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Graf IR, Machta BB. A bifurcation integrates information from many noisy ion channels and allows for milli-Kelvin thermal sensitivity in the snake pit organ. Proc Natl Acad Sci U S A 2024; 121:e2308215121. [PMID: 38294944 PMCID: PMC10861916 DOI: 10.1073/pnas.2308215121] [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: 05/18/2023] [Accepted: 12/10/2023] [Indexed: 02/02/2024] Open
Abstract
In various biological systems, information from many noisy molecular receptors must be integrated into a collective response. A striking example is the thermal imaging organ of pit vipers. Single nerve fibers in the organ reliably respond to milli-Kelvin (mK) temperature increases, a thousand times more sensitive than their molecular sensors, thermo-transient receptor potential (TRP) ion channels. Here, we propose a mechanism for the integration of this molecular information. In our model, amplification arises due to proximity to a dynamical bifurcation, separating a regime with frequent and regular action potentials (APs), from a regime where APs are irregular and infrequent. Near the transition, AP frequency can have an extremely sharp dependence on temperature, naturally accounting for the thousand-fold amplification. Furthermore, close to the bifurcation, most of the information about temperature available in the TRP channels' kinetics can be read out from the times between consecutive APs even in the presence of readout noise. A key model prediction is that the coefficient of variation in the distribution of interspike times decreases with AP frequency, and quantitative comparison with experiments indeed suggests that nerve fibers of snakes are located very close to the bifurcation. While proximity to such bifurcation points typically requires fine-tuning of parameters, we propose that having feedback act from the order parameter (AP frequency) onto the control parameter robustly maintains the system in the vicinity of the bifurcation. This robustness suggests that similar feedback mechanisms might be found in other sensory systems which also need to detect tiny signals in a varying environment.
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Affiliation(s)
| | - Benjamin B. Machta
- Department of Physics, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
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2
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Wang L, Cai R, Chen XZ, Peng JB. Molecular insights into the structural and dynamical changes of calcium channel TRPV6 induced by its interaction with phosphatidylinositol 4,5-bisphosphate. J Biomol Struct Dyn 2023; 41:6559-6568. [PMID: 35950523 PMCID: PMC9918602 DOI: 10.1080/07391102.2022.2109752] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/30/2022] [Indexed: 10/15/2022]
Abstract
Transient receptor potential vanilloid subfamily member 6 (TRPV6) is an epithelial calcium channel that regulates the initial step of the transcellular calcium transport pathway. TRPV6 is expressed in the kidney, intestine, placenta, and other tissues, and the dysregulation of the channel is implicated in several human cancers. It has been reported that phosphatidylinositol 4,5-bisphosphate (PIP2) activates TRPV6 and its close homologue TRPV5; however, the underlying molecular mechanism is less clear. Recently, a structure of rabbit TRPV5 in complex with dioctanoyl (diC8) PIP2, a soluble form of PIP2, was determined by cryo-electron microscopy. Based on this structure, the structural model of human TRPV6 with PIP2 was set up, and then molecular dynamics simulations were performed for TRPV6 with and without PIP2. Simulation results show that the positively charged residues responsible for TRPV5 binding of diC8 PIP2 are conserved in the interactions between TRPV6 and PIP2. The binding of PIP2 to TRPV6 increases the distance between the diagonally opposed residues D542 in the selectivity filter and that between the diagonally opposed M578 residues in the lower gate of TRPV6. A secondary structural analysis reveals that residues M578 in TRPV6 undergo structural and position changes during the binding of PIP2 with TRPV6. In addition, principal component analysis indicates that the binding of PIP2 increases the dynamical motions of both the selectivity filter and the lower gate of TRPV6. These changes induced by PIP2 favor the channel opening. Thus, this study provides a basis for understanding the mechanism underlying the PIP2-induced TRPV6 channel activation.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ruiqi Cai
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7 Edmonton, AB, Canada
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7 Edmonton, AB, Canada
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294
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3
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Bai S, Wei Y, Liu R, Chen Y, Ma W, Wang M, Chen L, Luo Y, Du J. The role of transient receptor potential channels in metastasis. Biomed Pharmacother 2023; 158:114074. [PMID: 36493698 DOI: 10.1016/j.biopha.2022.114074] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
Metastasis is the hallmark of failed tumor treatment and is typically associated with death due to cancer. Transient receptor potential (TRP) channels affect changes in intracellular calcium concentrations and participate at every stage of metastasis. Further, they increase the migratory ability of tumor cells, promote angiogenesis, regulate immune function, and promote the growth of tumor cells through changes in gene expression and function. In this review, we explore the potential mechanisms of action of TRP channels, summarize their role in tumor metastasis, compile inhibitors of TRP channels relevant in tumors, and discuss current challenges in research on TRP channels involved in tumor metastasis.
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Affiliation(s)
- Suwen Bai
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Yuan Wei
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Rong Liu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei, Anhui 230032, China
| | - Yuhua Chen
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Wanling Ma
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Minghua Wang
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Li Chen
- Department of obstetrics and gynecology, The Seventh Affiliated Hospital, Sun Yat-sen University, Zhenyuan Rd, Guangming Dist., Shenzhen, Guangdong 518107, China
| | - Yumei Luo
- Longgang District People's Hospital of Shenzhen & The Second Affiliated Hospital, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China.
| | - Juan Du
- Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China.
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4
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Claveras Cabezudo A, Feriel Khoualdi A, D’Avanzo N. Computational Prediction of Phosphoinositide Binding to Hyperpolarization-Activated Cyclic-Nucleotide Gated Channels. Front Physiol 2022; 13:859087. [PMID: 35399260 PMCID: PMC8990809 DOI: 10.3389/fphys.2022.859087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 12/31/2022] Open
Abstract
Protein-lipid interactions are key regulators of ion channel function. Numerous ion channels, including hyperpolarization-activated cyclic-nucleotide gated (HCN) channels have been shown to be regulated by phosphoinositides (PIPs), with important implications in cardiac and neuronal function. Specifically, PIPs have been shown to enhance HCN activation. Using computational approaches, we aim to identify potential binding sites for HCN1-PIP interactions. Computational docking and coarse-grained simulations indicate that PIP binding to HCN1 channels is not well coordinated, but rather occurs over a broad surface of charged residues primarily in the HCN-domain, S2 and S3 helices that can be loosely organized in 2 or 3 overlapping clusters. Thus, PIP-HCN1 interactions are more resembling of electrostatic interactions that occur in myristoylated alanine-rich C kinase substrate (MARCKS) proteins, than the specifically coordinated interactions that occur in pleckstrin homology domains (PH domains) or ion channels such as inward rectifier potassium (Kir) channels. Our results also indicate that phosphatidylinositol (PI) interactions with HCN1 are even lower affinity, explaining why unphosphorylated PI have no effect on HCN1 activation unlike phosphorylated PIPs.
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Affiliation(s)
- Ainara Claveras Cabezudo
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, Heidelberg, Germany
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
| | - Asma Feriel Khoualdi
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
| | - Nazzareno D’Avanzo
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
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Tariq K, Luikart BW. Striking a balance: PIP 2 and PIP 3 signaling in neuronal health and disease. EXPLORATION OF NEUROPROTECTIVE THERAPY 2022; 1:86-100. [PMID: 35098253 PMCID: PMC8797975 DOI: 10.37349/ent.2021.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphoinositides are membrane phospholipids involved in a variety of cellular processes like growth, development, metabolism, and transport. This review focuses on the maintenance of cellular homeostasis of phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidylinositol 3,4,5-trisphosphate (PIP3). The critical balance of these PIPs is crucial for regulation of neuronal form and function. The activity of PIP2 and PIP3 can be regulated through kinases, phosphatases, phospholipases and cholesterol microdomains. PIP2 and PIP3 carry out their functions either indirectly through their effectors activating integral signaling pathways, or through direct regulation of membrane channels, transporters, and cytoskeletal proteins. Any perturbations to the balance between PIP2 and PIP3 signaling result in neurodevelopmental and neurodegenerative disorders. This review will discuss the upstream modulators and downstream effectors of the PIP2 and PIP3 signaling, in the context of neuronal health and disease.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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Eaton-Fitch N, Cabanas H, du Preez S, Staines D, Marshall-Gradisnik S. The effect of IL-2 stimulation and treatment of TRPM3 on channel co-localisation with PIP 2 and NK cell function in myalgic encephalomyelitis/chronic fatigue syndrome patients. J Transl Med 2021; 19:306. [PMID: 34266470 PMCID: PMC8281618 DOI: 10.1186/s12967-021-02974-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/01/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious multifactorial disorder. The origin remains ambiguous, however reduced natural killer (NK) cell cytotoxicity is a consistent immunological feature of ME/CFS. Impaired transient receptor potential melastatin 3 (TRPM3), a phosphatidylinositol dependent channel, and impaired calcium mobilisation have been implicated in ME/CFS pathology. This investigation aimed to examine the localisation of TRPM3 at the NK cell plasma membrane and co-localisation with phosphatidylinositol 4,5-bisphosphate (PIP2). The effect of IL-2 priming and treatment using pregnenolone sulfate (PregS) and ononetin on TRPM3 co-localisation and NK cell cytotoxicity in ME/CFS patients and healthy controls (HC) was also investigated. METHODS NK cells were isolated from 15 ME/CFS patients and 15 age- and sex-matched HC. Immunofluorescent technique was used to determine co-localisation of TRPM3 with the NK cell membrane and with PIP2 of ME/CFS patients and HC. Flow cytometry was used to determine NK cell cytotoxicity. Following IL-2 stimulation and treatment with PregS and ononetin changes in co-localisation and NK cell cytotoxicity were measured. RESULTS Overnight treatment of NK cells with PregS and ononetin resulted in reduced co-localisation of TRPM3 with PIP2 and actin in HC. Co-localisation of TRPM3 with PIP2 in NK cells was significantly reduced in ME/CFS patients compared with HC following priming with IL-2. A significant increase in co-localisation of TRPM3 with PIP2 was reported following overnight treatment with ononetin within ME/CFS patients and between groups. Baseline NK cell cytotoxicity was significantly reduced in ME/CFS patients; however, no changes were observed following overnight incubation with IL-2, PregS and ononetin between HC and ME/CFS patients. IL-2 stimulation significantly enhanced NK cell cytotoxicity in HC and ME/CFS patients. CONCLUSION Significant changes in co-localisation suggest PIP2-dependent TRPM3 function may be impaired in ME/CFS patients. Stimulation of NK cells with IL-2 significantly enhanced cytotoxic function in ME/CFS patients demonstrating normal function compared with HC. A crosstalk exists between IL-2 and TRPM3 intracellular signalling pathways which are dependent on Ca2+ influx and PIP2. While IL-2R responds to IL-2 binding in vitro, Ca2+ dysregulation and impaired intracellular signalling pathways impede NK cell function in ME/CFS patients.
