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Dubey A, Baxter M, Hendargo KJ, Medrano-Soto A, Saier MH. The Pentameric Ligand-Gated Ion Channel Family: A New Member of the Voltage Gated Ion Channel Superfamily? Int J Mol Sci 2024; 25:5005. [PMID: 38732224 PMCID: PMC11084639 DOI: 10.3390/ijms25095005] [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: 02/20/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
In this report we present seven lines of bioinformatic evidence supporting the conclusion that the Pentameric Ligand-gated Ion Channel (pLIC) Family is a member of the Voltage-gated Ion Channel (VIC) Superfamily. In our approach, we used the Transporter Classification Database (TCDB) as a reference and applied a series of bioinformatic methods to search for similarities between the pLIC family and members of the VIC superfamily. These include: (1) sequence similarity, (2) compatibility of topology and hydropathy profiles, (3) shared domains, (4) conserved motifs, (5) similarity of Hidden Markov Model profiles between families, (6) common 3D structural folds, and (7) clustering analysis of all families. Furthermore, sequence and structural comparisons as well as the identification of a 3-TMS repeat unit in the VIC superfamily suggests that the sixth transmembrane segment evolved into a re-entrant loop. This evidence suggests that the voltage-sensor domain and the channel domain have a common origin. The classification of the pLIC family within the VIC superfamily sheds light onto the topological origins of this family and its evolution, which will facilitate experimental verification and further research into this superfamily by the scientific community.
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Affiliation(s)
| | | | | | - Arturo Medrano-Soto
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA; (A.D.); (M.B.); (K.J.H.)
| | - Milton H. Saier
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA; (A.D.); (M.B.); (K.J.H.)
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2
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Stott JB, Greenwood IA. G protein βγ regulation of KCNQ-encoded voltage-dependent K channels. Front Physiol 2024; 15:1382904. [PMID: 38655029 PMCID: PMC11035767 DOI: 10.3389/fphys.2024.1382904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The KCNQ family is comprised of five genes and the expression products form voltage-gated potassium channels (Kv7.1-7.5) that have a major impact upon cellular physiology in many cell types. Each functional Kv7 channel forms as a tetramer that often associates with proteins encoded by the KCNE gene family (KCNE1-5) and is critically reliant upon binding of phosphatidylinositol bisphosphate (PIP2) and calmodulin. Other modulators like A-kinase anchoring proteins, ubiquitin ligases and Ca-calmodulin kinase II alter Kv7 channel function and trafficking in an isoform specific manner. It has now been identified that for Kv7.4, G protein βγ subunits (Gβγ) can be added to the list of key regulators and is paramount for channel activity. This article provides an overview of this nascent field of research, highlighting themes and directions for future study.
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Affiliation(s)
| | - Iain A. Greenwood
- Vascular Biology Research Group, Institute of Molecular and Clinical Sciences, St George’s University of London, London, United Kingdom
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3
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Li D, Shi D, Wang L. Structural insights in the permeation mechanism of an activated GIRK2 channel. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184231. [PMID: 37739205 DOI: 10.1016/j.bbamem.2023.184231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/19/2023] [Accepted: 09/14/2023] [Indexed: 09/24/2023]
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels play a significant role in physiopathology by the regulation of cell excitability. This regulation depends on the K+ ion conduction induced by structural constrictions: the selectivity filters (SFs), helix bundle crossings (HBCs), and G-loop gates. To explore why no permeation occurred when the constrictions were kept in the open state, a 4-K+-related occupancy mechanism was proposed. Unfortunately, this hypothesis was neither assessed, nor was the energetic characteristics presented. To identify the permeation mechanism on an atomic level, all-atom molecular dynamic (MD) simulations and a coupled quantum mechanics and molecular mechanics (QM/MM) method were used for the GIRK2 mutant R201A. It was found that the R201A had a moderate conductive capability in the presence of PIP2. Furthermore, the 4-K+ group of ions was found to dominate the conduction through the activated HBC gate. This shielding-like mechanism was assessed by the potential energy barrier along the conduction pathway. Mutation studies did further support the assumption that E152 was responsible for the mechanism. Moreover, E152 was most probably facilitating the inflow of ions from the SF to the cavity. On the contrary, N184 had no remarkable effect on this mechanism, except for the conduction efficiency. These findings highlighted the necessity of a multi-ion distribution for the conduction to take place, and indicated that the K+ migration was not only determined by the channel conductive state in the GIRK channel. The here presented multi-ion permeation mechanism may help to provide an effective way to regulate the channelopathies.
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Affiliation(s)
- Dailin Li
- Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, Xiamen University of Technology, Xiamen 361005, China.
| | - Dingyuan Shi
- Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, Xiamen University of Technology, Xiamen 361005, China
| | - Lei Wang
- Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, Xiamen University of Technology, Xiamen 361005, China
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4
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Gada KD, Chang M, Chandrashekar A, Plant LD, Noujaim SF, Logothetis DE. Mechanism of PKCε regulation of cardiac GIRK channel gating. Proc Natl Acad Sci U S A 2023; 120:e2212325120. [PMID: 36584301 PMCID: PMC9910474 DOI: 10.1073/pnas.2212325120] [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: 07/18/2022] [Accepted: 11/09/2022] [Indexed: 12/31/2022] Open
Abstract
G-protein-gated inwardly rectifying potassium (GIRK) channel activity is regulated by the membrane phospholipid, phosphatidylinositol-4,5-bisphosphate (PI 4,5P2). Constitutive activity of cardiac GIRK channels in atrial myocytes, that is implicated in atrial fibrillation (AF), is mediated via a protein kinase C-ε (PKCε)-dependent mechanism. The novel PKC isoform, PKCε, is reported to enhance the activity of cardiac GIRK channels. Here, we report that PKCε stimulation leads to activation of GIRK channels in mouse atria and in human stem cell-derived atrial cardiomyocytes (iPSCs). We identified residue GIRK4(S418) which when mutated to Ala abolished, or to Glu, mimicked the effects of PKCε on GIRK currents. PKCε strengthened the interactions of the cardiac GIRK isoforms, GIRK4 and GIRK1/4 with PIP2, an effect that was reversed in the GIRK4(S418A) mutant. This mechanistic insight into the PKCε-mediated increase in channel activity because of GIRK4(S418) phosphorylation, provides a precise druggable target to reverse AF-related pathologies due to GIRK overactivity.
