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Tang Y, Tian Y, Zhang CX, Wang GT. Olfactory Receptors and Tumorigenesis: Implications for Diagnosis and Targeted Therapy. Cell Biochem Biophys 2024:10.1007/s12013-024-01556-7. [PMID: 39365517 DOI: 10.1007/s12013-024-01556-7] [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] [Accepted: 09/17/2024] [Indexed: 10/05/2024]
Abstract
Olfactory receptors (ORs) are a class of G protein-coupled receptors (GPCR) widely distributed in olfactory sensory neurons and various non-olfactory tissues, serving significant physiological and pathological functions in the human body. Increasing evidence reveals the heightened expression of olfactory receptors in tumorous tissues and cells alongside normal tissues. Olfactory receptors have demonstrated influence over tumor cell proliferation and metastasis, establishing a close relationship with tumor initiation and progression. This review highlights the specific molecular actions and signaling pathways of olfactory receptors in the development of human tumors. The potential for precise tumor diagnosis and targeted therapy through therapeutic targeting of olfactory receptors as an adjunct anticancer treatment strategy is being considered.
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Affiliation(s)
- Yi Tang
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Ye Tian
- Department of Oncology, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, China
| | | | - Guo-Tai Wang
- Department of Hepatobiliary Surgery, Affiliated Hospital of Shaanxi University of Chinese Medicine, Sub No.2, Weiyang West Road, Qindu District, Xianyang, 712000, China.
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2
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Xi O, Guo W, Hu H. Analysis of Genes Associated with Feeding Preference and Detoxification in Various Developmental Stages of Aglais urticae. INSECTS 2024; 15:30. [PMID: 38249036 PMCID: PMC10816842 DOI: 10.3390/insects15010030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/27/2023] [Accepted: 12/30/2023] [Indexed: 01/23/2024]
Abstract
Herbivorous insects and host plants have developed a close and complex relationship over a long period of co-evolution. Some plants provide nutrients for insects, but plants' secondary metabolites also influence their growth and development. Urtica cannabina roots and leaves are poisonous, yet Aglais urticae larvae feed on them, so we aimed to clarify the mechanism enabling this interaction. At present, studies on the detoxification mechanism of the A. urticae are rare. In our study, first, we used the A. urticae larval odor selection behavior bioassay and choice feeding preference assay to analyze the feeding preferences of A. urticae on its host plant, U. cannabina. Next, we used transcriptome sequencing to obtain the unigenes annotated and classified by various databases, such as KEGG and GO. In this study, we found that U. cannabina could attract A. urticae larvae to feed via scent, and the feeding preference assay confirmed that larvae preferred U. cannabina leaves over three other plants: Cirsium japonicum, Cannabis sativa, and Arctium lappa. The activity of detoxifying enzymes GST and CarE changed in larvae that had consumed U. cannabina. Furthermore, through transcriptomic sequencing analysis, 77,624 unigenes were assembled from raw reads. The numbers of differentially expressed genes were calculated using pairwise comparisons of all life stages; the expression of detoxification enzyme genes was substantially higher in larvae than in the pupal and adult stages. Finally, we identified and summarized 34 genes associated with detoxification enzymes, such as UDP-glucose 4-epimerase gene, 5 Glutathione S-transferase genes, 4 Carboxylesterase genes, 4 Cytochrome P450 genes, 10 ATP-binding cassette genes, 4 Superoxide dismutase, and Peroxidase. Moreover, we identified 28 genes associated with the development of A. urticae. The qRT-PCR results were nearly consistent with the transcriptomic data, showing an increased expression level of four genes in larvae. Taken together, this study examines the correlation between A. urticae and host plants U. cannabina, uncovering a pronounced preference for A. urticae larvae toward host plants. Consistent with RNA-seq, we investigated the mechanism of A. urticae's interaction with host plants and identified detoxification-related genes. The present study provides theoretical support for studying insect adaptation mechanisms and biological control.
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Affiliation(s)
- Ouyan Xi
- College of Life Science and Technology, Xinjiang University, Urumqi 830046, China; (O.X.); (W.G.)
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi 830046, China
| | - Wentao Guo
- College of Life Science and Technology, Xinjiang University, Urumqi 830046, China; (O.X.); (W.G.)
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi 830046, China
| | - Hongying Hu
- College of Life Science and Technology, Xinjiang University, Urumqi 830046, China; (O.X.); (W.G.)
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi 830046, China
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3
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Hu Z, Yang J. Structural basis of properties, mechanisms, and channelopathy of cyclic nucleotide-gated channels. Channels (Austin) 2023; 17:2273165. [PMID: 37905307 PMCID: PMC10761061 DOI: 10.1080/19336950.2023.2273165] [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: 09/07/2023] [Accepted: 10/07/2023] [Indexed: 11/02/2023] Open
Abstract
Recent years have seen an outpouring of atomic or near atomic resolution structures of cyclic nucleotide-gated (CNG) channels, captured in closed, transition, pre-open, partially open, and fully open states. These structures provide unprecedented molecular insights into the activation, assembly, architecture, regulation, and channelopathy of CNG channels, as well as mechanistic explanations for CNG channel biophysical and pharmacological properties. This article summarizes recent advances in CNG channel structural biology, describes key structural features and elements, and illuminates a detailed conformational landscape of activation by cyclic nucleotides. The review also correlates structures with findings and properties delineated in functional studies, including nonselective monovalent cation selectivity, Ca2+ permeation and block, block by L-cis-diltiazem, location of the activation gate, lack of voltage-dependent gating, and modulation by lipids and calmodulin. A perspective on future research is also offered.
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Affiliation(s)
- Zhengshan Hu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Jian Yang
- Department of Biological Sciences, Columbia University, New York, NY, USA
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4
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Barret D, Schuster D, Rodrigues M, Leitner A, Picotti P, Schertler G, Kaupp U, Korkhov V, Marino J. Structural basis of calmodulin modulation of the rod cyclic nucleotide-gated channel. Proc Natl Acad Sci U S A 2023; 120:e2300309120. [PMID: 37011209 PMCID: PMC10104587 DOI: 10.1073/pnas.2300309120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/06/2023] [Indexed: 04/05/2023] Open
Abstract
Calmodulin (CaM) regulates many ion channels to control calcium entry into cells, and mutations that alter this interaction are linked to fatal diseases. The structural basis of CaM regulation remains largely unexplored. In retinal photoreceptors, CaM binds to the CNGB subunit of cyclic nucleotide-gated (CNG) channels and, thereby, adjusts the channel's Cyclic guanosine monophosphate (cGMP) sensitivity in response to changes in ambient light conditions. Here, we provide the structural characterization for CaM regulation of a CNG channel by using a combination of single-particle cryo-electron microscopy and structural proteomics. CaM connects the CNGA and CNGB subunits, resulting in structural changes both in the cytosolic and transmembrane regions of the channel. Cross-linking and limited proteolysis-coupled mass spectrometry mapped the conformational changes induced by CaM in vitro and in the native membrane. We propose that CaM is a constitutive subunit of the rod channel to ensure high sensitivity in dim light. Our mass spectrometry-based approach is generally relevant for studying the effect of CaM on ion channels in tissues of medical interest, where only minute quantities are available.
