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Staruschenko A, Alexander RT, Caplan MJ, Ilatovskaya DV. Calcium signalling and transport in the kidney. Nat Rev Nephrol 2024; 20:541-555. [PMID: 38641658 DOI: 10.1038/s41581-024-00835-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2024] [Indexed: 04/21/2024]
Abstract
The kidney plays a pivotal role in regulating calcium levels within the body. Approximately 98% of the filtered calcium is reabsorbed in the nephron, and this process is tightly controlled to maintain calcium homeostasis, which is required to facilitate optimal bone mineralization, preserve serum calcium levels within a narrow range, and support intracellular signalling mechanisms. The maintenance of these functions is attributed to a delicate balance achieved by various calcium channels, transporters, and calcium-binding proteins in renal cells. Perturbation of this balance due to deficiency or dysfunction of calcium channels and calcium-binding proteins can lead to severe complications. For example, polycystic kidney disease is linked to aberrant calcium transport and signalling. Furthermore, dysregulation of calcium levels can promote the formation of kidney stones. This Review provides an updated description of the key aspects of calcium handling in the kidney, focusing on the function of various calcium channels and the physiological stimuli that control these channels or are communicated through them. A discussion of the role of calcium as an intracellular second messenger and the pathophysiology of renal calcium dysregulation, as well as a summary of gaps in knowledge and future prospects, are also included.
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Affiliation(s)
- Alexander Staruschenko
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA.
- Hypertension and Kidney Research Center, University of South Florida, Tampa, FL, USA.
- James A. Haley Veterans Hospital, Tampa, FL, USA.
| | - R Todd Alexander
- Department of Paediatrics, University of Alberta, Edmonton, AB, Canada
- Women's and Children's Health Institute, Edmonton, AB, Canada
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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2
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Trofimov YA, Krylov NA, Minakov AS, Nadezhdin KD, Neuberger A, Sobolevsky AI, Efremov RG. Dynamic molecular portraits of ion-conducting pores characterize functional states of TRPV channels. Commun Chem 2024; 7:119. [PMID: 38824263 PMCID: PMC11144267 DOI: 10.1038/s42004-024-01198-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/06/2024] [Indexed: 06/03/2024] Open
Abstract
Structural biology is solving an ever-increasing number of snapshots of ion channel conformational ensembles. Deciphering ion channel mechanisms, however, requires understanding the ensemble dynamics beyond the static structures. Here, we present a molecular modeling-based approach characterizing the ion channel structural intermediates, or their "dynamic molecular portraits", by assessing water and ion conductivity along with the detailed evaluation of pore hydrophobicity and residue packing. We illustrate the power of this approach by analyzing structures of few vanilloid-subfamily transient receptor potential (TRPV) channels. Based on the pore architecture, there are three major states that are common for TRPVs, which we call α-closed, π-closed, and π-open. We show that the pore hydrophobicity and residue packing for the open state is most favorable for the pore conductance. On the contrary, the α-closed state is the most hydrophobic and always non-conducting. Our approach can also be used for structural and functional classification of ion channels.
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Affiliation(s)
- Yury A Trofimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | | | - Kirill D Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Roman G Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
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3
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Yu B, Lu Q, Li J, Cheng X, Hu H, Li Y, Che T, Hua Y, Jiang H, Zhang Y, Xian C, Yang T, Fu Y, Chen Y, Nan W, McCormick PJ, Xiong B, Duan J, Zeng B, Li Y, Fu Y, Zhang J. Cryo-EM structure of human HCN3 channel and its regulation by cAMP. J Biol Chem 2024; 300:107288. [PMID: 38636662 PMCID: PMC11126801 DOI: 10.1016/j.jbc.2024.107288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 03/30/2024] [Accepted: 04/08/2024] [Indexed: 04/20/2024] Open
Abstract
HCN channels are important for regulating heart rhythm and nerve activity and have been studied as potential drug targets for treating depression, arrhythmia, nerve pain, and epilepsy. Despite possessing unique pharmacological properties, HCN channels share common characteristics in that they are activated by hyperpolarization and modulated by cAMP and other membrane lipids. However, the mechanisms of how these ligands bind and modulate HCN channels are unclear. In this study, we solved structures of full-length human HCN3 using cryo-EM and captured two different states, including a state without any ligand bound and a state with cAMP bound. Our structures reveal the novel binding sites for cholesteryl hemisuccinate in apo state and show how cholesteryl hemisuccinate and cAMP binding cause conformational changes in different states. These findings explain how these small modulators are sensed in mammals at the molecular level. The results of our study could help to design more potent and specific compounds to influence HCN channel activity and offer new therapeutic possibilities for diseases that lack effective treatment.
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Affiliation(s)
- Bo Yu
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qiuyuan Lu
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jian Li
- College of Pharmacy, Gannan Medical University, Ganzhou, China
| | - Xinyu Cheng
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Han Hu
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Yuanshuo Li
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Tong Che
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yaoguang Hua
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Haihai Jiang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yuting Zhang
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Cuiling Xian
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Tingting Yang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Ying Fu
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yixiang Chen
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Weiwei Nan
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Peter J McCormick
- William Harvey Research Institute, Bart's and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Bing Xiong
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jingjing Duan
- Human Aging Research Institute (HARI), School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yanyan Li
- Department of Chemical Biology, School of Life Southern University of Science and Technology, Southern University of Science and Technology, Shenzhen, Guangdong, China; Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Jin Zhang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China.
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4
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Mahtani T, Sheth H, Smith LK, Benedict L, Brecier A, Ghasemlou N, Treanor B. The ion channel TRPV5 regulates B-cell signaling and activation. Front Immunol 2024; 15:1386719. [PMID: 38694510 PMCID: PMC11061418 DOI: 10.3389/fimmu.2024.1386719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/28/2024] [Indexed: 05/04/2024] Open
Abstract
Introduction B-cell activation triggers the release of endoplasmic reticulum calcium stores through the store-operated calcium entry (SOCE) pathway resulting in calcium influx by calcium release-activated calcium (CRAC) channels on the plasma membrane. B-cell-specific murine knockouts of SOCE do not impact humoral immunity suggesting that alternative channels may be important. Methods We identified a member of the calcium-permeable transient receptor potential (TRP) ion channel family, TRPV5, as a candidate channel expressed in B cells by a quantitative polymerase chain reaction (qPCR) screen. To further investigate the role of TRPV5 in B-cell responses, we generated a murine TRPV5 knockout (KO) by CRISPR-Cas9. Results We found TRPV5 polarized to B-cell receptor (BCR) clusters upon stimulation in a PI3K-RhoA-dependent manner. TRPV5 KO mice have normal B-cell development and mature B-cell numbers. Surprisingly, calcium influx upon BCR stimulation in primary TRPV5 KO B cells was not impaired; however, differential expression of other calcium-regulating proteins, such as ORAI1, may contribute to a compensatory mechanism for calcium signaling in these cells. We demonstrate that TRPV5 KO B cells have impaired spreading and contraction in response to membrane-bound antigen. Consistent with this, TRPV5 KO B cells have reduced BCR signaling measured through phospho-tyrosine residues. Lastly, we also found that TRPV5 is important for early T-dependent antigen specific responses post-immunization. Discussion Thus, our findings identify a role for TRPV5 in BCR signaling and B-cell activation.
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Affiliation(s)
- Trisha Mahtani
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Hena Sheth
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - L. K. Smith
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Leshawn Benedict
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Aurelie Brecier
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
| | - Nader Ghasemlou
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
| | - Bebhinn Treanor
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Immunology, University of Toronto, Toronto, ON, Canada
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5
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Liu W, Deng W, Hu L, Zou H. Advances in TRPV6 inhibitors for tumors by targeted therapies: Macromolecular proteins, synthetic small molecule compounds, and natural compounds. Eur J Med Chem 2024; 270:116379. [PMID: 38588625 DOI: 10.1016/j.ejmech.2024.116379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/30/2024] [Accepted: 03/31/2024] [Indexed: 04/10/2024]
Abstract
TRPV6, a Ca2+-selective member of the transient receptor potential vanilloid (TRPV) family, plays a key role in extracellular calcium transport, calcium ion reuptake, and maintenance of a local low calcium environment. An increasing number of studies have shown that TRPV6 is involved in the regulation of various diseases. Notably, overexpression of TRPV6 is closely related to the occurrence of various cancers. Research confirmed that knocking down TRPV6 could effectively reduce the proliferation and invasiveness of tumors by mainly mediating the calcium signaling pathway. Hence, TRPV6 has become a promising new drug target for numerous tumor treatments. However, the development of TRPV6 inhibitors is still in the early stage, and the existing TRPV6 inhibitors have poor selectivity and off-target effects. In this review, we focus on summarizing and describing the structure characters, and mechanisms of existing TRPV6 inhibitors to provide new ideas and directions for the development of novel TRPV6 inhibitors.
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Affiliation(s)
- Weikang Liu
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha 410013, China
| | - Wenwen Deng
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha 410013, China
| | - Liqing Hu
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha 410013, China.
| | - Hui Zou
- Key Laboratory of Study and Discovery of Small Targeted Molecules of Hunan Province, School of Medicine, Hunan Normal University, Changsha 410013, China.
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6
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Rohacs T. Phosphoinositide Regulation of TRP Channels: A Functional Overview in the Structural Era. Annu Rev Physiol 2024; 86:329-355. [PMID: 37871124 DOI: 10.1146/annurev-physiol-042022-013956] [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] [Indexed: 10/25/2023]
Abstract
Transient receptor potential (TRP) ion channels have diverse activation mechanisms including physical stimuli, such as high or low temperatures, and a variety of intracellular signaling molecules. Regulation by phosphoinositides and their derivatives is their only known common regulatory feature. For most TRP channels, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] serves as a cofactor required for activity. Such dependence on PI(4,5)P2 has been demonstrated for members of the TRPM subfamily and for the epithelial TRPV5 and TRPV6 channels. Intracellular TRPML channels show specific activation by PI(3,5)P2. Structural studies uncovered the PI(4,5)P2 and PI(3,5)P2 binding sites for these channels and shed light on the mechanism of channel opening. PI(4,5)P2 regulation of TRPV1-4 as well as some TRPC channels is more complex, involving both positive and negative effects. This review discusses the functional roles of phosphoinositides in TRP channel regulation and molecular insights gained from recent cryo-electron microscopy structures.
