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Yudin Y, Rohacs T. Inhibitory G i/O-coupled receptors in somatosensory neurons: Potential therapeutic targets for novel analgesics. Mol Pain 2018; 14:1744806918763646. [PMID: 29580154 PMCID: PMC5882016 DOI: 10.1177/1744806918763646] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Primary sensory neurons in the dorsal root ganglia and trigeminal ganglia are responsible for sensing mechanical and thermal stimuli, as well as detecting tissue damage. These neurons express ion channels that respond to thermal, mechanical, or chemical cues, conduct action potentials, and mediate transmitter release. These neurons also express a large number of G-protein coupled receptors, which are major transducers for extracellular signaling molecules, and their activation usually modulates the primary transduction pathways. Receptors that couple to phospholipase C via heterotrimeric Gq/11 proteins and those that activate adenylate cyclase via Gs are considered excitatory; they positively regulate somatosensory transduction and they play roles in inflammatory sensitization and pain, and in some cases also in inducing itch. On the other hand, receptors that couple to Gi/o proteins, such as opioid or GABAB receptors, are generally inhibitory. Their activation counteracts the effect of Gs-stimulation by inhibiting adenylate cyclase, as well as exerts effects on ion channels, usually resulting in decreased excitability. This review will summarize knowledge on Gi-coupled receptors in sensory neurons, focusing on their roles in ion channel regulation and discuss their potential as targets for analgesic and antipruritic medications.
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Affiliation(s)
- Yevgen Yudin
- 1 Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Tibor Rohacs
- 1 Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, USA
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52
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Choudhury N, Sikdar SK. 17β-estradiol potentiates TREK1 channel activity through G protein-coupled estrogen receptor. J Steroid Biochem Mol Biol 2018; 183:94-105. [PMID: 29883692 DOI: 10.1016/j.jsbmb.2018.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/10/2018] [Accepted: 06/04/2018] [Indexed: 11/21/2022]
Abstract
TWIK-related potassium channel 1 (TREK1), a two-pore domain potassium channel, is modulated by various hormones and neurotransmitters by activation of membrane receptor - coupled second messengers. 17β-estradiol is a neuromodulator capable of regulating several cellular processes including the activity of ion channels, in a rapid and non-genomic manner. The G protein-coupled estrogen receptor (GPER) is known to facilitate rapid actions of 17β-estradiol, though its role in modulation of ion channels is not widely explored. Several studies have shown both TREK1 and 17β-estradiol to be neuromodulatory but the interaction between them is not known. In the present study, using single channel cell-attached patch clamp electrophysiology in HEK293 cells, we show that 17β-estradiol increases the activity of hTREK1 channel by acting through hGPER and increasing the channel opening probability within minutes. The potentiation induced by 17β-estradiol is pertussis toxin - sensitive involving action of Gβγ subunits while the inhibitory effect of cAMP-PKA pathway on TREK1 is reduced. Protein phosphatases were also found to be important for the action of 17β-estradiol, which in concert with reduced activity of PKA, may alter the phosphorylation state of the channel and thus increase channel activity. Mutational studies revealed the serines at positions 315 and 348 in the C-terminal domain of hTREK1 to be the target sites for dephosphorylation induced by 17β-estradiol action through hGPER. Elucidation of the pathway for the potentiating action of 17β-estradiol via hGPER on hTREK1 channel activity will help us understand better one of the many possible neuroprotective mechanisms of 17β-estradiol and hTREK1 channel.
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Affiliation(s)
- Nasreen Choudhury
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, Karnataka, India.
| | - Sujit Kumar Sikdar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, Karnataka, India.
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Myeong J, Ko J, Kwak M, Kim J, Woo J, Ha K, Hong C, Yang D, Kim HJ, Jeon JH, So I. Dual action of the Gα q-PLCβ-PI(4,5)P 2 pathway on TRPC1/4 and TRPC1/5 heterotetramers. Sci Rep 2018; 8:12117. [PMID: 30108272 PMCID: PMC6092394 DOI: 10.1038/s41598-018-30625-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 08/03/2018] [Indexed: 11/09/2022] Open
Abstract
The transient receptor potential canonical (TRPC) 1 channel is widely distributed in mammalian cells and is involved in many physiological processes. TRPC1 is primarily considered a regulatory subunit that forms heterotetrameric channels with either TRPC4 or TRPC5 subunits. Here, we suggest that the regulation of TRPC1/4 and TRPC1/5 heterotetrameric channels by the Gαq-PLCβ pathway is self-limited and dynamically mediated by Gαq and PI(4,5)P2. We provide evidence indicating that Gαq protein directly interacts with either TRPC4 or TRPC5 of the heterotetrameric channels to permit activation. Simultaneously, Gαq-coupled PLCβ activation leads to the breakdown of PI(4,5)P2, which inhibits activity of TRPC1/4 and 1/5 channels.