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Affiliation(s)
- Diane C. A. Barret
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
| | - Dina Schuster
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8049Zurich, Switzerland
| | - Matthew J. Rodrigues
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
| | - Paola Picotti
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
| | | | - U. Benjamin Kaupp
- Life and Medical Sciences Institute, University of Bonn, 53115Bonn, Germany
- Max Planck Institute for Multidisciplinary Sciences, 37077Göttingen, Germany
| | - Volodymyr M. Korkhov
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8049Zurich, Switzerland
| | - Jacopo Marino
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
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5
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Geada S, Teixeira-Marques F, Teixeira B, Carvalho AL, Lousan N, Saraiva J, Murta J, Silva R, Zanlonghi X, Defoort-Dhellemmes S, Smirnov V, Dhaenens CM, Blanchet C, Meunier I, Marques JP. Mutational Spectrum, Ocular and Olfactory Phenotypes of CNGB1-Related RP-Olfactory Dysfunction Syndrome in a Multiethnic Cohort. Genes (Basel) 2023; 14:genes14040830. [PMID: 37107588 PMCID: PMC10137467 DOI: 10.3390/genes14040830] [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: 01/29/2023] [Revised: 03/17/2023] [Accepted: 03/26/2023] [Indexed: 04/29/2023] Open
Abstract
CNGB1 gene mutations are a well-known cause of autosomal recessive retinitis pigmentosa (RP), which was recently associated with olfactory dysfunction. The purpose of this study was to report the molecular spectrum and the ocular and olfactory phenotypes of a multiethnic cohort with CNGB1-associated RP. A cross-sectional case series was conducted at two ophthalmic genetics referral centers. Consecutive patients with molecularly confirmed CNGB1-related RP were included. All patients underwent a complete ophthalmological examination complemented by psychophysical olfactory evaluation. Fifteen patients (10 families: 8 Portuguese, 1 French, and 1 Turkish), mean aged 57.13 ± 15.37 years old (yo), were enrolled. Seven disease-causing variants were identified, two of which are reported for the first time: c.2565_2566del and c.2285G > T. Although 11/15 patients reported onset of nyctalopia before age 10, diagnosis was only established after 30 yo in 9/15. Despite widespread retinal degeneration being present in 14/15 probands, a relatively preserved visual acuity was observed throughout follow-up. Olfactory function was preserved in only 4/15 patients, all of whom carried at least one missense variant. Our study supports previous reports of an autosomal recessive RP-olfactory dysfunction syndrome in association with certain disease-causing variants in the CNGB1 gene and expands the mutational spectrum of CNGB1-related disease by reporting two novel variants.
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Affiliation(s)
- Sara Geada
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - Francisco Teixeira-Marques
- Department of Otorhinolaryngology, Centro Hospitalar do Tâmega e Sousa (CHTS), 4560-162 Penafiel, Portugal
| | - Bruno Teixeira
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - Ana Luísa Carvalho
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
- University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Nuno Lousan
- Department of Otorhinolaryngology, Centro Hospitalar do Tâmega e Sousa (CHTS), 4560-162 Penafiel, Portugal
| | - Jorge Saraiva
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
- University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Joaquim Murta
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Rufino Silva
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Xavier Zanlonghi
- Eye Department, Rennes University Hospital, 35 033 Rennes, France
| | - Sabine Defoort-Dhellemmes
- Department of Visual Exploration and Neuro-Ophthalmology, Robert Salengro Hospital, 59 037 Lille, France
- Sensgene Care Network, 67 091 Strasbourg, France
| | - Vasily Smirnov
- Department of Visual Exploration and Neuro-Ophthalmology, Robert Salengro Hospital, 59 037 Lille, France
- Sensgene Care Network, 67 091 Strasbourg, France
| | - Claire-Marie Dhaenens
- University of Lille, INSERM, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59 000 Lille, France
| | - Catherine Blanchet
- Reference Centre for Inherited Sensory Diseases, Montpellier University Hospital, 34 295 Montpellier, France
| | - Isabelle Meunier
- Sensgene Care Network, 67 091 Strasbourg, France
- Reference Centre for Inherited Sensory Diseases, Montpellier University Hospital, 34 295 Montpellier, France
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, 34 091 Montpellier, France
| | - João Pedro Marques
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
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6
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Unusual phototransduction via cross-motif signaling from G q to adenylyl cyclase in intrinsically photosensitive retinalganglion cells. Proc Natl Acad Sci U S A 2023; 120:e2216599120. [PMID: 36584299 PMCID: PMC9910442 DOI: 10.1073/pnas.2216599120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nonimage-forming vision in mammals is mediated primarily by melanopsin (OPN4)-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs). In mouse M1-ipRGCs, melanopsin predominantly activates, via Gαq,11,14, phospholipase C-β4 to open transient receptor 6 (TRPC6) and TRPC7 channels. In M2- and M4-ipRGCs, however, a prominent phototransduction mechanism involves the opening of hyperpolarization- and cyclic nucleotide-gated channels via cyclic nucleotide, although the upstream steps remain uncertain. We report here experiments, primarily on M4-ipRGCs, with photo-uncaging of cyclic nucleotides and virally expressed CNGA2 channels to conclude that the second messenger is cyclic adenosine monophosphate (cAMP) - very surprising considering that cyclic guanosine monophosphate (cGMP) is used in almost all cyclic nucleotide-mediated phototransduction mechanisms across the animal kingdom. We further found that the upstream G protein is likewise Gq, which via its Gβγ subunits directly activates adenylyl cyclase (AC). Our findings are a demonstration in a native cell of a cross-motif GPCR signaling pathway from Gq directly to AC with a specific function.
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Kim H, Kim H, Nguyen LT, Ha T, Lim S, Kim K, Kim SH, Han K, Hyeon SJ, Ryu H, Park YS, Kim SH, Kim IB, Hong GS, Lee SE, Choi Y, Cohen LB, Oh U. Amplification of olfactory signals by Anoctamin 9 is important for mammalian olfaction. Prog Neurobiol 2022; 219:102369. [PMID: 36330924 DOI: 10.1016/j.pneurobio.2022.102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Sensing smells of foods, prey, or predators determines animal survival. Olfactory sensory neurons in the olfactory epithelium (OE) detect odorants, where cAMP and Ca2+ play a significant role in transducing odorant inputs to electrical activity. Here we show Anoctamin 9, a cation channel activated by cAMP/PKA pathway, is expressed in the OE and amplifies olfactory signals. Ano9-deficient mice had reduced olfactory behavioral sensitivity, electro-olfactogram signals, and neural activity in the olfactory bulb. In line with the difference in olfaction between birds and other vertebrates, chick ANO9 failed to respond to odorants, whereas chick CNGA2, a major transduction channel, showed greater responses to cAMP. Thus, we concluded that the signal amplification by ANO9 is important for mammalian olfactory transduction.