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Affiliation(s)
- Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey;
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7
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Zhang X, Wang F, Su Y. TRPV: An emerging target in glaucoma and optic nerve damage. Exp Eye Res 2024; 239:109784. [PMID: 38199261 DOI: 10.1016/j.exer.2024.109784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/30/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
Transient receptor potential vanilloid (TRPV) channels are members of the TRP channel superfamily, which are ion channels that sense mechanical and osmotic stimuli and participate in Ca2+ signalling across the cell membrane. TRPV channels play important roles in maintaining the normal functions of an organism, and defects or abnormalities in TRPV channel function cause a range of diseases, including cardiovascular, neurological and urological disorders. Glaucoma is a group of chronic progressive optic nerve diseases with pathological changes that can occur in the tissues of the anterior and posterior segments of the eye, including the ciliary body, trabecular meshwork, Schlemm's canal, and retina. TRPV channels are expressed in these tissues and play various roles in glaucoma. In this article, we review various aspects of the pathogenesis of glaucoma, the structure and function of TRPV channels, the relationship between TRPV channels and systemic diseases, and the relationship between TRPV channels and ocular diseases, especially glaucoma, and we suggest future research directions. This information will help to further our understanding of TRPV channels and provide new ideas and targets for the treatment of glaucoma and optic nerve damage.
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Affiliation(s)
- Xiaotong Zhang
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Feng Wang
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China.
| | - Ying Su
- Eye Hospital, The First Affiliated Hospital, Harbin Medical University, Harbin, China.
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8
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Pumroy RA, De Jesús-Pérez JJ, Protopopova AD, Rocereta JA, Fluck EC, Fricke T, Lee BH, Rohacs T, Leffler A, Moiseenkova-Bell V. Molecular details of ruthenium red pore block in TRPV channels. EMBO Rep 2024; 25:506-523. [PMID: 38225355 PMCID: PMC10897480 DOI: 10.1038/s44319-023-00050-0] [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: 08/24/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/17/2024] Open
Abstract
Transient receptor potential vanilloid (TRPV) channels play a critical role in calcium homeostasis, pain sensation, immunological response, and cancer progression. TRPV channels are blocked by ruthenium red (RR), a universal pore blocker for a wide array of cation channels. Here we use cryo-electron microscopy to reveal the molecular details of RR block in TRPV2 and TRPV5, members of the two TRPV subfamilies. In TRPV2 activated by 2-aminoethoxydiphenyl borate, RR is tightly coordinated in the open selectivity filter, blocking ion flow and preventing channel inactivation. In TRPV5 activated by phosphatidylinositol 4,5-bisphosphate, RR blocks the selectivity filter and closes the lower gate through an interaction with polar residues in the pore vestibule. Together, our results provide a detailed understanding of TRPV subfamily pore block, the dynamic nature of the selectivity filter and allosteric communication between the selectivity filter and lower gate.
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Affiliation(s)
- Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - José J De Jesús-Pérez
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Anna D Protopopova
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Julia A Rocereta
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Tabea Fricke
- Institute for Neurophysiology, Hannover Medical School, 30625, Hannover, Germany
| | - Bo-Hyun Lee
- Department of Physiology and Convergence Medical Science, Institute of Health Sciences, Gyeongsang National University Medical School, Jinju, Korea
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Andreas Leffler
- Institute for Neurophysiology, Hannover Medical School, 30625, Hannover, Germany
| | - Vera Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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9
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De Jesús-Pérez JJ, Gabrielle M, Raheem S, Fluck EC, Rohacs T, Moiseenkova-Bell VY. Structural mechanism of TRPV5 inhibition by econazole. Structure 2024; 32:148-156.e5. [PMID: 38141613 PMCID: PMC10872542 DOI: 10.1016/j.str.2023.11.012] [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: 08/03/2023] [Revised: 11/01/2023] [Accepted: 11/28/2023] [Indexed: 12/25/2023]
Abstract
The calcium-selective TRPV5 channel activated by phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is involved in calcium homeostasis. Recently, cryoelectron microscopy (cryo-EM) provided molecular details of TRPV5 modulation by exogenous and endogenous molecules. However, the details of TRPV5 inhibition by the antifungal agent econazole (ECN) remain elusive due to the low resolution of the currently available structure. In this study, we employ cryo-EM to comprehensively examine how the ECN inhibits TRPV5. By combining our structural findings with site-directed mutagenesis, calcium measurements, electrophysiology, and molecular dynamics simulations, we determined that residues F472 and L475 on the S4 helix, along with residue W495 on the S5 helix, collectively constitute the ECN-binding site. Additionally, the structure of TRPV5 in the presence of ECN and PI(4,5)P2, which does not show the bound activator, reveals a potential inhibition mechanism in which ECN competes with PI(4,5)P2, preventing the latter from binding, and ultimately pore closure.
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Affiliation(s)
- José J De Jesús-Pérez
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew Gabrielle
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Sumiyya Raheem
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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10
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Melancon K, Pliushcheuskaya P, Meiler J, Künze G. Targeting ion channels with ultra-large library screening for hit discovery. Front Mol Neurosci 2024; 16:1336004. [PMID: 38249296 PMCID: PMC10796734 DOI: 10.3389/fnmol.2023.1336004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/23/2024] Open
Abstract
Ion channels play a crucial role in a variety of physiological and pathological processes, making them attractive targets for drug development in diseases such as diabetes, epilepsy, hypertension, cancer, and chronic pain. Despite the importance of ion channels in drug discovery, the vastness of chemical space and the complexity of ion channels pose significant challenges for identifying drug candidates. The use of in silico methods in drug discovery has dramatically reduced the time and cost of drug development and has the potential to revolutionize the field of medicine. Recent advances in computer hardware and software have enabled the screening of ultra-large compound libraries. Integration of different methods at various scales and dimensions is becoming an inevitable trend in drug development. In this review, we provide an overview of current state-of-the-art computational chemistry methodologies for ultra-large compound library screening and their application to ion channel drug discovery research. We discuss the advantages and limitations of various in silico techniques, including virtual screening, molecular mechanics/dynamics simulations, and machine learning-based approaches. We also highlight several successful applications of computational chemistry methodologies in ion channel drug discovery and provide insights into future directions and challenges in this field.
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Affiliation(s)
- Kortney Melancon
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | | | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
- Medical Faculty, Institute for Drug Discovery, Leipzig University, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, Leipzig University, Leipzig, Germany
| | - Georg Künze
- Medical Faculty, Institute for Drug Discovery, Leipzig University, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, Leipzig University, Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany
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11
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Humer C, Radiskovic T, Horváti K, Lindinger S, Groschner K, Romanin C, Höglinger C. Bidirectional Allosteric Coupling between PIP 2 Binding and the Pore of the Oncochannel TRPV6. Int J Mol Sci 2024; 25:618. [PMID: 38203789 PMCID: PMC10779433 DOI: 10.3390/ijms25010618] [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: 12/08/2023] [Revised: 12/31/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
The epithelial ion channel TRPV6 plays a pivotal role in calcium homeostasis. Channel function is intricately regulated at different stages, involving the lipid phosphatidylinositol-4,5-bisphosphate (PIP2). Given that dysregulation of TRPV6 is associated with various diseases, including different types of cancer, there is a compelling need for its pharmacological targeting. Structural studies provide insights on how TRPV6 is affected by different inhibitors, with some binding to sites else occupied by lipids. These include the small molecule cis-22a, which, however, also binds to and thereby blocks the pore. By combining calcium imaging, electrophysiology and optogenetics, we identified residues within the pore and the lipid binding site that are relevant for regulation by cis-22a and PIP2 in a bidirectional manner. Yet, mutation of the cytosolic pore exit reduced inhibition by cis-22a but preserved sensitivity to PIP2 depletion. Our data underscore allosteric communication between the lipid binding site and the pore and vice versa for most sites along the pore.
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Affiliation(s)
- Christina Humer
- Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria; (C.H.); (T.R.); (C.R.)
| | - Tamara Radiskovic
- Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria; (C.H.); (T.R.); (C.R.)
| | - Kata Horváti
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, 1117 Budapest, Hungary;
| | - Sonja Lindinger
- Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria; (C.H.); (T.R.); (C.R.)
| | - Klaus Groschner
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, 8010 Graz, Austria;
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria; (C.H.); (T.R.); (C.R.)
| | - Carmen Höglinger
- Institute of Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria; (C.H.); (T.R.); (C.R.)
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12
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Zou W, Zhang L, Hu Y, Gao Y, Zhang J, Zheng J. The role of TRPV ion channels in adipocyte differentiation: What is the evidence? Cell Biochem Funct 2024; 42:e3933. [PMID: 38269518 DOI: 10.1002/cbf.3933] [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: 07/25/2023] [Revised: 12/27/2023] [Accepted: 01/09/2024] [Indexed: 01/26/2024]
Abstract
Obesity is a complex disorder, and the incidence of obesity continues to rise at an alarming rate worldwide. In particular, the growing incidence of overweight and obesity in children is a major health concern. However, the underlying mechanisms of obesity remain unclear and the efficacy of several approaches for weight loss is limited. As an important calcium-permeable temperature-sensitive cation channel, transient receptor potential vanilloid (TRPV) ion channels directly participate in thermo-, mechano-, and chemosensory responses. Modulation of TRPV ion channel activity can alter the physiological function of the ion channel, leading to neurodegenerative diseases, chronic pain, cancer, and skin disorders. In recent years, increasing studies have demonstrated that TRPV ion channels are abundantly expressed in metabolic organs, including the liver, adipose tissue, skeletal muscle, pancreas, and central nervous system, which has been implicated in various metabolic diseases, including obesity and diabetes mellitus. In addition, as an important process for the pathophysiology of adipocyte metabolism, adipocyte differentiation plays a critical role in obesity. In this review, we focus on the role of TRPV ion channels in adipocyte differentiation to broaden the ideas for prevention and control strategies for obesity.
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Affiliation(s)
- Wenyu Zou
- Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Ling Zhang
- Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Yongyan Hu
- Laboratory Animal Facility, Peking University First Hospital, Beijing, China
| | - Ying Gao
- Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Junqing Zhang
- Department of Endocrinology, Peking University First Hospital, Beijing, China
| | - Jia Zheng
- Department of Endocrinology, Peking University First Hospital, Beijing, China
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13
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Neuberger A, Sobolevsky AI. Molecular pharmacology of the onco-TRP channel TRPV6. Channels (Austin) 2023; 17:2266669. [PMID: 37838981 PMCID: PMC10578198 DOI: 10.1080/19336950.2023.2266669] [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: 07/31/2023] [Accepted: 09/29/2023] [Indexed: 10/17/2023] Open
Abstract
TRPV6, a representative of the vanilloid subfamily of TRP channels, serves as the principal calcium uptake channel in the gut. Dysregulation of TRPV6 results in disturbed calcium homeostasis leading to a variety of human diseases, including many forms of cancer. Inhibitors of this oncochannel are therefore particularly needed. In this review, we provide an overview of recent advances in structural pharmacology that uncovered the molecular mechanisms of TRPV6 inhibition by a variety of small molecules, including synthetic and natural, plant-derived compounds as well as some prospective and clinically approved drugs.