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Affiliation(s)
- Jongyun Myeong
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.,Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Juyeon Ko
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Misun Kwak
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jinsung Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Joohan Woo
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Kotdaji Ha
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Chansik Hong
- Department of Physiology, Chosun University School of Medicine, Kwangju, 61452, Republic of Korea
| | - Dongki Yang
- Department of Physiology, Gachon University College of Medicine, Incheon, 21936, Republic of Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
| | - Ju-Hong Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
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Ca 2+ Regulation of TRP Ion Channels. Int J Mol Sci 2018; 19:ijms19041256. [PMID: 29690581 PMCID: PMC5979445 DOI: 10.3390/ijms19041256] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
Ca2+ signaling influences nearly every aspect of cellular life. Transient receptor potential (TRP) ion channels have emerged as cellular sensors for thermal, chemical and mechanical stimuli and are major contributors to Ca2+ signaling, playing an important role in diverse physiological and pathological processes. Notably, TRP ion channels are also one of the major downstream targets of Ca2+ signaling initiated either from TRP channels themselves or from various other sources, such as G-protein coupled receptors, giving rise to feedback regulation. TRP channels therefore function like integrators of Ca2+ signaling. A growing body of research has demonstrated different modes of Ca2+-dependent regulation of TRP ion channels and the underlying mechanisms. However, the precise actions of Ca2+ in the modulation of TRP ion channels remain elusive. Advances in Ca2+ regulation of TRP channels are critical to our understanding of the diversified functions of TRP channels and complex Ca2+ signaling.
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Przibilla J, Dembla S, Rizun O, Lis A, Jung M, Oberwinkler J, Beck A, Philipp SE. Ca 2+-dependent regulation and binding of calmodulin to multiple sites of Transient Receptor Potential Melastatin 3 (TRPM3) ion channels. Cell Calcium 2018; 73:40-52. [PMID: 29880196 DOI: 10.1016/j.ceca.2018.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/19/2018] [Accepted: 03/30/2018] [Indexed: 10/17/2022]
Abstract
TRPM3 proteins assemble to Ca2+-permeable cation channels in the plasma membrane, which act as nociceptors of noxious heat and mediators of insulin and cytokine release. Here we show that TRPM3 channel activity is strongly dependent on intracellular Ca2+. Conceivably, this effect is attributed to the Ca2+ binding protein calmodulin, which binds to TRPM3 in a Ca2+-dependent manner. We identified five calmodulin binding sites within the amino terminus of TRPM3, which displayed different binding affinities in dependence of Ca2+. Mutations of lysine residues in calmodulin binding site 2 strongly reduced calmodulin binding and TRPM3 activity indicating the importance of this domain for TRPM3-mediated Ca2+ signaling. Our data show that TRPM3 channels are regulated by intracellular Ca2+ and provide the basis for a mechanistic understanding of the regulation of TRPM3 by calmodulin.
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Affiliation(s)
- Julia Przibilla
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Sandeep Dembla
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Oleksandr Rizun
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Annette Lis
- Department of Biophysics, Centre for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg 66421, Germany
| | - Martin Jung
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany; Zentrum für Human- und Molekularbiologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Stephan E Philipp
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany.
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Abstract
Heat sensation, the ability to detect warm and noxious temperatures, is an ancient and indispensable sensory process. Noxious temperatures can have detrimental effects on the physiology and integrity of cells, and therefore, the detection of environmental hot temperatures is absolutely crucial for survival. Temperature-sensitive ion channels, which conduct ions in a highly temperature-dependent manner, have been put forward as molecular thermometers expressed at the endings of sensory neurons. In particular, several temperature-sensitive members of the transient receptor potential (TRP) superfamily of ion channels have been identified, and a multitude of in vivo studies have shown that the capsaicin-sensitive TRPV1 channel plays a key role as a noxious heat sensor. However, Trpv1-deficient mice display a residual heat sensitivity suggesting the existence of additional heat sensor(s). In this chapter, we provide evidence for the role of the non-selective calcium-permeable TRPM3 ion channel as an additional heat sensor that acts independently of TRPV1, and give an update of the modulation of this channel by various molecular mechanisms. Finally, we compare antagonists of TRPM3 to specific blockers of TRPV1 as potential analgesic drugs to treat pathological pain.
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Cho CH, Hwang EM, Park JY. Emerging Roles of TWIK-1 Heterodimerization in the Brain. Int J Mol Sci 2017; 19:E51. [PMID: 29295556 PMCID: PMC5796001 DOI: 10.3390/ijms19010051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 12/29/2022] Open
Abstract
Two-pore domain K⁺ (K2P) channels play essential roles in regulating resting membrane potential and cellular excitability. Although TWIK-1 (TWIK-tandem of pore domains in a weak inward rectifying K⁺ channel) was the first identified member of the K2P channel family, it is only in recent years that the physiological roles of TWIK-1 have been studied in depth. A series of reports suggest that TWIK-1 may underlie diverse functions, such as intrinsic excitability of neurons, astrocytic passive conductance, and astrocytic glutamate release, as a homodimer or heterodimer with other K2P isotypes. Here, we summarize expression patterns and newly identified functions of TWIK-1 in the brain.
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Affiliation(s)
- Chang-Hoon Cho
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 136-703, Korea.
| | - Eun Mi Hwang
- Korea Institute of Science and Technology (KIST), Center for Functional Connectomics, Seoul 02792, Korea.
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Korea.
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 136-703, Korea.
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58
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Abstract
G protein-coupled receptor stimulation inhibits TRPM3 channel activity through direct binding of the Gβγ subunit to the channel.
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Affiliation(s)
- László Csanády
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
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