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Affiliation(s)
- Natalie Eaton-Fitch
- School of Medical Sciences, Griffith University, Gold Coast, Australia. .,National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia. .,Consortium Health International for Myalgic Encephalomyelitis, Griffith University, Gold Coast, Australia.
| | - Hélène Cabanas
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.,Consortium Health International for Myalgic Encephalomyelitis, Griffith University, Gold Coast, Australia
| | - Stanley du Preez
- School of Medical Sciences, Griffith University, Gold Coast, Australia.,National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.,Consortium Health International for Myalgic Encephalomyelitis, Griffith University, Gold Coast, Australia
| | - Donald Staines
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.,Consortium Health International for Myalgic Encephalomyelitis, Griffith University, Gold Coast, Australia
| | - Sonya Marshall-Gradisnik
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.,Consortium Health International for Myalgic Encephalomyelitis, Griffith University, Gold Coast, Australia
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7
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Zhang F, Lin Y, Min W, Hou Y, Yuan K, Wang J, Yang P. Computational discovery, structural optimization and biological evaluation of novel inhibitors targeting transient receptor potential vanilloid type 3 (TRPV3). Bioorg Chem 2021; 114:105093. [PMID: 34182309 DOI: 10.1016/j.bioorg.2021.105093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/24/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Transient receptor potential vanilloid type 3 (TRPV3) is a Ca2+ permeable nonselective cation channel and expressed abundantly in skin keratinocytes. TRPV3 emerges as an attractive target for treatment of pruritic, inflammatory, pain and skin-related diseases. However, only a few reports of TRPV3 inhibitors exist at present besides some patents. Therefore, TRPV3 research has always been fraught with challenges. Through a combination of virtual screening and biological evaluation, compound P1 (10 μM) was identified as a top hit with 34.5% inhibitory effect on 2-APB (1 mM)-evoked currents of mTRPV3-WT. Further structural optimization provided the inhibitor PC5 with the best activity (IC50 = 2.63 ± 0.28 μM), and point mutation assays indicated that amino acids V629 and F633 are crucial for the binding of PC5 and TRPV3. In summary, these newly discovered inhibitors could serve as promising lead compounds for the development of TRPV3 inhibitors in the future.
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Affiliation(s)
- Fang Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yiyu Lin
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Wenjian Min
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yi Hou
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Kai Yuan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Jin Wang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Peng Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
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8
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Two Decades of Evolution of Our Understanding of the Transient Receptor Potential Melastatin 2 (TRPM2) Cation Channel. Life (Basel) 2021; 11:life11050397. [PMID: 33925466 PMCID: PMC8145809 DOI: 10.3390/life11050397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 02/07/2023] Open
Abstract
The transient receptor potential melastatin (TRPM) family belongs to the superfamily of TRP ion channels. It consists of eight family members that are involved in a plethora of cellular functions. TRPM2 is a homotetrameric Ca2+-permeable cation channel activated upon oxidative stress and is important, among others, for body heat control, immune cell activation and insulin secretion. Invertebrate TRPM2 proteins are channel enzymes; they hydrolyze the activating ligand, ADP-ribose, which is likely important for functional regulation. Since its cloning in 1998, the understanding of the biophysical properties of the channel has greatly advanced due to a vast number of structure–function studies. The physiological regulators of the channel have been identified and characterized in cell-free systems. In the wake of the recent structural biochemistry revolution, several TRPM2 cryo-EM structures have been published. These structures have helped to understand the general features of the channel, but at the same time have revealed unexplained mechanistic differences among channel orthologues. The present review aims at depicting the major research lines in TRPM2 structure-function. It discusses biophysical properties of the pore and the mode of action of direct channel effectors, and interprets these functional properties on the basis of recent three-dimensional structural models.
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Abstract
Ion channel are embedded in the lipid bilayers of biological membranes. Membrane phospholipids constitute a barrier to ion movement, and they have been considered for a long time as a passive environment for channel proteins. Membrane phospholipids, however, do not only serve as a passive amphipathic environment, but they also modulate channel activity by direct specific lipid-protein interactions. Phosphoinositides are quantitatively minor components of biological membranes, and they play roles in many cellular functions, including membrane traffic, cellular signaling and cytoskeletal organization. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is mainly found in the inner leaflet of the plasma membrane. Its role as a potential ion channel regulator was first appreciated over two decades ago and by now this lipid is a well-established cofactor or regulator of many different ion channels. The past two decades witnessed the steady development of techniques to study ion channel regulation by phosphoinositides with progress culminating in recent cryoEM structures that allowed visualization of how PI(4,5)P2 opens some ion channels. This chapter will provide an overview of the methods to study regulation by phosphoinositides, focusing on plasma membrane ion channels and PI(4,5)P2.
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10
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Liu G, Fu D, Tian H, Dai A. The mechanism of ions in pulmonary hypertension. Pulm Circ 2021; 11:2045894020987948. [PMID: 33614016 PMCID: PMC7869166 DOI: 10.1177/2045894020987948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022] Open
Abstract
Pulmonary hypertension(PH)is a kind of hemodynamic and pathophysiological state, in which the pulmonary artery pressure (PAP) rises above a certain threshold. The main pathological manifestation is pulmonary vasoconstriction and remodelling progressively. More and more studies have found that ions play a major role in the pathogenesis of PH. Many vasoactive substances, inflammatory mediators, transcription-inducing factors, apoptosis mediators, redox substances and translation modifiers can control the concentration of ions inside and outside the cell by regulating the activity of ion channels, which can regulate vascular contraction, cell proliferation, migration, apoptosis, inflammation and other functions. We all know that there are no effective drugs to treat PH. Ions are involved in the occurrence and development of PH, so it is necessary to clarify the mechanism of ions in PH as a therapeutic target for PH. The main ions involved in PH are calcium ion (Ca2+), potassium ion (K+), sodium ion (Na+) and chloride ion (Cl-). Here, we mainly discuss the distribution of these ions and their channels in pulmonary arteries and their role in the pathogenesis of PH.
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Affiliation(s)
- Guogu Liu
- Department of Graduate School, University of South China,
Hengyang, China
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Daiyan Fu
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Heshen Tian
- Department of Graduate School, University of South China,
Hengyang, China
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Aiguo Dai
- Department of Respiratory Diseases, Hunan University of Chinese
Medicine, Changsha, China
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11
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Structure-Function Relationship of TRPM2: Recent Advances, Contradictions, and Open Questions. Int J Mol Sci 2020; 21:ijms21186481. [PMID: 32899872 PMCID: PMC7555694 DOI: 10.3390/ijms21186481] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 12/21/2022] Open
Abstract
When in a particular scientific field, major progress is rapidly reached after a long period of relative stand-still, this is often achieved by the development or exploitation of new techniques and methods. A striking example is the new insights brought into the understanding of the gating mechanism of the transient receptor potential melastatin type 2 cation channel (TRPM2) by cryogenic electron microscopy structure analysis. When conventional methods are complemented by new ones, it is quite natural that established researchers are not fully familiar with the possibilities and limitations of the new method. On the other hand, newcomers may need some assistance in perceiving the previous knowledge in detail; they may not realize that some of their interpretations are at odds with previous results and need refinement. This may in turn trigger further studies with new and promising perspectives, combining the promises of several methodological approaches. With this review, I aim to give a comprehensive overview on functional data of several orthologous of TRPM2 that are nicely explained by structural studies. Moreover, I wish to point out some functional contradictions raised by the structural data. Finally, some open questions and some lines of possible future experimental approaches shall be discussed.