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Affiliation(s)
- Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
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14
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Gu Y, Li Y, Ma B, Ren K, Cao C, Gu N. Probing Conformational Transition of TRPV5 Induced by Mechanical Force Using Coarse-Grained Molecular Dynamics. J Chem Inf Model 2023; 63:6768-6777. [PMID: 37871325 DOI: 10.1021/acs.jcim.3c00614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Transient receptor potential vanilloid 5 (TRPV5) is a calcium-selective TRP channel that plays a crucial role in calcium homeostasis regulation. However, there are still many issues that need to be addressed, such as the specific conformational transition of TRPV5 and the specific functions of each structure in cation gating. Here, we build a model of the calcium ion transport protein from Xenopus oocytes in the presence of the lipid membrane and water molecules. Due to the activation process of ion channels are global and collective, coarse-grained molecular dynamics (CG-MD) simulations of the potential of mean force along the conformational transition pathway are performed. The CG-MD simulations show that the S6 helix plays a vital role in the TRPV5 conformational transition. Most importantly, these simulated trajectories indicate that the activation of ion channels happens before the extension and rotation of S6 helices, revealing that TRPV5 has a unique gating mechanism different from TRPV6. The present work demonstrates how the mechanical force acting on the S6 helix opens the TRPV5 channel gates. These results deepen our understanding of the TRPV5 gating mechanism.
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Affiliation(s)
- Yinwei Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China
| | - Yan Li
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China
| | - Baocai Ma
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China
| | - Ke Ren
- Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, China
| | - Chen Cao
- School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing 211166, China
| | - Ning Gu
- State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210009, China
- Medical School, Nanjing University, Nanjing 210093, China
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15
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Huang J, Chen J. Hydrophobic gating in bundle-crossing ion channels: a case study of TRPV4. Commun Biol 2023; 6:1094. [PMID: 37891195 PMCID: PMC10611814 DOI: 10.1038/s42003-023-05471-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Transmembrane ion channels frequently regulate ion permeation by forming bundle crossing of the pore-lining helices when deactivated. The resulting physical constriction is believed to serve as the de facto gate that imposes the major free energy barrier to ion permeation. Intriguingly, many ion channels also contain highly hydrophobic inner pores enclosed by bundle crossing, which can undergo spontaneous dewetting and give rise to a "vapor barrier" to block ion flow even in the absence of physical constriction. Using atomistic simulations, we show that hydrophobic gating and bundle-crossing mechanisms co-exist and complement one and another in the human TRPV4 channel. In particular, a single hydrophilic mutation in the lower pore can increase pore hydration and reduce the ion permeation free energy barrier by about half without affecting the bundle crossing. We believe that hydrophobic gating may play a key role in other bundle-crossing ion channels with hydrophobic inner pores.
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Affiliation(s)
- Jian Huang
- Department of Chemistry University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Jianhan Chen
- Department of Chemistry University of Massachusetts Amherst, Amherst, MA, 01003, USA.
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16
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Vydra Bousova K, Zouharova M, Jiraskova K, Vetyskova V. Interaction of Calmodulin with TRPM: An Initiator of Channel Modulation. Int J Mol Sci 2023; 24:15162. [PMID: 37894842 PMCID: PMC10607381 DOI: 10.3390/ijms242015162] [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: 08/19/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Transient receptor potential melastatin (TRPM) channels, a subfamily of the TRP superfamily, constitute a diverse group of ion channels involved in mediating crucial cellular processes like calcium homeostasis. These channels exhibit complex regulation, and one of the key regulatory mechanisms involves their interaction with calmodulin (CaM), a cytosol ubiquitous calcium-binding protein. The association between TRPM channels and CaM relies on the presence of specific CaM-binding domains in the channel structure. Upon CaM binding, the channel undergoes direct and/or allosteric structural changes and triggers down- or up-stream signaling pathways. According to current knowledge, ion channel members TRPM2, TRPM3, TRPM4, and TRPM6 are directly modulated by CaM, resulting in their activation or inhibition. This review specifically focuses on the interplay between TRPM channels and CaM and summarizes the current known effects of CaM interactions and modulations on TRPM channels in cellular physiology.
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17
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Lee BH, De Jesús Pérez JJ, Moiseenkova-Bell V, Rohacs T. Structural basis of the activation of TRPV5 channels by long-chain acyl-Coenzyme-A. Nat Commun 2023; 14:5883. [PMID: 37735536 PMCID: PMC10514044 DOI: 10.1038/s41467-023-41577-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 09/10/2023] [Indexed: 09/23/2023] Open
Abstract
Long-chain acyl-coenzyme A (LC-CoA) is a crucial metabolic intermediate that plays important cellular regulatory roles, including activation and inhibition of ion channels. The structural basis of ion channel regulation by LC-CoA is not known. Transient receptor potential vanilloid 5 and 6 (TRPV5 and TRPV6) are epithelial calcium-selective ion channels. Here, we demonstrate that LC-CoA activates TRPV5 and TRPV6 in inside-out patches, and both exogenously supplied and endogenously produced LC-CoA can substitute for the natural ligand phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in maintaining channel activity in intact cells. Utilizing cryo-electron microscopy, we determined the structure of LC-CoA-bound TRPV5, revealing an open configuration with LC-CoA occupying the same binding site as PI(4,5)P2 in previous studies. This is consistent with our finding that PI(4,5)P2 could not further activate the channels in the presence of LC-CoA. Our data provide molecular insights into ion channel regulation by a metabolic signaling molecule.
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Affiliation(s)
- Bo-Hyun Lee
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ, USA
- Department of Physiology, Gyeongsang National University Medical School, Jinju, Korea
| | - José J De Jesús Pérez
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Vera Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ, USA.
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18
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Wang L, Cai R, Chen XZ, Peng JB. Molecular insights into the structural and dynamical changes of calcium channel TRPV6 induced by its interaction with phosphatidylinositol 4,5-bisphosphate. J Biomol Struct Dyn 2023; 41:6559-6568. [PMID: 35950523 PMCID: PMC9918602 DOI: 10.1080/07391102.2022.2109752] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/30/2022] [Indexed: 10/15/2022]
Abstract
Transient receptor potential vanilloid subfamily member 6 (TRPV6) is an epithelial calcium channel that regulates the initial step of the transcellular calcium transport pathway. TRPV6 is expressed in the kidney, intestine, placenta, and other tissues, and the dysregulation of the channel is implicated in several human cancers. It has been reported that phosphatidylinositol 4,5-bisphosphate (PIP2) activates TRPV6 and its close homologue TRPV5; however, the underlying molecular mechanism is less clear. Recently, a structure of rabbit TRPV5 in complex with dioctanoyl (diC8) PIP2, a soluble form of PIP2, was determined by cryo-electron microscopy. Based on this structure, the structural model of human TRPV6 with PIP2 was set up, and then molecular dynamics simulations were performed for TRPV6 with and without PIP2. Simulation results show that the positively charged residues responsible for TRPV5 binding of diC8 PIP2 are conserved in the interactions between TRPV6 and PIP2. The binding of PIP2 to TRPV6 increases the distance between the diagonally opposed residues D542 in the selectivity filter and that between the diagonally opposed M578 residues in the lower gate of TRPV6. A secondary structural analysis reveals that residues M578 in TRPV6 undergo structural and position changes during the binding of PIP2 with TRPV6. In addition, principal component analysis indicates that the binding of PIP2 increases the dynamical motions of both the selectivity filter and the lower gate of TRPV6. These changes induced by PIP2 favor the channel opening. Thus, this study provides a basis for understanding the mechanism underlying the PIP2-induced TRPV6 channel activation.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ruiqi Cai
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7 Edmonton, AB, Canada
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7 Edmonton, AB, Canada
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294
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19
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Szollosi A, Almássy J. Functional characterization of the transient receptor potential melastatin 2 (TRPM2) cation channel from Nematostella vectensis reconstituted into lipid bilayer. Sci Rep 2023; 13:11471. [PMID: 37454209 PMCID: PMC10349829 DOI: 10.1038/s41598-023-38640-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
Transient receptor potential melastatin 2 (TRPM2) cation channel activity is required for insulin secretion, immune cell activation and body heat control. Channel activation upon oxidative stress is involved in the pathology of stroke and neurodegenerative disorders. Cytosolic Ca2+, ADP-ribose (ADPR) and phosphatidylinositol-4,5-bisphosphate (PIP2) are the obligate activators of the channel. Several TRPM2 cryo-EM structures have been resolved to date, yet functionality of the purified protein has not been tested. Here we reconstituted overexpressed and purified TRPM2 from Nematostella vectensis (nvTRPM2) into lipid bilayers and found that the protein is fully functional. Consistent with the observations in native membranes, nvTRPM2 in lipid bilayers is co-activated by cytosolic Ca2+ and either ADPR or ADPR-2'-phosphate (ADPRP). The physiological metabolite ADPRP has a higher apparent affinity than ADPR. In lipid bilayers nvTRPM2 displays a large linear unitary conductance, its open probability (Po) shows little voltage dependence and is stable over several minutes. Po is high without addition of exogenous PIP2, but is largely blunted by treatment with poly-L-Lysine, a polycation that masks PIP2 headgroups. These results indicate that PIP2 or some other activating phosphoinositol lipid co-purifies with nvTRPM2, suggesting a high PIP2 binding affinity of nvTRPM2 under physiological conditions.