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Affiliation(s)
- Kirin D. Gada
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
| | - Mengmeng Chang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL33602
| | - Aishwarya Chandrashekar
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
| | - Leigh D. Plant
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
- Center for Drug Discovery, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
| | - Sami F. Noujaim
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL33602
| | - Diomedes E. Logothetis
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
- Center for Drug Discovery, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
- Department of Chemistry and Chemical Biology, Bouvé College of Health Sciences and College of Science, Northeastern University, Boston, MA02115
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5
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Lee SJ, Maeda S, Gao J, Nichols CG. Oxidation Driven Reversal of PIP 2-dependent Gating in GIRK2 Channels. FUNCTION 2023; 4:zqad016. [PMID: 37168492 PMCID: PMC10165546 DOI: 10.1093/function/zqad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/24/2023] [Accepted: 04/03/2023] [Indexed: 05/13/2023] Open
Abstract
Physiological activity of G protein gated inward rectifier K+ (GIRK, Kir3) channel, dynamically regulated by three key ligands, phosphoinositol-4,5-bisphosphate (PIP2), Gβγ, and Na+, underlies cellular electrical response to multiple hormones and neurotransmitters in myocytes and neurons. In a reducing environment, matching that inside cells, purified GIRK2 (Kir3.2) channels demonstrate low basal activity, and expected sensitivity to the above ligands. However, under oxidizing conditions, anomalous behavior emerges, including rapid loss of PIP2 and Na+-dependent activation and a high basal activity in the absence of any agonists, that is now paradoxically inhibited by PIP2. Mutagenesis identifies two cysteine residues (C65 and C190) as being responsible for the loss of PIP2 and Na+-dependent activity and the elevated basal activity, respectively. The results explain anomalous findings from earlier studies and illustrate the potential pathophysiologic consequences of oxidation on GIRK channel function, as well as providing insight to reversed ligand-dependence of Kir and KirBac channels.
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Affiliation(s)
| | - Shoji Maeda
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan, USA
| | - Jian Gao
- Department of Cell Biology and Physiology and the Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Colin G Nichols
- Department of Cell Biology and Physiology and the Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
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6
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Bukiya AN, Rosenhouse-Dantsker A. From Crosstalk to Synergism: The Combined Effect of Cholesterol and PI(4,5)P 2 on Inwardly Rectifying Potassium Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:169-191. [PMID: 36988881 DOI: 10.1007/978-3-031-21547-6_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Inwardly rectifying potassium (Kir) channels are integral membrane proteins that control the flux of potassium ions across cell membranes and regulate membrane permeability. All eukaryotic Kir channels require the membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) for activation. In recent years, it has become evident that the function of many members of this family of channels is also mediated by another essential lipid-cholesterol. Here, we focus on members of the Kir2 and Kir3 subfamilies and their modulation by these two key lipids. We discuss how PI(4,5)P2 and cholesterol bind to Kir2 and Kir3 channels and how they affect channel activity. We also discuss the accumulating evidence indicating that there is interplay between PI(4,5)P2 and cholesterol in the modulation of Kir2 and Kir3 channels. In particular, we review the crosstalk between PI(4,5)P2 and cholesterol in the modulation of the ubiquitously expressed Kir2.1 channel and the synergy between these two lipids in the modulation of the Kir3.4 channel, which is primarily expressed in the heart. Additionally, we demonstrate that there is also synergy in the modulation of Kir3.2 channels, which are expressed in the brain. These observations suggest that alterations in the relative levels PI(4,5)P2 and cholesterol may fine-tune Kir channel activity.
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Affiliation(s)
- Anna N Bukiya
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, USA
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Rosenhouse-Dantsker A, Gazgalis D, Logothetis DE. PI(4,5)P 2 and Cholesterol: Synthesis, Regulation, and Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:3-59. [PMID: 36988876 DOI: 10.1007/978-3-031-21547-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is the most abundant membrane phosphoinositide and cholesterol is an essential component of the plasma membrane (PM). Both lipids play key roles in a variety of cellular functions including as signaling molecules and major regulators of protein function. This chapter provides an overview of these two important lipids. Starting from a brief description of their structure, synthesis, and regulation, the chapter continues to describe the primary functions and signaling processes in which PI(4,5)P2 and cholesterol are involved. While PI(4,5)P2 and cholesterol can act independently, they often act in concert or affect each other's impact. The chapters in this volume on "Cholesterol and PI(4,5)P2 in Vital Biological Functions: From Coexistence to Crosstalk" focus on the emerging relationship between cholesterol and PI(4,5)P2 in a variety of biological systems and processes. In this chapter, the next section provides examples from the ion channel field demonstrating that PI(4,5)P2 and cholesterol can act via common mechanisms. The chapter ends with a discussion of future directions.
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Affiliation(s)
| | - Dimitris Gazgalis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
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8
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Moseng MA, Su CC, Rios K, Cui M, Lyu M, Glaza P, Klenotic PA, Delpire E, Yu EW. Inhibition mechanism of NKCC1 involves the carboxyl terminus and long-range conformational coupling. SCIENCE ADVANCES 2022; 8:eabq0952. [PMID: 36306358 PMCID: PMC9616490 DOI: 10.1126/sciadv.abq0952] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
The Na-K-2Cl cotransporter-1 (NKCC1) is an electroneutral Na+-dependent transporter responsible for simultaneously translocating Na+, K+, and Cl- ions into cells. In human tissue, NKCC1 plays a critical role in regulating cytoplasmic volume, fluid intake, chloride homeostasis, and cell polarity. Here, we report four structures of human NKCC1 (hNKCC1), both in the absence and presence of loop diuretic (bumetanide or furosemide), using single-particle cryo-electron microscopy. These structures allow us to directly observe various novel conformations of the hNKCC1 dimer. They also reveal two drug-binding sites located at the transmembrane and cytosolic carboxyl-terminal domains, respectively. Together, our findings enable us to delineate an inhibition mechanism that involves a coupled movement between the cytosolic and transmembrane domains of hNKCC1.
