1
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Clark S, Jeong H, Posert R, Goehring A, Gouaux E. The structure of the Caenorhabditis elegans TMC-2 complex suggests roles of lipid-mediated subunit contacts in mechanosensory transduction. Proc Natl Acad Sci U S A 2024; 121:e2314096121. [PMID: 38354260 PMCID: PMC10895266 DOI: 10.1073/pnas.2314096121] [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: 08/15/2023] [Accepted: 12/21/2023] [Indexed: 02/16/2024] Open
Abstract
Mechanotransduction is the process by which a mechanical force, such as touch, is converted into an electrical signal. Transmembrane channel-like (TMC) proteins are an evolutionarily conserved family of membrane proteins whose function has been linked to a variety of mechanosensory processes, including hearing and balance sensation in vertebrates and locomotion in Drosophila. TMC1 and TMC2 are components of ion channel complexes, but the molecular features that tune these complexes to diverse mechanical stimuli are unknown. Caenorhabditis elegans express two TMC homologs, TMC-1 and TMC-2, both of which are the likely pore-forming subunits of mechanosensitive ion channels but differ in their expression pattern and functional role in the worm. Here, we present the single-particle cryo-electron microscopy structure of the native TMC-2 complex isolated from C. elegans. The complex is composed of two copies of the pore-forming TMC-2 subunit, the calcium and integrin binding protein CALM-1 and the transmembrane inner ear protein TMIE. Comparison of the TMC-2 complex to the recently published cryo-EM structure of the C. elegans TMC-1 complex highlights conserved protein-lipid interactions, as well as a π-helical structural motif in the pore-forming helices, that together suggest a mechanism for TMC-mediated mechanosensory transduction.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - Hanbin Jeong
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - Rich Posert
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - April Goehring
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
- HHMI, Oregon Health and Science University, Portland, OR97239
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
- HHMI, Oregon Health and Science University, Portland, OR97239
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2
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Pandey P, Shrestha B, Lee Y. Acid and Alkali Taste Sensation. Metabolites 2023; 13:1131. [PMID: 37999227 PMCID: PMC10673112 DOI: 10.3390/metabo13111131] [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: 09/19/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/25/2023] Open
Abstract
Living organisms rely on pH levels for a multitude of crucial biological processes, such as the digestion of food and the facilitation of enzymatic reactions. Among these organisms, animals, including insects, possess specialized taste organs that enable them to discern between acidic and alkaline substances present in their food sources. This ability is vital, as the pH of these compounds directly influences both the nutritional value and the overall health impact of the ingested substances. In response to the various chemical properties of naturally occurring compounds, insects have evolved peripheral taste organs. These sensory structures play a pivotal role in identifying and distinguishing between nourishing and potentially harmful foods. In this concise review, we aim to provide an in-depth examination of the molecular mechanisms governing pH-dependent taste responses, encompassing both acidic and alkaline stimuli, within the peripheral taste organs of the fruit fly, Drosophila melanogaster, drawing insights from a comprehensive analysis of existing research articles.
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Affiliation(s)
| | | | - Youngseok Lee
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea; (P.P.); (B.S.)
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3
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Gat A, Pechuk V, Peedikayil-Kurien S, Karimi S, Goldman G, Sela S, Lubliner J, Krieg M, Oren-Suissa M. Integration of spatially opposing cues by a single interneuron guides decision-making in C. elegans. Cell Rep 2023; 42:113075. [PMID: 37691148 DOI: 10.1016/j.celrep.2023.113075] [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: 01/13/2023] [Revised: 07/11/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023] Open
Abstract
The capacity of animals to respond to hazardous stimuli in their surroundings is crucial for their survival. In mammals, complex evaluations of the environment require large numbers and different subtypes of neurons. The nematode C. elegans avoids hazardous chemicals they encounter by reversing their direction of movement. How does the worms' compact nervous system process the spatial information and direct motion change? We show here that a single interneuron, AVA, receives glutamatergic excitatory and inhibitory signals from head and tail sensory neurons, respectively. AVA integrates the spatially distinct and opposing cues, whose output instructs the animal's behavioral decision. We further find that the differential activation of AVA stems from distinct localization of inhibitory and excitatory glutamate-gated receptors along AVA's process and from different threshold sensitivities of the sensory neurons. Our results thus uncover a cellular mechanism that mediates spatial computation of nociceptive cues for efficient decision-making in C. elegans.
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Affiliation(s)
- Asaf Gat
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Vladyslava Pechuk
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sonu Peedikayil-Kurien
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Shadi Karimi
- Neurophotonics and Mechanical Systems Biology, ICFO (Institut de Ciencies Fot'oniques), The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Gal Goldman
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sapir Sela
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jazz Lubliner
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Michael Krieg
- Neurophotonics and Mechanical Systems Biology, ICFO (Institut de Ciencies Fot'oniques), The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Meital Oren-Suissa
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel.
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4
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Clark S, Jeong H, Goehring A, Kang Y, Gouaux E. Large-scale growth of C. elegans and isolation of membrane protein complexes. Nat Protoc 2023; 18:2699-2716. [PMID: 37495753 DOI: 10.1038/s41596-023-00852-5] [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] [Received: 11/11/2022] [Accepted: 05/02/2023] [Indexed: 07/28/2023]
Abstract
Purification of membrane proteins for biochemical and structural studies is commonly achieved by recombinant overexpression in heterologous cell lines. However, many membrane proteins do not form a functional complex in a heterologous system, and few methods exist to purify sufficient protein from a native source for use in biochemical, biophysical and structural studies. Here, we provide a detailed protocol for the isolation of membrane protein complexes from transgenic Caenorhabditis elegans. We describe how to grow a genetically modified C. elegans line in abundance using standard laboratory equipment, and how to optimize purification conditions on a small scale using fluorescence-detection size-exclusion chromatography. Optimized conditions can then be applied to a large-scale preparation, enabling the purification of adequate quantities of a target protein for structural, biochemical and biophysical studies. Large-scale worm growth can be accomplished in ~9 d, and each optimization experiment can be completed in less than 1 d. We have used these methods to isolate the transmembrane channel-like protein 1 complex, as well as three additional protein complexes (transmembrane-like channel 2, lipid transfer protein and 'Protein S'), from transgenic C. elegans, demonstrating the utility of this approach in purifying challenging, low-abundance membrane protein complexes.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Hanbin Jeong
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, OR, USA
| | - Yunsik Kang
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA.
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, OR, USA.
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5
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Clark S, Jeong H, Posert R, Goehring A, Gouaux E. Structure of C. elegans TMC-2 complex suggests roles of lipid-mediated subunit contacts in mechanosensory transduction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.16.553618. [PMID: 37645790 PMCID: PMC10462014 DOI: 10.1101/2023.08.16.553618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Mechanotransduction is the process by which a mechanical force, such as touch, is converted into an electrical signal. Transmembrane channel-like (TMC) proteins are an evolutionarily-conserved family of ion channels whose function has been linked to a variety of mechanosensory processes, including hearing and balance sensation in vertebrates and locomotion in Drosophila. The molecular features that tune homologous TMC ion channel complexes to diverse mechanical stimuli are unknown. Caenorhabditis elegans express two TMC homologs, TMC-1 and TMC-2, both of which are the likely pore-forming subunits of mechanosensitive ion channels but differ in their expression pattern and functional role in the worm. Here we present the single particle cryo-electron microscopy structure of the native TMC-2 complex isolated from C. elegans. The complex is composed of two copies each of the pore-forming TMC-2 subunit, the calcium and integrin binding protein CALM-1 and the transmembrane inner ear protein TMIE. Comparison of the TMC-2 complex to the recently published cryo-EM structure of the C. elegans TMC-1 complex reveals differences in subunit composition and highlights conserved protein-lipid interactions, as well as other structural features, that together suggest a mechanism for TMC-mediated mechanosensory transduction.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Hanbin Jeong
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Rich Posert
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
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6
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The tetraspan LHFPL5 is critical to establish maximal force sensitivity of the mechanotransduction channel of cochlear hair cells. Cell Rep 2023; 42:112245. [PMID: 36917610 DOI: 10.1016/j.celrep.2023.112245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/28/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
The mechanoelectrical transduction (MET) channel of cochlear hair cells is gated by the tip link, but the mechanisms that establish the exquisite force sensitivity of this MET channel are not known. Here, we show that the tetraspan lipoma HMGIC fusion partner-like 5 (LHFPL5) directly couples the tip link to the MET channel. Disruption of these interactions severely perturbs MET. Notably, the N-terminal cytoplasmic domain of LHFPL5 binds to an amphipathic helix in TMC1, a critical gating domain conserved between different MET channels. Mutations in the amphipathic helix of TMC1 or in the N-terminus of LHFPL5 that perturb interactions of LHFPL5 with the amphipathic helix affect channel responses to mechanical force. We conclude that LHFPL5 couples the tip link to the MET channel and that channel gating depends on a structural element in TMC1 that is evolutionarily conserved between MET channels. Overall, our findings support a tether model for transduction channel gating by the tip link.
