are elusive. It exists in two populations in the cell: at the cell surface where it controls divalent cation fluxes, and in intracellular vesicles where it controls zinc uptake and release. Here we report that TrpM7 is palmitoylated at a cluster of cysteines at the C terminal end of its Trp domain. Palmitoylation controls the exit of TrpM7 from the endoplasmic reticulum and the distribution of TrpM7 between cell surface and intracellular pools. Using the Retention Using Selective Hooks (RUSH) system, we demonstrate that palmitoylated TrpM7 traffics from the Golgi to the surface membrane whereas non-palmitoylated TrpM7 is sequestered in intracellular vesicles. We identify the Golgi-resident enzyme zDHHC17 and surface membrane-resident enzyme zDHHC5 as responsible for palmitoylating TrpM7 and find that TrpM7-mediated transmembrane calcium uptake is significantly reduced when TrpM7 is not palmitoylated. The closely related channel/kinase TrpM6 is also palmitoylated on the C terminal side of its Trp domain. Our findings demonstrate that palmitoylation controls ion channel activity of TrpM7 and that TrpM7 trafficking is dependant on its palmitoylation. We define a new mechanism for post translational modification and regulation of TrpM7 and other Trps.
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Affiliation(s)
- Xing Gao
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Chien-Wen Kuo
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Alice Main
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Elaine Brown
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Francisco J Rios
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Livia De Lucca Camargo
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Sheon Mary
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Krzysztof Wypijewski
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Caglar Gök
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Rhian M Touyz
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom; Research Institute of the McGill University Health Centre, McGill University, Montreal, Canada
| | - William Fuller
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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15
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Differential CFTR-Interactome Proximity Labeling Procedures Identify Enrichment in Multiple SLC Transporters. Int J Mol Sci 2022; 23:ijms23168937. [PMID: 36012204 PMCID: PMC9408702 DOI: 10.3390/ijms23168937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Proteins interacting with CFTR and its mutants have been intensively studied using different experimental approaches. These studies provided information on the cellular processes leading to proper protein folding, routing to the plasma membrane, recycling, activation and degradation. Recently, new approaches have been developed based on the proximity labeling of protein partners or proteins in close vicinity and their subsequent identification by mass spectrometry. In this study, we evaluated TurboID- and APEX2-based proximity labeling of WT CFTR and compared the obtained data to those reported in databases. The CFTR-WT interactome was then compared to that of two CFTR (G551D and W1282X) mutants and the structurally unrelated potassium channel KCNK3. The two proximity labeling approaches identified both known and additional CFTR protein partners, including multiple SLC transporters. Proximity labeling approaches provided a more comprehensive picture of the CFTR interactome and improved our knowledge of the CFTR environment.
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16
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Rodrigues T, Piccirillo S, Magi S, Preziuso A, Dos Santos Ramos V, Serfilippi T, Orciani M, Maciel Palacio Alvarez M, Luis Dos Santos Tersariol I, Amoroso S, Lariccia V. Control of Ca 2+ and metabolic homeostasis by the Na +/Ca 2+ exchangers (NCXs) in health and disease. Biochem Pharmacol 2022; 203:115163. [PMID: 35803319 DOI: 10.1016/j.bcp.2022.115163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022]
Abstract
Spatial and temporal control of calcium (Ca2+) levels is essential for the background rhythms and responses of living cells to environmental stimuli. Whatever other regulators a given cellular activity may have, localized and wider scale Ca2+ events (sparks, transients, and waves) are hierarchical determinants of fundamental processes such as cell contraction, excitability, growth, metabolism and survival. Different cell types express specific channels, pumps and exchangers to efficiently generate and adapt Ca2+ patterns to cell requirements. The Na+/Ca2+ exchangers (NCXs) in particular contribute to Ca2+ homeostasis by buffering intracellular Ca2+ loads according to the electrochemical gradients of substrate ions - i.e., Ca2+ and sodium (Na+) - and under a dynamic control of redundant regulatory processes. An interesting feature of NCX emerges from the strict relationship that connects transporter activity with cell metabolism: on the one hand NCX operates under constant control of ATP-dependent regulatory processes, on the other hand the ion fluxes generated through NCX provide mechanistic support for the Na+-driven uptake of glutamate and Ca2+ influx to fuel mitochondrial respiration. Proof of concept evidence highlights therapeutic potential of preserving a timed and balanced NCX activity in a growing rate of diseases (including excitability, neurodegenerative, and proliferative disorders) because of an improved ability of stressed cells to safely maintain ion gradients and mitochondrial bioenergetics. Here, we will summarize and review recent works that have focused on the pathophysiological roles of NCXs in balancing the two-way relationship between Ca2+ signals and metabolism.
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Affiliation(s)
- Tiago Rodrigues
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP, Brazil.
| | - Silvia Piccirillo
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Simona Magi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Alessandra Preziuso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vyctória Dos Santos Ramos
- Interdisciplinary Center for Biochemistry Investigation (CIIB), University of Mogi das Cruzes (UMC), Mogi das Cruzes, SP, Brazil
| | - Tiziano Serfilippi
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Monia Orciani
- Department of Clinical and Molecular Sciences, Histology, University "Politecnica delle Marche", Ancona, Italy.
| | - Marcela Maciel Palacio Alvarez
- Department of Biochemistry, São Paulo School of Medicine, Federal University of São Paulo (Unifesp) São Paulo, SP, Brazil
| | | | - Salvatore Amoroso
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Vincenzo Lariccia
- Department of Biomedical Sciences and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
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17
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Gök C, Robertson AD, Fuller W. Insulin-induced palmitoylation regulates the Cardiac Na+/Ca2+ exchanger NCX1. Cell Calcium 2022; 104:102567. [DOI: 10.1016/j.ceca.2022.102567] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 11/02/2022]
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18
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Morciano G, Rimessi A, Patergnani S, Vitto VAM, Danese A, Kahsay A, Palumbo L, Bonora M, Wieckowski MR, Giorgi C, Pinton P. Calcium dysregulation in heart diseases: Targeting calcium channels to achieve a correct calcium homeostasis. Pharmacol Res 2022; 177:106119. [PMID: 35131483 DOI: 10.1016/j.phrs.2022.106119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 12/16/2022]
Abstract
Intracellular calcium signaling is a universal language source shared by the most part of biological entities inside cells that, all together, give rise to physiological and functional anatomical units, the organ. Although preferentially recognized as signaling between cell life and death processes, in the heart it assumes additional relevance considered the importance of calcium cycling coupled to ATP consumption in excitation-contraction coupling. The concerted action of a plethora of exchangers, channels and pumps inward and outward calcium fluxes where needed, to convert energy and electric impulses in muscle contraction. All this without realizing it, thousands of times, every day. An improper function of those proteins (i.e., variation in expression, mutations onset, dysregulated channeling, differential protein-protein interactions) being part of this signaling network triggers a short circuit with severe acute and chronic pathological consequences reported as arrhythmias, cardiac remodeling, heart failure, reperfusion injury and cardiomyopathies. By acting with chemical, peptide-based and pharmacological modulators of these players, a correction of calcium homeostasis can be achieved accompanied by an amelioration of clinical symptoms. This review will focus on all those defects in calcium homeostasis which occur in the most common cardiac diseases, including myocardial infarction, arrhythmia, hypertrophy, heart failure and cardiomyopathies. This part will be introduced by the state of the art on the proteins involved in calcium homeostasis in cardiomyocytes and followed by the therapeutic treatments that to date, are able to target them and to revert the pathological phenotype.