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Affiliation(s)
- Mitchell A. Moseng
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Kerri Rios
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, MA 02115, USA
| | - Meinan Lyu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Przemyslaw Glaza
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Philip A. Klenotic
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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9
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Unravelling biological roles and mechanisms of GABA BR on addiction and depression through mood and memory disorders. Biomed Pharmacother 2022; 155:113700. [PMID: 36152411 DOI: 10.1016/j.biopha.2022.113700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/23/2022] Open
Abstract
The metabotropic γ-aminobutyric acid type B receptor (GABABR) remains a hotspot in the recent research area. Being an idiosyncratic G-protein coupled receptor family member, the GABABR manifests adaptively tailored functionality under multifarious modulations by a constellation of agents, pointing to cross-talk between receptors and effectors that converge on the domains of mood and memory. This review systematically summarizes the latest achievements in signal transduction mechanisms of the GABABR-effector-regulator complex and probes how the up-and down-regulation of membrane-delimited GABABRs are associated with manifold intrinsic and extrinsic agents in synaptic strength and plasticity. Neuropsychiatric conditions depression and addiction share the similar pathophysiology of synapse inadaptability underlying negative mood-related processes, memory formations, and impairments. In the attempt to emphasize all convergent discoveries, we hope the insights gained on the GABABR system mechanisms of action are conducive to designing more therapeutic candidates so as to refine the prognosis rate of diseases and minimize side effects.
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Gazgalis D, Cantwell L, Xu Y, Thakur GA, Cui M, Guarnieri F, Logothetis DE. Use of a Molecular Switch Probe to Activate or Inhibit GIRK1 Heteromers In Silico Reveals a Novel Gating Mechanism. Int J Mol Sci 2022; 23:ijms231810820. [PMID: 36142730 PMCID: PMC9502415 DOI: 10.3390/ijms231810820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/16/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
G protein-gated inwardly rectifying K+ (GIRK) channels form highly active heterotetramers in the body, such as in neurons (GIRK1/GIRK2 or GIRK1/2) and heart (GIRK1/GIRK4 or GIRK1/4). Based on three-dimensional atomic resolution structures for GIRK2 homotetramers, we built heterotetrameric GIRK1/2 and GIRK1/4 models in a lipid bilayer environment. By employing a urea-based activator ML297 and its molecular switch, the inhibitor GAT1587, we captured channel gating transitions and K+ ion permeation in sub-microsecond molecular dynamics (MD) simulations. This allowed us to monitor the dynamics of the two channel gates (one transmembrane and one cytosolic) as well as their control by the required phosphatidylinositol bis 4-5-phosphate (PIP2). By comparing differences in the two trajectories, we identify three hydrophobic residues in the transmembrane domain 1 (TM1) of GIRK1, namely, F87, Y91, and W95, which form a hydrophobic wire induced by ML297 and de-induced by GAT1587 to orchestrate channel gating. This includes bending of the TM2 and alignment of a dipole of two acidic GIRK1 residues (E141 and D173) in the permeation pathway to facilitate K+ ion conduction. Moreover, the TM movements drive the movement of the Slide Helix relative to TM1 to adjust interactions of the CD-loop that controls the gating of the cytosolic gate. The simulations reveal that a key basic residue that coordinates PIP2 to stabilize the pre-open and open states of the transmembrane gate flips in the inhibited state to form a direct salt-bridge interaction with the cytosolic gate and destabilize its open state.
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Affiliation(s)
- Dimitrios Gazgalis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
| | - Lucas Cantwell
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
| | - Yu Xu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Frank Guarnieri
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Diomedes E. Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA 02115, USA
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
- Department of Chemistry and Chemical Biology, College of Science, Boston, MA 02115, USA
- Roux Institute, Northeastern University, Portland, ME 04101, USA
- Correspondence:
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11
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Luo H, Marron Fernandez de Velasco E, Wickman K. Neuronal G protein-gated K + channels. Am J Physiol Cell Physiol 2022; 323:C439-C460. [PMID: 35704701 PMCID: PMC9362898 DOI: 10.1152/ajpcell.00102.2022] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels exert a critical inhibitory influence on neurons. Neuronal GIRK channels mediate the G protein-dependent, direct/postsynaptic inhibitory effect of many neurotransmitters including γ-aminobutyric acid (GABA), serotonin, dopamine, adenosine, somatostatin, and enkephalin. In addition to their complex regulation by G proteins, neuronal GIRK channel activity is sensitive to PIP2, phosphorylation, regulator of G protein signaling (RGS) proteins, intracellular Na+ and Ca2+, and cholesterol. The application of genetic and viral manipulations in rodent models, together with recent progress in the development of GIRK channel modulators, has increased our understanding of the physiological and behavioral impact of neuronal GIRK channels. Work in rodent models has also revealed that neuronal GIRK channel activity is modified, transiently or persistently, by various stimuli including exposure drugs of abuse, changes in neuronal activity patterns, and aversive experience. A growing body of preclinical and clinical evidence suggests that dysregulation of GIRK channel activity contributes to neurological diseases and disorders. The primary goals of this review are to highlight fundamental principles of neuronal GIRK channel biology, mechanisms of GIRK channel regulation and plasticity, the nascent landscape of GIRK channel pharmacology, and the potential relevance of GIRK channels to the pathophysiology and treatment of neurological diseases and disorders.