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Affiliation(s)
- Andras Szollosi
- Department of Biochemistry, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
- ELKH-SE Ion Channel Research Group, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
- HCEMM-SE Molecular Channelopathies Research Group, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
| | - János Almássy
- Department of Physiology, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary
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20
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Luo ZH, Ma JX, Zhang W, Tian AX, Gong SW, Li Y, Lai YX, Ma XL. Alterations in the microenvironment and the effects produced of TRPV5 in osteoporosis. J Transl Med 2023; 21:327. [PMID: 37198647 DOI: 10.1186/s12967-023-04182-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 05/05/2023] [Indexed: 05/19/2023] Open
Abstract
The pathogenesis of osteoporosis involves multiple factors, among which alterations in the bone microenvironment play a crucial role in disrupting normal bone metabolic balance. Transient receptor potential vanilloid 5 (TRPV5), a member of the TRPV family, is an essential determinant of the bone microenvironment, acting at multiple levels to influence its properties. TRPV5 exerts a pivotal influence on bone through the regulation of calcium reabsorption and transportation while also responding to steroid hormones and agonists. Although the metabolic consequences of osteoporosis, such as loss of bone calcium, reduced mineralization capacity, and active osteoclasts, have received significant attention, this review focuses on the changes in the osteoporotic microenvironment and the specific effects of TRPV5 at various levels.
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Affiliation(s)
- Zhi-Heng Luo
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Jian-Xiong Ma
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Wei Zhang
- Centre for Translational Medicine Research & Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xue Yuan Avenue, Shenzhen University Town, Shenzhen, 518055, Guangdong, People's Republic of China
| | - Ai-Xian Tian
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Shu-Wei Gong
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Yan Li
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China
| | - Yu-Xiao Lai
- Centre for Translational Medicine Research & Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xue Yuan Avenue, Shenzhen University Town, Shenzhen, 518055, Guangdong, People's Republic of China.
| | - Xin-Long Ma
- Tianjin Hospital, Tianjin University, Jie Fang Nan Road 406, Tianjin, 300211, People's Republic of China.
- Tianjin Key Laboratory of Orthopedic Biomechanics and Medical Engineering, Tianjin Hospital, Tianjin, 300050, People's Republic of China.
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21
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Won J, Kim J, Jeong H, Kim J, Feng S, Jeong B, Kwak M, Ko J, Im W, So I, Lee HH. Molecular architecture of the Gα i-bound TRPC5 ion channel. Nat Commun 2023; 14:2550. [PMID: 37137991 PMCID: PMC10156788 DOI: 10.1038/s41467-023-38281-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/21/2023] [Indexed: 05/05/2023] Open
Abstract
G-protein coupled receptors (GPCRs) and ion channels serve as key molecular switches through which extracellular stimuli are transformed into intracellular effects, and it has long been postulated that ion channels are direct effector molecules of the alpha subunit of G-proteins (Gα). However, no complete structural evidence supporting the direct interaction between Gα and ion channels is available. Here, we present the cryo-electron microscopy structures of the human transient receptor potential canonical 5 (TRPC5)-Gαi3 complexes with a 4:4 stoichiometry in lipid nanodiscs. Remarkably, Gαi3 binds to the ankyrin repeat edge of TRPC5 ~ 50 Å away from the cell membrane. Electrophysiological analysis shows that Gαi3 increases the sensitivity of TRPC5 to phosphatidylinositol 4,5-bisphosphate (PIP2), thereby rendering TRPC5 more easily opened in the cell membrane, where the concentration of PIP2 is physiologically regulated. Our results demonstrate that ion channels are one of the direct effector molecules of Gα proteins triggered by GPCR activation-providing a structural framework for unraveling the crosstalk between two major classes of transmembrane proteins: GPCRs and ion channels.
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Affiliation(s)
- Jongdae Won
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jinsung Kim
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea
| | - Hyeongseop Jeong
- Center for Research Equipment, Korea Basic Science Institute, Chungcheongbuk-do, 28119, Republic of Korea
| | - Jinhyeong Kim
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea
| | - Shasha Feng
- Department of Biological Sciences and Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Byeongseok Jeong
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea
| | - Misun Kwak
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea
| | - Juyeon Ko
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea
- Department of Physiology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Wonpil Im
- Department of Biological Sciences and Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Insuk So
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 03080, Republic of Korea.
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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22
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Ives CM, Thomson NJ, Zachariae U. A cooperative knock-on mechanism underpins Ca2+-selective cation permeation in TRPV channels. J Gen Physiol 2023; 155:213957. [PMID: 36943243 PMCID: PMC10038842 DOI: 10.1085/jgp.202213226] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 11/15/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
The selective exchange of ions across cellular membranes is a vital biological process. Ca2+-mediated signaling is implicated in a broad array of physiological processes in cells, while elevated intracellular concentrations of Ca2+ are cytotoxic. Due to the significance of this cation, strict Ca2+ concentration gradients are maintained across the plasma and organelle membranes. Therefore, Ca2+ signaling relies on permeation through selective ion channels that control the flux of Ca2+ ions. A key family of Ca2+-permeable membrane channels is the polymodal signal-detecting transient receptor potential (TRP) ion channels. TRP channels are activated by a wide variety of cues including temperature, small molecules, transmembrane voltage, and mechanical stimuli. While most members of this family permeate a broad range of cations non-selectively, TRPV5 and TRPV6 are unique due to their strong Ca2+ selectivity. Here, we address the question of how some members of the TRPV subfamily show a high degree of Ca2+ selectivity while others conduct a wider spectrum of cations. We present results from all-atom molecular dynamics simulations of ion permeation through two Ca2+-selective and two non-selective TRPV channels. Using a new method to quantify permeation cooperativity based on mutual information, we show that Ca2+-selective TRPV channel permeation occurs by a three-binding site knock-on mechanism, whereas a two-binding site knock-on mechanism is observed in non-selective TRPV channels. Each of the ion binding sites involved displayed greater affinity for Ca2+ over Na+. As such, our results suggest that coupling to an extra binding site in the Ca2+-selective TRPV channels underpins their increased selectivity for Ca2+ over Na+ ions. Furthermore, analysis of all available TRPV channel structures shows that the selectivity filter entrance region is wider for the non-selective TRPV channels, slightly destabilizing ion binding at this site, which is likely to underlie mechanistic decoupling.
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Affiliation(s)
- Callum M Ives
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
| | - Neil J Thomson
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
- Biochemistry and Drug Discovery, School of Life Sciences, University of Dundee , Dundee, UK
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23
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Liu X, Wang Y, Weng Z, Xu Q, Zhou C, Tang J, Chen XZ. Inhibition of TRPP3 by calmodulin through Ca 2+/calmodulin-dependent protein kinase II. CELL INSIGHT 2023; 2:100088. [PMID: 37193065 PMCID: PMC10134200 DOI: 10.1016/j.cellin.2023.100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 05/18/2023]
Abstract
Transient receptor potential (TRP) polycystin-3 (TRPP3) is a non-selective cation channel activated by Ca2+ and protons and is involved in regulating ciliary Ca2+ concentration, hedgehog signaling and sour tasting. The TRPP3 channel function and regulation are still not well understood. Here we investigated regulation of TRPP3 by calmodulin (CaM) by means of electrophysiology and Xenopus oocytes as an expression model. We found that TRPP3 channel function is enhanced by calmidazolium, a CaM antagonist, and inhibited by CaM through binding of the CaM N-lobe to a TRPP3 C-terminal domain not overlapped with the EF-hand. We further revealed that the TRPP3/CaM interaction promotes phosphorylation of TRPP3 at threonine 591 by Ca2+/CaM-dependent protein kinase II, which mediates the inhibition of TRPP3 by CaM.
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Affiliation(s)
- Xiong Liu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
| | - Yifang Wang
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Ziyi Weng
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Qinyi Xu
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
| | - Cefan Zhou
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - JingFeng Tang
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, T6G 2H7, Edmonton, AB, Canada
- National “111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, Hubei, 430068, China
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Intracellular Helix-Loop-Helix Domain Modulates Inactivation Kinetics of Mammalian TRPV5 and TRPV6 Channels. Int J Mol Sci 2023; 24:ijms24054470. [PMID: 36901904 PMCID: PMC10003196 DOI: 10.3390/ijms24054470] [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: 11/17/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 03/12/2023] Open
Abstract
TRPV5 and TRPV6 are calcium-selective ion channels expressed at the apical membrane of epithelial cells. Important for systemic calcium (Ca2+) homeostasis, these channels are considered gatekeepers of this cation transcellular transport. Intracellular Ca2+ exerts a negative control over the activity of these channels by promoting inactivation. TRPV5 and TRPV6 inactivation has been divided into fast and slow phases based on their kinetics. While slow inactivation is common to both channels, fast inactivation is characteristic of TRPV6. It has been proposed that the fast phase depends on Ca2+ binding and that the slow phase depends on the binding of the Ca2+/Calmodulin complex to the internal gate of the channels. Here, by means of structural analyses, site-directed mutagenesis, electrophysiology, and molecular dynamic simulations, we identified a specific set of amino acids and interactions that determine the inactivation kinetics of mammalian TRPV5 and TRPV6 channels. We propose that the association between the intracellular helix-loop-helix (HLH) domain and the TRP domain helix (TDh) favors the faster inactivation kinetics observed in mammalian TRPV6 channels.
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Abstract
The ability to detect stimuli from the environment plays a pivotal role in our survival. The molecules that allow the detection of such signals include ion channels, which are proteins expressed in different cells and organs. Among these ion channels, the transient receptor potential (TRP) family responds to the presence of diverse chemicals, temperature, and osmotic changes, among others. This family of ion channels includes the TRPV or vanilloid subfamily whose members serve several physiological functions. Although these proteins have been studied intensively for the last two decades, owing to their structural and functional complexities, a number of controversies regarding their function still remain. Here, we discuss some salient features of their regulation in light of these controversies and outline some of the efforts pushing the field forward.