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Affiliation(s)
- Giampaolo Morciano
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
| | - Alessandro Rimessi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Simone Patergnani
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Veronica A M Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Alberto Danese
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Asrat Kahsay
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Laura Palumbo
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Massimo Bonora
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism. Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
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19
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Main A, Boguslavskyi A, Howie J, Kuo CW, Rankin A, Burton FL, Smith GL, Hajjar R, Baillie GS, Campbell KS, Shattock MJ, Fuller W. Dynamic but discordant alterations in zDHHC5 expression and palmitoylation of its substrates in cardiac pathologies. Front Physiol 2022; 13:1023237. [PMID: 36277202 PMCID: PMC9581287 DOI: 10.3389/fphys.2022.1023237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022] Open
Abstract
S-palmitoylation is an essential lipid modification catalysed by zDHHC-palmitoyl acyltransferases that regulates the localisation and activity of substrates in every class of protein and tissue investigated to date. In the heart, S-palmitoylation regulates sodium-calcium exchanger (NCX1) inactivation, phospholemman (PLM) inhibition of the Na+/K+ ATPase, Nav1.5 influence on membrane excitability and membrane localisation of heterotrimeric G-proteins. The cell surface localised enzyme zDHHC5 palmitoylates NCX1 and PLM and is implicated in injury during anoxia/reperfusion. Little is known about how palmitoylation remodels in cardiac diseases. We investigated expression of zDHHC5 in animal models of left ventricular hypertrophy (LVH) and heart failure (HF), along with HF tissue from humans. zDHHC5 expression increased rapidly during onset of LVH, whilst HF was associated with decreased zDHHC5 expression. Paradoxically, palmitoylation of the zDHHC5 substrate NCX1 was significantly reduced in LVH but increased in human HF, while palmitoylation of the zDHHC5 substrate PLM was unchanged in all settings. Overexpression of zDHHC5 in rabbit ventricular cardiomyocytes did not alter palmitoylation of its substrates or overall cardiomyocyte contractility, suggesting changes in zDHHC5 expression in disease may not be a primary driver of pathology. zDHHC5 itself is regulated by post-translational modifications, including palmitoylation in its C-terminal tail. We found that in HF palmitoylation of zDHHC5 changed in the same manner as palmitoylation of NCX1, suggesting additional regulatory mechanisms may be involved. This study provides novel evidence that palmitoylation of cardiac substrates is altered in the setting of HF, and that expression of zDHHC5 is dysregulated in both hypertrophy and HF.
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Affiliation(s)
- Alice Main
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andri Boguslavskyi
- School of Cardiovascular and Metabolic Medicine and Sciences, King's College London, London, United Kingdom
| | - Jacqueline Howie
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Chien-Wen Kuo
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Aileen Rankin
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Francis L Burton
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Roger Hajjar
- Flagship Pioneering, Cambridge, MA, United States
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
| | - Michael J Shattock
- School of Cardiovascular and Metabolic Medicine and Sciences, King's College London, London, United Kingdom
| | - William Fuller
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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20
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Ottolia M, John S, Hazan A, Goldhaber JI. The Cardiac Na + -Ca 2+ Exchanger: From Structure to Function. Compr Physiol 2021; 12:2681-2717. [PMID: 34964124 DOI: 10.1002/cphy.c200031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ca2+ homeostasis is essential for cell function and survival. As such, the cytosolic Ca2+ concentration is tightly controlled by a wide number of specialized Ca2+ handling proteins. One among them is the Na+ -Ca2+ exchanger (NCX), a ubiquitous plasma membrane transporter that exploits the electrochemical gradient of Na+ to drive Ca2+ out of the cell, against its concentration gradient. In this critical role, this secondary transporter guides vital physiological processes such as Ca2+ homeostasis, muscle contraction, bone formation, and memory to name a few. Herein, we review the progress made in recent years about the structure of the mammalian NCX and how it relates to function. Particular emphasis will be given to the mammalian cardiac isoform, NCX1.1, due to the extensive studies conducted on this protein. Given the degree of conservation among the eukaryotic exchangers, the information highlighted herein will provide a foundation for our understanding of this transporter family. We will discuss gene structure, alternative splicing, topology, regulatory mechanisms, and NCX's functional role on cardiac physiology. Throughout this article, we will attempt to highlight important milestones in the field and controversial topics where future studies are required. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Scott John
- Department of Medicine (Cardiology), UCLA, Los Angeles, California, USA
| | - Adina Hazan
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
| | - Joshua I Goldhaber
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
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21
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Gök C, Plain F, Robertson AD, Howie J, Baillie GS, Fraser NJ, Fuller W. Dynamic Palmitoylation of the Sodium-Calcium Exchanger Modulates Its Structure, Affinity for Lipid-Ordered Domains, and Inhibition by XIP. Cell Rep 2021; 31:107697. [PMID: 32521252 PMCID: PMC7296346 DOI: 10.1016/j.celrep.2020.107697] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/07/2020] [Accepted: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
The transmembrane sodium-calcium (Na-Ca) exchanger 1 (NCX1) regulates cytoplasmic Ca levels by facilitating electrogenic exchange of Ca for Na. Palmitoylation, the only reversible post-translational modification known to modulate NCX1 activity, controls NCX1 inactivation. Here, we show that palmitoylation of NCX1 modifies the structural arrangement of the NCX1 dimer and controls its affinity for lipid-ordered membrane domains. NCX1 palmitoylation occurs dynamically at the cell surface under the control of the enzymes zDHHC5 and APT1. We identify the position of the endogenous exchange inhibitory peptide (XIP) binding site within the NCX1 regulatory intracellular loop and demonstrate that palmitoylation controls the ability of XIP to bind this site. We also show that changes in NCX1 palmitoylation change cytosolic Ca. Our results thus demonstrate the broad molecular consequences of NCX1 palmitoylation and highlight a means to manipulate the inactivation of this ubiquitous ion transporter that could ameliorate pathologies linked to Ca overload via NCX1. NCX1 is dynamically palmitoylated at the cell surface by zDHHC5 and APT1 Palmitoylation modifies the NCX1 dimer’s structure and affinity for lipid rafts We identify the binding site of the endogenous XIP domain in NCX1’s regulatory loop Palmitoylation modifies NCX1 XIP affinity and hence regulates intracellular Ca
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Affiliation(s)
- Caglar Gök
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Fiona Plain
- School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, UK
| | - Alan D Robertson
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Jacqueline Howie
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - George S Baillie
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Niall J Fraser
- School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, UK
| | - William Fuller
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
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22
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Gök C, Main A, Gao X, Kerekes Z, Plain F, Kuo CW, Robertson AD, Fraser NJ, Fuller W. Insights into the molecular basis of the palmitoylation and depalmitoylation of NCX1. Cell Calcium 2021; 97:102408. [PMID: 33873072 PMCID: PMC8278489 DOI: 10.1016/j.ceca.2021.102408] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/30/2021] [Accepted: 04/06/2021] [Indexed: 11/23/2022]
Abstract
Catalyzed by zDHHC-PAT enzymes and reversed by thioesterases, protein palmitoylation is the only post-translational modification recognized to regulate the sodium/calcium exchanger NCX1. NCX1 palmitoylation occurs at a single site at position 739 in its large regulatory intracellular loop. An amphipathic ɑ-helix between residues 740-756 is a critical for NCX1 palmitoylation. Given the rich background of the structural elements involving in NCX1 palmitoylation, the molecular basis of NCX1 palmitoylation is still relatively poorly understood. Here we found that (1) the identity of palmitoylation machinery of NCX1 controls its spatial organization within the cell, (2) the NCX1 amphipathic ɑ-helix directly interacts with zDHHC-PATs, (3) NCX1 is still palmitoylated when it is arrested in either Golgi or ER, indicating that NCX1 is a substrate for multiple zDHHC-PATs, (4) the thioesterase APT1 but not APT2 as a part of NCX1-depalmitoylation machinery governs subcellular organization of NCX1, (5) APT1 catalyzes NCX1 depalmitoylation in the Golgi but not in the ER. We also report that NCX2 and NCX3 are dually palmitoylated, with important implications for substrate recognition and enzyme catalysis by zDHHC-PATs. Our results could support new molecular or pharmacological strategies targeting the NCX1 palmitoylation and depalmitoylation machinery.