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7
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Goodman MB, Haswell ES, Vásquez V. Mechanosensitive membrane proteins: Usual and unusual suspects in mediating mechanotransduction. J Gen Physiol 2023; 155:e202213248. [PMID: 36696153 PMCID: PMC9930137 DOI: 10.1085/jgp.202213248] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
This Viewpoint, which accompanies a Special Issue focusing on membrane mechanosensors, discusses unifying and unique features of both established and emerging mechanosensitive (MS) membrane proteins, their distribution across protein families and phyla, and current and future challenges in the study of these important proteins and their partners. MS membrane proteins are essential for tissue development, cellular motion, osmotic homeostasis, and sensing external and self-generated mechanical cues like those responsible for touch and proprioception. Though researchers' attention and this Viewpoint focus on a few famous ion channels that are considered the usual suspects as MS mechanosensors, we also discuss some of the more unusual suspects, such as G-protein coupled receptors. As the field continues to grow, so too will the list of proteins suspected to function as mechanosensors and the diversity of known MS membrane proteins.
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Affiliation(s)
- Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Elizabeth S. Haswell
- Department of Biology, Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
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8
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Park SJ, Ja WW. The basics of base sensing. Nat Metab 2023; 5:364-365. [PMID: 36941449 DOI: 10.1038/s42255-023-00763-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Affiliation(s)
- Scarlet J Park
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - William W Ja
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA.
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9
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Mi T, Mack JO, Koolmees W, Lyon Q, Yochimowitz L, Teng ZQ, Jiang P, Montell C, Zhang YV. Alkaline taste sensation through the alkaliphile chloride channel in Drosophila. Nat Metab 2023; 5:466-480. [PMID: 36941450 PMCID: PMC10665042 DOI: 10.1038/s42255-023-00765-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 02/09/2023] [Indexed: 03/23/2023]
Abstract
The sense of taste is an important sentinel governing what should or should not be ingested by an animal, with high pH sensation playing a critical role in food selection. Here we explore the molecular identities of taste receptors detecting the basic pH of food using Drosophila melanogaster as a model. We identify a chloride channel named alkaliphile (Alka), which is both necessary and sufficient for aversive taste responses to basic food. Alka forms a high-pH-gated chloride channel and is specifically expressed in a subset of gustatory receptor neurons (GRNs). Optogenetic activation of alka-expressing GRNs is sufficient to suppress attractive feeding responses to sucrose. Conversely, inactivation of these GRNs causes severe impairments in the aversion to high pH. Altogether, our discovery of Alka as an alkaline taste receptor lays the groundwork for future research on alkaline taste sensation in other animals.
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Affiliation(s)
- Tingwei Mi
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - John O Mack
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | | | - Quinn Lyon
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | | | - Zhao-Qian Teng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - Craig Montell
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Yali V Zhang
- Monell Chemical Senses Center, Philadelphia, PA, USA.
- Department of Physiology, The Diabetes Research Center, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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10
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Li S, Al-Sheikh U, Chen Y, Kang L. Nematode homologs of the sour taste receptor Otopetrin1 are evolutionarily conserved acid-sensitive proton channels. Front Cell Dev Biol 2023; 11:1133890. [PMID: 36776560 PMCID: PMC9909269 DOI: 10.3389/fcell.2023.1133890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Numerous taste receptors and related molecules have been identified in vertebrates and invertebrates. Otopetrin1 has recently been identified as mammalian sour taste receptor which is essential for acid sensation. However, whether other Otopetrin proteins are involved in PH-sensing remains unknown. In C. elegans, there are eight otopetrin homologous genes but their expression patterns and functions have not been reported so far. Through heterologous expression in HEK293T cells, we found that ceOTOP1a can be activated by acid in NMDG+ solution without conventional cations, which generated inward currents and can be blocked by zinc ions. Moreover, we found that Otopetrin channels are widely expressed in numerous tissues, especially in sensory neurons in the nematode. These results suggest that the biophysical characteristics of the Otopetrin channels in nematodes are generally conserved. However, a series of single gene mutations of otopetrins, which were constructed by CRISPR-Cas9 method, did not affect either calcium responses in ASH polymodal sensory neurons to acid stimulation or acid avoidance behaviors, suggesting that Otopetrin channels might have diverse functions among species. This study reveals that nematode Otopetrins are evolutionarily conserved acid-sensitive proton channels, and provides a framework for further revealing the function and mechanisms of Otopetrin channels in both invertebrates and vertebrates.
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Affiliation(s)
- Shitian Li
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yili Chen
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,*Correspondence: Yili Chen, ; Lijun Kang,
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China,*Correspondence: Yili Chen, ; Lijun Kang,
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11
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Tian L, Zhang H, Yang S, Luo A, Kamau PM, Hu J, Luo L, Lai R. Vertebrate OTOP1 is also an alkali-activated channel. Nat Commun 2023; 14:26. [PMID: 36596786 PMCID: PMC9810603 DOI: 10.1038/s41467-022-35754-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/23/2022] [Indexed: 01/04/2023] Open
Abstract
Although alkaline sensation is critical for survival, alkali-activated receptors are yet to be identified in vertebrates. Here, we showed that the OTOP1 channel can be directly activated by extracellular alkali. Notably, OTOP1 biphasically mediated proton influx and efflux with extracellular acid and base stimulation, respectively. Mutations of K221 and R554 at the S5-S6 and S11-S12 linkers significantly reduced alkali affinity without affecting acid activation, suggesting that different domains are responsible for acid- and alkali-activation of OTOP1. The selectivity for H+ was significantly higher in OTOP1 activated by alkali than that by acid, further suggesting that the two activations might be independent gating processes. Given that the alkali-activation of OTOP1 and the required key residues were conserved in the six representative vertebrates, we cautiously propose that OTOP1 participates in alkaline sensation in vertebrates. Thus, our study identified OTOP1 as an alkali-activated channel.
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Affiliation(s)
- Lifeng Tian
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,School of Molecular Medicine, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China.,The cancer Hospital of the University of Chinese Academy of Sciences, Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, 310022, Hangzhou, China
| | - Hao Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shilong Yang
- College of Wildlife and Protected Area, Northeast Forestry University, 150040, Harbin, China
| | - Anna Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Peter Muiruri Kamau
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,Sino-African Joint Research Center, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China
| | - Jingmei Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Lei Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China. .,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China. .,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China. .,School of Molecular Medicine, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China. .,Sino-African Joint Research Center, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.
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12
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Wu J, Wang L, Ervin JF, Wang SHJ, Soderblom E, Ko D, Yan D. GABA signaling triggered by TMC-1/Tmc delays neuronal aging by inhibiting the PKC pathway in C. elegans. SCIENCE ADVANCES 2022; 8:eadc9236. [PMID: 36542715 PMCID: PMC9770988 DOI: 10.1126/sciadv.adc9236] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
Aging causes functional decline and degeneration of neurons and is a major risk factor of neurodegenerative diseases. To investigate the molecular mechanisms underlying neuronal aging, we developed a new pipeline for neuronal proteomic profiling in young and aged animals. While the overall translational machinery is down-regulated, certain proteins increase expressions upon aging. Among these aging-up-regulated proteins, the conserved channel protein TMC-1/Tmc has an anti-aging function in all neurons tested, and the neuroprotective function of TMC-1 occurs by regulating GABA signaling. Moreover, our results show that metabotropic GABA receptors and G protein GOA-1/Goα are required for the anti-neuronal aging functions of TMC-1 and GABA, and the activation of GABA receptors prevents neuronal aging by inhibiting the PLCβ-PKC pathway. Last, we show that the TMC-1-GABA-PKC signaling axis suppresses neuronal functional decline caused by a pathogenic form of human Tau protein. Together, our findings reveal the neuroprotective function of the TMC-1-GABA-PKC signaling axis in aging and disease conditions.