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Affiliation(s)
- Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Luan Thien Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Taewoong Ha
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Sujin Lim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyungmin Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Soon Ho Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Kyungreem Han
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Jae Hyeon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hoon Ryu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yong Soo Park
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Sang Hyun Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - In-Beom Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Eun Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yunsook Choi
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Lawrence B Cohen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
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8
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A multivesicular body-like organelle mediates stimulus-regulated trafficking of olfactory ciliary transduction proteins. Nat Commun 2022; 13:6889. [PMID: 36371422 PMCID: PMC9653401 DOI: 10.1038/s41467-022-34604-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 10/28/2022] [Indexed: 11/13/2022] Open
Abstract
Stimulus transduction in cilia of olfactory sensory neurons is mediated by odorant receptors, Gαolf, adenylate cyclase-3, cyclic nucleotide-gated and chloride ion channels. Mechanisms regulating trafficking and localization of these proteins in the dendrite are unknown. By lectin/immunofluorescence staining and in vivo correlative light-electron microscopy (CLEM), we identify a retinitis pigmentosa-2 (RP2), ESCRT-0 and synaptophysin-containing multivesicular organelle that is not part of generic recycling/degradative/exosome pathways. The organelle's intraluminal vesicles contain the olfactory transduction proteins except for Golf subunits Gγ13 and Gβ1. Instead, Gβ1 colocalizes with RP2 on the organelle's outer membrane. The organelle accumulates in response to stimulus deprivation, while odor stimuli or adenylate cyclase activation cause outer membrane disintegration, release of intraluminal vesicles, and RP2/Gβ1 translocation to the base of olfactory cilia. Together, these findings reveal the existence of a dendritic organelle that mediates both stimulus-regulated storage of olfactory ciliary transduction proteins and membrane-delimited sorting important for G protein heterotrimerization.
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9
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Schirmeyer J, Eick T, Schulz E, Hummert S, Sattler C, Schmauder R, Benndorf K. Subunit promotion energies for channel opening in heterotetrameric olfactory CNG channels. PLoS Comput Biol 2022; 18:e1010376. [PMID: 35998156 PMCID: PMC9512249 DOI: 10.1371/journal.pcbi.1010376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 09/26/2022] [Accepted: 07/11/2022] [Indexed: 11/18/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) ion channels of olfactory sensory neurons contain three types of homologue subunits, two CNGA2 subunits, one CNGA4 subunit and one CNGB1b subunit. Each subunit carries an intracellular cyclic nucleotide binding domain (CNBD) whose occupation by up to four cyclic nucleotides evokes channel activation. Thereby, the subunits interact in a cooperative fashion. Here we studied 16 concatamers with systematically disabled, but still functional, binding sites and quantified channel activation by systems of intimately coupled state models transferred to 4D hypercubes, thereby exploiting a weak voltage dependence of the channels. We provide the complete landscape of free energies for the complex activation process of heterotetrameric channels, including 32 binding steps, in both the closed and open channel, as well as 16 closed-open isomerizations. The binding steps are specific for the subunits and show pronounced positive cooperativity for the binding of the second and the third ligand. The energetics of the closed-open isomerizations were disassembled to elementary subunit promotion energies for channel opening, ΔΔGfpn, adding to the free energy of the closed-open isomerization of the empty channel, E0. The ΔΔGfpn values are specific for the four subunits and presumably invariant for the specific patterns of liganding. In conclusion, subunit cooperativity is confined to the CNBD whereas the subunit promotion energies for channel opening are independent. Olfactory sensory neurons (OSNs) in the nose transmit the information of odor molecules to electrical signals that are conducted to central parts of the brain. Olfactory cyclic nucleotide-gated (CNG) ion channels, located in the cell membrane of the OSNs, are relevant proteins in this process. These olfactory CNG channels are formed by three types of homologue subunits and each of these subunits contains a cyclic nucleotide binding domain (CNBD). A channel is activated by the binding of up to four cyclic nucleotides. The process of channel activation is only poorly understood. Herein we analyzed this activation process in great detail by concatenating these four subunits, disabling the CNBDs by mutations and performing extended computational fit analyses providing all 32 constants for the different binding steps at different degrees of liganding and, in addition, elementary subunit promotion energies for channel opening for all subunits. Our data suggest that subunit cooperativity is confined to the action of the CNBD.
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Affiliation(s)
- Jana Schirmeyer
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Thomas Eick
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eckhard Schulz
- Schmalkalden University of Applied Sciences, Faculty of Electrical Engineering, Blechhammer, Schmalkalden, Germany
| | - Sabine Hummert
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Schmalkalden University of Applied Sciences, Faculty of Electrical Engineering, Blechhammer, Schmalkalden, Germany
| | - Christian Sattler
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Ralf Schmauder
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Klaus Benndorf
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- * E-mail:
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10
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Xue J, Han Y, Zeng W, Jiang Y. Structural mechanisms of assembly, permeation, gating, and pharmacology of native human rod CNG channel. Neuron 2022; 110:86-95.e5. [PMID: 34699778 PMCID: PMC8738139 DOI: 10.1016/j.neuron.2021.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/15/2021] [Accepted: 10/01/2021] [Indexed: 01/07/2023]
Abstract
Mammalian cyclic nucleotide-gated (CNG) channels are nonselective cation channels activated by cGMP or cAMP and play essential roles in the signal transduction of the visual and olfactory sensory systems. CNGA1, the principal component of the CNG channel from rod photoreceptors, can by itself form a functional homotetrameric channel and has been used as the model system in the majority of rod CNG studies. However, the native rod CNG functions as a heterotetramer consisting of three A1 and one B1 subunits and exhibits different functional properties than the CNGA1 homomer. Here we present the functional analysis of human rod CNGA1/B1 heterotetramer and its cryo-EM structures in apo, cGMP-bound, cAMP-bound, and L-cis-Diltiazem-blocked states. These structures, with resolution ranging from 2.6 to 3.3 Å, elucidate the structural mechanisms underlying the 3:1 subunit stoichiometry, the asymmetrical gating upon cGMP activation, and the unique pharmacological property of the native rod CNG channel.