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Affiliation(s)
- Caglar Gök
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Alice Main
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Xing Gao
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Zsombor Kerekes
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Fiona Plain
- School of Medicine, Ninewells Hospital, University of Dundee, Dundee, DD1 9SY, United Kingdom
| | - Chien-Wen Kuo
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Alan D Robertson
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Niall J Fraser
- School of Medicine, Ninewells Hospital, University of Dundee, Dundee, DD1 9SY, United Kingdom
| | - William Fuller
- Institute of Cardiovascular & Medical Sciences, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
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Main A, Fuller W. Protein S-Palmitoylation: advances and challenges in studying a therapeutically important lipid modification. FEBS J 2021; 289:861-882. [PMID: 33624421 DOI: 10.1111/febs.15781] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/01/2021] [Accepted: 02/22/2021] [Indexed: 12/11/2022]
Abstract
The lipid post-translational modification S-palmitoylation is a vast developing field, with the modification itself and the enzymes that catalyse the reversible reaction implicated in a number of diseases. In this review, we discuss the past and recent advances in the experimental tools used in this field, including pharmacological tools, animal models and techniques to understand how palmitoylation controls protein localisation and function. Additionally, we discuss the obstacles to overcome in order to advance the field, particularly to the point at which modulating palmitoylation may be achieved as a therapeutic strategy.
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Affiliation(s)
- Alice Main
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - William Fuller
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
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24
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Miles MR, Seo J, Jiang M, Wilson ZT, Little J, Hao J, Andrade J, Ueberheide B, Tseng GN. Global identification of S-palmitoylated proteins and detection of palmitoylating (DHHC) enzymes in heart. J Mol Cell Cardiol 2021; 155:1-9. [PMID: 33636221 DOI: 10.1016/j.yjmcc.2021.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 02/12/2021] [Accepted: 02/15/2021] [Indexed: 10/22/2022]
Abstract
High-throughput experiments suggest that almost 20% of human proteins may be S-palmitoylatable, a post-translational modification (PTM) whereby fatty acyl chains, most commonly palmitoyl chain, are linked to cysteine thiol groups that impact on protein trafficking, distribution and function. In human, protein S-palmitoylation is mediated by a group of 23 palmitoylating 'Asp-His-His-Cys' domain-containing (DHHC) enzymes. There is no information on the scope of protein S-palmitoylation, or the pattern of DHHC enzyme expression, in the heart. We used resin-assisted capture to pull down S-palmitoylated proteins from human, dog, and rat hearts, followed by proteomic search to identify proteins in the pulldowns. We identified 454 proteins present in at least 2 species-specific pulldowns. These proteins are operationally called 'cardiac palmitoylome'. Enrichment analysis based on Gene Ontology terms 'cellular component' indicated that cardiac palmitoylome is involved in cell-cell and cell-substrate junctions, plasma membrane microdomain organization, vesicular trafficking, and mitochondrial enzyme organization. Importantly, cardiac palmitoylome is uniquely enriched in proteins participating in the organization and function of t-tubules, costameres and intercalated discs, three microdomains critical for excitation-contraction coupling and intercellular communication of cardiomyocytes. We validated antibodies targeting DHHC enzymes, and detected eleven of them expressed in hearts across species. In conclusion, we provide resources useful for investigators interested in studying protein S-palmitoylation and its regulation by DHHC enzymes in the heart. We also discuss challenges in these efforts, and suggest methods and tools that should be developed to overcome these challenges.
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Affiliation(s)
- Madeleine R Miles
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States
| | - John Seo
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States
| | - Min Jiang
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States
| | - Zachary T Wilson
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States
| | - Janay Little
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States
| | - Jon Hao
- Poochon Scientific, Frederick, MD, United States
| | - Joshua Andrade
- Proteomics Laboratory, Division of Advance Research Technology, New York University, School School of Medicine, New York, NY, United States
| | - Beatrix Ueberheide
- Proteomics Laboratory, Division of Advance Research Technology, New York University, School School of Medicine, New York, NY, United States; Department of Biochemistry and Molecular Pharmacology, New York University, School of Medicine, New York, NY, United States; Department of Neurology, New York University, School of Medicine, New York, NY, United States
| | - Gea-Ny Tseng
- Department of Physiology & Biophysics, Virginia Commonwealth University, Richmond, VA, United States.
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25
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Losada de la Lastra A, Hassan S, Tate EW. Deconvoluting the biology and druggability of protein lipidation using chemical proteomics. Curr Opin Chem Biol 2021; 60:97-112. [PMID: 33221680 DOI: 10.1016/j.cbpa.2020.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 10/01/2020] [Accepted: 10/06/2020] [Indexed: 01/13/2023]
Abstract
Lipids are indispensable cellular building blocks, and their post-translational attachment to proteins makes them important regulators of many biological processes. Dysfunction of protein lipidation is also implicated in many pathological states, yet its systematic analysis presents significant challenges. Thanks to innovations in chemical proteomics, lipidation can now be readily studied by metabolic tagging using functionalized lipid analogs, enabling global profiling of lipidated substrates using mass spectrometry. This has spearheaded the first deconvolution of their full scope in a range of contexts, from cells to pathogens and multicellular organisms. Protein N-myristoylation, S-acylation, and S-prenylation are the most well-studied lipid post-translational modifications because of their extensive contribution to the regulation of diverse cellular processes. In this review, we focus on recent advances in the study of these post-translational modifications, with an emphasis on how novel mass spectrometry methods have elucidated their roles in fundamental biological processes.
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Affiliation(s)
- Ana Losada de la Lastra
- Department of Chemistry, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK
| | - Sarah Hassan
- Department of Chemistry, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK
| | - Edward W Tate
- Department of Chemistry, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK.
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Main A, Robertson-Gray O, Fuller W. Cyclophilin D palmitoylation and permeability transition: a new twist in the tale of myocardial ischaemia-reperfusion injury. Cardiovasc Res 2021; 117:15-17. [PMID: 32449761 PMCID: PMC7797206 DOI: 10.1093/cvr/cvaa149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Alice Main
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Olivia Robertson-Gray
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - William Fuller
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, Sir James Black Building, University of Glasgow, Glasgow G12 8QQ, UK
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27
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Gök C, Fuller W. Topical review: Shedding light on molecular and cellular consequences of NCX1 palmitoylation. Cell Signal 2020; 76:109791. [DOI: 10.1016/j.cellsig.2020.109791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 01/21/2023]
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Reilly L, Alvarado FJ, Lang D, Abozeid S, Van Ert H, Spellman C, Warden J, Makielski JC, Glukhov AV, Eckhardt LL. Genetic Loss of IK1 Causes Adrenergic-Induced Phase 3 Early Afterdepolariz ations and Polymorphic and Bidirectional Ventricular Tachycardia. Circ Arrhythm Electrophysiol 2020; 13:e008638. [PMID: 32931337 DOI: 10.1161/circep.120.008638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Arrhythmia syndromes associated with KCNJ2 mutations have been described clinically; however, little is known of the underlying arrhythmia mechanism. We create the first patient inspired KCNJ2 transgenic mouse and study effects of this mutation on cardiac function, IK1, and Ca2+ handling, to determine the underlying cellular arrhythmic pathogenesis. METHODS A cardiac-specific KCNJ2-R67Q mouse was generated and bred for heterozygosity (R67Q+/-). Echocardiography was performed at rest, under anesthesia. In vivo ECG recording and whole heart optical mapping of intact hearts was performed before and after adrenergic stimulation in wild-type (WT) littermate controls and R67Q+/- mice. IK1 measurements, action potential characterization, and intracellular Ca2+ imaging from isolated ventricular myocytes at baseline and after adrenergic stimulation were performed in WT and R67Q+/- mice. RESULTS R67Q+/- mice (n=17) showed normal cardiac function, structure, and baseline electrical activity compared with WT (n=10). Following epinephrine and caffeine, only the R67Q+/- mice had bidirectional ventricular tachycardia, ventricular tachycardia, frequent ventricular ectopy, and/or bigeminy and optical mapping demonstrated high prevalence of spontaneous and sustained ventricular arrhythmia. Both R67Q+/- (n=8) and WT myocytes (n=9) demonstrated typical n-shaped IK1 IV relationship; however, following isoproterenol, max outward IK1 increased by ≈20% in WT but decreased by ≈24% in R67Q+/- (P<0.01). R67Q+/- myocytes (n=5) demonstrated prolonged action potential duration at 90% repolarization and after 10 nmol/L isoproterenol compared with WT (n=7; P<0.05). Ca2+ transient amplitude, 50% decay rate, and sarcoplasmic reticulum Ca2+ content were not different between WT (n=18) and R67Q+/- (n=16) myocytes. R67Q+/- myocytes (n=10) under adrenergic stimulation showed frequent spontaneous development of early afterdepolarizations that occurred at phase 3 of action potential repolarization. CONCLUSIONS KCNJ2 mutation R67Q+/- causes adrenergic-dependent loss of IK1 during terminal repolarization and vulnerability to phase 3 early afterdepolarizations. This model clarifies a heretofore unknown arrhythmia mechanism and extends our understanding of treatment implications for patients with KCNJ2 mutation.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Francisco J Alvarado
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Di Lang
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Sara Abozeid
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Hannah Van Ert
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Cordell Spellman
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jarrett Warden
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jonathan C Makielski
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Alexey V Glukhov
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
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29
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Plain F, Howie J, Kennedy J, Brown E, Shattock MJ, Fraser NJ, Fuller W. Control of protein palmitoylation by regulating substrate recruitment to a zDHHC-protein acyltransferase. Commun Biol 2020; 3:411. [PMID: 32737405 PMCID: PMC7395175 DOI: 10.1038/s42003-020-01145-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/15/2020] [Indexed: 12/18/2022] Open
Abstract
Although palmitoylation regulates numerous cellular processes, as yet efforts to manipulate this post-translational modification for therapeutic gain have proved unsuccessful. The Na-pump accessory sub-unit phospholemman (PLM) is palmitoylated by zDHHC5. Here, we show that PLM palmitoylation is facilitated by recruitment of the Na-pump α sub-unit to a specific site on zDHHC5 that contains a juxtamembrane amphipathic helix. Site-specific palmitoylation and GlcNAcylation of this helix increased binding between the Na-pump and zDHHC5, promoting PLM palmitoylation. In contrast, disruption of the zDHHC5-Na-pump interaction with a cell penetrating peptide reduced PLM palmitoylation. Our results suggest that by manipulating the recruitment of specific substrates to particular zDHHC-palmitoyl acyl transferases, the palmitoylation status of individual proteins can be selectively altered, thus opening the door to the development of molecular modulators of protein palmitoylation for the treatment of disease.
