101
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Zhuo RG, Liu XY, Zhang SZ, Wei XL, Zheng JQ, Xu JP, Ma XY. Insights into the stimulatory mechanism of 2-aminoethoxydiphenyl borate on TREK-2 potassium channel. Neuroscience 2015; 300:85-93. [PMID: 25982558 DOI: 10.1016/j.neuroscience.2015.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 12/11/2022]
Abstract
2-Aminoethoxydiphenyl borate (2-APB) has been recently identified as a common agonist of TWIK-related K(+) channel (TREK)/TRAAK channels, a subfamily of two-pore domain K(+) (K2P) channels. TREK-2 displays much higher sensitivity to 2-APB compared with TREK-1, despite that these two channels share the highest homology among K2P members. However, the structural basis for their difference in response to 2-APB still remains unknown. Here we identified that the cytosolic C-terminus (Ct) domain plays a dominant role in controlling the stimulatory effects of 2-APB on TREK-2 channel. The distal Ct region negatively regulates the effect of 2-APB, while the proximal Ct is sufficient to evoke the full 2-APB activation of the channel. Further mapping within the proximal Ct revealed that His368 is required for 2-APB activation, and the cooperation of the other non-conserved residues is also necessary. We also identified a secondary active site for 2-APB, which is located at the bottom of the transmembrane segment M2. Finally, we demonstrated that key residues or domains required for 2-APB activation are not involved in the gating mechanism of the selectivity filter. In summary, we reveal a unique modulatory model of TREK-2-Ct that distinguishes it from TREK-1 in high sensitivity to 2-APB. The cooperation of the non-conserved residues within the proximal Ct of TREK-2 plays a dominant role in the 2-APB-induced channel opening, whereas the distal Ct negatively regulates the process.
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Affiliation(s)
- R-G Zhuo
- Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China; State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - X-Y Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - S-Z Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - X-L Wei
- State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - J-Q Zheng
- State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
| | - J-P Xu
- Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
| | - X-Y Ma
- State Key Laboratory of Toxicology and Medical Countermeasures, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
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102
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Battle AR, Ridone P, Bavi N, Nakayama Y, Nikolaev YA, Martinac B. Lipid-protein interactions: Lessons learned from stress. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1744-56. [PMID: 25922225 DOI: 10.1016/j.bbamem.2015.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/13/2015] [Accepted: 04/18/2015] [Indexed: 12/11/2022]
Abstract
Biological membranes are essential for normal function and regulation of cells, forming a physical barrier between extracellular and intracellular space and cellular compartments. These physical barriers are subject to mechanical stresses. As a consequence, nature has developed proteins that are able to transpose mechanical stimuli into meaningful intracellular signals. These proteins, termed Mechanosensitive (MS) proteins provide a variety of roles in response to these stimuli. In prokaryotes these proteins form transmembrane spanning channels that function as osmotically activated nanovalves to prevent cell lysis by hypoosmotic shock. In eukaryotes, the function of MS proteins is more diverse and includes physiological processes such as touch, pain and hearing. The transmembrane portion of these channels is influenced by the physical properties such as charge, shape, thickness and stiffness of the lipid bilayer surrounding it, as well as the bilayer pressure profile. In this review we provide an overview of the progress to date on advances in our understanding of the intimate biophysical and chemical interactions between the lipid bilayer and mechanosensitive membrane channels, focusing on current progress in both eukaryotic and prokaryotic systems. These advances are of importance due to the increasing evidence of the role the MS channels play in disease, such as xerocytosis, muscular dystrophy and cardiac hypertrophy. Moreover, insights gained from lipid-protein interactions of MS channels are likely relevant not only to this class of membrane proteins, but other bilayer embedded proteins as well. This article is part of a Special Issue entitled: Lipid-protein interactions.
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Affiliation(s)
- A R Battle
- Menzies Health Institute Queensland and School of Pharmacy, Griffith University, Gold Coast Campus, QLD 4222, Australia
| | - P Ridone
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - N Bavi
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia
| | - Y Nakayama
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Y A Nikolaev
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia
| | - B Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, Australia.
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103
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Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
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104
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Dong YY, Pike ACW, Mackenzie A, McClenaghan C, Aryal P, Dong L, Quigley A, Grieben M, Goubin S, Mukhopadhyay S, Ruda GF, Clausen MV, Cao L, Brennan PE, Burgess-Brown NA, Sansom MSP, Tucker SJ, Carpenter EP. K2P channel gating mechanisms revealed by structures of TREK-2 and a complex with Prozac. Science 2015; 347:1256-9. [PMID: 25766236 DOI: 10.1126/science.1261512] [Citation(s) in RCA: 240] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
TREK-2 (KCNK10/K2P10), a two-pore domain potassium (K2P) channel, is gated by multiple stimuli such as stretch, fatty acids, and pH and by several drugs. However, the mechanisms that control channel gating are unclear. Here we present crystal structures of the human TREK-2 channel (up to 3.4 angstrom resolution) in two conformations and in complex with norfluoxetine, the active metabolite of fluoxetine (Prozac) and a state-dependent blocker of TREK channels. Norfluoxetine binds within intramembrane fenestrations found in only one of these two conformations. Channel activation by arachidonic acid and mechanical stretch involves conversion between these states through movement of the pore-lining helices. These results provide an explanation for TREK channel mechanosensitivity, regulation by diverse stimuli, and possible off-target effects of the serotonin reuptake inhibitor Prozac.
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Affiliation(s)
- Yin Yao Dong
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Alexandra Mackenzie
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Conor McClenaghan
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK
| | - Prafulla Aryal
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK. Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Liang Dong
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Andrew Quigley
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Mariana Grieben
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Solenne Goubin
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Gian Filippo Ruda
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Michael V Clausen
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Lishuang Cao
- Pfizer Neusentis, Granta Park, Cambridge CB21 6GS, UK
| | - Paul E Brennan
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | | | - Mark S P Sansom
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK. Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Stephen J Tucker
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK.
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK. OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PN, UK.
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