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12
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Shamsaldeen YA, Lione LA, Benham CD. Dysregulation of TRPV4, eNOS and caveolin-1 contribute to endothelial dysfunction in the streptozotocin rat model of diabetes. Eur J Pharmacol 2020; 888:173441. [PMID: 32810492 DOI: 10.1016/j.ejphar.2020.173441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/30/2022]
Abstract
Endothelial dysfunction is a common complication in diabetes in which endothelium-dependent vasorelaxation is impaired. The aim of this study was to examine the involvement of the TRPV4 ion channel in type 1 diabetic endothelial dysfunction and the possible association of endothelial dysfunction with reduced expression of TRPV4, endothelial nitric oxide synthase (eNOS) and caveolin-1. Male Wistar rats (350-450 g) were injected with 65 mg/kg i.p. streptozotocin (STZ) or vehicle. Endothelial function was investigated in aortic rings and mesenteric arteries using organ bath and myograph, respectively. TRPV4 function was studied with fura-2 calcium imaging in endothelial cells cultured from aortas from control and STZ treated rats. TRPV4, caveolin-1 and eNOS expression was investigated in these cells using immunohistochemistry. STZ-treated diabetic rats showed significant endothelial dysfunction characterised by impaired muscarinic-induced vasorelaxation (aortic rings: STZ-diabetics: Emax = 29.6 ± 9.3%; control: Emax = 77.2 ± 2.5% P˂0.001), as well as significant impairment in TRPV4-induced vasorelaxation (aortic rings, 4αPDD STZ-diabetics: Emax = 56.0 ± 5.5%; control: Emax = 81.1 ± 2.1% P˂0.001). Furthermore, STZ-diabetic primary aortic endothelial cells showed a significant reduction in TRPV4-induced intracellular calcium elevation (P˂0.05) compared with the control group. This was associated with significantly lower expression of TRPV4, caveolin-1 and eNOS and this was reversed by insulin treatment of the endothelial cultures from STZ -diabetic rats. Taken together, these data are consistent with the hypothesis that signalling through TRPV4, caveolin-1, and eNOS is downregulated in STZ-diabetic aortic endothelial cells and restored by insulin treatment.
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Affiliation(s)
- Yousif A Shamsaldeen
- School of Life and Medical Sciences, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB, UK; Department of Pharmacy, Kuwait Hospital, Sabah Alsalem, 44001, Kuwait.
| | - Lisa A Lione
- School of Life and Medical Sciences, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB, UK
| | - Christopher D Benham
- School of Life and Medical Sciences, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB, UK
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Bousova K, Barvik I, Herman P, Hofbauerová K, Monincova L, Majer P, Zouharova M, Vetyskova V, Postulkova K, Vondrasek J. Mapping of CaM, S100A1 and PIP2-Binding Epitopes in the Intracellular N- and C-Termini of TRPM4. Int J Mol Sci 2020; 21:E4323. [PMID: 32560560 PMCID: PMC7352223 DOI: 10.3390/ijms21124323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 12/27/2022] Open
Abstract
Molecular determinants of the binding of various endogenous modulators to transient receptor potential (TRP) channels are crucial for the understanding of necessary cellular pathways, as well as new paths for rational drug designs. The aim of this study was to characterise interactions between the TRP cation channel subfamily melastatin member 4 (TRPM4) and endogenous intracellular modulators-calcium-binding proteins (calmodulin (CaM) and S100A1) and phosphatidylinositol 4, 5-bisphosphate (PIP2). We have found binding epitopes at the N- and C-termini of TRPM4 shared by CaM, S100A1 and PIP2. The binding affinities of short peptides representing the binding epitopes of N- and C-termini were measured by means of fluorescence anisotropy (FA). The importance of representative basic amino acids and their combinations from both peptides for the binding of endogenous TRPM4 modulators was proved using point alanine-scanning mutagenesis. In silico protein-protein docking of both peptides to CaM and S100A1 and extensive molecular dynamics (MD) simulations enabled the description of key stabilising interactions at the atomic level. Recently solved cryo-Electron Microscopy (EM) structures made it possible to put our findings into the context of the entire TRPM4 channel and to deduce how the binding of these endogenous modulators could allosterically affect the gating of TRPM4. Moreover, both identified binding epitopes seem to be ideally positioned to mediate the involvement of TRPM4 in higher-order hetero-multimeric complexes with important physiological functions.
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Affiliation(s)
- Kristyna Bousova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
| | - Ivan Barvik
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague, Czech Republic; (I.B.); (P.H.); (K.H.)
| | - Petr Herman
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague, Czech Republic; (I.B.); (P.H.); (K.H.)
| | - Kateřina Hofbauerová
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague, Czech Republic; (I.B.); (P.H.); (K.H.)
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic
| | - Lenka Monincova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
| | - Monika Zouharova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
- Second Faculty of Medicine, Charles University, V Uvalu 84, 150 06 Prague, Czech Republic
| | - Veronika Vetyskova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
| | - Klara Postulkova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
| | - Jiri Vondrasek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 2, 16000 Prague, Czech Republic; (L.M.); (P.M.); (M.Z.); (V.V.); (K.P.); (J.V.)
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14
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Talarico C, Gervasoni S, Manelfi C, Pedretti A, Vistoli G, Beccari AR. Combining Molecular Dynamics and Docking Simulations to Develop Targeted Protocols for Performing Optimized Virtual Screening Campaigns on The hTRPM8 Channel. Int J Mol Sci 2020; 21:E2265. [PMID: 32218173 PMCID: PMC7177470 DOI: 10.3390/ijms21072265] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/19/2020] [Accepted: 03/20/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND There is an increasing interest in TRPM8 ligands of medicinal interest, the rational design of which can be nowadays supported by structure-based in silico studies based on the recently resolved TRPM8 structures. Methods: The study involves the generation of a reliable hTRPM8 homology model, the reliability of which was assessed by a 1.0 μs MD simulation which was also used to generate multiple receptor conformations for the following structure-based virtual screening (VS) campaigns; docking simulations utilized different programs and involved all monomers of the selected frames; the so computed docking scores were combined by consensus approaches based on the EFO algorithm. Results: The obtained models revealed very satisfactory performances; LiGen™ provided the best results among the tested docking programs; the combination of docking results from the four monomers elicited a markedly beneficial effect on the computed consensus models. Conclusions: The generated hTRPM8 model appears to be amenable for successful structure-based VS studies; cross-talk modulating effects between interacting monomers on the binding sites can be accounted for by combining docking simulations as performed on all the monomers; this strategy can have general applicability for docking simulations involving quaternary protein structures with multiple identical binding pockets.
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Affiliation(s)
- Carmine Talarico
- Dompé Farmaceutici SpA, Via Campo di Pile, 67100 L’Aquila, Italy; (C.T.); (C.M.)
| | - Silvia Gervasoni
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli, 25, I-20133 Milano, Italy; (S.G.); (A.P.); (G.V.)
| | - Candida Manelfi
- Dompé Farmaceutici SpA, Via Campo di Pile, 67100 L’Aquila, Italy; (C.T.); (C.M.)
| | - Alessandro Pedretti
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli, 25, I-20133 Milano, Italy; (S.G.); (A.P.); (G.V.)
| | - Giulio Vistoli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli, 25, I-20133 Milano, Italy; (S.G.); (A.P.); (G.V.)
| | - Andrea R. Beccari
- Dompé Farmaceutici SpA, Via Campo di Pile, 67100 L’Aquila, Italy; (C.T.); (C.M.)
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15
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Pumroy RA, Fluck EC, Ahmed T, Moiseenkova-Bell VY. Structural insights into the gating mechanisms of TRPV channels. Cell Calcium 2020; 87:102168. [PMID: 32004816 DOI: 10.1016/j.ceca.2020.102168] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 02/06/2023]
Abstract
Transient Receptor Potential channels from the vanilloid subfamily (TRPV) are a group of cation channels modulated by a variety of endogenous stimuli as well as a range of natural and synthetic compounds. Their roles in human health make them of keen interest, particularly from a pharmacological perspective. However, despite this interest, the complexity of these channels has made it difficult to obtain high resolution structures until recently. With the cryo-EM resolution revolution, TRPV channel structural biology has blossomed to produce dozens of structures, covering every TRPV family member and a variety of approaches to examining channel modulation. Here, we review all currently available TRPV structures and the mechanistic insights into gating that they reveal.
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Affiliation(s)
- Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Tofayel Ahmed
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA.
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16
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Lopez JJ, Jardin I, Albarrán L, Sanchez-Collado J, Cantonero C, Salido GM, Smani T, Rosado JA. Molecular Basis and Regulation of Store-Operated Calcium Entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:445-469. [PMID: 31646520 DOI: 10.1007/978-3-030-12457-1_17] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous mechanism for Ca2+ influx in mammalian cells with important physiological implications. Since the discovery of SOCE more than three decades ago, the mechanism that communicates the information about the amount of Ca2+ accumulated in the intracellular Ca2+ stores to the plasma membrane channels and the nature of these channels have been matters of intense investigation and debate. The stromal interaction molecule-1 (STIM1) has been identified as the Ca2+ sensor of the intracellular Ca2+ compartments that activates the store-operated channels. STIM1 regulates two types of store-dependent channels: the Ca2+ release-activated Ca2+ (CRAC) channels, formed by Orai1 subunits, that conduct the highly Ca2+ selective current I CRAC and the cation permeable store-operated Ca2+ (SOC) channels, which consist of Orai1 and TRPC1 proteins and conduct the non-selective current I SOC. While the crystal structure of Drosophila CRAC channel has already been solved, the architecture of the SOC channels still remains unclear. The dynamic interaction of STIM1 with the store-operated channels is modulated by a number of proteins that either support the formation of the functional STIM1-channel complex or protect the cell against Ca2+ overload.