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Affiliation(s)
- Haichang Luo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
| | | | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
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12
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Cui M, Xu K, Gada K, Shalomov B, Ban M, Eptaminitaki GC, Kawano T, Plant LD, Dascal N, Logothetis DE. A novel small molecule selective activator of homomeric GIRK4 channels. J Biol Chem 2022; 298:102009. [PMID: 35525275 PMCID: PMC9194863 DOI: 10.1016/j.jbc.2022.102009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/27/2022] [Accepted: 05/02/2022] [Indexed: 11/26/2022] Open
Abstract
G protein–sensitive inwardly rectifying potassium (GIRK) channels are important pharmaceutical targets for neuronal, cardiac, and endocrine diseases. Although a number of GIRK channel modulators have been discovered in recent years, most lack selectivity. GIRK channels function as either homomeric (i.e., GIRK2 and GIRK4) or heteromeric (e.g., GIRK1/2, GIRK1/4, and GIRK2/3) tetramers. Activators, such as ML297, ivermectin, and GAT1508, have been shown to activate heteromeric GIRK1/2 channels better than GIRK1/4 channels with varying degrees of selectivity but not homomeric GIRK2 and GIRK4 channels. In addition, VU0529331 was discovered as the first homomeric GIRK channel activator, but it shows weak selectivity for GIRK2 over GIRK4 (or G4) homomeric channels. Here, we report the first highly selective small-molecule activator targeting GIRK4 homomeric channels, 3hi2one-G4 (3-[2-(3,4-dimethoxyphenyl)-2-oxoethyl]-3-hydroxy-1-(1-naphthylmethyl)-1,3-dihydro-2H-indol-2-one). We show that 3hi2one-G4 does not activate GIRK2, GIRK1/2, or GIRK1/4 channels. Using molecular modeling, mutagenesis, and electrophysiology, we analyzed the binding site of 3hi2one-G4 formed by the transmembrane 1, transmembrane 2, and slide helix regions of the GIRK4 channel, near the phosphatidylinositol-4,5-bisphosphate binding site, and show that it causes channel activation by strengthening channel–phosphatidylinositol-4,5-bisphosphate interactions. We also identify slide helix residue L77 in GIRK4, corresponding to residue I82 in GIRK2, as a major determinant of isoform-specific selectivity. We propose that 3hi2one-G4 could serve as a useful pharmaceutical probe in studying GIRK4 channel function and may also be pursued in drug optimization studies to tackle GIRK4-related diseases such as primary aldosteronism and late-onset obesity.
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Affiliation(s)
- Meng Cui
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA; Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA.
| | - Keman Xu
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Kirin Gada
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Boris Shalomov
- Department of Physiology and Pharmacology and Sagol School of Neuroscience, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Michelle Ban
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Giasemi C Eptaminitaki
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Takeharu Kawano
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA; Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Nathan Dascal
- Department of Physiology and Pharmacology and Sagol School of Neuroscience, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA; Chemistry and Chemical Biology, College of Science, Northeastern University, Boston, MA 02115, USA; Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA.
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13
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Friesacher T, Reddy HP, Bernsteiner H, Carlo Combista J, Shalomov B, Bera AK, Zangerl-Plessl EM, Dascal N, Stary-Weinzinger A. A selectivity filter mutation provides insights into gating regulation of a K + channel. Commun Biol 2022; 5:345. [PMID: 35411015 PMCID: PMC9001731 DOI: 10.1038/s42003-022-03303-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 03/22/2022] [Indexed: 11/13/2022] Open
Abstract
G-protein coupled inwardly rectifying potassium (GIRK) channels are key players in inhibitory neurotransmission in heart and brain. We conducted molecular dynamics simulations to investigate the effect of a selectivity filter (SF) mutation, G154S, on GIRK2 structure and function. We observe mutation-induced loss of selectivity, changes in ion occupancy and altered filter geometry. Unexpectedly, we reveal aberrant SF dynamics in the mutant to be correlated with motions in the binding site of the channel activator Gβγ. This coupling is corroborated by electrophysiological experiments, revealing that GIRK2wt activation by Gβγ reduces the affinity of Ba2+ block. We further present a functional characterization of the human GIRK2G154S mutant validating our computational findings. This study identifies an allosteric connection between the SF and a crucial activator binding site. This allosteric gating mechanism may also apply to other potassium channels that are modulated by accessory proteins. Gly selectivity filter (TIGYGYR) mutant of the GIRK2 channel causes rare but severe neurological disorder called the Keppen-Lubinsky syndrome. Here, the authors explore the molecular mechanism of action of this glycine to serine mutant causing disease and identify an allosteric connection between the selectivity filter and a crucial activator binding site.
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Affiliation(s)
- Theres Friesacher
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Josef-Holaubek-Platz 2, 1090, Vienna, Austria
| | - Haritha P Reddy
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.,Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Harald Bernsteiner
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Josef-Holaubek-Platz 2, 1090, Vienna, Austria
| | - J Carlo Combista
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Boris Shalomov
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Amal K Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Eva-Maria Zangerl-Plessl
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Josef-Holaubek-Platz 2, 1090, Vienna, Austria
| | - Nathan Dascal
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 69978, Israel.
| | - Anna Stary-Weinzinger
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Josef-Holaubek-Platz 2, 1090, Vienna, Austria.
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14
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Abstract
Cholesterol is one of the main components found in plasma membranes and is involved in lipid-dependent signaling enabled by integral membrane proteins such as inwardly rectifying potassium (Kir) channels. Similar to other ion channels, most of the Kir channels are down-regulated by cholesterol. One of the very few notable exceptions is Kir3.4, which is up-regulated by this important lipid. Here, we discovered and characterized a molecular switch that controls the impact (up-regulation vs. down-regulation) of cholesterol on Kir3.4. Our results provide a detailed molecular mechanism of tunable cholesterol regulation of a potassium channel. Cholesterol decreases the activity of the majority of ion channels while increasing the activity of only a few, yet it remains unclear how. Here, we used the inwardly rectifying potassium channel Kir3.4, which is up-regulated by cholesterol, as a tool to address this question. Employing mutagenesis and electrophysiology, we discovered a molecular switch that controls the impact of cholesterol on the channel. Through a single point mutation at position 182 in the transmembrane domain of Kir3.4, we converted the cholesterol-driven up-regulation of the channel into down-regulation. Microseconds-long coarse-grained and atomistic molecular dynamics simulations revealed that the effect of the point mutation propagated toward the selectivity filter of the channel whose conformation controls the conductance of the channel. Planar lipid bilayer experiments validated these results, showing that although cholesterol up-regulated Kir3.4 by increasing its open probability, cholesterol down-regulated the mutant by decreasing its conductance. Further studies underscored the role of mutation-specific alterations of cholesterol distribution in proximity to the channel in cholesterol’s impact on channel activity, highlighting the role of subtle molecular differences in determining how cholesterol distributes around proteins and affects their function.
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15
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Sajid A, Saeed MS, Malik RM, Fazal S, Malik S, Kamal MA. Prediction of Secondary and Tertiary Structure and Docking of Rb1WT
And Rb1R661W Proteins. CURRENT BIOTECHNOLOGY 2022. [DOI: 10.2174/2211550111666220127100203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Background:
Retinoblastoma, a malignancy occurring in the juvenile cells of the retina,
is responsible for light detection. It is one of the most emerging ra re childhood and infant cancer.