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Affiliation(s)
- Jieyu Wu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Liuyang Wang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - John F. Ervin
- Bryan Brain Bank and Biorepository, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Shih-Hsiu J. Wang
- Department of Pathology & Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Erik Soderblom
- Proteomics and Metabolomics Shared Resource and Duke Center for Genomic and Computational Biology, Duke University Medical School, Durham, NC 27710, USA
| | - Dennis Ko
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Regeneration Next, and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA
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13
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Qiu X, Müller U. Sensing sound: Cellular specializations and molecular force sensors. Neuron 2022; 110:3667-3687. [PMID: 36223766 PMCID: PMC9671866 DOI: 10.1016/j.neuron.2022.09.018] [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: 06/15/2022] [Revised: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
Organisms of all phyla express mechanosensitive ion channels with a wide range of physiological functions. In recent years, several classes of mechanically gated ion channels have been identified. Some of these ion channels are intrinsically mechanosensitive. Others depend on accessory proteins to regulate their response to mechanical force. The mechanotransduction machinery of cochlear hair cells provides a particularly striking example of a complex force-sensing machine. This molecular ensemble is embedded into a specialized cellular compartment that is crucial for its function. Notably, mechanotransduction channels of cochlear hair cells are not only critical for auditory perception. They also shape their cellular environment and regulate the development of auditory circuitry. Here, we summarize recent discoveries that have shed light on the composition of the mechanotransduction machinery of cochlear hair cells and how this machinery contributes to the development and function of the auditory system.
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Affiliation(s)
- Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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Sexually dimorphic architecture and function of a mechanosensory circuit in C. elegans. Nat Commun 2022; 13:6825. [PMID: 36369281 PMCID: PMC9652301 DOI: 10.1038/s41467-022-34661-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022] Open
Abstract
How sensory perception is processed by the two sexes of an organism is still only partially understood. Despite some evidence for sexual dimorphism in auditory and olfactory perception, whether touch is sensed in a dimorphic manner has not been addressed. Here we find that the neuronal circuit for tail mechanosensation in C. elegans is wired differently in the two sexes and employs a different combination of sex-shared sensory neurons and interneurons in each sex. Reverse genetic screens uncovered cell- and sex-specific functions of the alpha-tubulin mec-12 and the sodium channel tmc-1 in sensory neurons, and of the glutamate receptors nmr-1 and glr-1 in interneurons, revealing the underlying molecular mechanisms that mediate tail mechanosensation. Moreover, we show that only in males, the sex-shared interneuron AVG is strongly activated by tail mechanical stimulation, and accordingly is crucial for their behavioral response. Importantly, sex reversal experiments demonstrate that the sexual identity of AVG determines both the behavioral output of the mechanosensory response and the molecular pathways controlling it. Our results present extensive sexual dimorphism in a mechanosensory circuit at both the cellular and molecular levels.
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15
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Zhang X, Liu J, Pan T, Ward A, Liu J, Xu XZS. A cilia-independent function of BBSome mediated by DLK-MAPK signaling in C. elegans photosensation. Dev Cell 2022; 57:1545-1557.e4. [PMID: 35649417 DOI: 10.1016/j.devcel.2022.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 04/03/2022] [Accepted: 05/04/2022] [Indexed: 11/03/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a genetic disorder that affects primary cilia. BBSome, a protein complex composed of eight BBS proteins, regulates the structure and function of cilia, and its malfunction causes BBS in humans. Here, we report a cilia-independent function of BBSome. To identify genes that regulate the C. elegans photoreceptor protein LITE-1 in ciliated ASH photosensory neurons, we performed a genetic screen and isolated bbs mutants. Functional analysis revealed that BBSome regulates LITE-1 protein stability independently of cilia. Through another round of genetic screening, we found that this cilia-independent function of BBSome is mediated by DLK-MAPK signaling, which acts downstream of BBSome to control LITE-1 stability via Rab5-mediated endocytosis. BBSome exerts its function by regulating the expression of DLK. BBSome also regulates the expression of LZK, a mammalian DLK in human cells. These studies identify a cilia-independent function of BBSome and uncover DLK as an evolutionarily conserved BBSome effector.
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Affiliation(s)
- Xinxing Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical, School, Ann Arbor, MI 48109, USA
| | - Jinzhi Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical, School, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tong Pan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical, School, Ann Arbor, MI 48109, USA
| | - Alex Ward
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan Medical, School, Ann Arbor, MI 48109, USA.
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16
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Iliff AJ, Wang C, Ronan EA, Hake AE, Guo Y, Li X, Zhang X, Zheng M, Liu J, Grosh K, Duncan RK, Xu XZS. The nematode C. elegans senses airborne sound. Neuron 2021; 109:3633-3646.e7. [PMID: 34555314 PMCID: PMC8602785 DOI: 10.1016/j.neuron.2021.08.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/21/2021] [Accepted: 08/27/2021] [Indexed: 11/26/2022]
Abstract
Unlike olfaction, taste, touch, vision, and proprioception, which are
widespread across animal phyla, hearing is found only in vertebrates and some
arthropods. The vast majority of invertebrate species are thus considered
insensitive to sound. Here, we challenge this conventional view by showing that
the earless nematode C. elegans senses airborne sound at
frequencies reaching the kHz range. Sound vibrates C. elegans
skin, which acts as a pressure-to-displacement transducer similar to vertebrate
eardrum, activates sound-sensitive FLP/PVD neurons attached to the skin, and
evokes phonotaxis behavior. We identified two nAChRs that transduce sound
signals independently of ACh, revealing an unexpected function of nAChRs in
mechanosensation. Thus, the ability to sense airborne sound is not restricted to
vertebrates and arthropods as previously thought, and might have evolved
multiple times independently in the animal kingdom, suggesting convergent
evolution. Our studies also demonstrate that animals without ears may not be
presumed to be sound insensitive. Hearing is thought to exist only in vertebrates and some arthropods, but
not other animal phyla. Here, Xu and colleagues report that the earless nematode
C. elegans senses airborne sound and engages in phonotaxis.
Thus, hearing might have evolved multiple times independently in the animal
kingdom, suggesting convergent evolution.
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Affiliation(s)
- Adam J Iliff
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Can Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Elizabeth A Ronan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alison E Hake
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuling Guo
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xia Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinxing Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Maohua Zheng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Karl Grosh
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - R Keith Duncan
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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17
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How JJ, Navlakha S, Chalasani SH. Neural network features distinguish chemosensory stimuli in Caenorhabditis elegans. PLoS Comput Biol 2021; 17:e1009591. [PMID: 34752447 PMCID: PMC8604368 DOI: 10.1371/journal.pcbi.1009591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 11/19/2021] [Accepted: 10/26/2021] [Indexed: 11/19/2022] Open
Abstract
Nervous systems extract and process information from the environment to alter animal behavior and physiology. Despite progress in understanding how different stimuli are represented by changes in neuronal activity, less is known about how they affect broader neural network properties. We developed a framework for using graph-theoretic features of neural network activity to predict ecologically relevant stimulus properties, in particular stimulus identity. We used the transparent nematode, Caenorhabditis elegans, with its small nervous system to define neural network features associated with various chemosensory stimuli. We first immobilized animals using a microfluidic device and exposed their noses to chemical stimuli while monitoring changes in neural activity of more than 50 neurons in the head region. We found that graph-theoretic features, which capture patterns of interactions between neurons, are modulated by stimulus identity. Further, we show that a simple machine learning classifier trained using graph-theoretic features alone, or in combination with neural activity features, can accurately predict salt stimulus. Moreover, by focusing on putative causal interactions between neurons, the graph-theoretic features were almost twice as predictive as the neural activity features. These results reveal that stimulus identity modulates the broad, network-level organization of the nervous system, and that graph theory can be used to characterize these changes. Animals use their nervous systems to detect and respond to changes in their external environment. A central challenge in computational neuroscience is to determine how specific properties of these stimuli affect interactions between neurons. While most studies have focused on the neurons in the sensory periphery, recent advances allow us to probe how the rest of the nervous system responds to sensory stimulation. We recorded activity of neurons within the C. elegans head region while the animal was exposed to various chemosensory stimuli. We then used computational methods to identify various stimuli by analyzing neural activity. Specifically, we used a combination of population-level activity statistics (e.g., average, standard deviation, frequency-based measures) and graph-theoretic features of functional network structure (e.g., transitivity, which is the existence of strongly connected triplets of neurons) to accurately predict salt stimulus. Our method is general and can be used across species, particularly in instances where the identities of individual neurons are unknown. These results also suggest that neural activity downstream of the sensory periphery contains a signature of changes in the environment.
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Affiliation(s)
- Javier J. How
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, California, United States of America
| | - Saket Navlakha
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, California, United States of America
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
- * E-mail: (SN); (SHC)
| | - Sreekanth H. Chalasani
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, California, United States of America
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, San Diego, La Jolla, California, United States of America
- * E-mail: (SN); (SHC)
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18
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Kaulich E, Walker DS, Tang YQ, Schafer WR. The Caenorhabditis elegans tmc-1 is involved in egg-laying inhibition in response to harsh touch. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 34414364 PMCID: PMC8369342 DOI: 10.17912/micropub.biology.000439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/06/2022]
Abstract
The conserved family of Transmembrane channel-like (TMC) proteins has attracted significant interest since two members appear to be key components of the mammalian hair cell mechanotransducer involved in hearing. C. elegans expresses two TMC proteins, TMC-1 and TMC-2. TMC-1 is widely expressed in in both muscles and the nervous system. This wide expression pattern suggests that TMC-1 might serve different functions in the various neurons. TMC-1 has previously been shown to function in neurons, playing a role in chemosensation in the ASH neurons and mechanosensation in OLQ neurons, further supporting this hypothesis. tmc-1 is expressed in the high-threshold mechanosensory neuron, ALA. We show that tmc-1 mutants show defects in the ALA-dependent inhibition of egg-laying in response to a harsh mechanical stimulus.