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Affiliation(s)
- Fiona Plain
- School of Medicine, University of Dundee, Dundee, UK
| | - Jacqueline Howie
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jennifer Kennedy
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Elaine Brown
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Michael J Shattock
- Cardiovascular Division, The Rayne Institute, King's College London, London, UK
| | | | - William Fuller
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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30
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Palmitoylation of the K ATP channel Kir6.2 subunit promotes channel opening by regulating PIP 2 sensitivity. Proc Natl Acad Sci U S A 2020; 117:10593-10602. [PMID: 32332165 DOI: 10.1073/pnas.1918088117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A physiological role for long-chain acyl-CoA esters to activate ATP-sensitive K+ (KATP) channels is well established. Circulating palmitate is transported into cells and converted to palmitoyl-CoA, which is a substrate for palmitoylation. We found that palmitoyl-CoA, but not palmitic acid, activated the channel when applied acutely. We have altered the palmitoylation state by preincubating cells with micromolar concentrations of palmitic acid or by inhibiting protein thioesterases. With acyl-biotin exchange assays we found that Kir6.2, but not sulfonylurea receptor (SUR)1 or SUR2, was palmitoylated. These interventions increased the KATP channel mean patch current, increased the open time, and decreased the apparent sensitivity to ATP without affecting surface expression. Similar data were obtained in transfected cells, rat insulin-secreting INS-1 cells, and isolated cardiac myocytes. Kir6.2ΔC36, expressed without SUR, was also positively regulated by palmitoylation. Mutagenesis of Kir6.2 Cys166 prevented these effects. Clinical variants in KCNJ11 that affect Cys166 had a similar gain-of-function phenotype, but was more pronounced. Molecular modeling studies suggested that palmitoyl-C166 and selected large hydrophobic mutations make direct hydrophobic contact with Kir6.2-bound PIP2 Patch-clamp studies confirmed that palmitoylation of Kir6.2 at Cys166 enhanced the PIP2 sensitivity of the channel. Physiological relevance is suggested since palmitoylation blunted the regulation of KATP channels by α1-adrenoreceptor stimulation. The Cys166 residue is conserved in some other Kir family members (Kir6.1 and Kir3, but not Kir2), which are also subject to regulated palmitoylation, suggesting a general mechanism to control the open state of certain Kir channels.
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31
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Cortassa S, Caceres V, Tocchetti CG, Bernier M, de Cabo R, Paolocci N, Sollott SJ, Aon MA. Metabolic remodelling of glucose, fatty acid and redox pathways in the heart of type 2 diabetic mice. J Physiol 2020; 598:1393-1415. [PMID: 30462352 PMCID: PMC7739175 DOI: 10.1113/jp276824] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 11/15/2018] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Hearts from type 2 diabetic animals display perturbations in excitation-contraction coupling, impairing myocyte contractility and delaying relaxation, along with altered substrate consumption patterns. Under high glucose and β-adrenergic stimulation conditions, palmitate can, at least in part, offset left ventricle (LV) dysfunction in hearts from diabetic mice, improving contractility and relaxation while restoring coronary perfusion pressure. Fluxome calculations of central catabolism in diabetic hearts show that, in the presence of palmitate, there is a metabolic remodelling involving tricarboxylic acid cycle, polyol and pentose phosphate pathways, leading to improved redox balance in cytoplasmic and mitochondrial compartments. Under high glucose and increased energy demand, the metabolic/fluxomic redirection leading to restored redox balance imparted by palmitate helps explain maintained LV function and may contribute to designing novel therapeutic approaches to prevent cardiac dysfunction in diabetic patients. ABSTRACT Type-2 diabetes (T2DM) leads to reduced myocardial performance, and eventually heart failure. Excessive accumulation of lipids and glucose is central to T2DM cardiomyopathy. Previous data showed that palmitate (Palm) or glutathione preserved heart mitochondrial energy/redox balance under excess glucose, rescuing β-adrenergic-stimulated cardiac excitation-contraction coupling. However, the mechanisms underlying the accompanying improved contractile performance have been largely ignored. Herein we explore in intact heart under substrate excess the metabolic remodelling associated with cardiac function in diabetic db/db mice subjected to stress given by β-adrenergic stimulation with isoproterenol and high glucose compared to their non-diabetic controls (+/+, WT) under euglycaemic conditions. When perfused with Palm, T2DM hearts exhibited improved contractility/relaxation compared to WT, accompanied by extensive metabolic remodelling as demonstrated by metabolomics-fluxomics combined with bioinformatics and computational modelling. The T2DM heart metabolome showed significant differences in the abundance of metabolites in pathways related to glucose, lipids and redox metabolism. Using a validated computational model of heart's central catabolism, comprising glucose and fatty acid (FA) oxidation in cytoplasmic and mitochondrial compartments, we estimated that fluxes through glucose degradation pathways are ∼2-fold lower in heart from T2DM vs. WT under all conditions studied. Palm addition elicits improvement of the redox status via enhanced β-oxidation and decreased glucose uptake, leading to flux-redirection away from redox-consuming pathways (e.g. polyol) while maintaining the flux through redox-generating pathways together with glucose-FA 'shared fuelling' of oxidative phosphorylation. Thus, available FAs such as Palm may help improve function via enhanced redox balance in T2DM hearts during peaks of hyperglycaemia and increased workload.