It is initiated by the mutation in Rb1, a first tumor suppressor gene located on chromosome 13q14.
Rb1 protein is responsible for cell cycle regulation.
Methods:
In our study, secondary and 3D-Structural predictions of Rb1WT and Rb1R661W were made
by comparative or homology modeling to find any structural change leading to the disruption in its
further interactions. Quality assurance of the structures was done by Ramachandran Plot for a stable
structure. Both the proteins were then applied by docking process with proteins of interest.
Results:
Secondary structure showed a number of mutations in helixes, β-Hairpins of Rb1R661W. The
major change was the loss of β-Hairpin loop, extension and shortening of helixes. 3D comparison
structure showed a change in the groove of Rb1R661W. Docking results, unlike RB1 WT, had different
and no interactions with some of the proteins of interest. This mutation in Rb1 protein had a deleterious
effect on the protein functionality.
Conclusion:
This study will help to design the appropriate therapy and also understand the mechanism
of disease of retinoblastoma, for researchers and pharmaceuticals.
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Affiliation(s)
- Aimen Sajid
- Capital University of Science and Technology, Islamabad, Pakistan
| | | | - Rabbiah Manzoor Malik
- Capital University of Science and Technology, Islamabad, Pakistan
- Wah Medical College, Wah Cantt, Pakistan
| | - Sahar Fazal
- Capital University of Science and Technology, Islamabad, Pakistan
| | - Shaukat Malik
- Capital University of Science and Technology, Islamabad, Pakistan
| | - Mohammad Amjad Kamal
- West China School of Nursing / Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China
- King Fahd Medical Research
Center, King Abdulaziz University, P. O. Box 80216, Jeddah 21589, Saudi Arabia
- Enzymoics, 7 Peterlee
Place, Hebersham, NSW 2770; Novel Global Community Educational Foundation, Australia
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16
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Fagnen C, Bannwarth L, Oubella I, Zuniga D, Haouz A, Forest E, Scala R, Bendahhou S, De Zorzi R, Perahia D, Vénien-Bryan C. Integrative Study of the Structural and Dynamical Properties of a KirBac3.1 Mutant: Functional Implication of a Highly Conserved Tryptophan in the Transmembrane Domain. Int J Mol Sci 2021; 23:335. [PMID: 35008764 PMCID: PMC8745282 DOI: 10.3390/ijms23010335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/18/2021] [Accepted: 12/23/2021] [Indexed: 12/02/2022] Open
Abstract
ATP-sensitive potassium (K-ATP) channels are ubiquitously expressed on the plasma membrane of cells in several organs, including the heart, pancreas, and brain, and they govern a wide range of physiological processes. In pancreatic β-cells, K-ATP channels composed of Kir6.2 and SUR1 play a key role in coupling blood glucose and insulin secretion. A tryptophan residue located at the cytosolic end of the transmembrane helix is highly conserved in eukaryote and prokaryote Kir channels. Any mutation on this amino acid causes a gain of function and neonatal diabetes mellitus. In this study, we have investigated the effect of mutation on this highly conserved residue on a KirBac channel (prokaryotic homolog of mammalian Kir6.2). We provide the crystal structure of the mutant KirBac3.1 W46R (equivalent to W68R in Kir6.2) and its conformational flexibility properties using HDX-MS. In addition, the detailed dynamical view of the mutant during the gating was investigated using the in silico method. Finally, functional assays have been performed. A comparison of important structural determinants for the gating mechanism between the wild type KirBac and the mutant W46R suggests interesting structural and dynamical clues and a mechanism of action of the mutation that leads to the gain of function.
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Affiliation(s)
- Charline Fagnen
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, 4 Ave. des Sciences, 91190 Gif-sur-Yvette, France;
| | - Ludovic Bannwarth
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Iman Oubella
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Dania Zuniga
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Ahmed Haouz
- Institut Pasteur, C2RT-Plate-Forme de Cristallographie CNRS-UMR3528, 75724 Paris, France;
| | - Eric Forest
- CNRS, IBS, CEA, University Grenoble Alpes, 38044 Grenoble, France;
| | - Rosa Scala
- CNRS UMR7370, LP2M, Labex ICST, Faculté de Médecine, University Côte d’Azur, 06560 Nice, France; (R.S.); (S.B.)
| | - Saïd Bendahhou
- CNRS UMR7370, LP2M, Labex ICST, Faculté de Médecine, University Côte d’Azur, 06560 Nice, France; (R.S.); (S.B.)
| | - Rita De Zorzi
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Licio Giorgeri 1, 34127 Trieste, Italy;
| | - David Perahia
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, 4 Ave. des Sciences, 91190 Gif-sur-Yvette, France;
| | - Catherine Vénien-Bryan
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
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17
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Weng J, Wang A, Zhang D, Liao C, Li G. A double bilayer to study the nonequilibrium environmental response of GIRK2 in complex states. Phys Chem Chem Phys 2021; 23:15784-15795. [PMID: 34286758 DOI: 10.1039/d1cp01785c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels play essential roles in electrical signaling in neurons and muscle cells. Nonequilibrium environments provide crucial driving forces behind many cellular events. Here, we apply the antiparallel alignment double bilayer model to study GIRK2 in response to the time-dependent membrane potential. Using molecular dynamics and umbrella sampling, we examined the time-dependent environmental impact on the ion conduction, energy basis, and primary motions of GIRK2 in different complex states with phosphatidylinositol-4,5-bisphosphate (PIP2) and G-protein βγ subunits (Gβγ). The antiparallel alignment double bilayer model enables us to study the transport performance in inward and outward K+ and mixed K+ and Na+. We obtained the recoverable discharge process of GIRK2 complexed with both PIP2 and Gβγ, compared with occasional conduction under PIP2-only regulation. Calculations of potential of mean force suggest different regulation by the helix bundle crossing (HBC) gate and G-loop gate regarding different complex states and under a membrane potential. In a nonequilibrium environment, distinct functional rocking motions of GIRK2 were identified under strengthened correlations between the transmembrane helices and downstream cytoplasmic domains with binding of PIP2, cations, and Gβγ. The findings suggest the potential domain motions and dynamics associated with a nonequilibrium environment and highlight the application of the antiparallel alignment double bilayer model to investigate factors in an asymmetric environment.