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Affiliation(s)
- Eva Kaulich
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Denise S Walker
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Yi-Quan Tang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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19
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Liu S, Wang S, Zou L, Xiong W. Mechanisms in cochlear hair cell mechano-electrical transduction for acquisition of sound frequency and intensity. Cell Mol Life Sci 2021; 78:5083-5094. [PMID: 33871677 PMCID: PMC11072359 DOI: 10.1007/s00018-021-03840-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/30/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Sound signals are acquired and digitized in the cochlea by the hair cells that further transmit the coded information to the central auditory pathways. Any defect in hair cell function may induce problems in the auditory system and hearing-based brain function. In the past 2 decades, our understanding of auditory transduction has been substantially deepened because of advances in molecular, structural, and functional studies. Results from these experiments can be perfectly embedded in the previously established profile from anatomical, histological, genetic, and biophysical research. This review aims to summarize the progress on the molecular and cellular mechanisms of the mechano-electrical transduction (MET) channel in the cochlear hair cells, which is involved in the acquisition of sound frequency and intensity-the two major parameters of an acoustic cue. We also discuss recent studies on TMC1, the molecule likely to form the MET channel pore.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
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20
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Liu W, Wang J, Zhang HY, Yang YC, Kang RX, Bai P, Fu H, Chen LR, Gao YP, Tan EK. Symbiotic bacteria attenuate Drosophila oviposition repellence to alkaline through acidification. INSECT SCIENCE 2021; 28:403-414. [PMID: 32725723 DOI: 10.1111/1744-7917.12857] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 06/27/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Metazoans harbor a wealth of symbionts that are ever-changing the environment by taking up resources and/or excreting metabolites. One such common environmental modification is a change in pH. Conventional wisdom holds that symbionts facilitate the survival and production of their hosts in the wild, but this notion lacks empirical evidence. Here, we report that symbiotic bacteria in the genus Enterococcus attenuate the oviposition avoidance of alkaline environments in Drosophila. We studied the effects of alkalinity on oviposition preference for the first time, and found that flies are robustly disinclined to oviposit on alkali-containing substrates. This innate repulsion to alkaline environments is explained, in part, by the fact that alkalinity compromises the health and lifespan of both offspring and parent Drosophila. Enterococcus dramatically diminished or even completely reversed the ovipositional avoidance of alkalinity in Drosophila. Mechanistically, Enterococcus generate abundant lactate during fermentation, which neutralizes the residual alkali in an egg-laying substrate. In conclusion, Enterococcus protects Drosophila from alkali stress by acidifying the ovipositional substrate, and ultimately improves the fitness of the Drosophila population. Our results demonstrate that symbionts are profound factors in the Drosophila ovipositional decision, and extend our understanding of the intimate interactions between Drosophila and their symbionts.
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Affiliation(s)
- Wei Liu
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital Campus, Singapore
| | - Jie Wang
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Hong-Yu Zhang
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Ying-Chun Yang
- Department of Basic Medical, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Ru-Xue Kang
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Peng Bai
- Department of Basic Medical, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Hui Fu
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Li-Rong Chen
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Yan-Ping Gao
- Department of Medical Laboratory Science, Fenyang College, Shanxi Medical University, Shanxi, China
| | - Eng King Tan
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital Campus, Singapore
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21
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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22
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Olfactory perception of food abundance regulates dietary restriction-mediated longevity via a brain-to-gut signal. NATURE AGING 2021; 1:255-268. [PMID: 33796867 PMCID: PMC8009090 DOI: 10.1038/s43587-021-00039-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The role of food nutrients in mediating the positive effect of dietary restriction (DR) on longevity has been extensively characterized, but how non-nutrient food components regulate lifespan is not well understood. Here, we show that food-associated odors shorten the lifespan of C. elegans under DR but not those fed ad libitum, revealing a specific effect of food odors on DR-mediated longevity. Food odors act on a neural circuit comprising the sensory neurons ADF and CEP, and the interneuron RIC. This olfactory circuit signals the gut to suppress DR-mediated longevity via octopamine, the invertebrate homolog of norepinephrine, by regulating the energy sensor AMPK through a Gq-PLCβ-CaMKK-dependent mechanism. In mouse primary cells, we find that norepinephrine signaling regulates AMPK through a similar mechanism. Our results identify a brain-gut axis that regulates DR-mediated longevity by relaying olfactory information about food abundance from the brain to the gut.
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23
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Fan Y, Zou W, Liu J, Al-Sheikh U, Cheng H, Duan D, Du Chen, Liu S, Chen L, Xu J, Ruhomutally F, Kang L. Polymodal Functionality of C. elegans OLL Neurons in Mechanosensation and Thermosensation. Neurosci Bull 2021; 37:611-622. [PMID: 33555565 PMCID: PMC8099987 DOI: 10.1007/s12264-021-00629-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 08/25/2020] [Indexed: 12/04/2022] Open
Abstract
Sensory modalities are important for survival but the molecular mechanisms remain challenging due to the polymodal functionality of sensory neurons. Here, we report the C. elegans outer labial lateral (OLL) sensilla sensory neurons respond to touch and cold. Mechanosensation of OLL neurons resulted in cell-autonomous mechanically-evoked Ca2+ transients and rapidly-adapting mechanoreceptor currents with a very short latency. Mechanotransduction of OLL neurons might be carried by a novel Na+ conductance channel, which is insensitive to amiloride. The bona fide mechano-gated Na+-selective degenerin/epithelial Na+ channels, TRP-4, TMC, and Piezo proteins are not involved in this mechanosensation. Interestingly, OLL neurons also mediated cold but not warm responses in a cell-autonomous manner. We further showed that the cold response of OLL neurons is not mediated by the cold receptor TRPA-1 or the temperature-sensitive glutamate receptor GLR-3. Thus, we propose the polymodal functionality of OLL neurons in mechanosensation and cold sensation.
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Affiliation(s)
- Yuedan Fan
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Wenjuan Zou
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Jia Liu
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Hankui Cheng
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Duo Duan
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Du Chen
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Siyan Liu
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Luyi Chen
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Jilei Xu
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Firdosh Ruhomutally
- Department of Human Sciences and Psychology, University of South Africa (UNISA), Pretoria, 0003, South Africa
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China. .,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China.
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24
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Li S, Yan Z. Mechanotransduction Ion Channels in Hearing and Touch. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:371-385. [DOI: 10.1007/978-981-16-4254-8_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Abstract
Mechanosensation such as touch, hearing and proprioception, is functionally regulated by mechano-gated ion channels through the process of transduction. Mechano-gated channels are a subtype of gated ion channels engaged in converting mechanical stimuli to chemical or electrical signals thereby modulating sensation. To date, a few families of mechano-gated channels (DEG/ENaC, TRPN, K2P, TMC and Piezo) have been identified in eukaryotes. Using a tractable genetic model organism Caenorhabditis elegans, the molecular mechanism of mechanosensation have been the focus of much research to comprehend the process of mechanotransduction. Comprising of almost all metazoans classes of ion channels, transporters and receptors, C. elegans is a powerful genetic model to explore mechanosensitive behaviors such as touch sensation and proprioception. The nematode relies primarily on its sensory abilities to survive in its natural environment. Genetic screening, calcium imaging and electrophysiological analysis have established that ENaC proteins and TRPN channel (TRP-4 protein) can characterize mechano-gated channels in C. elegans. A recent study reported that TMCs are likely the pore-forming subunit of a mechano-gated channel in C. elegans. Nevertheless, it still remains unclear whether Piezo as well as other candidate proteins can form mechano-gated channels in C. elegans.