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Affiliation(s)
- Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
| | - Viviane Caceres
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD, 21205, USA
- Posgraduate Program in Rehabilitation Sciences, Dept. Health Sciences, Federal University of Santa Catarina, Ararangua, SC, Brazil
| | - Carlo G Tocchetti
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD, 21205, USA
- Dipartimento di Scienze Mediche Traslazionali, Universita' degli Studi di Napoli Federico II Via Pansini 5, Edificio 2, 80131, Napoli, Italy
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, The Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Biomedical Sciences, University of Padova, via Marzolo 3, 35131, Padova, Italy
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
- Translational Gerontology Branch, National Institute on Aging/NIH, Baltimore, MD, 21224, USA
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Magi S, Piccirillo S, Preziuso A, Amoroso S, Lariccia V. Mitochondrial localization of NCXs: Balancing calcium and energy homeostasis. Cell Calcium 2020; 86:102162. [DOI: 10.1016/j.ceca.2020.102162] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 01/04/2023]
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33
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Essandoh K, Philippe JM, Jenkins PM, Brody MJ. Palmitoylation: A Fatty Regulator of Myocardial Electrophysiology. Front Physiol 2020; 11:108. [PMID: 32140110 PMCID: PMC7042378 DOI: 10.3389/fphys.2020.00108] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/30/2020] [Indexed: 01/02/2023] Open
Abstract
Regulation of cardiac physiology is well known to occur through the action of kinases that reversibly phosphorylate ion channels, calcium handling machinery, and signaling effectors. However, it is becoming increasingly apparent that palmitoylation or S-acylation, the post-translational modification of cysteines with saturated fatty acids, plays instrumental roles in regulating the localization, activity, stability, sorting, and function of numerous proteins, including proteins known to have essential functions in cardiomyocytes. However, the impact of this modification on cardiac physiology requires further investigation. S-acylation is catalyzed by the zDHHC family of S-acyl transferases that localize to intracellular organelle membranes or the sarcolemma. Recent work has begun to uncover functions of S-acylation in the heart, particularly in the regulation of cardiac electrophysiology, including modification of the sodium-calcium exchanger, phospholemman and the cardiac sodium pump, as well as the voltage-gated sodium channel. Elucidating the regulatory functions of zDHHC enzymes in cardiomyocytes and determination of how S-acylation is altered in the diseased heart will shed light on how these modifications participate in cardiac pathogenesis and potentially identify novel targets for the treatment of cardiovascular disease. Indeed, proteins with critical signaling roles in the heart are also S-acylated, including receptors and G-proteins, yet the dynamics and functions of these modifications in myocardial physiology have not been interrogated. Here, we will review what is known about zDHHC enzymes and substrate S-acylation in myocardial physiology and highlight future areas of investigation that will uncover novel functions of S-acylation in cardiac homeostasis and pathophysiology.
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Affiliation(s)
- Kobina Essandoh
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Julie M Philippe
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Matthew J Brody
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, United States.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
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34
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Cracking the code of sodium/calcium exchanger (NCX) gating: Old and new complexities surfacing from the deep web of secondary regulations. Cell Calcium 2020; 87:102169. [PMID: 32070925 DOI: 10.1016/j.ceca.2020.102169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/14/2022]
Abstract
Cell membranes spatially define gradients that drive the complexity of biological signals. To guarantee movements and exchanges of solutes between compartments, membrane transporters negotiate the passages of ions and other important molecules through lipid bilayers. The Na+/Ca2+ exchangers (NCXs) in particular play central roles in balancing Na+ and Ca2+ fluxes across diverse proteolipid borders in all eukaryotic cells, influencing cellular functions and fate by multiple means. To prevent progression from balance to disease, redundant regulatory mechanisms cooperate at multiple levels (transcriptional, translational, and post-translational) and guarantee that the activities of NCXs are finely-tuned to cell homeostatic requirements. When this regulatory network is disturbed by pathological forces, cells may approach the end of life. In this review, we will discuss the main findings, controversies and open questions about regulatory mechanisms that control NCX functions in health and disease.
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35
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Offringa-Hup A. INAD and Duchenne muscular dystrophy, two ends of the iPLA2β spectrum. Med Hypotheses 2020; 137:109589. [PMID: 32006920 DOI: 10.1016/j.mehy.2020.109589] [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: 10/24/2019] [Revised: 12/21/2019] [Accepted: 01/21/2020] [Indexed: 11/30/2022]
Abstract
Infantile neuroaxonal dystrophy (INAD) and Duchenne muscular dystrophy (DMD) are two deadly neuromuscular degenerative diseases of childhood. Knowledge on their pathophysiological mechanisms may direct us towards treatment or a cure. Although these diseases are caused by two totally different gene-mutations and cause different clinical pictures, in this article I propose a common disease mechanism in the two. This common mechanism is induced by defects in the response to cellular stress and injury. THE HYPOTHESIS: Depletion of iPLA2β in INAD and increased activity of iPLA2β in DMD eventually lead to similar defects in the response to cell stress and injury. According to this hypothesis, the depletion of iPLA2β in INAD primarily blocks repair mechanisms by the inability to form a mitochondrial permeability transition pore (PTP). Forming of the PTP is necessary to release mitochondrial coenzyme A (CoA) into the cytoplasm for activation of palmitoylation and massive endocytosis as a repair response. In DMD the increased activity of iPLA2β causes exhaustion of the stress signalling cascade by increased and prolonged PTP opening. Continuous leaking of mitochondrial CoA through the PTP leads to the inability of the cell to build a sufficient mitochondrial:cytoplasmic CoA gradient, also causing insufficient release of mitochondrial CoA as a response to cell stress and injury. Decreased palmitoylation capacity and decreased endocytosis and membrane remodelling are implicated in proven pathophysiological mechanisms in INAD and DMD. The described mechanism in INAD and DMD, may be considered a common mechanism of repair in case of cell stress and injury. Beside their role in INAD and DMD, they may therefore be implicated in other neurodegenerative diseases as well. Available research shows involvement of iPLA2β in other neurodegenerative diseases. We might be able to divide neurodegenerative diseases in "INAD-like disease-mechanism" or "DMD-like disease-mechanism", depending on decreased or increased iPLA2β activity.
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Gök C, Fuller W. Regulation of NCX1 by palmitoylation. Cell Calcium 2020; 86:102158. [PMID: 31935590 DOI: 10.1016/j.ceca.2019.102158] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/28/2019] [Accepted: 12/29/2019] [Indexed: 11/17/2022]
Abstract
Palmitoylation (S-acylation) is the reversible conjugation of a fatty acid (usually C16 palmitate) to intracellular cysteine residues of proteins via a thioester linkage. Palmitoylation anchors intracellular regions of proteins to membranes because the palmitoylated cysteine is recruited to the lipid bilayer. NCX1 is palmitoylated at a single cysteine in its large regulatory intracellular loop. The presence of an amphipathic α-helix immediately adjacent to the NCX1 palmitoylation site is required for NCX1 palmitoylation. The NCX1 palmitoylation site is conserved through most metazoan phlya. Although palmitoylation does not regulate the normal forward or reverse ion transport modes of NCX1, NCX1 palmitoylation is required for its inactivation: sodium-dependent inactivation and inactivation by PIP2 depletion are significantly impaired for unpalmitoylatable NCX1. Here we review the role of palmitoylation in regulating NCX1 activity, and highlight future questions that must be addressed to fully understand the importance of this regulatory mechanism for sodium and calcium transport in cardiac muscle.
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Affiliation(s)
- Caglar Gök
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - William Fuller
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK. https://twitter.com@FullerLabGlas
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Scranton K, John S, Escobar A, Goldhaber JI, Ottolia M. Modulation of the cardiac Na +-Ca 2+ exchanger by cytoplasmic protons: Molecular mechanisms and physiological implications. Cell Calcium 2019; 87:102140. [PMID: 32070924 DOI: 10.1016/j.ceca.2019.102140] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/06/2019] [Accepted: 12/07/2019] [Indexed: 01/31/2023]
Abstract
A precise temporal and spatial control of intracellular Ca2+ concentration is essential for a coordinated contraction of the heart. Following contraction, cardiac cells need to rapidly remove intracellular Ca2+ to allow for relaxation. This task is performed by two transporters: the plasma membrane Na+-Ca2+ exchanger (NCX) and the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA). NCX extrudes Ca2+ from the cell, balancing the Ca2+entering the cytoplasm during systole through L-type Ca2+ channels. In parallel, following SR Ca2+ release, SERCA activity replenishes the SR, reuptaking Ca2+ from the cytoplasm. The activity of the mammalian exchanger is fine-tuned by numerous ionic allosteric regulatory mechanisms. Micromolar concentrations of cytoplasmic Ca2+ potentiate NCX activity, while an increase in intracellular Na+ levels inhibits NCX via a mechanism known as Na+-dependent inactivation. Protons are also powerful inhibitors of NCX activity. By regulating NCX activity, Ca2+, Na+ and H+ couple cell metabolism to Ca2+ homeostasis and therefore cardiac contractility. This review summarizes the recent progress towards the understanding of the molecular mechanisms underlying the ionic regulation of the cardiac NCX with special emphasis on pH modulation and its physiological impact on the heart.