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Affiliation(s)
- Jose J Lopez
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Isaac Jardin
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain.
| | - Letizia Albarrán
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Jose Sanchez-Collado
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Carlos Cantonero
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Gines M Salido
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics and Group of Cardiovascular Pathophysiology, Institute of Biomedicine of Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/University of Sevilla, Sevilla, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
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17
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Deák F, Anderson RE, Fessler JL, Sherry DM. Novel Cellular Functions of Very Long Chain-Fatty Acids: Insight From ELOVL4 Mutations. Front Cell Neurosci 2019; 13:428. [PMID: 31616255 PMCID: PMC6763723 DOI: 10.3389/fncel.2019.00428] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 09/06/2019] [Indexed: 12/22/2022] Open
Abstract
Elongation of Very Long chain fatty acids-4 (ELOVL4) protein is a member of the ELOVL family of fatty acid elongases that is collectively responsible for catalyzing formation of long chain fatty acids. ELOVL4 is the only family member that catalyzes production of Very Long Chain Saturated Fatty Acids (VLC-SFA) and Very Long Chain Polyunsaturated Fatty Acids (VLC-PUFA) with chain lengths ≥28 carbons. ELOVL4 and its VLC-SFA and VLC-PUFA products are emerging as important regulators of synaptic signaling and neuronal survival in the central nervous system (CNS). Distinct sets of mutations in ELOVL4 cause three different neurological diseases in humans. Heterozygous inheritance of one set of autosomal dominant ELOVL4 mutations that leads to truncation of the ELOVL4 protein causes Stargardt-like macular dystrophy (STGD3), an aggressive juvenile-onset retinal degeneration. Heterozygous inheritance of a different set of autosomal dominant ELOVL4 mutations that leads to a full-length protein with single amino acid substitutions causes spinocerebellar ataxia 34 (SCA34), a late-onset neurodegenerative disease characterized by gait ataxia and cerebellar atrophy. Homozygous inheritance of a different set of ELOVL4 mutations causes a more severe disease with infantile onset characterized by seizures, spasticity, intellectual disability, ichthyosis, and premature death. ELOVL4 is expressed widely in the CNS and is found primarily in neurons. ELOVL4 is expressed in cell-specific patterns within different regions of the CNS that are likely to be related to disease symptoms. In the retina, ELOVL4 is expressed exclusively in photoreceptors and produces VLC-PUFA that are incorporated into phosphatidylcholine and enriched in the light sensitive membrane disks of the photoreceptor outer segments. VLC-PUFA are enzymatically converted into "elovanoid" compounds that appear to provide paracrine signals that promote photoreceptor and neuronal survival. In the brain, the main ELOVL4 products are VLC-SFA that are incorporated into sphingolipids and enriched in synaptic vesicles, where they regulate kinetics of presynaptic neurotransmitter release. Understanding the function of ELOVL4 and its VLC-SFA and VLC-PUFA products will advance our understanding of basic mechanisms in neural signaling and has potential for developing novel therapies for seizure and neurodegenerative diseases.
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Affiliation(s)
- Ferenc Deák
- Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Robert E Anderson
- Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jennifer L Fessler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - David M Sherry
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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18
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Picardo MCD, Sugimura YK, Dorst KE, Kallurkar PS, Akins VT, Ma X, Teruyama R, Guinamard R, Kam K, Saha MS, Del Negro CA. Trpm4 ion channels in pre-Bötzinger complex interneurons are essential for breathing motor pattern but not rhythm. PLoS Biol 2019; 17:e2006094. [PMID: 30789900 PMCID: PMC6400419 DOI: 10.1371/journal.pbio.2006094] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 03/05/2019] [Accepted: 02/05/2019] [Indexed: 12/21/2022] Open
Abstract
Inspiratory breathing movements depend on pre-Bötzinger complex (preBötC) interneurons that express calcium (Ca2+)-activated nonselective cationic current (ICAN) to generate robust neural bursts. Hypothesized to be rhythmogenic, reducing ICAN is predicted to slow down or stop breathing; its contributions to motor pattern would be reflected in the magnitude of movements (output). We tested the role(s) of ICAN using reverse genetic techniques to diminish its putative ion channels Trpm4 or Trpc3 in preBötC neurons in vivo. Adult mice transduced with Trpm4-targeted short hairpin RNA (shRNA) progressively decreased the tidal volume of breaths yet surprisingly increased breathing frequency, often followed by gasping and fatal respiratory failure. Mice transduced with Trpc3-targeted shRNA survived with no changes in breathing. Patch-clamp and field recordings from the preBötC in mouse slices also showed an increase in the frequency and a decrease in the magnitude of preBötC neural bursts in the presence of Trpm4 antagonist 9-phenanthrol, whereas the Trpc3 antagonist pyrazole-3 (pyr-3) showed inconsistent effects on magnitude and no effect on frequency. These data suggest that Trpm4 mediates ICAN, whose influence on frequency contradicts a direct role in rhythm generation. We conclude that Trpm4-mediated ICAN is indispensable for motor output but not the rhythmogenic core mechanism of the breathing central pattern generator.
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Affiliation(s)
- Maria Cristina D. Picardo
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Yae K. Sugimura
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Kaitlyn E. Dorst
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Prajkta S. Kallurkar
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Victoria T. Akins
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Xingru Ma
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Ryoichi Teruyama
- Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Romain Guinamard
- Signalisation, Electrophysiologie et Imagerie des Lésions d’Ischémie-Reperfusion Myocardique, Normandie Université, UNICAEN, Caen, France
| | - Kaiwen Kam
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University, Chicago, Illinois, United States of America
| | - Margaret S. Saha
- Department of Biology, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
| | - Christopher A. Del Negro
- Department of Applied Science, Integrated Science Center, William & Mary, Williamsburg, Virginia, United States of America
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19
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Fu Y, Wang C, Zhang D, Xin Y, Li J, Zhang Y, Chu X. Increased TRPC6 expression is associated with tubular epithelial cell proliferation and inflammation in diabetic nephropathy. Mol Immunol 2018; 94:75-81. [DOI: 10.1016/j.molimm.2017.12.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/12/2017] [Accepted: 12/15/2017] [Indexed: 01/09/2023]
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20
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Grundy L, Daly DM, Chapple C, Grundy D, Chess-Williams R. TRPV1 enhances the afferent response to P2X receptor activation in the mouse urinary bladder. Sci Rep 2018; 8:197. [PMID: 29317663 PMCID: PMC5760578 DOI: 10.1038/s41598-017-18136-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 11/29/2017] [Indexed: 11/09/2022] Open
Abstract
Both TRPV1 and P2X receptors present on bladder sensory nerve fibres have been implicated in mechanosensation during bladder filling. The aim of this study was to determine possible interactions between these receptors in modulating afferent nerve activity. In wildtype (TRPV1+/+) and TRPV1 knockout (TRPV1-/-) mice, bladder afferent nerve activity, intravesical pressure, and luminal ATP and acetylcholine levels were determined and also intracellular calcium responses of dissociated pelvic DRG neurones and primary mouse urothelial cells (PMUCs). Bladder afferent nerve responses to the purinergic agonist αβMethylene-ATP were depressed in TRPV1-/- mice (p ≤ 0.001) and also in TRPV1+/+ mice treated with the TRPV1-antagonist capsazepine (10 µM; p ≤ 0.001). These effects were independent of changes in bladder compliance or contractility. Responses of DRG neuron to αβMethylene-ATP (30 µM) were unchanged in the TRPV1-/- mice, but the proportion of responsive neurones was reduced (p ≤ 0.01). Although the TRPV1 agonist capsaicin (1 µM) did not evoke intracellular responses in PMUCs from TRPV1+/+ mice, luminal ATP levels were reduced in the TRPV1-/- mice (p ≤ 0.001) compared to wildtype. TRPV1 modulates P2X mediated afferent responses and provides a mechanistic basis for the decrease in sensory symptoms observed following resiniferatoxin and capsaicin treatment for lower urinary tract symptoms.
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Affiliation(s)
- Luke Grundy
- Centre for Urology Research, Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, 4229, Australia
- Visceral Pain Group, University of Adelaide, SAHMRI, Adelaide, Australia
| | - Donna M Daly
- Department of Pharmacy and Biomedical Science, University of Central Lancashire, Preston, PR1 2HE, UK
| | | | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Russ Chess-Williams
- Centre for Urology Research, Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, 4229, Australia.
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21
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Jirku M, Lansky Z, Bednarova L, Sulc M, Monincova L, Majer P, Vyklicky L, Vondrasek J, Teisinger J, Bousova K. The characterization of a novel S100A1 binding site in the N-terminus of TRPM1. Int J Biochem Cell Biol 2016; 78:186-193. [PMID: 27435061 DOI: 10.1016/j.biocel.2016.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/11/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022]
Abstract
Transient receptor potential melastatin-1 channel (TRPM1) is an important mediator of calcium influx into the cell that is expressed in melanoma and ON-bipolar cells. Similar to other members of the TRP channel family, the intracellular N- and C- terminal domains of TRPM1 are expected to play important roles in the modulation of TRPM1 receptor function. Among the most commonly occurring modulators of TRP channels are the cytoplasmically expressed calcium binding proteins calmodulin and S100 calcium-binding protein A1 (S100A1), but the interaction of TRPM1 with S100A1 has not been described yet. Here, using a combination of biophysical and bioinformatics methods, we have determined that the N-terminal L242-E344 region of TRPM1 is a S100A1 binding domain. We show that formation of the TRPM1/S100A1 complex is calcium-dependent. Moreover, our structural model of the complex explained data obtained from fluorescence spectroscopy measurements revealing that the complex formation is facilitated through interactions of clusters positively charged (K271A, R273A, R274A) and hydrophobic (L263A, V270A, L276A) residues at the N-terminus of TRPM1. Taken together, our data suggest a molecular mechanism for the potential regulation of TRPM1 by S100A1.