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Affiliation(s)
- Jing Xue
- Howard Hughes Medical Institute and Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yan Han
- Howard Hughes Medical Institute and Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Weizhong Zeng
- Howard Hughes Medical Institute and Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Youxing Jiang
- Howard Hughes Medical Institute and Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA,Lead Contact: Youxing Jiang, Ph.D., Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9040, Tel. 214 645-6027; Fax. 214 645-6042;
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11
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Barret DCA, Schertler GFX, Kaupp UB, Marino J. The structure of the native CNGA1/CNGB1 CNG channel from bovine retinal rods. Nat Struct Mol Biol 2022; 29:32-39. [PMID: 34969975 DOI: 10.1038/s41594-021-00700-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 11/09/2021] [Indexed: 11/09/2022]
Abstract
In rod photoreceptors of the retina, the cyclic nucleotide-gated (CNG) channel is composed of three CNGA and one CNGB subunits, and it closes in response to light activation to generate an electrical signal that is conveyed to the brain. Here we report the cryo-EM structure of the closed state of the native rod CNG channel isolated from bovine retina. The structure reveals differences between CNGA1 and CNGB1 subunits. Three CNGA1 subunits are tethered at their C terminus by a coiled-coil region. The C-helix in the cyclic nucleotide-binding domain of CNGB1 features a different orientation from that in the three CNGA1 subunits. The arginine residue R994 of CNGB1 reaches into the ionic pathway and blocks the pore, thus introducing an additional gate, which is different from the central hydrophobic gate known from homomeric CNGA channels. These results address the long-standing question of how CNGB1 subunits contribute to the function of CNG channels in visual and olfactory neurons.
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Affiliation(s)
- Diane C A Barret
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland.,Department of Biology, ETH-Zurich, Zurich, Switzerland
| | - U Benjamin Kaupp
- Center for Advanced European Studies and Research (CAESAR), Bonn, Germany.,Life and Medical Sciences Institute LIMES, University of Bonn, Bonn, Germany
| | - Jacopo Marino
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland.
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12
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Thermodynamic profile of mutual subunit control in a heteromeric receptor. Proc Natl Acad Sci U S A 2021; 118:2100469118. [PMID: 34301910 PMCID: PMC8325370 DOI: 10.1073/pnas.2100469118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) ion channels of olfactory neurons are tetrameric membrane receptors that are composed of two A2 subunits, one A4 subunit, and one B1b subunit. Each subunit carries a cyclic nucleotide-binding domain in the carboxyl terminus, and the channels are activated by the binding of cyclic nucleotides. The mechanism of cooperative channel activation is still elusive. Using a complete set of engineered concatenated olfactory CNG channels, with all combinations of disabled binding sites and fit analyses with systems of allosteric models, the thermodynamics of microscopic cooperativity for ligand binding was subunit- and state-specifically quantified. We show, for the closed channel, that preoccupation of each of the single subunits increases the affinity of each other subunit with a Gibbs free energy (ΔΔG) of ∼-3.5 to ∼-5.5 kJ ⋅ mol-1, depending on the subunit type, with the only exception that a preoccupied opposite A2 subunit has no effect on the other A2 subunit. Preoccupation of two neighbor subunits of a given subunit causes the maximum affinity increase with ΔΔG of ∼-9.6 to ∼-9.9 kJ ⋅ mol-1 Surprisingly, triple preoccupation leads to fewer negative ΔΔG values for a given subunit as compared to double preoccupation. Channel opening increases the affinity of all subunits. The equilibrium constants of closed-open isomerizations systematically increase with progressive liganding. This work demonstrates, on the example of the heterotetrameric olfactory CNG channel, a strategy to derive detailed insights into the specific mutual control of the individual subunits in a multisubunit membrane receptor.
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13
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Boccaccio A, Menini A, Pifferi S. The cyclic AMP signaling pathway in the rodent main olfactory system. Cell Tissue Res 2021; 383:429-443. [PMID: 33447881 DOI: 10.1007/s00441-020-03391-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/10/2020] [Indexed: 01/15/2023]
Abstract
Odor perception begins with the detection of odorant molecules by the main olfactory epithelium located in the nasal cavity. Odorant molecules bind to and activate a large family of G-protein-coupled odorant receptors and trigger a cAMP-mediated transduction cascade that converts the chemical stimulus into an electrical signal transmitted to the brain. Morever, odorant receptors and cAMP signaling plays a relevant role in olfactory sensory neuron development and axonal targeting to the olfactory bulb. This review will first explore the physiological response of olfactory sensory neurons to odorants and then analyze the different components of cAMP signaling and their different roles in odorant detection and olfactory sensory neuron development.
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Affiliation(s)
- Anna Boccaccio
- Institute of Biophysics, National Research Council (CNR), Genova, Italy.
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.,Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
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14
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Lelle M, Otte M, Bonus M, Gohlke H, Benndorf K. Fluorophore-Labeled Cyclic Nucleotides as Potent Agonists of Cyclic Nucleotide-Regulated Ion Channels. Chembiochem 2020; 21:2311-2320. [PMID: 32227403 PMCID: PMC7497086 DOI: 10.1002/cbic.202000116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/26/2020] [Indexed: 12/22/2022]
Abstract
High-affinity fluorescent derivatives of cyclic adenosine and guanosine monophosphate are powerful tools for investigating their natural targets. Cyclic nucleotide-regulated ion channels belong to these targets and are vital for many signal transduction processes, such as vision and olfaction. The relation of ligand binding to activation gating is still challenging, and there is a need for fluorescent probes that enable the process to be broken down to the single-molecule level. This inspired us to prepare fluorophore-labeled cyclic nucleotides, which are composed of a bright dye and a nucleotide derivative with a thiophenol motif at position 8 that has already been shown to enable superior binding affinity. These bioconjugates were prepared by a novel cross-linking strategy that involves substitution of the nucleobase with a modified thiophenolate in good yield. Both fluorescent nucleotides are potent activators of different cyclic nucleotide-regulated ion channels with respect to the natural ligand and previously reported substances. Molecular docking of the probes excluding the fluorophore reveals that the high potency can be attributed to additional hydrophobic and cation-π interactions between the ligand and the protein. Moreover, the introduced substances have the potential to investigate related target proteins, such as cAMP- and cGMP-dependent protein kinases, exchange proteins directly activated by cAMP or phosphodiesterases.