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Affiliation(s)
- Junben Weng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. and University of Chinese Academy of Sciences, Beijing, China
| | - Anhui Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Dinglin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. and University of Chinese Academy of Sciences, Beijing, China
| | - Chenyi Liao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Guohui Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
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18
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Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
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19
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Lei S, Hu B. Ionic and signaling mechanisms involved in neurotensin-mediated excitation of central amygdala neurons. Neuropharmacology 2021; 196:108714. [PMID: 34271017 DOI: 10.1016/j.neuropharm.2021.108714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 10/20/2022]
Abstract
Neurotensin (NT) serves as a neuromodulator in the brain where it regulates a variety of physiological functions. Whereas the central amygdala (CeA) expresses NT peptide and NTS1 receptors and application of NT has been shown to excite CeA neurons, the underlying cellular and molecular mechanisms have not been determined. We found that activation of NTS1 receptors increased the neuronal excitability of the lateral nucleus (CeL) of CeA. Both phospholipase Cβ (PLCβ) and phosphatidylinositol 4,5-bisphosphate (PIP2) depletion were required, whereas intracellular Ca2+ release and PKC were unnecessary for NT-elicited excitation of CeL neurons. NT increased the input resistance and time constants of CeL neurons, suggesting that NT excites CeL neurons by decreasing a membrane conductance. Depressions of the inwardly rectifying K+ (Kir) channels including both the Kir2 subfamily and the GIRK channels were required for NT-elicited excitation of CeL neurons. Activation of NTS1 receptors in the CeL led to GABAergic inhibition of medial nucleus of CeA neurons, suggesting that NT modulates the network activity in the amygdala. Our results may provide a cellular and molecular mechanism to explain the physiological functions of NT in vivo.
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Affiliation(s)
- Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA.
| | - Binqi Hu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA
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20
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Fagnen C, Bannwarth L, Zuniga D, Oubella I, De Zorzi R, Forest E, Scala R, Guilbault S, Bendahhou S, Perahia D, Vénien-Bryan C. Unexpected Gating Behaviour of an Engineered Potassium Channel Kir. Front Mol Biosci 2021; 8:691901. [PMID: 34179097 PMCID: PMC8222812 DOI: 10.3389/fmolb.2021.691901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/26/2021] [Indexed: 11/24/2022] Open
Abstract
In this study, we investigated the dynamics and functional characteristics of the KirBac3.1 S129R, a mutated bacterial potassium channel for which the inner pore-lining helix (TM2) was engineered so that the bundle crossing is trapped in an open conformation. The structure of this channel has been previously determined at high atomic resolution. We explored the dynamical characteristics of this open state channel using an in silico method MDeNM that combines molecular dynamics simulations and normal modes. We captured the global and local motions at the mutation level and compared these data with HDX-MS experiments. MDeNM provided also an estimation of the probability of the different opening states that are in agreement with our electrophysiological experiments. In the S129R mutant, the Arg129 mutation releases the two constriction points in the channel that existed in the wild type but interestingly creates another restriction point.
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Affiliation(s)
- Charline Fagnen
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Université, Paris, France.,Laboratoire de Biologie et de Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Ludovic Bannwarth
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Université, Paris, France
| | - Dania Zuniga
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Université, Paris, France
| | - Iman Oubella
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Université, Paris, France
| | - Rita De Zorzi
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy
| | - Eric Forest
- IBS University Grenoble Alpes, CNRS, CEA, Grenoble, France
| | - Rosa Scala
- Faculté de Médecine, CNRS UMR7370, LP2M, Labex ICST, University Côte d'Azur, Nice, France
| | - Samuel Guilbault
- Faculté de Médecine, CNRS UMR7370, LP2M, Labex ICST, University Côte d'Azur, Nice, France
| | - Saïd Bendahhou
- Faculté de Médecine, CNRS UMR7370, LP2M, Labex ICST, University Côte d'Azur, Nice, France
| | - David Perahia
- Laboratoire de Biologie et de Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
| | - Catherine Vénien-Bryan
- UMR 7590, CNRS, Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, IMPMC, Sorbonne Université, Paris, France
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21
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Ningoo M, Plant LD, Greka A, Logothetis DE. PIP 2 regulation of TRPC5 channel activation and desensitization. J Biol Chem 2021; 296:100726. [PMID: 33933453 PMCID: PMC8191310 DOI: 10.1016/j.jbc.2021.100726] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/20/2021] [Accepted: 04/28/2021] [Indexed: 10/27/2022] Open
Abstract
Transient receptor potential canonical type 5 (TRPC5) ion channels are expressed in the brain and kidney and have been identified as promising therapeutic targets whose selective inhibition can protect against diseases driven by a leaky kidney filter, such as focal segmental glomerular sclerosis. TRPC5 channels are activated not only by elevated levels of extracellular Ca2+or lanthanide ions but also by G protein (Gq/11) stimulation. Phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis by phospholipase C enzymes leads to PKC-mediated phosphorylation of TRPC5 channels and their subsequent desensitization. However, the roles of PIP2 in activation and maintenance of TRPC5 channel activity via its hydrolysis product diacyl glycerol (DAG), as well as the mechanism of desensitization of TRPC5 activity by DAG-stimulated PKC activity, remain unclear. Here, we designed experiments to distinguish between the processes underlying channel activation and inhibition. Employing whole-cell patch-clamp, we used an optogenetic tool to dephosphorylate PIP2 and assess channel-PIP2 interactions influenced by activators, such as DAG, or inhibitors, such as PKC phosphorylation. Using total internal reflection microscopy, we assessed channel cell surface density. We show that PIP2 controls both the PKC-mediated inhibition and the DAG- and lanthanide-mediated activation of TRPC5 currents via control of gating rather than channel cell surface density. These mechanistic insights promise to aid in the development of more selective and precise inhibitors to block TRPC5 channel activity and illuminate new opportunities for targeted therapies for a group of chronic kidney diseases for which there is currently a great unmet need.
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Affiliation(s)
- Mehek Ningoo
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA
| | - Anna Greka
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA; Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA; Department of Chemistry and Chemical Biology, College of Science, Northeastern University, Boston, Massachusetts, USA.