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Affiliation(s)
- Michaela Jirku
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czech Republic
| | - Lucie Bednarova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Miroslav Sulc
- Institute of Microbiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Faculty of Science, Charles University in Prague, 12843 Prague, Czech Republic
| | - Lenka Monincova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Ladislav Vyklicky
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Jiri Vondrasek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Jan Teisinger
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Kristyna Bousova
- Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
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22
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Tóth BI, Konrad M, Ghosh D, Mohr F, Halaszovich CR, Leitner MG, Vriens J, Oberwinkler J, Voets T. Regulation of the transient receptor potential channel TRPM3 by phosphoinositides. ACTA ACUST UNITED AC 2016; 146:51-63. [PMID: 26123194 PMCID: PMC4485019 DOI: 10.1085/jgp.201411339] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
TRPM3 is dynamically regulated by plasma membrane PI(4,5)P2 and related PIPs. The transient receptor potential (TRP) channel TRPM3 is a calcium-permeable cation channel activated by heat and by the neurosteroid pregnenolone sulfate (PregS). TRPM3 is highly expressed in sensory neurons, where it plays a key role in heat sensing and inflammatory hyperalgesia, and in pancreatic β cells, where its activation enhances glucose-induced insulin release. However, despite its functional importance, little is known about the cellular mechanisms that regulate TRPM3 activity. Here, we provide evidence for a dynamic regulation of TRPM3 by membrane phosphatidylinositol phosphates (PIPs). Phosphatidylinositol 4,5-bisphosphate (PI[4,5]P2) and ATP applied to the intracellular side of excised membrane patches promote recovery of TRPM3 from desensitization. The stimulatory effect of cytosolic ATP on TRPM3 reflects activation of phosphatidylinositol kinases (PI-Ks), leading to resynthesis of PIPs in the plasma membrane. Various PIPs directly enhance TRPM3 activity in cell-free inside-out patches, with a potency order PI(3,4,5)P3 > PI(3,5)P2 > PI(4,5)P2 ≈ PI(3,4)P2 >> PI(4)P. Conversely, TRPM3 activity is rapidly and reversibly inhibited by activation of phosphatases that remove the 5-phosphate from PIPs. Finally, we show that recombinant TRPM3, as well as the endogenous TRPM3 in insuloma cells, is rapidly and reversibly inhibited by activation of phospholipase C–coupled muscarinic acetylcholine receptors. Our results reveal basic cellular mechanisms whereby membrane receptors can regulate TRPM3 activity.
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Affiliation(s)
- Balázs I Tóth
- Laboratory of Ion Channel Research and TRP Research Platform Leuven (TRPLe) and Laboratory of Obstetrics and Experimental Gynaecology, KU Leuven, 3000 Leuven, Belgium
| | - Maik Konrad
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Debapriya Ghosh
- Laboratory of Ion Channel Research and TRP Research Platform Leuven (TRPLe) and Laboratory of Obstetrics and Experimental Gynaecology, KU Leuven, 3000 Leuven, Belgium
| | - Florian Mohr
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Christian R Halaszovich
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Michael G Leitner
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Joris Vriens
- Laboratory of Ion Channel Research and TRP Research Platform Leuven (TRPLe) and Laboratory of Obstetrics and Experimental Gynaecology, KU Leuven, 3000 Leuven, Belgium Laboratory of Ion Channel Research and TRP Research Platform Leuven (TRPLe) and Laboratory of Obstetrics and Experimental Gynaecology, KU Leuven, 3000 Leuven, Belgium
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Thomas Voets
- Laboratory of Ion Channel Research and TRP Research Platform Leuven (TRPLe) and Laboratory of Obstetrics and Experimental Gynaecology, KU Leuven, 3000 Leuven, Belgium
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23
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Zheng W, Qin F. A combined coarse-grained and all-atom simulation of TRPV1 channel gating and heat activation. ACTA ACUST UNITED AC 2016; 145:443-56. [PMID: 25918362 PMCID: PMC4411258 DOI: 10.1085/jgp.201411335] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Coarse-grained modeling and all-atom molecular dynamics simulation provide insight into the mechanism for heat activation of TRPV1 gating. The transient receptor potential (TRP) channels act as key sensors of various chemical and physical stimuli in eukaryotic cells. Despite years of study, the molecular mechanisms of TRP channel activation remain unclear. To elucidate the structural, dynamic, and energetic basis of gating in TRPV1 (a founding member of the TRPV subfamily), we performed coarse-grained modeling and all-atom molecular dynamics (MD) simulation based on the recently solved high resolution structures of the open and closed form of TRPV1. Our coarse-grained normal mode analysis captures two key modes of collective motions involved in the TRPV1 gating transition, featuring a quaternary twist motion of the transmembrane domains (TMDs) relative to the intracellular domains (ICDs). Our transition pathway modeling predicts a sequence of structural movements that propagate from the ICDs to the TMDs via key interface domains (including the membrane proximal domain and the C-terminal domain), leading to sequential opening of the selectivity filter followed by the lower gate in the channel pore (confirmed by modeling conformational changes induced by the activation of ICDs). The above findings of coarse-grained modeling are robust to perturbation by lipids. Finally, our MD simulation of the ICD identifies key residues that contribute differently to the nonpolar energy of the open and closed state, and these residues are predicted to control the temperature sensitivity of TRPV1 gating. These computational predictions offer new insights to the mechanism for heat activation of TRPV1 gating, and will guide our future electrophysiology and mutagenesis studies.
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Affiliation(s)
- Wenjun Zheng
- Department of Physics and Department of Physiology and Biophysical Sciences, State University of New York at Buffalo, Buffalo, NY 14260
| | - Feng Qin
- Department of Physics and Department of Physiology and Biophysical Sciences, State University of New York at Buffalo, Buffalo, NY 14260
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24
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Chakraborty S, Rebecchi M, Kaczocha M, Puopolo M. Dopamine modulation of transient receptor potential vanilloid type 1 (TRPV1) receptor in dorsal root ganglia neurons. J Physiol 2016; 594:1627-42. [PMID: 26563747 DOI: 10.1113/jp271198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/04/2015] [Indexed: 01/11/2023] Open
Abstract
The transient receptor potential vanilloid type 1 (TRPV1) receptor plays a key role in the modulation of nociceptor excitability. To address whether dopamine can modulate the activity of TRPV1 channels in nociceptive neurons, the effects of dopamine and dopamine receptor agonists were tested on the capsaicin-activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons. Dopamine or SKF 81297 (an agonist at D1/D5 receptors), caused inhibition of both inward and outward currents by ∼60% and ∼48%, respectively. The effect of SKF 81297 was reversed by SCH 23390 (an antagonist at D1/D5 receptors), confirming that it was mediated by activation of D1/D5 dopamine receptors. In contrast, quinpirole (an agonist at D2 receptors) had no significant effect on the capsaicin-activated current. Inhibition of the capsaicin-activated current by SKF 81297 was mediated by G protein coupled receptors (GPCRs), and highly dependent on external calcium. The inhibitory effect of SKF 81297 on the capsaicin-activated current was not affected when the protein kinase A (PKA) activity was blocked with H89, or when the protein kinase C (PKC) activity was blocked with bisindolylmaleimide II (BIM). In contrast, when the calcium-calmodulin-dependent protein kinase II (CaMKII) was blocked with KN-93, the inhibitory effect of SKF 81297 on the capsaicin-activated current was greatly reduced, suggesting that activation of D1/D5 dopamine receptors may be preferentially linked to CaMKII activity. We suggest that modulation of TRPV1 channels by dopamine in nociceptive neurons may represent a way for dopamine to modulate incoming noxious stimuli.
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Affiliation(s)
- Saikat Chakraborty
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Mario Rebecchi
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
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25
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Characterization of the part of N-terminal PIP2 binding site of the TRPM1 channel. Biophys Chem 2015; 207:135-42. [DOI: 10.1016/j.bpc.2015.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/23/2015] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
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26
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Bertin S, Raz E. Transient Receptor Potential (TRP) channels in T cells. Semin Immunopathol 2015; 38:309-19. [PMID: 26468011 DOI: 10.1007/s00281-015-0535-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/01/2015] [Indexed: 12/16/2022]
Abstract
The transient receptor potential (TRP) family of ion channels is widely expressed in many cell types and plays various physiological roles. Growing evidence suggests that certain TRP channels are functionally expressed in the immune system. Indeed, an increasing number of reports have demonstrated the functional expression of several TRP channels in innate and adaptive immune cells and have highlighted their critical role in the activation and function of these cells. However, very few reviews have been entirely dedicated to this subject. Here, we will summarize the recent findings with regards to TRP channel expression in T cells and discuss their emerging role as regulators of T cell activation and functions. Moreover, these studies suggest that beyond their pharmaceutical interest in pain management, certain TRP channels may represent potential novel therapeutic targets for various immune-related diseases.