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Affiliation(s)
- Kyle Scranton
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Scott John
- Department of Medicine (Cardiology), UCLA, Los Angeles, CA 90095, USA; Cardiovascular Research Laboratory, UCLA, Los Angeles, CA 90095, USA
| | - Ariel Escobar
- Department of Bioengineering, School of Engineering, UC Merced, Merced, CA 95343, USA
| | - Joshua I Goldhaber
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, UCLA, Los Angeles, CA 90095, USA; Cardiovascular Research Laboratory, UCLA, Los Angeles, CA 90095, USA.
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Hilgemann DW, Lin MJ, Fine M, Deisl C. On the existence of endocytosis driven by membrane phase separations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183007. [PMID: 31202864 DOI: 10.1016/j.bbamem.2019.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/31/2019] [Accepted: 06/06/2019] [Indexed: 01/15/2023]
Abstract
Large endocytic responses can occur rapidly in diverse cell types without dynamins, clathrin, or actin remodeling. Our experiments suggest that membrane phase separations are crucial with more ordered plasma membrane domains being internalized. Not only do these endocytic processes rely on coalescence of membrane domains, they are promoted by participation of membrane proteins in such domains, one important regulatory influence being palmitoylation. Membrane actin cytoskeleton in general resists membrane phase transitions, and its remodeling may play many roles. Besides membrane 'caging' and 'pinching' roles, typically ascribed to clathrin and dynamins, cytoskeleton remodeling may modify local membrane tension and buckling, as well as the presence and location of actin- and tension-free membrane patches. Endocytosis that depends on membrane phase separations becomes activated in metabolic stress and in response to Ca and PI3 kinase signaling. Internalized membrane traffics normally, and the secretory pathway eventually resupplies membrane to the plasmalemma or directs internalized membrane to other locations, including the extracellular space as exosomes. We describe here that endocytosis driven by membrane phase transitions is regulated by the same signaling mechanisms that regulate macropinocytosis, and it may play diverse roles in cells from nutrient assimilation to membrane recycling, cell migration, and the initiation of quiescent or hibernating cell states. Membrane ordering and phase separations have been shown to promote endocytosis in diverse cell types, including fibroblasts, myocytes, glial cells, and immune cells. We propose that clathrin/dynamin-independent endocytosis represents a continuum of related mechanisms with variable but universal dependence on membrane ordering and actin remodeling. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
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Affiliation(s)
- Donald W Hilgemann
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA.
| | - Mei-Jung Lin
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
| | - Michael Fine
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
| | - Christine Deisl
- University of Texas Southwestern Medical Center, Department of Physiology, 5323 Harry Hines Boulevard, Dallas, TX 75235-9040, USA
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Liao QS, Du Q, Lou J, Xu JY, Xie R. Roles of Na +/Ca 2+ exchanger 1 in digestive system physiology and pathophysiology. World J Gastroenterol 2019; 25:287-299. [PMID: 30686898 PMCID: PMC6343099 DOI: 10.3748/wjg.v25.i3.287] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/20/2018] [Accepted: 12/28/2018] [Indexed: 02/06/2023] Open
Abstract
The Na+/Ca2+ exchanger (NCX) protein family is a part of the cation/Ca2+ exchanger superfamily and participates in the regulation of cellular Ca2+ homeostasis. NCX1, the most important subtype in the NCX family, is expressed widely in various organs and tissues in mammals and plays an especially important role in the physiological and pathological processes of nerves and the cardiovascular system. In the past few years, the function of NCX1 in the digestive system has received increasing attention; NCX1 not only participates in the healing process of gastric ulcer and gastric mucosal injury but also mediates the development of digestive cancer, acute pancreatitis, and intestinal absorption. This review aims to explore the roles of NCX1 in digestive system physiology and pathophysiology in order to guide clinical treatments.
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Affiliation(s)
- Qiu-Shi Liao
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563000, Guizhou Province, China
| | - Qian Du
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563000, Guizhou Province, China
| | - Jun Lou
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563000, Guizhou Province, China
| | - Jing-Yu Xu
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563000, Guizhou Province, China
| | - Rui Xie
- Department of Gastroenterology, Affiliated Hospital to Zunyi Medical College, Zunyi 563000, Guizhou Province, China
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Abstract
Drug transporter proteins are critical to the distribution of a wide range of endogenous compounds and xenobiotics such as hormones, bile acids, peptides, lipids, sugars, and drugs. There are two classes of drug transporters- the solute carrier (SLC) transporters and ATP-binding cassette (ABC) transporters -which predominantly differ in the energy source utilized to transport substrates across a membrane barrier. Despite their hydrophobic nature and residence in the membrane bilayer, drug transporters have dynamic structures and adopt many conformations during the translocation process. Whereas there is significant literature evidence for the substrate specificity and structure-function relationship for clinically relevant drug transporters proteins, there is less of an understanding in the regulatory mechanisms that contribute to the functional expression of these proteins. Post-translational modifications have been shown to modulate drug transporter functional expression via a wide range of molecular mechanisms. These modifications commonly occur through the addition of a functional group (e.g. phosphorylation), a small protein (e.g. ubiquitination), sugar chains (e.g. glycosylation), or lipids (e.g. palmitoylation) on solvent accessible amino acid residues. These covalent additions often occur as a result of a signaling cascade and may be reversible depending on the type of modification and the intended fate of the signaling event. Here, we review the significant role in which post-translational modifications contribute to the dynamic regulation and functional consequences of SLC and ABC drug transporters and highlight recent progress in understanding their roles in transporter structure, function, and regulation.
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Affiliation(s)
- Lindsay C Czuba
- Department of Pharmaceutical Sciences, University of Maryland, 20 Penn Street, Baltimore, MD 21201, USA
| | | | - Peter W Swaan
- Department of Pharmaceutical Sciences, University of Maryland, 20 Penn Street, Baltimore, MD 21201, USA.
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Lariccia V, Amoroso S. Calcium- and ATP-dependent regulation of Na/Ca exchange function in BHK cells: Comparison of NCX1 and NCX3 exchangers. Cell Calcium 2018; 73:95-103. [PMID: 29705719 DOI: 10.1016/j.ceca.2018.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 04/16/2018] [Indexed: 12/27/2022]
Abstract
Na+/Ca2+ exchangers (NCX) mediate bidirectional Ca2+ fluxes across cell membranes and contribute to Ca2+ homeostasis in many cell types. Exchangers are regulated by gating reactions that depend on Na+ and Ca2+ binding to transport and regulatory sites. A Na+i-dependent inactivation is prominent in all isoforms, whereas Ca2+i-dependent regulation varies among isoforms. Here we characterize new details of NCX operation and describe differences and similarities between NCX3 and NCX1 regulation by intracellular Ca2+ and ATP. To compare isoforms, we employed BHK cells expressing NCX3 or NCX1 constitutively and exchange activity was analysed in whole-cell and excised patch recordings under "zero-trans" conditions (i.e., with only one transported ion species on each side). Using BHK cells with low cytoplasmic Ca2+ buffering, outward (reverse) currents, reflecting Ca2+ influx, are activated by applying extracellular Ca2+ (Cao) in the presence of Na+ on the cytoplasmic side. When firstly activated, peak outward NCX3 currents rapidly decay over seconds and then typically develop a secondary transient peak with slower kinetics, until Cao removal abolishes all outward current. The delayed rise of outward current is the signature of an activating process since peak outward NCX3 currents elicited at subsequent Cao bouts remain stimulated for minutes and slower decline towards a non-zero level during continued Cao application. Secondary transient peaks and current stimulation are suppressed by increasing the intracellular Ca2+ buffer capacity or by replacing cytoplasmic ATP with the analogues AMP-PNP or ATPγS. In BHK cells expressing NCX1, outward currents activated under identical settings decay to a steady-state level during single Cao application and are significantly larger, causing strong and long-lived run down of subsequent outward currents. NCX1 current run down is not prevented by increasing cytoplasmic Ca2+ buffering but secondary transient peaks in the outward current profile can be resolved in the presence of ATP. Finally, inward currents recorded in patches excised from NCX3-expressing cells reveal a proteolysis-sensitive, Ca-dependent inactivation process that is unusual for NCX1 forward activity. Together, our results suggest that NCX function is regulated more richly than appreciated heretofore, possibly including processes that are lost in excised membrane patches.