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Affiliation(s)
- Marco Lelle
- Institute of Physiology IIUniversity Hospital JenaKollegiengasse 907743JenaGermany
| | - Maik Otte
- Institute of Physiology IIUniversity Hospital JenaKollegiengasse 907743JenaGermany
| | - Michele Bonus
- Institute for Pharmaceutical and Medicinal ChemistryHeinrich Heine University DüsseldorfUniversitätsstrasse 140225DüsseldorfGermany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal ChemistryHeinrich Heine University DüsseldorfUniversitätsstrasse 140225DüsseldorfGermany
- John von Neumann Institute for Computing (NIC)Jülich Supercomputing Centre (JSC) andInstitute of Biological Information Processing (IBI-7: Structural Biochemistry)Forschungszentrum Jülich GmbHWilhelm-Johnen-Strasse52425JülichGermany
| | - Klaus Benndorf
- Institute of Physiology IIUniversity Hospital JenaKollegiengasse 907743JenaGermany
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15
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Awareness of olfactory impairment in a cohort of patients with CNGB1-associated retinitis pigmentosa. Eye (Lond) 2019; 34:783-784. [PMID: 31570810 DOI: 10.1038/s41433-019-0609-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 09/12/2019] [Indexed: 11/08/2022] Open
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16
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Charbel Issa P, Reuter P, Kühlewein L, Birtel J, Gliem M, Tropitzsch A, Whitcroft KL, Bolz HJ, Ishihara K, MacLaren RE, Downes SM, Oishi A, Zrenner E, Kohl S, Hummel T. Olfactory Dysfunction in Patients With CNGB1-Associated Retinitis Pigmentosa. JAMA Ophthalmol 2019; 136:761-769. [PMID: 29800053 DOI: 10.1001/jamaophthalmol.2018.1621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Importance Co-occurrence of retinitis pigmentosa (RP) and olfactory dysfunction may have a common genetic cause. Objective To report olfactory function and the retinal phenotype in patients with biallelic mutations in CNGB1, a gene coding for a signal transduction channel subunit expressed in rod photoreceptors and olfactory sensory neurons. Design, Setting, and Participants This case series was conducted from August 2015 through July 2017. The setting was a multicenter study involving 4 tertiary referral centers for inherited retinal dystrophies. Participants were 9 patients with CNGB1-associated RP. Main Outcomes and Measures Results of olfactory testing, ocular phenotyping, and molecular genetic testing using targeted next-generation sequencing. Results Nine patients were included in the study, 3 of whom were female. Their ages ranged between 34 and 79 years. All patients had an early onset of night blindness but were usually not diagnosed as having RP before the fourth decade because of slow retinal degeneration. Retinal features were characteristic of a rod-cone dystrophy. Olfactory testing revealed reduced or absent olfactory function, with all except one patient scoring in the lowest quartile in relation to age-related norms. Brain magnetic resonance imaging and electroencephalography measurements in response to olfactory stimulation were available for 1 patient and revealed no visible olfactory bulbs and reduced responses to odor, respectively. Molecular genetic testing identified 5 novel (c.1312C>T, c.2210G>A, c.2492+1G>A, c.2763C>G, and c.3044_3050delGGAAATC) and 5 previously reported mutations in CNGB1. Conclusions and Relevance Mutations in CNGB1 may cause an autosomal recessive RP-olfactory dysfunction syndrome characterized by a slow progression of retinal degeneration and variable anosmia or hyposmia.
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Affiliation(s)
- Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Peggy Reuter
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Laura Kühlewein
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Johannes Birtel
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Martin Gliem
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Anke Tropitzsch
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Katherine L Whitcroft
- University College London (UCL) Ear Institute and Royal National Throat, Nose and Ear Hospital, London, United Kingdom.,Centre for the Study of the Senses, Institute of Philosophy, School of Advanced Study, University of London, London, United Kingdom.,Smell and Taste Clinic, Department of Otorhinolaryngology-Head and Neck Surgery, Technische Universität Dresden, Dresden, Germany
| | - Hanno J Bolz
- Bioscientia Center for Human Genetics, Ingelheim, Germany.,Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Kenji Ishihara
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Robert E MacLaren
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Akio Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Eberhart Zrenner
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology-Head and Neck Surgery, Technische Universität Dresden, Dresden, Germany
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17
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Lelle M, Otte M, Thon S, Bertinetti D, Herberg FW, Benndorf K. Chemical synthesis and biological activity of novel brominated 7-deazaadenosine-3',5'-cyclic monophosphate derivatives. Bioorg Med Chem 2019; 27:1704-1713. [PMID: 30879860 DOI: 10.1016/j.bmc.2019.03.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/09/2019] [Accepted: 03/11/2019] [Indexed: 11/19/2022]
Abstract
Synthetic derivatives of cyclic adenosine monophosphate, such as halogenated or other more hydrophobic analogs, are widely used compounds, to investigate diverse signal transduction pathways of eukaryotic cells. This inspired us to develop cyclic nucleotides, which exhibit chemical structures composed of brominated 7-deazaadenines and the phosphorylated ribosugar. The synthesized 8-bromo- and 7-bromo-7-deazaadenosine-3',5'-cyclic monophosphates rank among the most potent activators of cyclic nucleotide-regulated ion channels as well as cAMP-dependent protein kinase. Moreover, these substances bind tightly to exchange proteins directly activated by cAMP.
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Affiliation(s)
- Marco Lelle
- Institute of Physiology II, University Hospital Jena, Kollegiengasse 9, 07743 Jena, Germany
| | - Maik Otte
- Institute of Physiology II, University Hospital Jena, Kollegiengasse 9, 07743 Jena, Germany
| | - Susanne Thon
- Institute of Physiology II, University Hospital Jena, Kollegiengasse 9, 07743 Jena, Germany
| | - Daniela Bertinetti
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Friedrich W Herberg
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Klaus Benndorf
- Institute of Physiology II, University Hospital Jena, Kollegiengasse 9, 07743 Jena, Germany.
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18
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The regulatory role of the kinase-homology domain in receptor guanylyl cyclases: nothing 'pseudo' about it! Biochem Soc Trans 2018; 46:1729-1742. [PMID: 30420416 DOI: 10.1042/bst20180472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/08/2018] [Accepted: 10/11/2018] [Indexed: 01/05/2023]
Abstract
The availability of genome sequence information and a large number of protein structures has allowed the cataloging of genes into various families, based on their function and predicted biochemical activity. Intriguingly, a number of proteins harbor changes in the amino acid sequence at residues, that from structural elucidation, are critical for catalytic activity. Such proteins have been categorized as 'pseudoenzymes'. Here, we review the role of the pseudokinase (or kinase-homology) domain in receptor guanylyl cyclases. These are multidomain single-pass, transmembrane proteins harboring an extracellular ligand-binding domain, and an intracellular domain composed of a kinase-homology domain that regulates the activity of the associated guanylyl cyclase domain. Mutations that lie in the kinase-homology domain of these receptors are associated with human disease, and either abolish or enhance cGMP production by these receptors to alter downstream signaling events. This raises the interesting possibility that one could identify molecules that bind to the pseudokinase domain and regulate the activities of these receptors, in order to alleviate symptoms in patients harboring these mutations.