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Affiliation(s)
- Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China
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26
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Zhang W, He F, Ronan EA, Liu H, Gong J, Liu J, Xu XS. Regulation of photosensation by hydrogen peroxide and antioxidants in C. elegans. PLoS Genet 2020; 16:e1009257. [PMID: 33301443 PMCID: PMC7755287 DOI: 10.1371/journal.pgen.1009257] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/22/2020] [Accepted: 11/05/2020] [Indexed: 11/22/2022] Open
Abstract
The eyeless C. elegans exhibits robust phototaxis behavior in response to short-wavelength light, particularly UV light. C. elegans senses light through LITE-1, a unique photoreceptor protein that belongs to the invertebrate taste receptor family. However, it remains unclear how LITE-1 is regulated. Here, we performed a forward genetic screen for genes that when mutated suppress LITE-1 function. One group of lite-1 suppressors are the genes required for producing the two primary antioxidants thioredoxin and glutathione, suggesting that oxidization of LITE-1 inhibits its function. Indeed, the oxidant hydrogen peroxide (H2O2) suppresses phototaxis behavior and inhibits the photoresponse in photoreceptor neurons, whereas other sensory behaviors are relatively less vulnerable to H2O2. Conversely, antioxidants can rescue the phenotype of lite-1 suppressor mutants and promote the photoresponse. As UV light illumination generates H2O2, we propose that upon light activation of LITE-1, light-produced H2O2 then deactivates LITE-1 to terminate the photoresponse, while antioxidants may promote LITE-1’s recovery from its inactive state. Our studies provide a potential mechanism by which H2O2 and antioxidants act synergistically to regulate photosensation in C. elegans. The nematode C. elegans possesses a unique photoreceptor protein, LITE-1, which mediates a light-avoidance behavior upon light exposure. C. elegans avoids short-wavelength light, particularly UV light, providing a potential mechanism by which worms escape from the dangerous UV rays in the sunlight. However, it is not clear how LITE-1 is regulated. Here, we performed a genetic screen to identify genes regulating LITE-1. We uncovered six genes that when mutated suppress LITE-1 function. All these genes are involved in regenerating cellular antioxidants that function to clear reactive oxygen species, particularly hydrogen peroxide (H2O2), suggesting that the function of LITE-1 is vulnerable to H2O2. Indeed, we show that H2O2 exposure inhibits LITE-1 function, while antioxidants promote it. Notably, other sensory functions are relatively less sensitive to H2O2. As UV light illumination is known to generate H2O2 within the cell, this provides a potential mechanism to turn off LITE-1. Our results uncover a potential mechanism of LITE-1 regulation, where antioxidants and oxidants act to promote and suppress LITE-1 function, respectively.
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Affiliation(s)
- Wenyuan Zhang
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Feiteng He
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Elizabeth A. Ronan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Hongkang Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jianke Gong
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (JL); (XZSX)
| | - X.Z. Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail: (JL); (XZSX)
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27
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Abstract
Sound-induced mechanical stimuli are detected by elaborate mechanosensory transduction (MT) machinery in highly specialized hair cells of the inner ear. Genetic studies of inherited deafness in the past decades have uncovered several molecular constituents of the MT complex, and intense debate has surrounded the molecular identity of the pore-forming subunits. How the MT components function in concert in response to physical stimulation is not fully understood. In this review, we summarize and discuss multiple lines of evidence supporting the hypothesis that transmembrane channel-like 1 is a long-sought MT channel subunit. We also review specific roles of other components of the MT complex, including protocadherin 15, cadherin 23, lipoma HMGIC fusion partner-like 5, transmembrane inner ear, calcium and integrin-binding family member 2, and ankyrins. Based on these recent advances, we propose a unifying theory of hair cell MT that may reconcile most of the functional discoveries obtained to date. Finally, we discuss key questions that need to be addressed for a comprehensive understanding of hair cell MT at molecular and atomic levels.
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Affiliation(s)
- Wang Zheng
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
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28
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Jia YL, Zhang YJ, Guo D, Li CY, Ma JY, Gao CF, Wu SF. A Mechanosensory Receptor TMC Regulates Ovary Development in the Brown Planthopper Nilaparvata lugens. Front Genet 2020; 11:573603. [PMID: 33193678 PMCID: PMC7649262 DOI: 10.3389/fgene.2020.573603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/02/2020] [Indexed: 11/29/2022] Open
Abstract
Transmembrane channel-like (TMC) genes encode a family of evolutionarily conserved membrane proteins. Mutations in the TMC1 and TMC2 cause deafness in humans and mice. However, their functions in insects are is still not well known. Here we cloned three tmc genes, Nltmc3, Nltmc5, and Nltmc7 from brown planthoppers. The predicted amino acid sequences showed high identity with other species homologs and have the characteristic eight or nine transmembrane domains and TMC domain architecture. We detected these three genes in all developmental stages and examined tissues. Interestingly, we found Nltmc3 was highly expressed in the female reproductive organ especially in the oviduct. RNAi-mediated silencing of Nltmc3 substantially decreased the egg-laying number and impaired ovary development. Our results indicate that Nltmc3 has an essential role in the ovary development of brown planthoppers.
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Affiliation(s)
- Ya-Long Jia
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Yi-Jie Zhang
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Di Guo
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Chen-Yu Li
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Jun-Yu Ma
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Cong-Fen Gao
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Shun-Fan Wu
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
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29
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Iliff AJ, Xu XZS. C. elegans: a sensible model for sensory biology. J Neurogenet 2020; 34:347-350. [PMID: 33191820 PMCID: PMC7856205 DOI: 10.1080/01677063.2020.1823386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023]
Abstract
From Sydney Brenner's backyard to hundreds of labs across the globe, inspiring six Nobel Prize winners along the way, Caenorhabditis elegans research has come far in the past half century. The journey is not over. The virtues of C. elegans research are numerous and have been recounted extensively. Here, we focus on the remarkable progress made in sensory neurobiology research in C. elegans. This nematode continues to amaze researchers as we are still adding new discoveries to the already rich repertoire of sensory capabilities of this deceptively simple animal. Worms possess the sense of taste, smell, touch, light, temperature and proprioception, each of which is being studied in genetic, molecular, cellular and systems-level detail. This impressive organism can even detect less commonly recognized sensory cues such as magnetic fields and humidity.
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Affiliation(s)
- Adam J Iliff
- Department of Molecular and Integrative Physiology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - X Z Shawn Xu
- Department of Molecular and Integrative Physiology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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30
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Mehle EA, Sojka SE, K C M, Zel RM, Reese SJ, Ferkey DM. The C. elegans TRPV channel proteins OSM-9 and OCR-2 contribute to aversive chemical sensitivity. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 32666046 PMCID: PMC7352062 DOI: 10.17912/micropub.biology.000277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emily A Mehle
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Savannah E Sojka
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Medha K C
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Rosy M Zel
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Sebastian J Reese
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260
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31
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Capsaicin Functions as Drosophila Ovipositional Repellent and Causes Intestinal Dysplasia. Sci Rep 2020; 10:9963. [PMID: 32561812 PMCID: PMC7305228 DOI: 10.1038/s41598-020-66900-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/28/2020] [Indexed: 12/13/2022] Open
Abstract
Plants generate a plethora of secondary compounds (toxins) that potently influence the breadth of the breeding niches of animals, including Drosophila. Capsaicin is an alkaloid irritant from hot chili peppers, and can act as a deterrent to affect animal behaviors, such as egg laying choice. However, the mechanism underlying this ovipositional avoidance remains unknown. Here, we report that Drosophila females exhibit a robust ovipositional aversion to capsaicin. First, we found that females were robustly repelled from laying eggs on capsaicin-containing sites. Second, genetic manipulations show that the ovipositional aversion to capsaicin is mediated by activation of nociceptive neurons expressing the painless gene. Finally, we found that capsaicin compromised the health and lifespan of flies through intestinal dysplasia and oxidative innate immunity. Overall, our study suggests that egg-laying sensation converts capsaicin into an aversive behavior for female Drosophila, mirroring an adaptation to facilitate the survival and fitness of both parents and offspring.
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32
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Wheeler NJ, Heimark ZW, Airs PM, Mann A, Bartholomay LC, Zamanian M. Genetic and functional diversification of chemosensory pathway receptors in mosquito-borne filarial nematodes. PLoS Biol 2020; 18:e3000723. [PMID: 32511224 PMCID: PMC7302863 DOI: 10.1371/journal.pbio.3000723] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 06/18/2020] [Accepted: 05/20/2020] [Indexed: 12/25/2022] Open
Abstract
Lymphatic filariasis (LF) afflicts over 60 million people worldwide and leads to severe pathological outcomes in chronic cases. The nematode parasites (Nematoda: Filarioidea) that cause LF require both arthropod (mosquito) intermediate hosts and mammalian definitive hosts for their propagation. The invasion and migration of filarial worms through host tissues are complex and critical to survival, yet little is known about the receptors and signaling pathways that mediate directed migration in these medically important species. In order to better understand the role of chemosensory signaling in filarial worm taxis, we employ comparative genomics, transcriptomics, reverse genetics, and chemical approaches to identify putative chemosensory receptor proteins and perturb chemotaxis phenotypes in filarial worms. We find that chemoreceptor family size is correlated with the presence of environmental (extrahost) stages in nematode life cycles, and that filarial worms contain compact and highly diverged chemoreceptor complements and lineage-specific ion channels that are predicted to operate downstream of chemoreceptor activation. In Brugia malayi, an etiological agent of LF, chemoreceptor expression patterns correspond to distinct parasite migration events across the life cycle. To interrogate the role of chemosensation in the migration of larval worms, arthropod and mammalian infectious stage Brugia parasites were incubated in nicotinamide, an agonist of the nematode transient receptor potential (TRP) channel OSM-9. Exposure of microfilariae to nicotinamide alters intramosquito migration, and exposure of L3s reduces chemotaxis toward host-associated cues in vitro. Nicotinamide also potently modulates thermosensory responses in L3s, suggesting a polymodal sensory role for Brugia osm-9. Reverse genetic studies implicate both Brugia osm-9 and the cyclic nucleotide-gated (CNG) channel subunit tax-4 in larval chemotaxis toward host serum, and these ion channel subunits partially rescue sensory defects in Caenorhabditis elegans osm-9 and tax-4 knock-out strains. Together, these data reveal genetic and functional diversification of chemosensory signaling proteins in filarial worms and encourage a more thorough investigation of clade- and parasite-specific facets of nematode sensory receptor biology.