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Affiliation(s)
- Tamara Rosenbaum
- Department of Cognitive Neuroscience, Neuroscience Division, Institute for Cellular Physiology, National Autonomous University of Mexico, Coyoacán, México;
| | - León D Islas
- Department of Physiology, School of Medicine, National Autonomous University of Mexico, Coyoacán, México
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26
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Zuidscherwoude M, van Goor MK, Roig SR, Thijssen N, van Erp M, Fransen J, van der Wijst J, Hoenderop JG. Functional basis for calmodulation of the TRPV5 calcium channel. J Physiol 2023; 601:859-878. [PMID: 36566502 DOI: 10.1113/jp282952] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/06/2022] [Indexed: 12/26/2022] Open
Abstract
Within the transient receptor potential (TRP) superfamily of ion channels, TRPV5 is a highly Ca2+ -selective channel important for active reabsorption of Ca2+ in the kidney. Its channel activity is controlled by a negative feedback mechanism involving calmodulin (CaM) binding. Combining advanced microscopy techniques and biochemical assays, this study characterized the dynamic lobe-specific CaM regulation. We demonstrate for the first time that functional (full-length) TRPV5 interacts with CaM in the absence of Ca2+ , and this interaction is intensified at increasing Ca2+ concentrations sensed by the CaM C-lobe that achieves channel pore blocking. Channel inactivation occurs without requiring CaM N-lobe calcification. Moreover, we show a Ca2+ -dependent binding stoichiometry at the single channel level. In conclusion, our study proposes a new model for CaM-dependent regulation - calmodulation - of this uniquely Ca2+ -selective TRP channel TRPV5 that involves apoCaM interaction and lobe-specific actions, which may be of significant physiological relevance given its role as gatekeeper of Ca2+ transport in the kidney. KEY POINTS: The renal Ca2+ channel TRPV5 is an important player in maintenance of the body's Ca2+ homeostasis. Activity of TRPV5 is controlled by a negative feedback loop that involves calmodulin (CaM), a protein with two Ca2+ -binding lobes. We investigated the dynamics of the interaction between TRPV5 and CaM with advanced fluorescence microscopy techniques. Our data support a new model for CaM-dependent regulation of TRPV5 channel activity with CaM lobe-specific actions and demonstrates Ca2+ -dependent binding stoichiometries. This study improves our understanding of the mechanism underlying fast channel inactivation, which is physiologically relevant given the gatekeeper function of TRPV5 in Ca2+ reabsorption in the kidney.
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Affiliation(s)
- Malou Zuidscherwoude
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mark K van Goor
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sara R Roig
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Imaging Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Niky Thijssen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Merijn van Erp
- Radboudumc Technology Centre Microscopy, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jack Fransen
- Radboudumc Technology Centre Microscopy, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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27
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Rosenbaum T, Morales-Lázaro SL. Regulation of ThermoTRP Channels by PIP2 and Cholesterol. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:245-277. [PMID: 36988884 DOI: 10.1007/978-3-031-21547-6_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Transient receptor potential (TRP) ion channels are proteins that are expressed by diverse tissues and that play pivotal functions in physiology. These channels are polymodal and are activated by several stimuli. Among TRPs, some members of this family of channels respond to changes in ambient temperature and are known as thermoTRPs. These proteins respond to heat or cold in the noxious range and some of them to temperatures considered innocuous, as well as to mechanical, osmotic, and/or chemical stimuli. In addition to this already complex ability to respond to different signals, the activity of these ion channels can be fine-tuned by lipids. Two lipids well known to modulate ion channel activity are phosphatidylinositol 4,5-bisphosphate (PIP2) and cholesterol. These lipids can either influence the function of these proteins through direct interaction by binding to a site in the structure of the ion channel or through indirect mechanisms, which can include modifying membrane properties, such as curvature and rigidity, by regulating their expression or by modulating the actions of other molecules or signaling pathways that affect the physiology of ion channels. Here, we summarize the key aspects of the regulation of thermoTRP channels by PIP2 and cholesterol.
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Affiliation(s)
- Tamara Rosenbaum
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Sara L Morales-Lázaro
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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28
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Arreola J, López-Romero AE, Pérez-Cornejo P, Rodríguez-Menchaca AA. Phosphatidylinositol 4,5-Bisphosphate and Cholesterol Regulators of the Calcium-Activated Chloride Channels TMEM16A and TMEM16B. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:279-304. [PMID: 36988885 DOI: 10.1007/978-3-031-21547-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Chloride fluxes through homo-dimeric calcium-activated channels TMEM16A and TMEM16B are critical to blood pressure, gastrointestinal motility, hormone, fluid and electrolyte secretion, pain sensation, sensory transduction, and neuronal and muscle excitability. Their gating depends on the voltage-dependent binding of two intracellular calcium ions to a high-affinity site formed by acidic residues from α-helices 6-8 in each monomer. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a low-abundant lipid of the inner leaflet, supports TMEM16A function; it allows TMEM16A to evade the down-regulation induced by calcium, poly-L-lysine, or PI(4,5)P2 5-phosphatase. In stark contrast, adding or removing PI(4,5)P2 diminishes or increases TMEM16B function, respectively. PI(4,5)P2-binding sites on TMEM16A, and presumably on TMEM16B, are on the cytosolic side of α-helices 3-5, opposite the calcium-binding sites. This modular structure suggested that PI(4,5)P2 and calcium cooperate to maintain the conductive state in TMEM16A. Cholesterol, the second-largest constituent of the plasma membrane, also regulates TMEM16A though the mechanism, functional outcomes, binding site(s), and effects on TMEM16A and TMEM16B remain unknown.
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Affiliation(s)
- Jorge Arreola
- Physics Institute, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico.
| | | | - Patricia Pérez-Cornejo
- Department of Physiology and Biophysics, School of Medicine, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Aldo A Rodríguez-Menchaca
- Department of Physiology and Biophysics, School of Medicine, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
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29
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Fan J, Hu L, Yue Z, Liao D, Guo F, Ke H, Jiang D, Yang Y, Lei X. Structural basis of TRPV3 inhibition by an antagonist. Nat Chem Biol 2023; 19:81-90. [PMID: 36302896 DOI: 10.1038/s41589-022-01166-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 09/08/2022] [Indexed: 12/31/2022]
Abstract
The TRPV3 channel plays vital roles in skin physiology. Dysfunction of TRPV3 causes skin diseases, including Olmsted syndrome. However, the lack of potent and selective inhibitors impedes the validation of TRPV3 as a therapeutic target. In this study, we identified Trpvicin as a potent and subtype-selective inhibitor of TRPV3. Trpvicin exhibits pharmacological potential in the inhibition of itch and hair loss in mouse models. Cryogenic electron microscopy structures of TRPV3 and the pathogenic G573S mutant complexed with Trpvicin reveal detailed ligand-binding sites, suggesting that Trpvicin inhibits the TRPV3 channel by stabilizing it in a closed state. Our G573S mutant structures demonstrate that the mutation causes a dilated pore, generating constitutive opening activity. Trpvicin accesses additional binding sites inside the central cavity of the G573S mutant to remodel the channel symmetry and block the channel. Together, our results provide mechanistic insights into the inhibition of TRPV3 by Trpvicin and support TRPV3-related drug development.
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Affiliation(s)
- Junping Fan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Linghan Hu
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - Zongwei Yue
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | | | - Fusheng Guo
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Han Ke
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Daohua Jiang
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
| | - Yong Yang
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.
| | - Xiaoguang Lei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
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30
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Feng S, Pumroy RA, Protopopova AD, Moiseenkova‐Bell VY, Im W. Modulation of TRPV2 by endogenous and exogenous ligands: A computational study. Protein Sci 2023; 32:e4490. [PMID: 36327382 PMCID: PMC9794027 DOI: 10.1002/pro.4490] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/17/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Transient receptor potential vanilloid (TRPV) channels play various important roles in human physiology. As membrane proteins, these channels are modulated by their endogenous lipid environment as the recent wealth of structural studies has revealed functional and structural lipid binding sites. Additionally, it has been shown that exogenous ligands can exchange with some of these lipids to alter channel gating. Here, we used molecular dynamics simulations to examine how one member of the TRPV family, TRPV2, interacts with endogenous lipids and the pharmacological modulator cannabidiol (CBD). By computationally reconstituting TRPV2 into a typical plasma membrane environment, which includes phospholipids, cholesterol, and phosphatidylinositol (PIP) in the inner leaflet, we showed that most of the interacting surface lipids are phospholipids without strong specificity for headgroup types. Intriguingly, we observed that the C-terminal membrane proximal region of the channel binds preferentially to PIP lipids. We also modelled two structural lipids in the simulation: one in the vanilloid pocket and the other in the voltage sensor-like domain (VSLD) pocket. The simulation shows that the VSLD lipid dampens the fluctuation of the VSLD residues, while the vanilloid lipid exhibits heterogeneity both in its binding pose and in its influence on protein dynamics. Addition of CBD to our simulation system led to an open selectivity filter and a structural rearrangement that includes a clockwise rotation of the ankyrin repeat domains, TRP helix, and VSLD. Together, these results reveal the interplay between endogenous lipids and an exogenous ligand and their effect on TRPV2 stability and channel gating.
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Affiliation(s)
- Shasha Feng
- Departments of Biological SciencesLehigh UniversityBethlehemPennsylvaniaUSA
| | - Ruth A. Pumroy
- Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Anna D. Protopopova
- Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | | | - Wonpil Im
- Departments of Biological SciencesLehigh UniversityBethlehemPennsylvaniaUSA
- Department of ChemistryLehigh UniversityBethlehemPennsylvaniaUSA
- Department of BioengineeringLehigh UniversityBethlehemPennsylvaniaUSA
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31
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Walker V, Vuister GW. Biochemistry and pathophysiology of the Transient Potential Receptor Vanilloid 6 (TRPV6) calcium channel. Adv Clin Chem 2023; 113:43-100. [PMID: 36858649 DOI: 10.1016/bs.acc.2022.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
TRPV6 is a Transient Receptor Potential Vanilloid (TRPV) cation channel with high selectivity for Ca2+ ions. First identified in 1999 in a search for the gene which mediates intestinal Ca2+ absorption, its far more extensive repertoire as a guardian of intracellular Ca2+ has since become apparent. Studies on TRPV6-deficient mice demonstrated additional important roles in placental Ca2+ transport, fetal bone development and male fertility. The first reports of inherited deficiency in newborn babies appeared in 2018, revealing its physiological importance in humans. There is currently strong evidence that TRPV6 also contributes to the pathogenesis of some common cancers. The recently reported association of TRPV6 deficiency with non-alcoholic chronic pancreatitis suggests a role in normal pancreatic function. Over time and with greater awareness of TRPV6, other disease-associations are likely to emerge. Powerful analytical tools have provided invaluable insights into the structure and operation of TRPV6. Its roles in Ca2+ signaling and carcinogenesis, and the use of channel inhibitors in cancer treatment are being intensively investigated. This review first briefly describes the biochemistry and physiology of the channel, and analytical methods used to investigate these. The focus subsequently shifts to the clinical disorders associated with abnormal expression and the underlying pathophysiology. The aims of this review are to increase awareness of this channel, and to draw together findings from a wide range of sources which may help to formulate new ideas for further studies.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, United Kingdom.
| | - Geerten W Vuister
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom
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32
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Schmidpeter PAM, Wu D, Rheinberger J, Riegelhaupt PM, Tang H, Robinson CV, Nimigean CM. Anionic lipids unlock the gates of select ion channels in the pacemaker family. Nat Struct Mol Biol 2022; 29:1092-1100. [PMID: 36352139 PMCID: PMC10022520 DOI: 10.1038/s41594-022-00851-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 09/25/2022] [Indexed: 11/11/2022]
Abstract
Lipids play important roles in regulating membrane protein function, but the molecular mechanisms used are elusive. Here we investigated how anionic lipids modulate SthK, a bacterial pacemaker channel homolog, and HCN2, whose activity contributes to pacemaking in the heart and brain. Using SthK allowed the reconstitution of purified channels in controlled lipid compositions for functional and structural assays that are not available for the eukaryotic channels. We identified anionic lipids bound tightly to SthK and their exact binding locations and determined that they potentiate channel activity. Cryo-EM structures in the most potentiating lipids revealed an open state and identified a nonannular lipid bound with its headgroup near an intersubunit salt bridge that clamps the intracellular channel gate shut. Breaking this conserved salt bridge abolished lipid modulation in SthK and eukaryotic HCN2 channels, indicating that anionic membrane lipids facilitate channel opening by destabilizing these interactions. Our findings underline the importance of state-dependent protein-lipid interactions.