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19
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Dibattista M, Pifferi S, Boccaccio A, Menini A, Reisert J. The long tale of the calcium activated Cl - channels in olfactory transduction. Channels (Austin) 2017; 11:399-414. [PMID: 28301269 DOI: 10.1080/19336950.2017.1307489] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ca2+-activated Cl- currents have been implicated in many cellular processes in different cells, but for many years, their molecular identity remained unknown. Particularly intriguing are Ca2+-activated Cl- currents in olfactory transduction, first described in the early 90s. Well characterized electrophysiologically, they carry most of the odorant-induced receptor current in the cilia of olfactory sensory neurons (OSNs). After many attempts to determine their molecular identity, TMEM16B was found to be abundantly expressed in the cilia of OSNs in 2009 and having biophysical properties like those of the native olfactory channel. A TMEM16B knockout mouse confirmed that TMEM16B was indeed the olfactory Cl- channel but also suggested a limited role in olfactory physiology and behavior. The question then arises of what the precise role of TMEM16b in olfaction is. Here we review the long story of this channel and its possible roles.
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Affiliation(s)
- Michele Dibattista
- a Department of Basic Medical Sciences, Neuroscience and Sensory Organs , University of Bari A. Moro , Bari , Italy
| | - Simone Pifferi
- b Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy
| | | | - Anna Menini
- b Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy
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20
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Nache V, Wongsamitkul N, Kusch J, Zimmer T, Schwede F, Benndorf K. Deciphering the function of the CNGB1b subunit in olfactory CNG channels. Sci Rep 2016; 6:29378. [PMID: 27405959 PMCID: PMC4942689 DOI: 10.1038/srep29378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/15/2016] [Indexed: 11/29/2022] Open
Abstract
Olfactory cyclic nucleotide-gated (CNG) ion channels are key players in the signal transduction cascade of olfactory sensory neurons. The second messengers cAMP and cGMP directly activate these channels, generating a depolarizing receptor potential. Olfactory CNG channels are composed of two CNGA2 subunits and two modulatory subunits, CNGA4, and CNGB1b. So far the exact role of the modulatory subunits for channel activation is not fully understood. By measuring ligand binding and channel activation simultaneously, we show that in functional heterotetrameric channels not only the CNGA2 subunits and the CNGA4 subunit but also the CNGB1b subunit binds cyclic nucleotides and, moreover, also alone translates this signal to open the pore. In addition, we show that the CNGB1b subunit is the most sensitive subunit in a heterotetrameric channel to cyclic nucleotides and that it accelerates deactivation to a similar extent as does the CNGA4 subunit. In conclusion, the CNGB1b subunit participates in ligand-gated activation of olfactory CNG channels and, particularly, contributes to rapid termination of odorant signal in an olfactory sensory neuron.
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Affiliation(s)
- Vasilica Nache
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Nisa Wongsamitkul
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Jana Kusch
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Thomas Zimmer
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Frank Schwede
- BIOLOG Life Science Institute, Flughafendamm 9A, D-28199 Bremen, Germany
| | - Klaus Benndorf
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, D-07743 Jena, Germany
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21
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Ferrer I, Garcia-Esparcia P, Carmona M, Carro E, Aronica E, Kovacs GG, Grison A, Gustincich S. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease. Front Aging Neurosci 2016; 8:163. [PMID: 27458372 PMCID: PMC4932117 DOI: 10.3389/fnagi.2016.00163] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells’ own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson’s disease (PD), Alzheimer’s disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain.
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Affiliation(s)
- Isidro Ferrer
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Paula Garcia-Esparcia
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Margarita Carmona
- Institute of Neuropathology, Bellvitge University Hospital, Hospitalet de Llobregat, University of BarcelonaBarcelona, Spain; Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de LlobregatBarcelona, Spain
| | - Eva Carro
- Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED)Madrid, Spain; Neuroscience Group, Research Institute HospitalMadrid, Spain
| | - Eleonora Aronica
- Department of Neuropathology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna Vienna, Austria
| | - Alice Grison
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience Trieste, Italy
| | - Stefano Gustincich
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience Trieste, Italy
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22
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Lachén-Montes M, Fernández-Irigoyen J, Santamaría E. Deconstructing the molecular architecture of olfactory areas using proteomics. Proteomics Clin Appl 2016; 10:1178-1190. [PMID: 27226001 DOI: 10.1002/prca.201500147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/02/2016] [Accepted: 05/22/2016] [Indexed: 11/07/2022]
Abstract
The anatomy of the olfactory system is highly complex, comprising a system of olfactory receptors, pathways for the transmission of olfactory information, and structures for the recognition, discrimination, and memorization of odors. During the last years, proteomics has emerged as a large-scale comprehensive approach to characterize and quantify specific olfactory-related proteomes in different biological conditions such as olfactory learning, neurodegeneration, and ageing between others. The current work reviews recent applications of proteomics to olfaction with particular focus on quantitative proteome profiling studies performed on olfactory areas from laboratory animal models as well as proteomic characterizations performed on specific brain structures and fluids involved in human smell. Finally, we will also discuss the potential application of proteomics to study global proteome dynamics and posttranslationally modified proteomes in order to unravel cell-signaling networks that occur from peripheral structures to olfactory cortical areas during odor processing.
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Affiliation(s)
- Mercedes Lachén-Montes
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Joaquín Fernández-Irigoyen
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,Proteomics Unit, Navarrabiomed, Proteored-ISCIII, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Enrique Santamaría
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,Proteomics Unit, Navarrabiomed, Proteored-ISCIII, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
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23
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Solís-Chagoyán H, Flores-Soto E, Reyes-García J, Valdés-Tovar M, Calixto E, Montaño LM, Benítez-King G. Voltage-Activated Calcium Channels as Functional Markers of Mature Neurons in Human Olfactory Neuroepithelial Cells: Implications for the Study of Neurodevelopment in Neuropsychiatric Disorders. Int J Mol Sci 2016; 17:ijms17060941. [PMID: 27314332 PMCID: PMC4926474 DOI: 10.3390/ijms17060941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 11/16/2022] Open
Abstract
In adulthood, differentiation of precursor cells into neurons continues in several brain structures as well as in the olfactory neuroepithelium. Isolated precursors allow the study of the neurodevelopmental process in vitro. The aim of this work was to determine whether the expression of functional Voltage-Activated Ca2+ Channels (VACC) is dependent on the neurodevelopmental stage in neuronal cells obtained from the human olfactory epithelium of a single healthy donor. The presence of channel-forming proteins in Olfactory Sensory Neurons (OSN) was demonstrated by immunofluorescent labeling, and VACC functioning was assessed by microfluorometry and the patch-clamp technique. VACC were immunodetected only in OSN. Mature neurons responded to forskolin with a five-fold increase in Ca2+. By contrast, in precursor cells, a subtle response was observed. The involvement of VACC in the precursors’ response was discarded for the absence of transmembrane inward Ca2+ movement evoked by step depolarizations. Data suggest differential expression of VACC in neuronal cells depending on their developmental stage and also that the expression of these channels is acquired by OSN during maturation, to enable specialized functions such as ion movement triggered by membrane depolarization. The results support that VACC in OSN could be considered as a functional marker to study neurodevelopment.