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Affiliation(s)
- Samuel Bertin
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0663, USA.
| | - Eyal Raz
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0663, USA
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27
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Rohacs T. Phosphoinositide regulation of TRPV1 revisited. Pflugers Arch 2015; 467:1851-69. [PMID: 25754030 PMCID: PMC4537841 DOI: 10.1007/s00424-015-1695-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/12/2015] [Accepted: 02/16/2015] [Indexed: 01/22/2023]
Abstract
The heat- and capsaicin-sensitive transient receptor potential vanilloid 1 ion channel (TRPV1) is regulated by plasma membrane phosphoinositides. The effects of these lipids on this channel have been controversial. Recent articles re-ignited the debate and also offered resolution to place some of the data in a coherent picture. This review summarizes the literature on this topic and provides a detailed and critical discussion on the experimental evidence for the various effects of phosphatidylinositol 4,5-bisphosphayte [PI(4,5)P2 or PIP2] on TRPV1. We conclude that PI(4,5)P2 and potentially its precursor PI(4)P are positive cofactors for TRPV1, acting via direct interaction with the channel, and their depletion by Ca(2+)-induced activation of phospholipase Cδ isoforms (PLCδ) limits channel activity during capsaicin-induced desensitization. Other negatively charged lipids at higher concentrations can also support channel activity, which may explain some controversies in the literature. PI(4,5)P2 also partially inhibits channel activity in some experimental settings, and relief from this inhibition upon PLCβ activation may contribute to sensitization. The negative effect of PI(4,5)P2 is more controversial and its mechanism is less well understood. Other TRP channels from the TRPV and TRPC families may also undergo similar dual regulation by phosphoinositides, thus the complexity of TRPV1 regulation is not unique to this channel.
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Affiliation(s)
- Tibor Rohacs
- Department of Pharmacology and Physiology Rutgers, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, USA,
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28
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Bousova K, Jirku M, Bumba L, Bednarova L, Sulc M, Franek M, Vyklicky L, Vondrasek J, Teisinger J. PIP2 and PIP3 interact with N-terminus region of TRPM4 channel. Biophys Chem 2015; 205:24-32. [PMID: 26071843 DOI: 10.1016/j.bpc.2015.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/04/2015] [Accepted: 06/06/2015] [Indexed: 01/07/2023]
Abstract
The transient receptor potential melastatin 4 (TRPM4) is a calcium-activated non-selective ion channel broadly expressed in a variety of tissues. Receptor has been identified as a crucial modulator of numerous calcium dependent mechanisms in the cell such as immune response, cardiac conduction, neurotransmission and insulin secretion. It is known that phosphoinositide lipids (PIPs) play a unique role in the regulation of TRP channel function. However the molecular mechanism of this process is still unknown. We characterized the binding site of PIP2 and its structural analogue PIP3 in the E733-W772 proximal region of the TRPM4 N-terminus via biophysical and molecular modeling methods. The specific positions R755 and R767 in this domain were identified as being important for interactions with PIP2/PIP3 ligands. Their mutations caused a partial loss of PIP2/PIP3 binding specificity. The interaction of PIP3 with TRPM4 channels has never been described before. These findings provide new insight into the ligand binding domains of the TRPM4 channel.
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Affiliation(s)
- Kristyna Bousova
- 2nd Faculty of Medicine, Charles University in Prague, 15006 Prague, Czech Republic; Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Michaela Jirku
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic; Faculty of Science, Charles University in Prague, 12843 Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Lucie Bednarova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, Czech Republic
| | - Miroslav Sulc
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Miloslav Franek
- 3rd Faculty of Medicine, Charles University in Prague, 10000 Prague, Czech Republic
| | - Ladislav Vyklicky
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Jiri Vondrasek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, Czech Republic
| | - Jan Teisinger
- Institute of Physiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic.
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29
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Earley S, Brayden JE. Transient receptor potential channels in the vasculature. Physiol Rev 2015; 95:645-90. [PMID: 25834234 DOI: 10.1152/physrev.00026.2014] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca(2+) levels or subcellular Ca(2+) signaling events. In addition to directly mediating Ca(2+) entry, TRP channels influence intracellular Ca(2+) dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions.
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Affiliation(s)
- Scott Earley
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| | - Joseph E Brayden
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
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30
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Abstract
Transient Receptor Potential (TRP) channels are activated by stimuli as diverse as heat, cold, noxious chemicals, mechanical forces, hormones, neurotransmitters, spices, and voltage. Besides their presumably similar general architecture, probably the only common factor regulating them is phosphoinositides. The regulation of TRP channels by phosphoinositides is complex. There are a large number of TRP channels where phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2 or PIP2] acts as a positive cofactor, similarly to many other ion channels. In several cases, however, PI(4,5)P2 inhibits TRP channel activity, sometimes even concurrently with the activating effect. This chapter will provide a comprehensive overview of the literature on regulation of TRP channels by membrane phosphoinositides.
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31
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Mori MX, Inoue R. New experimental trends for phosphoinositides research on ion transporter/channel regulation. J Pharmacol Sci 2014; 126:186-97. [PMID: 25367262 DOI: 10.1254/jphs.14r14cp] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Phosphoinositides(4,5)-bisphosphates [PI(4,5)P2] critically controls membrane excitability, the disruption of which leads to pathophysiological states. PI(4,5)P2 plays a primary role in regulating the conduction and gating properties of ion channels/transporters, through electrostatic and hydrophobic interactions that allow direct associations. In recent years, the development of many molecular tools have brought deep insights into the mechanisms underlying PI(4,5)P2-mediated regulation. This review summarizes the methods currently available to manipulate the cell membrane PI(4,5)P2 level including pharmacological interventions as well as newly designed molecular tools. We concisely introduce materials and experimental designs suitable for the study of PI(4,5)P2-mediated regulation of ion-conducting molecules, in order to assist researchers who are interested in this area. It is our further hope that the knowledge introduced in this review will help to promote our understanding about the pathology of diseases such as cardiac arrhythmias, bipolar disorders, and Alzheimer's disease which are somehow associated with a disruption of PI(4,5)P2 metabolism.
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Affiliation(s)
- Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, School of Engineering, Kyoto University, Japan
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32
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Visser D, Middelbeek J, van Leeuwen FN, Jalink K. Function and regulation of the channel-kinase TRPM7 in health and disease. Eur J Cell Biol 2014; 93:455-65. [DOI: 10.1016/j.ejcb.2014.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/24/2014] [Accepted: 07/01/2014] [Indexed: 11/30/2022] Open
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33
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de Jong PR, Takahashi N, Harris AR, Lee J, Bertin S, Jeffries J, Jung M, Duong J, Triano AI, Lee J, Niv Y, Herdman DS, Taniguchi K, Kim CW, Dong H, Eckmann L, Stanford SM, Bottini N, Corr M, Raz E. Ion channel TRPV1-dependent activation of PTP1B suppresses EGFR-associated intestinal tumorigenesis. J Clin Invest 2014; 124:3793-806. [PMID: 25083990 DOI: 10.1172/jci72340] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 06/06/2014] [Indexed: 12/12/2022] Open
Abstract
The intestinal epithelium has a high rate of turnover, and dysregulation of pathways that regulate regeneration can lead to tumor development; however, the negative regulators of oncogenic events in the intestinal epithelium are not fully understood. Here we identified a feedback loop between the epidermal growth factor receptor (EGFR), a known mediator of proliferation, and the transient receptor potential cation channel, subfamily V, member 1 (TRPV1), in intestinal epithelial cells (IECs). We found that TRPV1 was expressed by IECs and was intrinsically activated upon EGFR stimulation. Subsequently, TRPV1 activation inhibited EGFR-induced epithelial cell proliferation via activation of Ca2+/calpain and resulting activation of protein tyrosine phosphatase 1B (PTP1B). In a murine model of multiple intestinal neoplasia (Apc(Min/+) mice), TRPV1 deficiency increased adenoma formation, and treatment of these animals with an EGFR kinase inhibitor reversed protumorigenic phenotypes, supporting a functional association between TRPV1 and EGFR signaling in IECs. Administration of a TRPV1 agonist suppressed intestinal tumorigenesis in Apc(Min/+) mice, similar to--as well as in conjunction with--a cyclooxygenase-2 (COX-2) inhibitor, which suggests that targeting both TRPV1 and COX-2 has potential as a therapeutic approach for tumor prevention. Our findings implicate TRPV1 as a regulator of growth factor signaling in the intestinal epithelium through activation of PTP1B and subsequent suppression of intestinal tumorigenesis.
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34
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Kweon HJ, Suh BC. Acid-sensing ion channels (ASICs): therapeutic targets for neurological diseases and their regulation. BMB Rep 2014; 46:295-304. [PMID: 23790972 PMCID: PMC4133903 DOI: 10.5483/bmbrep.2013.46.6.121] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Extracellular acidification occurs not only in pathological conditions such as inflammation and brain ischemia, but also in normal physiological conditions such as synaptic transmission. Acid-sensing ion channels (ASICs) can detect a broad range of physiological pH changes during pathological and synaptic cellular activities. ASICs are voltage-independent, proton-gated cation channels widely expressed throughout the central and peripheral nervous system. Activation of ASICs is involved in pain perception, synaptic plasticity, learning and memory, fear, ischemic neuronal injury, seizure termination, neuronal degeneration, and mechanosensation. Therefore, ASICs emerge as potential therapeutic targets for manipulating pain and neurological diseases. The activity of these channels can be regulated by many factors such as lactate, Zn2+, and Phe-Met-Arg-Phe amide (FMRFamide)-like neuropeptides by interacting with the channel’s large extracellular loop. ASICs are also modulated by G protein-coupled receptors such as CB1 cannabinoid receptors and 5-HT2. This review focuses on the physiological roles of ASICs and the molecular mechanisms by which these channels are regulated. [BMB Reports 2013; 46(6): 295-304]
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Affiliation(s)
- Hae-Jin Kweon
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Korea
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35
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Luo J, Walters ET, Carlton SM, Hu H. Targeting Pain-evoking Transient Receptor Potential Channels for the Treatment of Pain. Curr Neuropharmacol 2014; 11:652-63. [PMID: 24396340 PMCID: PMC3849790 DOI: 10.2174/1570159x113119990040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 06/19/2013] [Accepted: 06/19/2013] [Indexed: 02/06/2023] Open
Abstract
Chronic pain affects billions of lives globally and is a major public health problem in the United States. However, pain management is still a challenging task due to a lack of understanding of the fundamental mechanisms of pain. In the past decades transient receptor potential (TRP) channels have been identified as molecular sensors of tissue damage and inflammation. Activation/sensitization of TRP channels in peripheral nociceptors produces neurogenic inflammation and contributes to both somatic and visceral pain. Pharmacological and genetic studies have affirmed the role of TRP channels in multiple forms of inflammatory and neuropathic pain. Thus pain-evoking TRP channels emerge as promising therapeutic targets for a wide variety of pain and inflammatory conditions.