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Affiliation(s)
| | - Di Wu
- Department of Chemistry, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Jan Rheinberger
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
- Department of Structural Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | | | - Haiping Tang
- Department of Chemistry, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA.
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33
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Zhao S, Carnevale V, Gabrielle M, Gianti E, Rohacs T. Computational and functional studies of the PI(4,5)P 2 binding site of the TRPM3 ion channel reveal interactions with other regulators. J Biol Chem 2022; 298:102547. [PMID: 36181791 DOI: 10.1016/j.jbc.2022.102547] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/23/2022] [Accepted: 09/24/2022] [Indexed: 10/14/2022] Open
Abstract
Transient Receptor Potential Melastatin 3 (TRPM3) is a heat-activated ion channel expressed in peripheral sensory neurons and the central nervous system. TRPM3 activity depends on the membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but the molecular mechanism of activation by PI(4,5)P2 is not known. As no experimental structure of TRPM3 is available, we built a homology model of the channel in complex with PI(4,5)P2via molecular modeling. We identified putative contact residues for PI(4,5)P2 in the pre-S1 segment, the S4-S5 linker, and the proximal C-terminal TRP-domain. Mutating these residues increased sensitivity to inhibition of TRPM3 by decreasing PI(4,5)P2 levels. Changes in ligand-binding affinities via Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) showed reduced PI(4,5)P2 affinity for the mutants. Mutating PI(4,5)P2 interacting residues also reduced sensitivity for activation by the endogenous ligand pregnenolone sulfate (PregS), pointing to an allosteric interaction between PI(4,5)P2 and PregS. Similarly, mutating residues in the PI(4,5)P2 binding site in TRPM8 resulted in increased sensitivity to PI(4,5)P2 depletion, and reduced sensitivity to menthol. Mutations of most PI(4,5)P2-interacting residues in TRPM3 also increased sensitivity to inhibition by Gβγ, indicating allosteric interaction between Gβγ and PI(4,5)P2. Disease-associated gain-of-function TRPM3 mutations on the other hand, resulted in no change of PI(4,5)P2 sensitivity, indicating that mutations did not increase channel activity via increasing PI(4,5)P2 interactions. Our data provide insight into the mechanism of regulation of TRPM3 by PI(4,5)P2, its relationship to endogenous activators and inhibitors, as well as identify similarities and differences between PI(4,5)P2 regulation of TRPM3 and TRPM8.
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Affiliation(s)
- Siyuan Zhao
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ 07103
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, Temple University, Philadelphia, PA 19122; Department of Biology, Temple University, Philadelphia, PA 19122
| | - Matthew Gabrielle
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ 07103
| | - Eleonora Gianti
- Institute for Computational Molecular Science, Temple University, Philadelphia, PA 19122; Department of Chemistry, Temple University, Philadelphia, PA 19122.
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ 07103.
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34
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Rohacs T, Fluck EC, De Jesús-Pérez JJ, Moiseenkova-Bell VY. What structures did, and did not, reveal about the function of the epithelial Ca 2+ channels TRPV5 and TRPV6. Cell Calcium 2022; 106:102620. [PMID: 35834842 DOI: 10.1016/j.ceca.2022.102620] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 12/15/2022]
Abstract
Transient Receptor Potential Vanilloid 5 and 6 (TRPV5 and TRPV6) are Ca2+ selective epithelial ion channels. They are the products of a relatively recent gene duplication in mammals, and have high sequence homology to each other. Their functional properties are also much more similar to each other than to other members of the TRPV subfamily. They are both constitutively active, and this activity depends on the endogenous cofactor phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Both channels undergo Ca2+-induced inactivation, which is mediated by direct binding of the ubiquitous Ca2+ binding protein calmodulin (CaM) to the channels, and by a decrease in PI(4,5)P2 levels by Ca2+ -induced activation of phospholipase C (PLC). Recent cryo electron microscopy (cryo-EM) and X-ray crystallography structures provided detailed structural information for both TRPV5 and TRPV6. This review will discuss this structural information in the context of the function of these channels focusing on the mechanism of CaM inhibition, activation by PI(4,5)P2 and binding of pharmacological modulators.
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Affiliation(s)
- Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103, USA.
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - José J De Jesús-Pérez
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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35
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Rangel-Galván M, Castro ME, Perez-Aguilar JM, Caballero NA, Melendez FJ. Conceptual DFT, QTAIM, and Molecular Docking Approaches to Characterize the T-Type Calcium Channel Blocker Anandamide. Front Chem 2022; 10:920661. [PMID: 35910732 PMCID: PMC9329692 DOI: 10.3389/fchem.2022.920661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The anandamide is a relevant ligand due to its capacity of interacting with several proteins, including the T-type calcium channels, which play an important role in neuropathic pain and depression disorders. Hence, a detailed characterization of the chemical properties and conformational stability of anandamide may provide valuable information to understand its behavior in a biological context. Herein, conceptual DFT and QTAIM analyses were performed to theoretically characterize the chemical reactivity properties and the structural stability of conformations of anandamide, using the BP86/cc-pVTZ level of theory. Global reactivity description, based on conceptual DFT, indicates that the hardness increases and the electrophilicity index decreases for both, the hairpin and U-shape conformers relative to the extended conformers. Also, an increase in the chemical potential value and a decrease in the electronegativity and the electrophilicity index is observed in the ethanolamide open ring conformers in comparison with the corresponding closed ring structures. In addition, regarding the characterization of local reactivity descriptors, the maximum values of the Fukui and Parr functions indicate that the most probable location for a nucleophilic attack is either the hydroxyl oxygen located in the ethanolamide closed ring conformers or the carbonyl oxygen present in the open ring conformers. The most probable location for an electrophilic attack is in the alkyl double bond region in all anandamide conformers. According to the QTAIM results, the intramolecular hydrogen bond formation stabilizing the structure of anandamide has interaction energy values for the closed ring conformations of 12.33–12.46 kcal mol−1, indicating a strong interaction. Lastly, molecular docking calculations determined that a region in the pore, denominate as pore-blocking, is a probable site for the interaction of anandamide with the human Cav3.2 isoform of the T-type calcium channel family. The pore-blocking site contains hydrophobic residues where the non-polar part in the final alkyl region of anandamide established mainly alkyl-alkyl interactions, while the polar part (the ethanolamide group) interacts with the polar residue S900. The information based on conceptual DFT presented may aid in the design of drugs with similar chemical characteristics as those identified in anandamide so as to bind anandamide-interacting proteins, including the T-type calcium channels.
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Affiliation(s)
- Maricruz Rangel-Galván
- Lab. de Química Teórica, Centro de Investigación, Depto. de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - María Eugenia Castro
- Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- *Correspondence: María Eugenia Castro, ; Francisco J. Melendez,
| | - Jose Manuel Perez-Aguilar
- Lab. de Química Teórica, Centro de Investigación, Depto. de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Norma A. Caballero
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Francisco J. Melendez
- Lab. de Química Teórica, Centro de Investigación, Depto. de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- *Correspondence: María Eugenia Castro, ; Francisco J. Melendez,
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36
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Cabezas-Bratesco D, Mcgee FA, Colenso CK, Zavala K, Granata D, Carnevale V, Opazo JC, Brauchi SE. Sequence and structural conservation reveal fingerprint residues in TRP channels. eLife 2022; 11:73645. [PMID: 35686986 PMCID: PMC9242649 DOI: 10.7554/elife.73645] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
Transient receptor potential (TRP) proteins are a large family of cation-selective channels, surpassed in variety only by voltage-gated potassium channels. Detailed molecular mechanisms governing how membrane voltage, ligand binding, or temperature can induce conformational changes promoting the open state in TRP channels are still a matter of debate. Aiming to unveil distinctive structural features common to the transmembrane domains within the TRP family, we performed phylogenetic reconstruction, sequence statistics, and structural analysis over a large set of TRP channel genes. Here, we report an exceptionally conserved set of residues. This fingerprint is composed of twelve residues localized at equivalent three-dimensional positions in TRP channels from the different subtypes. Moreover, these amino acids are arranged in three groups, connected by a set of aromatics located at the core of the transmembrane structure. We hypothesize that differences in the connectivity between these different groups of residues harbor the apparent differences in coupling strategies used by TRP subgroups.
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Affiliation(s)
| | - Francisco A Mcgee
- Department of Biology, Temple University, Philadelphia, United States
| | - Charlotte K Colenso
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Kattina Zavala
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Daniele Granata
- Department of Biology, Temple University, Philadelphia, United States
| | | | - Juan C Opazo
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
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37
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TRPV6 Regulation by Cis-22a and Cholesterol. Biomolecules 2022; 12:biom12060804. [PMID: 35740929 PMCID: PMC9221249 DOI: 10.3390/biom12060804] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/03/2022] [Accepted: 06/05/2022] [Indexed: 02/04/2023] Open
Abstract
The highly calcium-selective transient receptor potential vanilloid-type channel TRPV6 is important for epithelial Ca2+ transport. Proper regulation of the inherently constitutively active TRPV6 channels is intricate in preserving Ca2+ homeostasis, whereby structural and functional data suggest that lipids hold an essential role. Altered expression levels or specific TRPV6 mutations may lead to diseases, hence, TRPV6 represents an interesting target for pharmacological modulation. Recent cryo-EM data identified that the specific TRPV6 blocker cis-22a binds, apart from the pore, to a site within the tetrameric channel that largely matches a lipid binding pocket, LBS-2. Therein, cis-22a may replace a lipid such as cholesterol that is bound in the open state. Based on site-directed mutagenesis and functional recordings, we identified and characterized a series of residues within LBS-2 that are essential for TRPV6 inhibition by cis-22a. Additionally, we investigated the modulatory potential of diverse cholesterol depletion efforts on TRPV6 activity. While LBS-2 mutants exhibited altered maximum currents, slow Ca2+-dependent inactivation (SCDI) as well as less inhibition by cis-22a, TRPV6 activity was resistant to cholesterol depletion. Hence, lipids other than cholesterol may predominate TRPV6 regulation when the channel is expressed in HEK293 cells.