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Affiliation(s)
- Héctor Solís-Chagoyán
- Laboratorio de Neurofarmacología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco No. 101, Col. San Lorenzo-Huipulco, Mexico City 14370, Mexico.
| | - Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
| | - Jorge Reyes-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
| | - Marcela Valdés-Tovar
- Laboratorio de Neurofarmacología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco No. 101, Col. San Lorenzo-Huipulco, Mexico City 14370, Mexico.
| | - Eduardo Calixto
- Departamento de Neurobiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco No. 101, Col. San Lorenzo-Huipulco, Mexico City 14370, Mexico.
| | - Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
| | - Gloria Benítez-King
- Laboratorio de Neurofarmacología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco No. 101, Col. San Lorenzo-Huipulco, Mexico City 14370, Mexico.
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Abstract
cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl cyclases (GCs), GC-A to GC-G, which mainly modulate submembrane cGMP microdomains. These GCs share a unique topology comprising an extracellular domain, a short transmembrane region, and an intracellular COOH-terminal catalytic (cGMP synthesizing) region. GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure/volume and energy balance. GC-B is activated by C-type natriuretic peptide, stimulating endochondral ossification in autocrine way. GC-C mediates the paracrine effects of guanylins on intestinal ion transport and epithelial turnover. GC-E and GC-F are expressed in photoreceptor cells of the retina, and their activation by intracellular Ca(2+)-regulated proteins is essential for vision. Finally, in the rodent system two olfactorial GCs, GC-D and GC-G, are activated by low concentrations of CO2and by peptidergic (guanylins) and nonpeptidergic odorants as well as by coolness, which has implications for social behaviors. In the past years advances in human and mouse genetics as well as the development of sensitive biosensors monitoring the spatiotemporal dynamics of cGMP in living cells have provided novel relevant information about this receptor family. This increased our understanding of the mechanisms of signal transduction, regulation, and (dys)function of the membrane GCs, clarified their relevance for genetic and acquired diseases and, importantly, has revealed novel targets for therapies. The present review aims to illustrate these different features of membrane GCs and the main open questions in this field.
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Affiliation(s)
- Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany
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25
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Wongsamitkul N, Nache V, Eick T, Hummert S, Schulz E, Schmauder R, Schirmeyer J, Zimmer T, Benndorf K. Quantifying the cooperative subunit action in a multimeric membrane receptor. Sci Rep 2016; 6:20974. [PMID: 26858151 PMCID: PMC4746656 DOI: 10.1038/srep20974] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/14/2016] [Indexed: 11/10/2022] Open
Abstract
In multimeric membrane receptors the cooperative action of the subunits prevents exact knowledge about the operation and the interaction of the individual subunits. We propose a method that permits quantification of ligand binding to and activation effects of the individual binding sites in a multimeric membrane receptor. The power of this method is demonstrated by gaining detailed insight into the subunit action in olfactory cyclic nucleotide-gated CNGA2 ion channels.
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Affiliation(s)
- Nisa Wongsamitkul
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Vasilica Nache
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Thomas Eick
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Sabine Hummert
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany.,Hochschule Schmalkalden, Fakultät Elektrotechnik, Blechhammer, 98574 Schmalkalden, Germany
| | - Eckhard Schulz
- Hochschule Schmalkalden, Fakultät Elektrotechnik, Blechhammer, 98574 Schmalkalden, Germany
| | - Ralf Schmauder
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Jana Schirmeyer
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Thomas Zimmer
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Klaus Benndorf
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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26
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Benítez-King G, Valdés-Tovar M, Trueta C, Galván-Arrieta T, Argueta J, Alarcón S, Lora-Castellanos A, Solís-Chagoyán H. The microtubular cytoskeleton of olfactory neurons derived from patients with schizophrenia or with bipolar disorder: Implications for biomarker characterization, neuronal physiology and pharmacological screening. Mol Cell Neurosci 2016; 73:84-95. [PMID: 26837043 DOI: 10.1016/j.mcn.2016.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 01/26/2016] [Accepted: 01/29/2016] [Indexed: 01/29/2023] Open
Abstract
Schizophrenia (SZ) and Bipolar Disorder (BD) are highly inheritable chronic mental disorders with a worldwide prevalence of around 1%. Despite that many efforts had been made to characterize biomarkers in order to allow for biological testing for their diagnoses, these disorders are currently detected and classified only by clinical appraisal based on the Diagnostic and Statistical Manual of Mental Disorders. Olfactory neuroepithelium-derived neuronal precursors have been recently proposed as a model for biomarker characterization. Because of their peripheral localization, they are amenable to collection and suitable for being cultured and propagated in vitro. Olfactory neuroepithelial cells can be obtained by a non-invasive brush-exfoliation technique from neuropsychiatric patients and healthy subjects. Neuronal precursors isolated from these samples undergo in vitro the cytoskeletal reorganization inherent to the neurodevelopment process which has been described as one important feature in the etiology of both diseases. In this paper, we will review the current knowledge on microtubular organization in olfactory neurons of patients with SZ and with BD that may constitute specific cytoskeletal endophenotypes and their relation with alterations in L-type voltage-activated Ca(2+) currents. Finally, the potential usefulness of neuronal precursors for pharmacological screening will be discussed.
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Affiliation(s)
- G Benítez-King
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico.
| | - M Valdés-Tovar
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
| | - C Trueta
- Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz (INPRFM), Calzada México-Xochimilco No. 101, Col. San Lorenzo-Huipulco, C.P. 14370, Tlalpan, Distrito Federal, Mexico
| | - T Galván-Arrieta
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
| | - J Argueta
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
| | - S Alarcón
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
| | - A Lora-Castellanos
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
| | - H Solís-Chagoyán
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Mexico
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27
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Tan L, Li Q, Xie XS. Olfactory sensory neurons transiently express multiple olfactory receptors during development. Mol Syst Biol 2015; 11:844. [PMID: 26646940 PMCID: PMC4704490 DOI: 10.15252/msb.20156639] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In mammals, each olfactory sensory neuron randomly expresses one, and only one, olfactory receptor (OR)--a phenomenon called the "one-neuron-one-receptor" rule. Although extensively studied, this rule was never proven for all ~1,000 OR genes in one cell at once, and little is known about its dynamics. Here, we directly tested this rule by single-cell transcriptomic sequencing of 178 cells from the main olfactory epithelium of adult and newborn mice. To our surprise, a subset of cells expressed multiple ORs. Most of these cells were developmentally immature. Our results illustrated how the "one-neuron-one-receptor" rule may have been established: At first, a single neuron temporarily expressed multiple ORs--seemingly violating the rule--and then all but one OR were eliminated. This work provided experimental evidence that epigenetic regulation in the olfactory system selects a single OR by suppressing a few transiently expressed ORs in a single cell during development.