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Affiliation(s)
- Nicolas J. Wheeler
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Zachary W. Heimark
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Paul M. Airs
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Alexis Mann
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Lyric C. Bartholomay
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mostafa Zamanian
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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33
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Yan Z, Su Z, Cheng X, Liu J. Caenorhabditis elegans body wall muscles sense mechanical signals with an amiloride-sensitive cation channel. Biochem Biophys Res Commun 2020; 527:581-587. [PMID: 32423813 DOI: 10.1016/j.bbrc.2020.04.130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/26/2020] [Indexed: 01/09/2023]
Abstract
C. elegans uses specialized mechanoreceptor neurons to sense various mechanical cues. However, whether other tissues and organs in C. elegans are able to perceive mechanical forces is not clear. In this study, with a whole-cell patch-clamp recording, we show that body wall muscles (BWMs) in C. elegans convert mechanical energy into ionic currents in a cell-autonomous manner. Mechano-gated ion channels in BWMs are blocked in amiloride or cation-free solutions. A further characterization of physiological properties of mechano-gate ion channels in BMWs and a genetic screening show that mechanosensation in BMWs is not dependent on UNC-105 and well-defined mechano-gated ion channels MEC-4 and TRP-4 in C. elegans. Taken together, our results demonstrate that BWMs in C. elegans function as mechanoreceptors to sense mechanical stimuli with an amiloride-sensitive, non-selective cation channel.
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Affiliation(s)
- Zhenzhen Yan
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Zexiong Su
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Xinran Cheng
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Jie Liu
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, 3800, Australia.
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34
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Tang YQ, Lee SA, Rahman M, Vanapalli SA, Lu H, Schafer WR. Ankyrin Is An Intracellular Tether for TMC Mechanotransduction Channels. Neuron 2020; 107:112-125.e10. [PMID: 32325031 PMCID: PMC7343241 DOI: 10.1016/j.neuron.2020.03.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/17/2020] [Accepted: 03/24/2020] [Indexed: 12/15/2022]
Abstract
Mechanotransduction channels have been proposed as force sensors in various physiological processes, such as hearing and touch. In particular, TMC1 has been shown to constitute the pore of hair cell mechanotransduction channels, but little is known about how force is sensed by TMC channels. Here, we identify UNC-44/ankyrin as an essential component of the TMC-1 mechanotransduction channel complex in the sensory cilia of Caenorhabditis elegans mechanoreceptor neurons. Ankyrin binds indirectly to TMC-1 via evolutionarily conserved CIB proteins, which are required for TMC-1-mediated mechanosensation in C. elegans OLQ neurons and body wall muscles. Mechanosensory activity conferred by ectopically expressed TMCs in mechanoinsensitive neurons depends on both ankyrin and CIB proteins, indicating that the ankyrin-CIB subcomplex is required for TMC mechanosensitivity. Our work indicates that ankyrin is a long-sought intracellular tether that transmits force to TMC mechanotransduction channels. TMC-1 functions as a mechanosensor in C. elegans neurons and muscles UNC-44/ankyrin binds indirectly to TMC-1 via CALM-1 CALM-1 and ankyrin are required for TMC-1-mediated mechanosensation Ankyrin acts as an intracellular tether to confer mechanosensitivity to TMC channels
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Affiliation(s)
- Yi-Quan Tang
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
| | - Sol Ah Lee
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA
| | - Mizanur Rahman
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Siva A Vanapalli
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, USA
| | - Hang Lu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK; Department of Biology, KU Leuven, 3000 Leuven, Belgium.
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35
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Dao J, Lee A, Drecksel DK, Bittlingmaier NM, Nelson TM. Characterization of TMC-1 in C. elegans sodium chemotaxis and sodium conditioned aversion. BMC Genet 2020; 21:37. [PMID: 32228447 PMCID: PMC7106803 DOI: 10.1186/s12863-020-00844-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 03/19/2020] [Indexed: 12/11/2022] Open
Abstract
Background While sodium is attractive at low and aversive at high concentrations in most studied species, including Caenorhabditis elegans, the molecular mechanisms behind transduction remain poorly understood. Additionally, past studies with C. elegans provide evidence that the nematode’s innate behavior can be altered by previous experiences. Here we investigated the molecular aspects of both innate and conditioned responses to salts. Transmembrane channel-like 1 (tmc-1) has been suggested to encode a sodium-sensitive channel required for sodium chemosensation in C. elegans, but its specific role remains unclear. Results We report that TMC-1 is necessary for sodium attraction, but not aversion in the nematode. We show that TMC-1 contributes to the nematode’s lithium induced attraction behavior, but not potassium or magnesium attraction thus clarifying the specificity of the response. In addition, we show that sodium conditioned aversion is dependent on TMC-1 and disrupts not only sodium induced attraction, but also lithium. Conclusions These findings represent the first time a role for TMC-1 has been described in sodium and lithium attraction in vivo, as well as in sodium conditioned aversion. Together this clarifies TMC-1’s importance in sodium hedonics and offer molecular insight into salt chemotaxis learning.
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Affiliation(s)
- Joseph Dao
- Department of Human Science, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Aileen Lee
- Department of International Health, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Dana K Drecksel
- Department of International Health, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Nicole M Bittlingmaier
- Department of Human Science, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Theodore M Nelson
- Department of Human Science, Georgetown University Medical Center, Washington, DC, 20057, USA.
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36
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Jin P, Jan LY, Jan YN. Mechanosensitive Ion Channels: Structural Features Relevant to Mechanotransduction Mechanisms. Annu Rev Neurosci 2020; 43:207-229. [PMID: 32084327 DOI: 10.1146/annurev-neuro-070918-050509] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Activation of mechanosensitive ion channels underlies a variety of fundamental physiological processes that require sensation of mechanical force. Different mechanosensitive channels adapt distinctive structures and mechanotransduction mechanisms to fit their biological roles. How mechanosensitive channels work, especially in animals, has been extensively studied in the past decade. Here we review key findings in the functional and structural characterizations of these channels and highlight the structural features relevant to the mechanotransduction mechanism of each specific channel.
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Affiliation(s)
- Peng Jin
- Department of Physiology, University of California, San Francisco, California 94158, USA;
| | - Lily Yeh Jan
- Department of Physiology, University of California, San Francisco, California 94158, USA; .,Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA
| | - Yuh-Nung Jan
- Department of Physiology, University of California, San Francisco, California 94158, USA; .,Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA
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37
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A Screen for Gene Paralogies Delineating Evolutionary Branching Order of Early Metazoa. G3-GENES GENOMES GENETICS 2020; 10:811-826. [PMID: 31879283 PMCID: PMC7003098 DOI: 10.1534/g3.119.400951] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The evolutionary diversification of animals is one of Earth’s greatest marvels, yet its earliest steps are shrouded in mystery. Animals, the monophyletic clade known as Metazoa, evolved wildly divergent multicellular life strategies featuring ciliated sensory epithelia. In many lineages epithelial sensoria became coupled to increasingly complex nervous systems. Currently, different phylogenetic analyses of single-copy genes support mutually-exclusive possibilities that either Porifera or Ctenophora is sister to all other animals. Resolving this dilemma would advance the ecological and evolutionary understanding of the first animals and the evolution of nervous systems. Here we describe a comparative phylogenetic approach based on gene duplications. We computationally identify and analyze gene families with early metazoan duplications using an approach that mitigates apparent gene loss resulting from the miscalling of paralogs. In the transmembrane channel-like (TMC) family of mechano-transducing channels, we find ancient duplications that define separate clades for Eumetazoa (Placozoa + Cnidaria + Bilateria) vs. Ctenophora, and one duplication that is shared only by Eumetazoa and Porifera. In the Max-like protein X (MLX and MLXIP) family of bHLH-ZIP regulators of metabolism, we find that all major lineages from Eumetazoa and Porifera (sponges) share a duplicated gene pair that is sister to the single-copy gene maintained in Ctenophora. These results suggest a new avenue for deducing deep phylogeny by choosing rather than avoiding ancient gene paralogies.