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Affiliation(s)
- Jialie Luo
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030
| | - Edgar T Walters
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030
| | - Susan M Carlton
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069
| | - Hongzhen Hu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030
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36
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Abstract
Human canonical transient receptor potential channel 5 (TRPC5) has been cloned from the Xq23 region on chromosome X as a suspect in nonsyndromic mental retardation. TRPC5 is a Ca(2+)-permeable cation channel predominantly expressed in the CNS, including the hippocampus, cerebellum, amygdala, sensory neurons, and retina. It also shows more restricted expression in the periphery, notably in the kidney and cardiovascular system. Homotetrameric TRPC5 channels are primarily activated by receptors coupled to Gq and phospholipase C and/or Gi proteins, but TRPC5 channels may also gate in a store-dependent manner, which requires other partner proteins such TRPC1, STIM1, and Orai1. There is an impressive array of other activators of TRPC5 channels, such as nitric oxide, lysophospholipids, sphingosine-1-phosphate, reduced thioredoxin, protons, lanthanides, and calcium, and many can cause its direct activation. Moreover, TRPC5 shows constitutive activity, and it is responsive to membrane stretch and cold. Thus, TRPC5 channels have significant potential for synergistic activation and may serve as an important focal point in Ca(2+) signalling and electrogenesis. Moreover, TRPC5 functions in partnership with about 60 proteins, including TRPC1, TRPC4, calmodulin, IP3 receptors, NHERF, NCS-1, junctate, stathmin 2, Ca(2+)-binding protein 1, caveolin, and SESTD1, while its desensitisation is mediated by both protein kinases A and C. TRPC5 has a distinct voltage dependence shared only with its closest relative, TRPC4. Its unique N-shaped activation curve underlined by intracellular Mg(2+) block seems to be perfectly "shaped" to trigger action potential discharge, but not to grossly interfere with the action potential shape. The range of biological functions of TRPC5 channels is also impressive, from neurotransmission to control of axon guidance and vascular smooth muscle cell migration and contractility. Recent studies of Trpc5 gene knockouts begin to uncover its roles in fear, anxiety, seizures, and cold sensing.
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Affiliation(s)
- Alexander V Zholos
- Department of Biophysics, Educational and Scientific Centre "Institute of Biology", Taras Shevchenko Kiev National University, Kiev, 03022, Ukraine,
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37
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Nilius B, Flockerzi V. What do we really know and what do we need to know: some controversies, perspectives, and surprises. Handb Exp Pharmacol 2014; 223:1239-80. [PMID: 24961986 DOI: 10.1007/978-3-319-05161-1_20] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
TRP channels comprise one of the most rapid growing research topics in ion channel research, in fields related to ion channels including channelopathies and translational medicine. We provide here a critical survey on our current knowledge of TRP channels and highlight some of the still open or controversial questions. This comprises questions related to evolution of TRP channels; biophysics, i.e., permeation; pore properties and gating; modulation; the still-elusive 3D structure; and channel subunits but also their role as general sensory channels and in human diseases. We will conclude that our knowledge on TRP channels is still at the very beginning of an exciting research journey.
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Affiliation(s)
- Bernd Nilius
- Department Cell Mol Medicine, Laboratory Ion Channel Research, KU Leuven, Campus Gasthuisberg, O&N 1, Herestraat 49-Bus 802, 3000, Leuven, Belgium,
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38
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Török Z, Crul T, Maresca B, Schütz GJ, Viana F, Dindia L, Piotto S, Brameshuber M, Balogh G, Péter M, Porta A, Trapani A, Gombos I, Glatz A, Gungor B, Peksel B, Vigh L, Csoboz B, Horváth I, Vijayan MM, Hooper PL, Harwood JL, Vigh L. Plasma membranes as heat stress sensors: from lipid-controlled molecular switches to therapeutic applications. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:1594-618. [PMID: 24374314 DOI: 10.1016/j.bbamem.2013.12.015] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/09/2013] [Accepted: 12/18/2013] [Indexed: 12/31/2022]
Abstract
The classic heat shock (stress) response (HSR) was originally attributed to protein denaturation. However, heat shock protein (Hsp) induction occurs in many circumstances where no protein denaturation is observed. Recently considerable evidence has been accumulated to the favor of the "Membrane Sensor Hypothesis" which predicts that the level of Hsps can be changed as a result of alterations to the plasma membrane. This is especially pertinent to mild heat shock, such as occurs in fever. In this condition the sensitivity of many transient receptor potential (TRP) channels is particularly notable. Small temperature stresses can modulate TRP gating significantly and this is influenced by lipids. In addition, stress hormones often modify plasma membrane structure and function and thus initiate a cascade of events, which may affect HSR. The major transactivator heat shock factor-1 integrates the signals originating from the plasma membrane and orchestrates the expression of individual heat shock genes. We describe how these observations can be tested at the molecular level, for example, with the use of membrane perturbers and through computational calculations. An important fact which now starts to be addressed is that membranes are not homogeneous nor do all cells react identically. Lipidomics and cell profiling are beginning to address the above two points. Finally, we observe that a deregulated HSR is found in a large number of important diseases where more detailed knowledge of the molecular mechanisms involved may offer timely opportunities for clinical interventions and new, innovative drug treatments. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.
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Affiliation(s)
- Zsolt Török
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary.
| | - Tim Crul
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Bruno Maresca
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Felix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Laura Dindia
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Stefano Piotto
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy
| | - Mario Brameshuber
- Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Gábor Balogh
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Mária Péter
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Amalia Porta
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy
| | - Alfonso Trapani
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy
| | - Imre Gombos
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Attila Glatz
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Burcin Gungor
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Begüm Peksel
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - László Vigh
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Bálint Csoboz
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Ibolya Horváth
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary
| | - Mathilakath M Vijayan
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada; Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Phillip L Hooper
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Medical School, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK
| | - László Vigh
- Institute of Biochemistry, Biological Research Centre of the Hung. Acad. Sci., Szeged H-6726, Hungary.
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39
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Abstract
Nociception is the process whereby primary afferent nerve fibers of the somatosensory system detect noxious stimuli. Pungent irritants from pepper, mint, and mustard plants have served as powerful pharmacological tools for identifying molecules and mechanisms underlying this initial step of pain sensation. These natural products have revealed three members of the transient receptor potential (TRP) ion channel family--TRPV1, TRPM8, and TRPA1--as molecular detectors of thermal and chemical stimuli that activate sensory neurons to produce acute or persistent pain. Analysis of TRP channel function and expression has validated the existence of nociceptors as a specialized group of somatosensory neurons devoted to the detection of noxious stimuli. These studies are also providing insight into the coding logic of nociception and how specification of nociceptor subtypes underlies behavioral discrimination of noxious thermal, chemical, and mechanical stimuli. Biophysical and pharmacological characterization of these channels has provided the intellectual and technical foundation for developing new classes of analgesic drugs.
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Affiliation(s)
- David Julius
- Department of Physiology, University of California, San Francisco, California 94158;
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40
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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41
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Nilius B, Bíró T. TRPV3: a ‘more than skinny’ channel. Exp Dermatol 2013; 22:447-52. [DOI: 10.1111/exd.12163] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Bernd Nilius
- Department of Cellular and Molecular Medicine; Laboratory Ion Channel Research; KU Leuven; Leuven Belgium
| | - Tamás Bíró
- DE-MTA “Lendület” Cellular Physiology Research Group; Department of Physiology; University of Debrecen; Medical and Health Science Center; Research Center for Molecular Medicine; Debrecen Hungary
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42
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Ambient temperature affects the temperature threshold for TRPM8 activation through interaction of phosphatidylinositol 4,5-bisphosphate. J Neurosci 2013; 33:6154-9. [PMID: 23554496 DOI: 10.1523/jneurosci.5672-12.2013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cold sensation is an important and fundamental sense for animals and it is known to be affected by ambient temperature. Transient Receptor Potential Melastatin 8 (TRPM8), a nonselective cation channel expressed in a subset of peripheral afferent fibers, acts as a cold sensor, having an activation threshold of ∼28°C. Although the cold temperature threshold of TRPM8 is affected by menthol or pH, ambient temperature has not been reported to affect it. Because the cold temperature threshold was thought to be unchanged by alterations in ambient temperature, the relativity of temperature sensing in different ambient temperatures could not be understood at the level of molecular function of thermosensitive TRP channels. Here, we show that ambient temperature changed the temperature threshold for activation of human and rat TRPM8 in a heterologous expression system and cold responses in mouse DRG neurons. Moreover, reducing the level of cellular phosphatidylinositol 4,5-bisphosphate (PIP2) attenuated changes in the cold temperature threshold after alterations in ambient temperature. A single amino acid mutation at position 1008 in the C terminus of TRPM8 (arginine to glutamine) also attenuated changes in the cold temperature threshold induced by ambient temperature. These findings suggest that ambient temperature does affect the temperature threshold for TRPM8 activation through interaction of PIP2.