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Affiliation(s)
- Vincenzo Lariccia
- Department of Biomedical Science and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
| | - Salvatore Amoroso
- Department of Biomedical Science and Public Health, School of Medicine, University "Politecnica delle Marche", Ancona, Italy.
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Howie J, Wypijewski KJ, Plain F, Tulloch LB, Fraser NJ, Fuller W. Greasing the wheels or a spanner in the works? Regulation of the cardiac sodium pump by palmitoylation. Crit Rev Biochem Mol Biol 2018; 53:175-191. [PMID: 29424237 DOI: 10.1080/10409238.2018.1432560] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The ubiquitous sodium/potassium ATPase (Na pump) is the most abundant primary active transporter at the cell surface of multiple cell types, including ventricular myocytes in the heart. The activity of the Na pump establishes transmembrane ion gradients that control numerous events at the cell surface, positioning it as a key regulator of the contractile and metabolic state of the myocardium. Defects in Na pump activity and regulation elevate intracellular Na in cardiac muscle, playing a causal role in the development of cardiac hypertrophy, diastolic dysfunction, arrhythmias and heart failure. Palmitoylation is the reversible conjugation of the fatty acid palmitate to specific protein cysteine residues; all subunits of the cardiac Na pump are palmitoylated. Palmitoylation of the pump's accessory subunit phospholemman (PLM) by the cell surface palmitoyl acyl transferase DHHC5 leads to pump inhibition, possibly by altering the relationship between the pump catalytic α subunit and specifically bound membrane lipids. In this review, we discuss the functional impact of PLM palmitoylation on the cardiac Na pump and the molecular basis of recognition of PLM by its palmitoylating enzyme DHHC5, as well as effects of palmitoylation on Na pump cell surface abundance in the cardiac muscle. We also highlight the numerous unanswered questions regarding the cellular control of this fundamentally important regulatory process.
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Affiliation(s)
- Jacqueline Howie
- a Institute of Cardiovascular and Medical Sciences , University of Glasgow , Glasgow , UK
| | | | - Fiona Plain
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - Lindsay B Tulloch
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - Niall J Fraser
- b Molecular and Clinical Medicine , University of Dundee , Dundee , UK
| | - William Fuller
- a Institute of Cardiovascular and Medical Sciences , University of Glasgow , Glasgow , UK
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Woon MT, Long PA, Reilly L, Evans JM, Keefe AM, Lea MR, Beglinger CJ, Balijepalli RC, Lee Y, Olson TM, Kamp TJ. Pediatric Dilated Cardiomyopathy-Associated LRRC10 (Leucine-Rich Repeat-Containing 10) Variant Reveals LRRC10 as an Auxiliary Subunit of Cardiac L-Type Ca 2+ Channels. J Am Heart Assoc 2018; 7:e006428. [PMID: 29431102 PMCID: PMC5850229 DOI: 10.1161/jaha.117.006428] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 11/10/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Genetic causes of dilated cardiomyopathy (DCM) are incompletely understood. LRRC10 (leucine-rich repeat-containing 10) is a cardiac-specific protein of unknown function. Heterozygous mutations in LRRC10 have been suggested to cause DCM, and deletion of Lrrc10 in mice results in DCM. METHODS AND RESULTS Whole-exome sequencing was carried out on a patient who presented at 6 weeks of age with DCM and her unaffected parents, filtering for rare, deleterious, recessive, and de novo variants. Whole-exome sequencing followed by trio-based filtering identified a homozygous recessive variant in LRRC10, I195T. Coexpression of I195T LRRC10 with the L-type Ca2+ channel (Cav1.2, β2CN2, and α2δ subunits) in HEK293 cells resulted in a significant ≈0.5-fold decrease in ICa,L at 0 mV, in contrast to the ≈1.4-fold increase in ICa,L by coexpression of LRRC10 (n=9-12, P<0.05). Coexpression of LRRC10 or I195T LRRC10 did not alter the surface membrane expression of Cav1.2. LRRC10 coexpression with Cav1.2 in the absence of auxiliary β2CN2 and α2δ subunits revealed coassociation of Cav1.2 and LRRC10 and a hyperpolarizing shift in the voltage dependence of activation (n=6-9, P<0.05). Ventricular myocytes from Lrrc10-/- mice had significantly smaller ICa,L, and coimmunoprecipitation experiments confirmed association between LRRC10 and the Cav1.2 subunit in mouse hearts. CONCLUSIONS Examination of a patient with DCM revealed homozygosity for a previously unreported LRRC10 variant: I195T. Wild-type and I195T LRRC10 function as cardiac-specific subunits of L-type Ca2+ channels and exert dramatically different effects on channel gating, providing a potential link to DCM.
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Affiliation(s)
- Marites T Woon
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Pamela A Long
- Mayo Graduate School, Molecular Pharmacology and Experimental Therapeutics Track, Mayo Clinic, Rochester, MN
| | - Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Jared M Evans
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | - Alexis M Keefe
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Martin R Lea
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Carl J Beglinger
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Ravi C Balijepalli
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Youngsook Lee
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Timothy M Olson
- Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN
| | - Timothy J Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 263] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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Russell J, Du Toit EF, Peart JN, Patel HH, Headrick JP. Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection. Cardiovasc Diabetol 2017; 16:155. [PMID: 29202762 PMCID: PMC5716308 DOI: 10.1186/s12933-017-0638-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/22/2017] [Indexed: 02/06/2023] Open
Abstract
Cardiovascular disease, predominantly ischemic heart disease (IHD), is the leading cause of death in diabetes mellitus (DM). In addition to eliciting cardiomyopathy, DM induces a ‘wicked triumvirate’: (i) increasing the risk and incidence of IHD and myocardial ischemia; (ii) decreasing myocardial tolerance to ischemia–reperfusion (I–R) injury; and (iii) inhibiting or eliminating responses to cardioprotective stimuli. Changes in ischemic tolerance and cardioprotective signaling may contribute to substantially higher mortality and morbidity following ischemic insult in DM patients. Among the diverse mechanisms implicated in diabetic impairment of ischemic tolerance and cardioprotection, changes in sarcolemmal makeup may play an overarching role and are considered in detail in the current review. Observations predominantly in animal models reveal DM-dependent changes in membrane lipid composition (cholesterol and triglyceride accumulation, fatty acid saturation vs. reduced desaturation, phospholipid remodeling) that contribute to modulation of caveolar domains, gap junctions and T-tubules. These modifications influence sarcolemmal biophysical properties, receptor and phospholipid signaling, ion channel and transporter functions, contributing to contractile and electrophysiological dysfunction, cardiomyopathy, ischemic intolerance and suppression of protective signaling. A better understanding of these sarcolemmal abnormalities in types I and II DM (T1DM, T2DM) can inform approaches to limiting cardiomyopathy, associated IHD and their consequences. Key knowledge gaps include details of sarcolemmal changes in models of T2DM, temporal patterns of lipid, microdomain and T-tubule changes during disease development, and the precise impacts of these diverse sarcolemmal modifications. Importantly, exercise, dietary, pharmacological and gene approaches have potential for improving sarcolemmal makeup, and thus myocyte function and stress-resistance in this ubiquitous metabolic disorder.