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22
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Boyle CA, Hu B, Quaintance KL, Lei S. Involvement of TRPC5 channels, inwardly rectifying K + channels, PLCβ and PIP 2 in vasopressin-mediated excitation of medial central amygdala neurons. J Physiol 2021; 599:3101-3119. [PMID: 33871877 DOI: 10.1113/jp281260] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 04/06/2021] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Activation of V1a vasopressin receptors facilitates neuronal excitability in the medial nucleus of central amygdala (CeM) V1a receptor activation excites about 80% CeM neurons by opening a cationic conductance and about 20% CeM neurons by suppressing an inwardly rectifying K+ (Kir) channel The cationic conductance activated by V1a receptors is identified as TRPC5 channels PLCβ-mediated depletion of PIP2 is involved in V1a receptor-elicited excitation of CeM neurons Intracellular Ca2+ release and PKC are unnecessary for V1a receptor-mediated excitation of CeM neurons ABSTRACT: Arginine vasopressin (AVP) serves as a hormone in the periphery to modulate water homeostasis and a neuromodulator in the brain to regulate a diverse range of functions including anxiety, social behaviour, cognitive activities and nociception. The amygdala is an essential brain region involved in modulating defensive and appetitive behaviours, pain and alcohol use disorders. Whereas activation of V1a receptors in the medial nucleus of the central amygdala (CeM) increases neuronal excitability, the involved ionic and signalling mechanisms have not been determined. We found that activation of V1a receptors in the CeM facilitated neuronal excitability predominantly by opening TRPC5 channels, although AVP excited about one fifth of the CeM neurons via suppressing an inwardly rectifying K+ (Kir) channel. G proteins and phospholipase Cβ (PLCβ) were required for AVP-elicited excitation of CeM neurons, whereas intracellular Ca2+ release and the activity of protein kinase C were unnecessary. Prevention of the depletion of phosphatidylinositol 4,5-bisphosphate (PIP2 ) blocked AVP-induced excitation of CeM neurons, suggesting that PLCβ-mediated depletion of PIP2 is involved in AVP-mediated excitation of CeM neurons. Our results may provide a cellular and molecular mechanism to explain the anxiogenic effects of AVP in the amygdala.
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Affiliation(s)
- Cody A Boyle
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA
| | - Binqi Hu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA
| | - Kati L Quaintance
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA
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23
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Cui M, Alhamshari Y, Cantwell L, Ei-Haou S, Eptaminitaki GC, Chang M, Abou-Assali O, Tan H, Xu K, Masotti M, Plant LD, Thakur GA, Noujaim SF, Milnes J, Logothetis DE. A benzopyran with antiarrhythmic activity is an inhibitor of Kir3.1-containing potassium channels. J Biol Chem 2021; 296:100535. [PMID: 33713702 PMCID: PMC8086025 DOI: 10.1016/j.jbc.2021.100535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 01/20/2023] Open
Abstract
Atrial fibrillation (AF) is the most commonly diagnosed cardiac arrhythmia and is associated with increased morbidity and mortality. Currently approved AF antiarrhythmic drugs have limited efficacy and/or carry the risk of ventricular proarrhythmia. The cardiac acetylcholine activated inwardly rectifying K+ current (IKACh), composed of Kir3.1/Kir3.4 heterotetrameric and Kir3.4 homotetrameric channel subunits, is one of the best validated atrial-specific ion channels. Previous research pointed to a series of benzopyran derivatives with potential for treatment of arrhythmias, but their mechanism of action was not defined. Here, we characterize one of these compounds termed Benzopyran-G1 (BP-G1) and report that it selectively inhibits the Kir3.1 (GIRK1 or G1) subunit of the KACh channel. Homology modeling, molecular docking, and molecular dynamics simulations predicted that BP-G1 inhibits the IKACh channel by blocking the central cavity pore. We identified the unique F137 residue of Kir3.1 as the critical determinant for the IKACh-selective response to BP-G1. The compound interacts with Kir3.1 residues E141 and D173 through hydrogen bonds that proved critical for its inhibitory activity. BP-G1 effectively blocked the IKACh channel response to carbachol in an in vivo rodent model and displayed good selectivity and pharmacokinetic properties. Thus, BP-G1 is a potent and selective small-molecule inhibitor targeting Kir3.1-containing channels and is a useful tool for investigating the role of Kir3.1 heteromeric channels in vivo. The mechanism reported here could provide the molecular basis for future discovery of novel, selective IKACh channel blockers to treat atrial fibrillation with minimal side effects.
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Affiliation(s)
- Meng Cui
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA.
| | - Yaser Alhamshari
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Lucas Cantwell
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Said Ei-Haou
- Department of Cardiac Biology, Xention Ltd, Cambridge, UK
| | - Giasemi C Eptaminitaki
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Mengmeng Chang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Obada Abou-Assali
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Haozhou Tan
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Keman Xu
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Meghan Masotti
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Sami F Noujaim
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - James Milnes
- Department of Cardiac Biology, Xention Ltd, Cambridge, UK
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, USA; Department of Chemistry and Chemical Biology, College of Science, Northeastern University, Boston, Massachusetts, USA; Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA.
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24
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Li DL, Hu L, Wang L, Chen CL. Permeation mechanisms through the selectivity filter and the open helix bundle crossing gate of GIRK2. Comput Struct Biotechnol J 2020; 18:3950-3958. [PMID: 33335691 PMCID: PMC7734222 DOI: 10.1016/j.csbj.2020.11.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 12/01/2022] Open
Abstract
G protein-gated inwardly rectifying potassium channels (GIRK) are essential for the regulation of cellular excitability, a physiological function that relies critically on the conduction of K+ ions, which is dependent on two molecular mechanisms, namely selectivity and gating. Molecular Dynamics (MD) studies have shown that K+ conduction remains inefficient even with open channel gates, therefore further detailed study on the permeation events is required. In this study, all-atom MD simulations were employed to investigate the permeation mechanism through the GIRK2 selectivity filter (SF) and its open helix bundle crossing (HBC) gate. Our results show that it is the SF rather than the HBC or the G-loop gate that determines the permeation efficiency upon activation of the channel. SF-permeation is accomplished by a water-K+ coupled mechanism and the entry to the S1 coordination site is likely affected by a SF tilt. Moreover, we show that a 4-K+ occupancy in the SF-HBC cavity is required for the permeation through an open HBC, where three K+ ions around E152 help to abolish the unfavorable cation-dipole interactions that function as an energy barrier, while the fourth K+ located near the HBC allows for the inward transport. These findings facilitate further understanding of the dynamic permeation mechanisms through GIRK2 and potentially provide an alternative regulatory approach for the Kir3 family given the overall high evolutionary residue conservation.