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43
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Cao C, Zakharian E, Borbiro I, Rohacs T. Interplay between calmodulin and phosphatidylinositol 4,5-bisphosphate in Ca2+-induced inactivation of transient receptor potential vanilloid 6 channels. J Biol Chem 2013; 288:5278-90. [PMID: 23300090 DOI: 10.1074/jbc.m112.409482] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epithelial Ca(2+) channel transient receptor potential vanilloid 6 (TRPV6) undergoes Ca(2+)-induced inactivation that protects the cell from toxic Ca(2+) overload and may also limit intestinal Ca(2+) transport. To dissect the roles of individual signaling pathways in this phenomenon, we studied the effects of Ca(2+), calmodulin (CaM), and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) in excised inside-out patches. The activity of TRPV6 strictly depended on the presence of PI(4,5)P(2), and Ca(2+)-CaM inhibited the channel at physiologically relevant concentrations. Ca(2+) alone also inhibited TRPV6 at high concentrations (IC(50) = ∼20 μM). A double mutation in the distal C-terminal CaM-binding site of TRPV6 (W695A/R699E) essentially eliminated inhibition by CaM in excised patches. In whole cell patch clamp experiments, this mutation reduced but did not eliminate Ca(2+)-induced inactivation. Providing excess PI(4,5)P(2) reduced the inhibition by CaM in excised patches and in planar lipid bilayers, but PI(4,5)P(2) did not inhibit binding of CaM to the C terminus of the channel. Overall, our data show a complex interplay between CaM and PI(4,5)P(2) and show that Ca(2+), CaM, and the depletion of PI(4,5)P(2) all contribute to inactivation of TRPV6.
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Affiliation(s)
- Chike Cao
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey 07103, USA
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44
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Pore collapse underlies irreversible inactivation of TRPM2 cation channel currents. Proc Natl Acad Sci U S A 2012; 109:13440-5. [PMID: 22847436 DOI: 10.1073/pnas.1204702109] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Ca(2+)-permeable cation channel transient receptor potential melastatin 2 (TRPM2) plays a key role in pathogen-evoked phagocyte activation, postischemic neuronal apoptosis, and glucose-evoked insulin secretion, by linking these cellular responses to oxidative stress. TRPM2 channels are coactivated by binding of intracellular ADP ribose and Ca(2+) to distinct cytosolically accessible sites on the channels. These ligands likely regulate the activation gate, conserved in the voltage-gated cation channel superfamily, that comprises a helix bundle formed by the intracellular ends of transmembrane helix six of each subunit. For several K(+) and TRPM family channels, activation gate opening requires the presence of phosphatidylinositol-bisphosphate (PIP(2)) in the inner membrane leaflet. Most TRPM family channels inactivate upon prolonged stimulation in inside-out patches; this "rundown" is due to PIP(2) depletion. TRPM2 currents also run down within minutes, but the molecular mechanism of this process is unknown. Here we report that high-affinity PIP(2) binding regulates Ca(2+) sensitivity of TRPM2 activation. Nevertheless, TRPM2 inactivation is not due to PIP(2) depletion; rather, it is state dependent, sensitive to permeating ions, and can be completely prevented by mutations in the extracellular selectivity filter. Introduction of two negative charges plus a single-residue insertion, to mimic the filter sequence of TRPM5, results in TRPM2 channels that maintain unabated maximal activity for over 1 h, and display altered permeation properties but intact ADP ribose/Ca(2+)-dependent gating. Thus, upon prolonged stimulation, the TRPM2 selectivity filter undergoes a conformational change reminiscent of that accompanying C-type inactivation of voltage-gated K(+) channels. The noninactivating TRPM2 variant will be invaluable for gating studies.
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45
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Klasen K, Hollatz D, Zielke S, Gisselmann G, Hatt H, Wetzel CH. The TRPM8 ion channel comprises direct Gq protein-activating capacity. Pflugers Arch 2012; 463:779-97. [PMID: 22460725 DOI: 10.1007/s00424-012-1098-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/12/2012] [Accepted: 03/14/2012] [Indexed: 11/29/2022]
Abstract
The transient receptor potential (TRP) family of ion channels comprises receptors that are activated by a vast variety of physical as well as chemical stimuli. TRP channels interact in a complex manner with several intracellular signaling cascades, both up- and downstream of receptor activation. Investigating cascades stimulated downstream of the cold and menthol receptor TRPM8, we found evidence for both, functional and structural interaction of TRPM8 with Gαq. We demonstrated menthol-evoked increase in intracellular Ca(2+) under extracellular Ca(2+)-free conditions, which was blocked by the PLC inhibitors U73122 or edelfosine. This metabotropic Ca(2+) signal could be observed also in cells expressing a channel-dead (i.e. non-conducting) or a chloride-conducting TRPM8 pore mutant. However, this intracellular metabotropic Ca(2+) signal could not be detected in Gαq deficient cells or in the presence of dominant-negative GαqX. Evidence for a close spatial proximity necessary for physical interaction of TRPM8 and Gαq was provided by acceptor bleaching experiments demonstrating FRET between TRPM8-CFP and Gαq-YFP. A Gαq-YFP mobility assay (FRAP) revealed a restricted diffusion of Gαq-YFP under conditions when TRPM8 is immobilized in the plasma membrane. Moreover, a menthol-induced and TRPM8-mediated G protein activation could be demonstrated by FRET experiments monitoring the dissociation of Gαq-YFP from a Gβ/Gγ-CFP complex, and by the exchange of radioactive [(35)S]GTPγS for GDP. Our observations lead to a view that extends the operational range of the TRPM8 receptor from its function as a pure ion channel to a molecular switch with additional metabotropic capacity.
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Affiliation(s)
- Katharina Klasen
- Lehrstuhl für Zellphysiologie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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46
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Brooks SM, Bernstein IL. Irritant-induced airway disorders. Immunol Allergy Clin North Am 2012; 31:747-68, vi. [PMID: 21978855 DOI: 10.1016/j.iac.2011.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Thousands of persons experience accidental high-level irritant exposures each year but most recover and few die. Irritants function differently than allergens because their actions proceed nonspecifically and by nonimmunologic mechanisms. For some individuals, the consequence of a single massive exposure to an irritant, gas, vapor or fume is persistent airway hyperresponsiveness and the clinical picture of asthma, referred to as reactive airways dysfunction syndrome (RADS). Repeated irritant exposures may lead to chronic cough and continual airway hyperresponsiveness. Cases of asthma attributed to repeated irritant-exposures may be the result of genetic and/or host factors.
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Affiliation(s)
- Stuart M Brooks
- Colleges of Public Health & Medicine, USF Health Science Center, University of South Florida, 13201 Bruce B. Downs Boulevard, Tampa, FL 33612, USA.
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47
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Putney JW, Tomita T. Phospholipase C signaling and calcium influx. Adv Biol Regul 2012; 52:152-64. [PMID: 21933679 PMCID: PMC3560308 DOI: 10.1016/j.advenzreg.2011.09.005] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/06/2011] [Indexed: 04/18/2023]
Affiliation(s)
- James W Putney
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences - NIH, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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48
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49
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Mak LH, Georgiades SN, Rosivatz E, Whyte GF, Mirabelli M, Vilar R, Woscholski R. A small molecule mimicking a phosphatidylinositol (4,5)-bisphosphate binding pleckstrin homology domain. ACS Chem Biol 2011; 6:1382-90. [PMID: 21958214 DOI: 10.1021/cb2003187] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inositol phospholipids have emerged as important key players in a wide variety of cellular functions. Among the seven existing inositol phospholipids, phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P(2)) has attracted much attention in recent years due to its important role in numerous cellular signaling events and regulations, which in turn impact several human diseases. This particular lipid is recognized in the cell by specific lipid binding domains, such as the Pleckstrin-homology (PH) domain, which is also employed as a tool to monitor this important lipid. Here, we describe the synthesis and biological characterization of a small molecule that mimics the PH domain as judged by its ability to bind specifically to only PI(4,5)P(2) and effectively compete with the PH domain in vitro and in a cellular environment. The binding constant of this small molecule PH domain mimetic (PHDM) was determined to be 17.6 ± 10.1 μM, similar in potency to the PH domain. Using NIH 3T3 mouse fibroblast cells we demonstrated that this compound is cell-permeable and able to modulate PI(4,5)P(2)-dependent effects in a cellular environment such as the endocytosis of the transferrin receptor, loss of mitochondria, as well as stress fiber formation. This highly PI(4,5)P(2)-specific chemical mimetic of a PH domain not only is a powerful research tool but might also be a lead compound in future drug developments targeting PI(4,5)P(2)-dependent diseases such as Lowe syndrome.
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Affiliation(s)
- Lok Hang Mak
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Savvas N. Georgiades
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Evelyn Rosivatz
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Gillian F. Whyte
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Marianna Mirabelli
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Ramon Vilar
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Rudiger Woscholski
- Department of Chemistry, ‡Division of Cell and Molecular Biology, and §Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
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50
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Comparative effects of menthol and icilin on the induced contraction of the smooth muscles of the vas deferens of normal and castrated rats. ACTA ACUST UNITED AC 2011. [DOI: 10.15407/fz57.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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