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Affiliation(s)
- Jake Russell
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Eugene F Du Toit
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Jason N Peart
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Hemal H Patel
- VA San Diego Healthcare System and Department of Anesthesiology, University of California San Diego, San Diego, USA
| | - John P Headrick
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia. .,School of Medical Science, Griffith University, Southport, QLD, 4217, Australia.
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46
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Plain F, Turnbull D, Fraser NJ, Fuller W. Understanding the rules governing NCX1 palmitoylation. Channels (Austin) 2017; 11:377-379. [PMID: 28617626 DOI: 10.1080/19336950.2017.1342501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Fiona Plain
- a Division of Molecular & Clinical Medicine , School of Medicine, University of Dundee , Dundee, Scotland , UK
| | - Dionne Turnbull
- b Division of Plant Sciences , School of Life Sciences, University of Dundee , Scotland , UK
| | - Niall J Fraser
- a Division of Molecular & Clinical Medicine , School of Medicine, University of Dundee , Dundee, Scotland , UK
| | - William Fuller
- a Division of Molecular & Clinical Medicine , School of Medicine, University of Dundee , Dundee, Scotland , UK
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47
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Plain F, Congreve SD, Yee RSZ, Kennedy J, Howie J, Kuo CW, Fraser NJ, Fuller W. An amphipathic α-helix directs palmitoylation of the large intracellular loop of the sodium/calcium exchanger. J Biol Chem 2017; 292:10745-10752. [PMID: 28432123 PMCID: PMC5481580 DOI: 10.1074/jbc.m116.773945] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/19/2017] [Indexed: 11/06/2022] Open
Abstract
The electrogenic sodium/calcium exchanger (NCX) mediates bidirectional calcium transport controlled by the transmembrane sodium gradient. NCX inactivation occurs in the absence of phosphatidylinositol 4,5-bisphosphate and is facilitated by palmitoylation of a single cysteine at position 739 within the large intracellular loop of NCX. The aim of this investigation was to identify the structural determinants of NCX1 palmitoylation. Full-length NCX1 (FL-NCX1) and a YFP fusion protein of the NCX1 large intracellular loop (YFP-NCX1) were expressed in HEK cells. Single amino acid changes around Cys-739 in FL-NCX1 and deletions on the N-terminal side of Cys-739 in YFP-NCX1 did not affect NCX1 palmitoylation, with the exception of the rare human polymorphism S738F, which enhanced FL-NCX1 palmitoylation, and D741A, which modestly reduced it. In contrast, deletion of a 21-amino acid segment enriched in aromatic amino acids on the C-terminal side of Cys-739 abolished YFP-NCX1 palmitoylation. We hypothesized that this segment forms an amphipathic α-helix whose properties facilitate Cys-739 palmitoylation. Introduction of negatively charged amino acids to the hydrophobic face or of helix-breaking prolines impaired palmitoylation of both YFP-NCX1 and FL-NCX1. Alanine mutations on the hydrophilic face of the helix significantly reduced FL-NCX1 palmitoylation. Of note, when the helix-containing segment was introduced adjacent to cysteines that are not normally palmitoylated, they became palmitoylation sites. In conclusion, we have identified an amphipathic α-helix in the NCX1 large intracellular loop that controls NCX1 palmitoylation. NCX1 palmitoylation is governed by a distal secondary structure element rather than by local primary sequence.
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Affiliation(s)
- Fiona Plain
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Samitha Dilini Congreve
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Rachel Sue Zhen Yee
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Jennifer Kennedy
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Jacqueline Howie
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Chien-Wen Kuo
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - Niall J Fraser
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
| | - William Fuller
- From the Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom
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48
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Issa H, Huc-Claustre E, Reddad T, Bonadé Bottino N, Tropis M, Houssin C, Daffé M, Bayan N, Dautin N. Click-chemistry approach to study mycoloylated proteins: Evidence for PorB and PorC porins mycoloylation in Corynebacterium glutamicum. PLoS One 2017; 12:e0171955. [PMID: 28199365 PMCID: PMC5310785 DOI: 10.1371/journal.pone.0171955] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/27/2017] [Indexed: 01/23/2023] Open
Abstract
Protein mycoloylation is a recently identified, new form of protein acylation. This post-translational modification consists in the covalent attachment of mycolic acids residues to serine. Mycolic acids are long chain, α-branched, β-hydroxylated fatty acids that are exclusively found in the cell envelope of Corynebacteriales, a bacterial order that includes important genera such as Mycobacterium, Nocardia or Corynebacterium. So far, only 3 mycoloylated proteins have been identified: PorA, PorH and ProtX from C. glutamicum. Whereas the identity and function of ProtX is unknown, PorH and PorA associate to form a membrane channel, the activity of which is dependent upon PorA mycoloylation. However, the exact role of mycoloylation and the generality of this phenomenon are still unknown. In particular, the identity of other mycoloylated proteins, if any, needs to be determined together with establishing whether such modification occurs in Corynebacteriales genera other than Corynebacterium. Here, we tested whether a metabolic labeling and click-chemistry approach could be used to detect mycoloylated proteins. Using a fatty acid alkyne analogue, we could indeed label PorA, PorH and ProtX and determine ProtX mycoloylation site. Importantly, we also show that two other porins from C. glutamicum, PorB and PorC are mycoloylated.
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Affiliation(s)
- Hanane Issa
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
- Holy Spirit University of Kaslik (USEK), Jounieh, Mount Lebanon, Lebanon
| | | | - Thamila Reddad
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Nolwenn Bonadé Bottino
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Maryelle Tropis
- Institute of Pharmacology and Structural Biology (IPBS), UMR 5089, France
| | - Christine Houssin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Mamadou Daffé
- Institute of Pharmacology and Structural Biology (IPBS), UMR 5089, France
| | - Nicolas Bayan
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Nathalie Dautin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
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49
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Hurst CH, Turnbull D, Plain F, Fuller W, Hemsley PA. Maleimide scavenging enhances determination of protein S-palmitoylation state in acyl-exchange methods. Biotechniques 2017; 62:69-75. [PMID: 28193150 PMCID: PMC5400063 DOI: 10.2144/000114516] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 12/09/2016] [Indexed: 11/23/2022] Open
Abstract
S-palmitoylation (S-acylation) is emerging as an important dynamic post-translational modification of cysteine residues within proteins. Current assays for protein S-palmitoylation involve either in vivo labeling or chemical cleavage of S-palmitoyl groups to reveal a free cysteine sulfhydryl that can be subsequently labeled with an affinity handle (acyl-exchange). Assays for protein S-palmitoylation using acyl-exchange chemistry therefore require blocking of non-S-palmitoylated cysteines, typically using N-ethylmaleimide (NEM), to prevent non-specific detection. This in turn necessitates multiple precipitation-based clean-up steps to remove reagents between stages, often leading to variable sample loss, reduced signal, or protein aggregation. These combine to reduce the sensitivity, reliability, and accuracy of these assays, which also require a substantial amount of time to perform. By substituting these precipitation steps with chemical scavenging of NEM by 2,3-dimethyl-1,3-butadiene in an aqueous Diels-Alder 4+2 cyclo-addition reaction, it is possible to greatly improve sensitivity and accuracy while reducing the hands-on time and overall time required for the assay.
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Affiliation(s)
- Charlotte H. Hurst
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, UK
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, UK
| | - Dionne Turnbull
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, UK
| | - Fiona Plain
- Division of Cardiovascular and Diabetes Medicine, Medical Research Institute, School of Medicine, Dentistry, and Nursing, University of Dundee, Dundee, UK
| | - William Fuller
- Division of Cardiovascular and Diabetes Medicine, Medical Research Institute, School of Medicine, Dentistry, and Nursing, University of Dundee, Dundee, UK
| | - Piers A. Hemsley
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, UK
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, UK
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50
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Effects of induced Na+/Ca2+ exchanger overexpression on the spatial distribution of L-type Ca2+ channels and junctophilin-2 in pressure-overloaded hearts. Biochem Biophys Res Commun 2016; 480:564-569. [DOI: 10.1016/j.bbrc.2016.10.090] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 10/24/2016] [Indexed: 02/08/2023]
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