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Affiliation(s)
- Dai-Lin Li
- Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, Xiamen University of Technology, Xiamen 361005, China
| | - Liang Hu
- School of Computer and Information Engineering, Xiamen University of Technology, Xiamen 361005, China
| | - Lei Wang
- Key Laboratory of Environmental Biotechnology (XMUT), Fujian Province University, Xiamen University of Technology, Xiamen 361005, China
| | - Chin-Ling Chen
- School of Computer and Information Engineering, Xiamen University of Technology, Xiamen 361005, China.,School of Information Engineering, Changchun Sci-Tech University, Changchun 130600, China.,Department of Computer Science and Information Engineering, Chaoyang University of Technology, Taichung 41349, Taiwan
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25
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Lu Y, Yang J, Sun J, Lu W, Wang JH. mRNA and miRNA profiles in the nucleus accumbens are associated with psychological stress-induced susceptible and resilient mice. Pharmacol Biochem Behav 2020; 199:173062. [PMID: 33098854 DOI: 10.1016/j.pbb.2020.173062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/15/2020] [Accepted: 10/18/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Stress may be one of the main causes of fear and anxiety. Previous studies have shown that the nucleus accumbens is involved in emotional responses. However, in the nucleus accumbens, the mRNA and miRNA profiles of stress susceptibility and resilience of psychological stress still need to be studied. MATERIALS AND METHODS In this study, by observing the conspecific being attacked, the witness group experienced psychological stress. After five days of psychological stress, the fear memory of mice was measured by social interaction test, and the degree of anxiety was measured by elevated plus maze. mRNA and miRNA profiles in the nucleus accumbens tissue of control, susceptible and resilient mice were established by high-throughput sequencing. RESULTS In susceptible mice versus resilient mice, the Differentially expressed genes (DEGs) may be related to psychological stress-induced susceptibility. DEGs enriched in Cell adhesion molecules, Neuroactive ligand-receptor interaction, Gap junction, PI3K-Akt, VEGF, Jak-STAT, Ras, and Chemokine pathways were up-regulated. DEGs enriched in cGMP-PKG, B cell receptor, and NOD-like receptor pathways were down- regulated. The sequencing results of mRNAs and miRNAs were verified by qRT-PCR and dual luciferase reporter assay. CONCLUSION The imbalance of different synapses and pathways in the nucleus accumbens may be related to susceptibility and resilience caused by psychological stress.
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Affiliation(s)
- Yanjun Lu
- Qingdao University, School of Pharmacy, Qingdao, Shandong 266021, China
| | - Jiuyong Yang
- Qingdao University, School of Pharmacy, Qingdao, Shandong 266021, China
| | - Jinyan Sun
- Qingdao University, School of Pharmacy, Qingdao, Shandong 266021, China
| | - Wei Lu
- Qingdao University, School of Pharmacy, Qingdao, Shandong 266021, China.
| | - Jin-Hui Wang
- Qingdao University, School of Pharmacy, Qingdao, Shandong 266021, China; University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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26
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New Structural insights into Kir channel gating from molecular simulations, HDX-MS and functional studies. Sci Rep 2020; 10:8392. [PMID: 32439887 PMCID: PMC7242327 DOI: 10.1038/s41598-020-65246-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/29/2020] [Indexed: 11/25/2022] Open
Abstract
Inward rectifier potassium (Kir) channels play diverse and important roles in shaping action potentials in biological membranes. An increasing number of diseases are now known to be directly associated with abnormal Kir function. However, the gating of Kir still remains unknown. To increase our understanding of its gating mechanism, a dynamical view of the entire channel is essential. Here the gating activation was studied using a recent developped in silico method, MDeNM, which combines normal mode analysis and molecular dynamics simulations that showed for the very first time the importance of interrelated collective and localized conformational movements. In particular, we highlighted the role played by concerted movements of the different regions throughout the entire protein, such as the cytoplasmic and transmembrane domains and the slide helices. In addition, the HDX-MS analysis achieved in these studies provided a comprehensive and detailed view of the dynamics associated with open/closed transition of the Kir channel in coherence with the theoretical results. MDeNM gives access to the probability of the different opening states that are in agreement with our electrophysiological experiments. The investigations presented in this article are important to remedy dysfunctional channels and are of interest for designing new pharmacological compounds.
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27
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Lamers J, van der Meer T, Testerink C. How Plants Sense and Respond to Stressful Environments. PLANT PHYSIOLOGY 2020; 182:1624-1635. [PMID: 32132112 PMCID: PMC7140927 DOI: 10.1104/pp.19.01464] [Citation(s) in RCA: 196] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/26/2020] [Indexed: 05/18/2023]
Abstract
Plants are exposed to an ever-changing environment to which they have to adjust accordingly. Their response is tightly regulated by complex signaling pathways that all start with stimulus perception. Here, we give an overview of the latest developments in the perception of various abiotic stresses, including drought, salinity, flooding, and temperature stress. We discuss whether proposed perception mechanisms are true sensors, which is well established for some abiotic factors but not yet fully elucidated for others. In addition, we review the downstream cellular responses, many of which are shared by various stresses but result in stress-specific physiological and developmental output. New sensing mechanisms have been identified, including heat sensing by the photoreceptor phytochrome B, salt sensing by glycosylinositol phosphorylceramide sphingolipids, and drought sensing by the specific calcium influx channel OSCA1. The simultaneous occurrence of multiple stress conditions shows characteristic downstream signaling signatures that were previously considered general signaling responses. The integration of sensing of multiple stress conditions and subsequent signaling responses is a promising venue for future research to improve the understanding of plant abiotic stress perception.
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Affiliation(s)
- Jasper Lamers
- Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB, Wageningen, The Netherlands
| | - Tom van der Meer
- Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB, Wageningen, The Netherlands
| | - Christa Testerink
- Laboratory of Plant Physiology, Plant Sciences Group, Wageningen University and Research, 6708PB, Wageningen, The Netherlands
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