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38
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Yelshanskaya MV, Sobolevsky AI. Ligand-Binding Sites in Vanilloid-Subtype TRP Channels. Front Pharmacol 2022; 13:900623. [PMID: 35652046 PMCID: PMC9149226 DOI: 10.3389/fphar.2022.900623] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/06/2022] [Indexed: 02/02/2023] Open
Abstract
Vanilloid-subfamily TRP channels TRPV1-6 play important roles in various physiological processes and are implicated in numerous human diseases. Advances in structural biology, particularly the "resolution revolution" in cryo-EM, have led to breakthroughs in molecular characterization of TRPV channels. Structures with continuously improving resolution uncover atomic details of TRPV channel interactions with small molecules and protein-binding partners. Here, we provide a classification of structurally characterized binding sites in TRPV channels and discuss the progress that has been made by structural biology combined with mutagenesis, functional recordings, and molecular dynamics simulations toward understanding of the molecular mechanisms of ligand action. Given the similarity in structural architecture of TRP channels, 16 unique sites identified in TRPV channels may be shared between TRP channel subfamilies, although the chemical identity of a particular ligand will likely depend on the local amino-acid composition. The characterized binding sites and molecular mechanisms of ligand action create a diversity of druggable targets to aid in the design of new molecules for tuning TRP channel function in disease conditions.
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Affiliation(s)
| | - Alexander I. Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
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39
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van Goor MK, van der Wijst J, Hoenderop JG. Title: Jealous protons sour another happy marriage; the story of how TRPV5 and PI(4,5)P2 split up. Cell Calcium 2022; 105:102609. [DOI: 10.1016/j.ceca.2022.102609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 05/30/2022] [Indexed: 11/28/2022]
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40
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Pumroy RA, Protopopova AD, Fricke TC, Lange IU, Haug FM, Nguyen PT, Gallo PN, Sousa BB, Bernardes GJL, Yarov-Yarovoy V, Leffler A, Moiseenkova-Bell VY. Structural insights into TRPV2 activation by small molecules. Nat Commun 2022; 13:2334. [PMID: 35484159 PMCID: PMC9051106 DOI: 10.1038/s41467-022-30083-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/14/2022] [Indexed: 12/14/2022] Open
Abstract
Transient receptor potential vanilloid 2 (TRPV2) is involved in many critical physiological and pathophysiological processes, making it a promising drug target. Here we present cryo-electron microscopy (cryo-EM) structures of rat TRPV2 in lipid nanodiscs activated by 2-aminoethoxydiphenyl borate (2-APB) and propose a TRPV2-specific 2-ABP binding site at the interface of S5 of one monomer and the S4-S5 linker of the adjacent monomer. In silico docking and electrophysiological studies confirm the key role of His521 and Arg539 in 2-APB activation of TRPV2. Additionally, electrophysiological experiments show that the combination of 2-APB and cannabidiol has a synergetic effect on TRPV2 activation, and cryo-EM structures demonstrate that both drugs were able to bind simultaneously. Together, our cryo-EM structures represent multiple functional states of the channel, providing a native picture of TRPV2 activation by small molecules and a structural framework for the development of TRPV2-specific activators.
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Affiliation(s)
- Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Anna D Protopopova
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Tabea C Fricke
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, 30625, Germany
| | - Iris U Lange
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, 30625, Germany
| | - Ferdinand M Haug
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, 30625, Germany
| | - Phuong T Nguyen
- Department of Physiology and Membrane Biology, University of California, Davis, CA, 95616, United States
| | - Pamela N Gallo
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Bárbara B Sousa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028, Portugal
| | - Gonçalo J L Bernardes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, 1649-028, Portugal
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, CA, 95616, United States
| | - Andreas Leffler
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, 30625, Germany
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States.
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41
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Fluck EC, Yazici AT, Rohacs T, Moiseenkova-Bell VY. Structural basis of TRPV5 regulation by physiological and pathophysiological modulators. Cell Rep 2022; 39:110737. [PMID: 35476976 PMCID: PMC9088182 DOI: 10.1016/j.celrep.2022.110737] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/02/2022] [Accepted: 04/05/2022] [Indexed: 12/11/2022] Open
Abstract
Transient receptor potential vanilloid 5 (TRPV5) is a kidney-specific Ca2+-selective ion channel that plays a key role in Ca2+ homeostasis. The basal activity of TRPV5 is balanced through activation by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and inhibition by Ca2+-bound calmodulin (CaM). Parathyroid hormone (PTH), the key extrinsic regulator of Ca2+ homeostasis, increases the activity of TRPV5 via protein kinase A (PKA)-mediated phosphorylation. Metabolic acidosis leads to reduced TRPV5 activity independent of PTH, causing hypercalciuria. Using cryoelectron microscopy (cryo-EM), we show that low pH inhibits TRPV5 by precluding PI(4,5)P2 activation. We capture intermediate conformations at low pH, revealing a transition from open to closed state. In addition, we demonstrate that PI(4,5)P2 is the primary modulator of channel gating, yet PKA controls TRPV5 activity by preventing CaM binding and channel inactivation. Our data provide detailed molecular mechanisms for regulation of TRPV5 by two key extrinsic modulators, low pH and PKA.
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Affiliation(s)
- Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aysenur Torun Yazici
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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42
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Khattar V, Wang L, Peng JB. Calcium selective channel TRPV6: Structure, function, and implications in health and disease. Gene 2022; 817:146192. [PMID: 35031425 PMCID: PMC8950124 DOI: 10.1016/j.gene.2022.146192] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 12/14/2022]
Abstract
Calcium-selective channel TRPV6 (Transient Receptor Potential channel family, Vanilloid subfamily member 6) belongs to the TRP family of cation channels and plays critical roles in transcellular calcium (Ca2+) transport, reuptake of Ca2+ into cells, and maintaining a local low Ca2+ environment for certain biological processes. Recent crystal and cryo-electron microscopy-based structures of TRPV6 have revealed mechanistic insights on how the protein achieves Ca2+ selectivity, permeation, and inactivation by calmodulin. The TRPV6 protein is expressed in a range of epithelial tissues such as the intestine, kidney, placenta, epididymis, and exocrine glands such as the pancreas, prostate and salivary, sweat, and mammary glands. The TRPV6 gene is a direct transcriptional target of the active form of vitamin D and is efficiently regulated to meet the body's need for Ca2+ demand. In addition, TRPV6 is also regulated by the level of dietary Ca2+ and under physiological conditions such as pregnancy and lactation. Genetic models of loss of function in TRPV6 display hypercalciuria, decreased bone marrow density, deficient weight gain, reduced fertility, and in some cases alopecia. The models also reveal that the channel plays an indispensable role in maintaining maternal-fetal Ca2+ transport and low Ca2+ environment in the epididymal lumen that is critical for male fertility. Most recently, loss of function mutations in TRPV6 gene is linked to transient neonatal hyperparathyroidism and early onset chronic pancreatitis. TRPV6 is overexpressed in a wide range of human malignancies and its upregulation is strongly correlated to tumor aggressiveness, metastasis, and poor survival in selected cancers. This review summarizes the current state of knowledge on the expression, structure, biophysical properties, function, polymorphisms, and regulation of TRPV6. The aberrant expression, polymorphisms, and dysfunction of this protein linked to human diseases are also discussed.
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Affiliation(s)
- Vinayak Khattar
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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43
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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44
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Abstract
Transient receptor potential (TRP) ion channels are sophisticated signaling machines that detect a wide variety of environmental and physiological signals. Every cell in the body expresses one or more members of the extended TRP channel family, which consists of over 30 subtypes, each likely possessing distinct pharmacological, biophysical, and/or structural attributes. While the function of some TRP subtypes remains enigmatic, those involved in sensory signaling are perhaps best characterized and have served as models for understanding how these excitatory ion channels serve as polymodal signal integrators. With the recent resolution revolution in cryo-electron microscopy, these and other TRP channel subtypes are now yielding their secrets to detailed atomic analysis, which is beginning to reveal structural underpinnings of stimulus detection and gating, ion permeation, and allosteric mechanisms governing signal integration. These insights are providing a framework for designing and evaluating modality-specific pharmacological agents for treating sensory and other TRP channel-associated disorders. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Melinda M Diver
- Department of Physiology, University of California, San Francisco, California, USA; .,Current affiliation: Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - John V Lin King
- Department of Physiology, University of California, San Francisco, California, USA; .,Current affiliation: Department of Biology, Stanford University, Palo Alto, California, USA
| | - David Julius
- Department of Physiology, University of California, San Francisco, California, USA;
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA; .,Howard Hughes Medical Institute, University of California, San Francisco, California, USA
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45
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Cheng WWL, Arcario MJ, Petroff JT. Druggable Lipid Binding Sites in Pentameric Ligand-Gated Ion Channels and Transient Receptor Potential Channels. Front Physiol 2022; 12:798102. [PMID: 35069257 PMCID: PMC8777383 DOI: 10.3389/fphys.2021.798102] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/02/2021] [Indexed: 12/17/2022] Open
Abstract
Lipids modulate the function of many ion channels, possibly through direct lipid-protein interactions. The recent outpouring of ion channel structures by cryo-EM has revealed many lipid binding sites. Whether these sites mediate lipid modulation of ion channel function is not firmly established in most cases. However, it is intriguing that many of these lipid binding sites are also known sites for other allosteric modulators or drugs, supporting the notion that lipids act as endogenous allosteric modulators through these sites. Here, we review such lipid-drug binding sites, focusing on pentameric ligand-gated ion channels and transient receptor potential channels. Notable examples include sites for phospholipids and sterols that are shared by anesthetics and vanilloids. We discuss some implications of lipid binding at these sites including the possibility that lipids can alter drug potency or that understanding protein-lipid interactions can guide drug design. Structures are only the first step toward understanding the mechanism of lipid modulation at these sites. Looking forward, we identify knowledge gaps in the field and approaches to address them. These include defining the effects of lipids on channel function in reconstituted systems using asymmetric membranes and measuring lipid binding affinities at specific sites using native mass spectrometry, fluorescence binding assays, and computational approaches.