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38
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Jia Y, Zhao Y, Kusakizako T, Wang Y, Pan C, Zhang Y, Nureki O, Hattori M, Yan Z. TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels. Neuron 2019; 105:310-321.e3. [PMID: 31761710 DOI: 10.1016/j.neuron.2019.10.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/05/2019] [Accepted: 10/09/2019] [Indexed: 11/28/2022]
Abstract
Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are pore-forming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.
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Affiliation(s)
- Yanyan Jia
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yimeng Zhao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yao Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Chengfang Pan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yuwei Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China.
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39
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Yue X, Sheng Y, Kang L, Xiao R. Distinct functions of TMC channels: a comparative overview. Cell Mol Life Sci 2019; 76:4221-4232. [PMID: 31584127 PMCID: PMC11105308 DOI: 10.1007/s00018-019-03214-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/18/2022]
Abstract
In the past two decades, transmembrane channel-like (TMC) proteins have attracted a significant amount of research interest, because mutations of Tmc1 lead to hereditary deafness. As evolutionarily conserved membrane proteins, TMC proteins are widely involved in diverse sensorimotor functions of many species, such as hearing, chemosensation, egg laying, and food texture detection. Interestingly, recent structural and physiological studies suggest that TMC channels may share a similar membrane topology with the Ca2+-activated Cl- channel TMEM16 and the mechanically activated OSCA1.2/TMEM63 channel. Namely, these channels form dimers and each subunit consists of ten transmembrane segments. Despite this important structural insight, a key question remains: what is the gating mechanism of TMC channels? The major technical hurdle to answer this question is that the reconstitution of TMC proteins as functional ion channels has been challenging in mammalian heterologous systems. Since TMC channels are conserved across taxa, genetic studies of TMC channels in model organisms such as C. elegans, Drosophila, and zebrafish may provide us critical information on the physiological function and regulation of TMCs. Here, we present a comparative overview on the diverse functions of TMC channels in different species.
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Affiliation(s)
- Xiaomin Yue
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sheng
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
| | - Lijun Kang
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.
| | - Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA.
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL, USA.
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
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40
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Liu S, Wang S, Zou L, Li J, Song C, Chen J, Hu Q, Liu L, Huang P, Xiong W. TMC1 is an essential component of a leak channel that modulates tonotopy and excitability of auditory hair cells in mice. eLife 2019; 8:47441. [PMID: 31661074 PMCID: PMC6853638 DOI: 10.7554/elife.47441] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/24/2019] [Indexed: 11/13/2022] Open
Abstract
Hearing sensation relies on the mechano-electrical transducer (MET) channel of cochlear hair cells, in which transmembrane channel-like 1 (TMC1) and transmembrane channel-like 2 (TMC2) have been proposed to be the pore-forming subunits in mammals. TMCs were also found to regulate biological processes other than MET in invertebrates, ranging from sensations to motor function. However, whether TMCs have a non-MET role remains elusive in mammals. Here, we report that in mouse hair cells, TMC1, but not TMC2, provides a background leak conductance, with properties distinct from those of the MET channels. By cysteine substitutions in TMC1, we characterized four amino acids that are required for the leak conductance. The leak conductance is graded in a frequency-dependent manner along the length of the cochlea and is indispensable for action potential firing. Taken together, our results show that TMC1 confers a background leak conductance in cochlear hair cells, which may be critical for the acquisition of sound-frequency and -intensity.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jie Li
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Chenmeng Song
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jiaofeng Chen
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Qun Hu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Lian Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Pingbo Huang
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China.,State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
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41
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Gong J, Liu J, Ronan EA, He F, Cai W, Fatima M, Zhang W, Lee H, Li Z, Kim GH, Pipe KP, Duan B, Liu J, Xu XZS. A Cold-Sensing Receptor Encoded by a Glutamate Receptor Gene. Cell 2019; 178:1375-1386.e11. [PMID: 31474366 DOI: 10.1016/j.cell.2019.07.034] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/31/2019] [Accepted: 07/17/2019] [Indexed: 12/11/2022]
Abstract
In search of the molecular identities of cold-sensing receptors, we carried out an unbiased genetic screen for cold-sensing mutants in C. elegans and isolated a mutant allele of glr-3 gene that encodes a kainate-type glutamate receptor. While glutamate receptors are best known to transmit chemical synaptic signals in the CNS, we show that GLR-3 senses cold in the peripheral sensory neuron ASER to trigger cold-avoidance behavior. GLR-3 transmits cold signals via G protein signaling independently of its glutamate-gated channel function, suggesting GLR-3 as a metabotropic cold receptor. The vertebrate GLR-3 homolog GluK2 from zebrafish, mouse, and human can all function as a cold receptor in heterologous systems. Mouse DRG sensory neurons express GluK2, and GluK2 knockdown in these neurons suppresses their sensitivity to cold but not cool temperatures. Our study identifies an evolutionarily conserved cold receptor, revealing that a central chemical receptor unexpectedly functions as a thermal receptor in the periphery.
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Affiliation(s)
- Jianke Gong
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, and International Research Center for Sensory Biology and Technology of MOST, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jinzhi Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, and International Research Center for Sensory Biology and Technology of MOST, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elizabeth A Ronan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Feiteng He
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, and International Research Center for Sensory Biology and Technology of MOST, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wei Cai
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mahar Fatima
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wenyuan Zhang
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, and International Research Center for Sensory Biology and Technology of MOST, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hankyu Lee
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhaoyu Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gun-Ho Kim
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, South Korea
| | - Kevin P Pipe
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bo Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, and International Research Center for Sensory Biology and Technology of MOST, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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42
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Cunningham CL, Müller U. Molecular Structure of the Hair Cell Mechanoelectrical Transduction Complex. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033167. [PMID: 30082452 DOI: 10.1101/cshperspect.a033167] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cochlear hair cells employ mechanically gated ion channels located in stereocilia that open in response to sound wave-induced motion of the basilar membrane, converting mechanical stimulation to graded changes in hair cell membrane potential. Membrane potential changes in hair cells cause neurotransmitter release from hair cells that initiate electrical signals in the nerve terminals of afferent fibers from spiral ganglion neurons. These signals are then propagated within the central nervous system (CNS) to mediate the sensation of hearing. Recent studies show that the mechanoelectrical transduction (MET) machinery of hair cells is formed by an ensemble of proteins. Candidate components forming the MET channel have been identified, but none alone fulfills all criteria necessary to define them as pore-forming subunits of the MET channel. We will review here recent findings on the identification and function of proteins that are components of the MET machinery in hair cells and consider remaining open questions.
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Affiliation(s)
- Christopher L Cunningham
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
| | - Ulrich Müller
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
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43
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Qiu X, Müller U. Mechanically Gated Ion Channels in Mammalian Hair Cells. Front Cell Neurosci 2018; 12:100. [PMID: 29755320 PMCID: PMC5932396 DOI: 10.3389/fncel.2018.00100] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/26/2018] [Indexed: 01/05/2023] Open
Abstract
Hair cells in the inner ear convert mechanical stimuli provided by sound waves and head movements into electrical signal. Several mechanically evoked ionic currents with different properties have been recorded in hair cells. The search for the proteins that form the underlying ion channels is still in progress. The mechanoelectrical transduction (MET) channel near the tips of stereociliary in hair cells, which is responsible for sensory transduction, has been studied most extensively. Several components of the sensory mechanotransduction machinery in stereocilia have been identified, including the multi-transmembrane proteins tetraspan membrane protein in hair cell stereocilia (TMHS)/LHFPL5, transmembrane inner ear (TMIE) and transmembrane channel-like proteins 1 and 2 (TMC1/2). However, there remains considerable uncertainty regarding the molecules that form the channel pore. In addition to the sensory MET channel, hair cells express the mechanically gated ion channel PIEZO2, which is localized near the base of stereocilia and not essential for sensory transduction. The function of PIEZO2 in hair cells is not entirely clear but it might have a role in damage sensing and repair processes. Additional stretch-activated channels of unknown molecular identity and function have been found to localize at the basolateral membrane of hair cells. Here, we review current knowledge regarding the different mechanically gated ion channels in hair cells and discuss open questions concerning their molecular composition and function.