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Affiliation(s)
- Wayland W L Cheng
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Mark J Arcario
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, United States
| | - John T Petroff
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, United States
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46
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Rangel-Galván M, Castro ME, Perez-Aguilar JM, Caballero NA, Rangel-Huerta A, Melendez FJ. Theoretical Study of the Structural Stability, Chemical Reactivity, and Protein Interaction for NMP Compounds as Modulators of the Endocannabinoid System. Molecules 2022; 27:414. [PMID: 35056729 PMCID: PMC8779749 DOI: 10.3390/molecules27020414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 01/02/2023] Open
Abstract
The cannabinoid receptors (CB1/CB2) and the T-type calcium channels are involved in disorders associated with both physiological pain and depressive behaviors. Valuable pharmacological species carbazole derivatives such as the NMP-4, NMP-7, and NMP-181 (Neuro Molecular Production) regulate both biological entities. In this work, DFT calculations were performed to characterize theoretically their structural and chemical reactivity properties using the BP86/cc-pVTZ level of theory. The molecular orbital contributions and the chemical reactivity analysis reveal that a major participation of the carbazole group is in the donor-acceptor interactions of the NMP compounds. The DFT analysis on the NMP compounds provides insights into the relevant functional groups involved during the ligand-receptor interactions. Molecular docking analysis is used to reveal possible sites of interaction of the NMP compounds with the Cav3.2 calcium channel. The interaction energy values and reported experimental evidence indicate that the site denominated as "Pore-blocking", which is formed mainly by hydrophobic residues and the T586 residue, is a probable binding site for the NMP compounds.
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Affiliation(s)
- Maricruz Rangel-Galván
- Centro de Investigación, Laboratorio de Química Teórica, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Edif. FCQ10, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico; (M.R.-G.); (J.M.P.-A.)
| | - María Eugenia Castro
- Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Complejo de Ciencias, ICUAP, Edif. IC8, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico
| | - Jose Manuel Perez-Aguilar
- Centro de Investigación, Laboratorio de Química Teórica, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Edif. FCQ10, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico; (M.R.-G.); (J.M.P.-A.)
| | - Norma A. Caballero
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Edif. BIO1, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico;
| | - Alejandro Rangel-Huerta
- Facultad de Ciencias de la Computación, Benemérita Universidad Autónoma de Puebla, Edif. CCO2, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico;
| | - Francisco J. Melendez
- Centro de Investigación, Laboratorio de Química Teórica, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Edif. FCQ10, 22 Sur y San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla C.P. 72570, Mexico; (M.R.-G.); (J.M.P.-A.)
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47
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Cai R, Chen XZ. Roles of Intramolecular Interactions in the Regulation of TRP Channels. Rev Physiol Biochem Pharmacol 2022; 186:29-56. [PMID: 35882668 DOI: 10.1007/112_2022_74] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The transient receptor potential (TRP) channels, classified into six (-A, -V, -P, -C, -M, -ML, -N and -Y) subfamilies, are important membrane sensors and mediators of diverse stimuli including pH, light, mechano-force, temperature, pain, taste, and smell. The mammalian TRP superfamily of 28 members share similar membrane topology with six membrane-spanning helices (S1-S6) and cytosolic N-/C-terminus. Abnormal function or expression of TRP channels is associated with cancer, skeletal dysplasia, immunodeficiency, and cardiac, renal, and neuronal diseases. The majority of TRP members share common functional regulators such as phospholipid PIP2, 2-aminoethoxydiphenyl borate (2-APB), and cannabinoid, while other ligands are more specific, such as allyl isothiocyanate (TRPA1), vanilloids (TRPV1), menthol (TRPM8), ADP-ribose (TRPM2), and ML-SA1 (TRPML1). The mechanisms underlying the gating and regulation of TRP channels remain largely unclear. Recent advances in cryogenic electron microscopy provided structural insights into 19 different TRP channels which all revealed close proximity of the C-terminus with the N-terminus and intracellular S4-S5 linker. Further studies found that some highly conserved residues in these regions of TRPV, -P, -C and -M members mediate functionally critical intramolecular interactions (i.e., within one subunit) between these regions. This review provides an overview on (1) intramolecular interactions in TRP channels and their effect on channel function; (2) functional roles of interplays between PIP2 (and other ligands) and TRP intramolecular interactions; and (3) relevance of the ligand-induced modulation of intramolecular interaction to diseases.
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Affiliation(s)
- Ruiqi Cai
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, Canada
| | - Xing-Zhen Chen
- Department of Physiology, Membrane Protein Disease Research Group, University of Alberta, Edmonton, AB, Canada.
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48
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Amini M, Chang Y, Wissenbach U, Flockerzi V, Schlenstedt G, Beck A. Activity of the yeast vacuolar TRP channel TRPY1 is inhibited by Ca 2+-calmodulin binding. J Biol Chem 2021; 297:101126. [PMID: 34461097 PMCID: PMC8449268 DOI: 10.1016/j.jbc.2021.101126] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
Transient receptor potential (TRP) cation channels, which are conserved across mammals, flies, fish, sea squirts, worms, and fungi, essentially contribute to cellular Ca2+ signaling. The activity of the unique TRP channel in yeast, TRP yeast channel 1 (TRPY1), relies on the vacuolar and cytoplasmic Ca2+ concentration. However, the mechanism(s) of Ca2+-dependent regulation of TRPY1 and possible contribution(s) of Ca2+-binding proteins are yet not well understood. Our results demonstrate a Ca2+-dependent binding of yeast calmodulin (CaM) to TRPY1. TRPY1 activity was increased in the cmd1–6 yeast strain, carrying a non–Ca2+-binding CaM mutant, compared with the parent strain expressing wt CaM (Cmd1). Expression of Cmd1 in cmd1–6 yeast rescued the wt phenotype. In addition, in human embryonic kidney 293 cells, hypertonic shock-induced TRPY1-dependent Ca2+ influx and Ca2+ release were increased by the CaM antagonist ophiobolin A. We found that coexpression of mammalian CaM impeded the activity of TRPY1 by reinforcing effects of endogenous CaM. Finally, inhibition of TRPY1 by Ca2+–CaM required the cytoplasmic amino acid stretch E33–Y92. In summary, our results show that TRPY1 is under inhibitory control of Ca2+–CaM and that mammalian CaM can replace yeast CaM for this inhibition. These findings add TRPY1 to the innumerable cellular proteins, which include a variety of ion channels, that use CaM as a constitutive or dissociable Ca2+-sensing subunit, and contribute to a better understanding of the modulatory mechanisms of Ca2+–CaM.
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Affiliation(s)
- Mahnaz Amini
- Experimentelle und Klinische Pharmakologie und Toxikologie/PZMS, Universität des Saarlandes, Homburg, Deutschland; Department of Medical Biochemistry and Molecular Biology/PZMS, Medical School, Saarland University, Homburg, Germany
| | - Yiming Chang
- Experimentelle und Klinische Pharmakologie und Toxikologie/PZMS, Universität des Saarlandes, Homburg, Deutschland; Department of Medical Biochemistry and Molecular Biology/PZMS, Medical School, Saarland University, Homburg, Germany
| | - Ulrich Wissenbach
- Experimentelle und Klinische Pharmakologie und Toxikologie/PZMS, Universität des Saarlandes, Homburg, Deutschland
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie/PZMS, Universität des Saarlandes, Homburg, Deutschland
| | - Gabriel Schlenstedt
- Department of Medical Biochemistry and Molecular Biology/PZMS, Medical School, Saarland University, Homburg, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie/PZMS, Universität des Saarlandes, Homburg, Deutschland.
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Fathizadeh A, Senning E, Elber R. Impact of the Protonation State of Phosphatidylinositol 4,5-Bisphosphate (PIP2) on the Binding Kinetics and Thermodynamics to Transient Receptor Potential Vanilloid (TRPV5): A Milestoning Study. J Phys Chem B 2021; 125:9547-9556. [PMID: 34396776 DOI: 10.1021/acs.jpcb.1c04052] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The binding of phosphatidylinositol 4,5-bisphosphate (PIP2) to the ion channel transient receptor potential vanilloid 5 (TRPV5) is critical for its function. We use atomically detailed simulations and the milestoning theory to compute the free energy profile and the kinetics of PIP2 binding to TRPV5. We estimate the rate of binding and the impact of the protonation state on the process. Several channel residues are identified as influential in the association event and will be interesting targets for mutation analysis. Our simulations reveal that PIP2 binds to TRPV5 in an unprotonated state and is protonated in the membrane. The switch between the protonation state of PIP2 is modeled as a diabatic transition and occurs about halfway through the reaction.
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Auto-inhibitory intramolecular S5/S6 interaction in the TRPV6 channel regulates breast cancer cell migration and invasion. Commun Biol 2021; 4:990. [PMID: 34413465 PMCID: PMC8376870 DOI: 10.1038/s42003-021-02521-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 08/04/2021] [Indexed: 11/09/2022] Open
Abstract
TRPV6, a Ca-selective channel, is abundantly expressed in the placenta, intestine, kidney and bone marrow. TRPV6 is vital to Ca homeostasis and its defective expression or function is linked to transient neonatal hyperparathyroidism, Lowe syndrome/Dent disease, renal stone, osteoporosis and cancers. The fact that the molecular mechanism underlying the function and regulation of TRPV6 is still not well understood hampers, in particular, the understanding of how TRPV6 contributes to breast cancer development. By electrophysiology and Ca imaging in Xenopus oocytes and cancer cells, molecular biology and numerical simulation, here we reveal an intramolecular S5/S6 helix interaction in TRPV6 that is functionally autoinhibitory and is mediated by the R532:D620 bonding. Predicted pathogenic mutation R532Q within S5 disrupts the S5/S6 interaction leading to gain-of-function of the channel, which promotes breast cancer cell progression through strengthening of the TRPV6/PI3K interaction, activation of a PI3K/Akt/GSK-3β cascade, and up-regulation of epithelial-mesenchymal transition and anti-apoptosis.
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