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Affiliation(s)
- Xufeng Qiu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ulrich Müller
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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44
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Yue X, Zhao J, Li X, Fan Y, Duan D, Zhang X, Zou W, Sheng Y, Zhang T, Yang Q, Luo J, Duan S, Xiao R, Kang L. TMC Proteins Modulate Egg Laying and Membrane Excitability through a Background Leak Conductance in C. elegans. Neuron 2018; 97:571-585.e5. [PMID: 29395910 DOI: 10.1016/j.neuron.2017.12.041] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/24/2017] [Accepted: 12/26/2017] [Indexed: 12/13/2022]
Abstract
Membrane excitability is a fundamentally important feature for all excitable cells including both neurons and muscle cells. However, the background depolarizing conductances in excitable cells, especially in muscle cells, are not well characterized. Although mutations in transmembrane channel-like (TMC) proteins TMC1 and TMC2 cause deafness and vestibular defects in mammals, their precise action modes are elusive. Here, we discover that both TMC-1 and TMC-2 are required for normal egg laying in C. elegans. Mutations in these TMC proteins cause membrane hyperpolarization and disrupt the rhythmic calcium activities in both neurons and muscles involved in egg laying. Mechanistically, TMC proteins enhance membrane depolarization through background leak currents and ectopic expression of both C. elegans and mammalian TMC proteins results in membrane depolarization. Therefore, we have identified an unexpected role of TMC proteins in modulating membrane excitability. Our results may provide mechanistic insights into the functions of TMC proteins in hearing loss and other diseases.
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Affiliation(s)
- Xiaomin Yue
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Jian Zhao
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Li
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuedan Fan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Duo Duan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyan Zhang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjuan Zou
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sheng
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
| | - Ting Zhang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Yang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhong Luo
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA; Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
| | - Lijun Kang
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China.
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45
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Li Z, Iliff AJ, Xu XZS. An Elegant Circuit for Balancing Risk and Reward. Neuron 2017; 92:933-935. [PMID: 27930906 DOI: 10.1016/j.neuron.2016.11.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Animals constantly encounter conflicting cues in natural environments. To survive and thrive, they must make appropriate behavioral decisions. In this issue, Ghosh et al. (2016) identified a neural circuit underlying multisensory threat-reward decision making using an elegant C. elegans model.
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Affiliation(s)
- Zhaoyu Li
- Life Sciences Institute, Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Adam J Iliff
- Life Sciences Institute, Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - X Z Shawn Xu
- Life Sciences Institute, Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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46
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Lee MJ, Sung HY, Jo H, Kim HW, Choi MS, Kwon JY, Kang K. Ionotropic Receptor 76b Is Required for Gustatory Aversion to Excessive Na+ in Drosophila. Mol Cells 2017; 40:787-795. [PMID: 29081083 PMCID: PMC5682255 DOI: 10.14348/molcells.2017.0160] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/23/2017] [Indexed: 12/31/2022] Open
Abstract
Avoiding ingestion of excessively salty food is essential for cation homeostasis that underlies various physiological processes in organisms. The molecular and cellular basis of the aversive salt taste, however, remains elusive. Through a behavioral reverse genetic screening, we discover that feeding suppression by Na+-rich food requires Ionotropic Receptor 76b (Ir76b) in Drosophila labellar gustatory receptor neurons (GRNs). Concentrated sodium solutions with various anions caused feeding suppression dependent on Ir76b. Feeding aversion to caffeine and high concentrations of divalent cations and sorbitol was unimpaired in Ir76b-deficient animals, indicating sensory specificity of Ir76b-dependent Na+ detection and the irrelevance of hyperosmolarity-driven mechanosensation to Ir76b-mediated feeding aversion. Ir76b-dependent Na+-sensing GRNs in both L- and s-bristles are required for repulsion as opposed to the previous report where the L-bristle GRNs direct only low-Na+ attraction. Our work extends the physiological implications of Ir76b from low-Na+ attraction to high-Na+ aversion, prompting further investigation of the physiological mechanisms that modulate two competing components of Na+-evoked gustation coded in heterogeneous Ir76b-positive GRNs.
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Affiliation(s)
- Min Jung Lee
- Samsung Medical Center, Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Suwon 16419,
Korea
- Dong-A ST Research Institute, Yongin 17073,
Korea
| | - Ha Yeon Sung
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419,
Korea
| | - HyunJi Jo
- Samsung Medical Center, Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Suwon 16419,
Korea
| | - Hyung-Wook Kim
- College of Life Sciences, Sejong University, Seoul 05006,
Korea
| | - Min Sung Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419,
Korea
| | - Jae Young Kwon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419,
Korea
| | - KyeongJin Kang
- Samsung Medical Center, Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Suwon 16419,
Korea
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47
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Abstract
Transmembrane channel-like (TMC) proteins have been implicated in hair cell mechanotransduction, Drosophila proprioception, and sodium sensing in the nematode C. elegans. In this issue of Neuron, Wang et al. (2016) report that C. elegans TMC-1 mediates nociceptor responses to high pH, not sodium, allowing the nematode to avoid strongly alkaline environments in which most animals cannot survive.
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Affiliation(s)
- Christian Spalthoff
- Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany; Collaborative Research Center 'Molecular Mechanisms of Sensory Processing', DFG SFB-889, 37075 Göttingen, Germany
| | - Martin C Göpfert
- Department of Cellular Neurobiology, University of Göttingen, 37077 Göttingen, Germany; Collaborative Research Center 'Molecular Mechanisms of Sensory Processing', DFG SFB-889, 37075 Göttingen, Germany.
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48
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Sánchez-Alcañiz JA, Benton R. Multisensory neural integration of chemical and mechanical signals. Bioessays 2017. [DOI: 10.1002/bies.201700060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Juan Antonio Sánchez-Alcañiz
- Faculty of Biology and Medicine; Center for Integrative Genomics; Génopode Building; University of Lausanne; Lausanne CH-1015 Switzerland
| | - Richard Benton
- Faculty of Biology and Medicine; Center for Integrative Genomics; Génopode Building; University of Lausanne; Lausanne CH-1015 Switzerland
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49
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An Aversive Response to Osmotic Upshift in Caenorhabditis elegans. eNeuro 2017; 4:eN-NWR-0282-16. [PMID: 28451641 PMCID: PMC5399755 DOI: 10.1523/eneuro.0282-16.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 12/12/2022] Open
Abstract
Environmental osmolarity presents a common type of sensory stimulus to animals. While behavioral responses to osmotic changes are important for maintaining a stable intracellular osmolarity, the underlying mechanisms are not fully understood. In the natural habitat of Caenorhabditis elegans, changes in environmental osmolarity are commonplace. It is known that the nematode acutely avoids shocks of extremely high osmolarity. Here, we show that C. elegans also generates gradually increased aversion of mild upshifts in environmental osmolarity. Different from an acute avoidance of osmotic shocks that depends on the function of a transient receptor potential vanilloid channel, the slow aversion to osmotic upshifts requires the cGMP-gated sensory channel subunit TAX-2. TAX-2 acts in several sensory neurons that are exposed to body fluid to generate the aversive response through a motor network that underlies navigation. Osmotic upshifts activate the body cavity sensory neuron URX, which is known to induce aversion upon activation. Together, our results characterize the molecular and cellular mechanisms underlying a novel sensorimotor response to osmotic stimuli and reveal that C. elegans engages different behaviors and the underlying mechanisms to regulate responses to extracellular osmolarity.
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Polymodal Responses in C. elegans Phasmid Neurons Rely on Multiple Intracellular and Intercellular Signaling Pathways. Sci Rep 2017; 7:42295. [PMID: 28195191 PMCID: PMC5307315 DOI: 10.1038/srep42295] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/09/2017] [Indexed: 12/03/2022] Open
Abstract
Animals utilize specialized sensory neurons enabling the detection of a wide range of environmental stimuli from the presence of toxic chemicals to that of touch. However, how these neurons discriminate between different kinds of stimuli remains poorly understood. By combining in vivo calcium imaging and molecular genetic manipulation, here we investigate the response patterns and the underlying mechanisms of the C. elegans phasmid neurons PHA/PHB to a variety of sensory stimuli. Our observations demonstrate that PHA/PHB neurons are polymodal sensory neurons which sense harmful chemicals, hyperosmotic solutions and mechanical stimulation. A repulsive concentration of IAA induces calcium elevations in PHA/PHB and both OSM-9 and TAX-4 are essential for IAA-sensing in PHA/PHB. Nevertheless, the PHA/PHB neurons are inhibited by copper and post-synaptically activated by copper removal. Neuropeptide is likely involved in copper removal-induced calcium elevations in PHA/PHB. Furthermore, mechanical stimulation activates PHA/PHB in an OSM-9-dependent manner. Our work demonstrates how PHA/PHB neurons respond to multiple environmental stimuli and lays a foundation for the further understanding of the mechanisms of polymodal signaling, such as nociception, in more complex organisms.
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