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Affiliation(s)
- Longzhi Tan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Qian Li
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - X Sunney Xie
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
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28
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Xie AJ, Liu EJ, Huang HZ, Hu Y, Li K, Lu Y, Wang JZ, Zhu LQ. Cnga2 Knockout Mice Display Alzheimer’s-Like Behavior Abnormities and Pathological Changes. Mol Neurobiol 2015; 53:4992-9. [DOI: 10.1007/s12035-015-9421-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
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29
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Flegel C, Schöbel N, Altmüller J, Becker C, Tannapfel A, Hatt H, Gisselmann G. RNA-Seq Analysis of Human Trigeminal and Dorsal Root Ganglia with a Focus on Chemoreceptors. PLoS One 2015; 10:e0128951. [PMID: 26070209 PMCID: PMC4466559 DOI: 10.1371/journal.pone.0128951] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/01/2015] [Indexed: 12/11/2022] Open
Abstract
The chemosensory capacity of the somatosensory system relies on the appropriate expression of chemoreceptors, which detect chemical stimuli and transduce sensory information into cellular signals. Knowledge of the complete repertoire of the chemoreceptors expressed in human sensory ganglia is lacking. This study employed the next-generation sequencing technique (RNA-Seq) to conduct the first expression analysis of human trigeminal ganglia (TG) and dorsal root ganglia (DRG). We analyzed the data with a focus on G-protein coupled receptors (GPCRs) and ion channels, which are (potentially) involved in chemosensation by somatosensory neurons in the human TG and DRG. For years, transient receptor potential (TRP) channels have been considered the main group of receptors for chemosensation in the trigeminal system. Interestingly, we could show that sensory ganglia also express a panel of different olfactory receptors (ORs) with putative chemosensory function. To characterize OR expression in more detail, we performed microarray, semi-quantitative RT-PCR experiments, and immunohistochemical staining. Additionally, we analyzed the expression data to identify further known or putative classes of chemoreceptors in the human TG and DRG. Our results give an overview of the major classes of chemoreceptors expressed in the human TG and DRG and provide the basis for a broader understanding of the reception of chemical cues.
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Affiliation(s)
- Caroline Flegel
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Nicole Schöbel
- Department of Animal Physiology, Ruhr-University Bochum, Bochum, Germany
| | | | | | | | - Hanns Hatt
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
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30
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McIntyre JC, Joiner AM, Zhang L, Iñiguez-Lluhí J, Martens JR. SUMOylation regulates ciliary localization of olfactory signaling proteins. J Cell Sci 2015; 128:1934-45. [PMID: 25908845 PMCID: PMC4457158 DOI: 10.1242/jcs.164673] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/24/2015] [Indexed: 11/20/2022] Open
Abstract
Cilia are evolutionarily conserved organelles found on many mammalian cell types, including neuronal populations. Although neuronal cilia, including those on olfactory sensory neurons (OSNs), are often delineated by localization of adenylyl cyclase 3 (AC3, also known as ADCY3), the mechanisms responsible for targeting integral membrane proteins are largely unknown. Post-translational modification by small ubiquitin-like modifier (SUMO) proteins plays an important role in protein localization processes such as nuclear-cytosolic transport. Here, we identified through bioinformatic analysis that adenylyl cyclases harbor conserved SUMOylation motifs, and show that AC3 is a substrate for SUMO modification. Functionally, overexpression of the SUMO protease SENP2 prevented ciliary localization of AC3, without affecting ciliation or cilia maintenance. Furthermore, AC3-SUMO mutants did not localize to cilia. To test whether SUMOylation is sufficient for cilia entry, we compared localization of ANO2, which possesses a SUMO motif, and ANO1, which lacks SUMOylation sites and does not localize to cilia. Introduction of SUMOylation sites into ANO1 was not sufficient for ciliary entry. These data suggest that SUMOylation is necessary but not sufficient for ciliary trafficking of select constituents, further establishing the link between ciliary and nuclear import.
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Affiliation(s)
- Jeremy C McIntyre
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100267, Gainesville, FL 32610, USA
| | - Ariell M Joiner
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lian Zhang
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100267, Gainesville, FL 32610, USA
| | - Jorge Iñiguez-Lluhí
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100267, Gainesville, FL 32610, USA
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31
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Nache V, Eick T, Schulz E, Schmauder R, Benndorf K. Hysteresis of ligand binding in CNGA2 ion channels. Nat Commun 2014; 4:2866. [PMID: 24287615 PMCID: PMC3868267 DOI: 10.1038/ncomms3866] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 11/04/2013] [Indexed: 01/19/2023] Open
Abstract
Tetrameric cyclic nucleotide-gated (CNG) channels mediate receptor potentials in olfaction and vision. The channels are activated by the binding of cyclic nucleotides to a binding domain embedded in the C terminus of each subunit. Here using a fluorescent cGMP derivative (fcGMP), we show for homotetrameric CNGA2 channels that ligand unbinding is ~50 times faster at saturating than at subsaturating fcGMP. Analysis with complex Markovian models reveals two pathways for ligand unbinding; the partially liganded open channel unbinds its ligands from closed states only, whereas the fully liganded channel reaches a different open state from which it unbinds all four ligands rapidly. Consequently, the transition pathways for ligand binding and activation of a fully liganded CNGA2 channel differ from that of ligand unbinding and deactivation, resulting in pronounced hysteresis of the gating mechanism. This concentration-dependent gating mechanism allows the channels to respond to changes in the cyclic nucleotide concentration with different kinetics. Cyclic nucleotide-gated channels mediate olfactory and visual responses. Using a fluorescent cGMP derivative, Nache et al. show that the rate of cyclic nucleotide release from CNGA2 depends on the extent to which this tetrameric receptor is liganded, revealing hysteresis in the gating mechanism.
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Affiliation(s)
- Vasilica Nache
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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32
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Wunder F, Quednau R, Geerts A, Barg M, Tersteegen A. Characterization of the cellular activity of PDE 4 inhibitors using two novel PDE 4 reporter cell lines. Mol Pharm 2013; 10:3697-705. [PMID: 23987244 DOI: 10.1021/mp400206m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We report here the generation and pharmacological characterization of two novel PDE 4B1 and PDE 4D3 reporter cell lines. Intracellular cAMP levels are monitored in these cells by a cAMP-sensitive biosensor. We used the recombinant PDE 4B1 and PDE 4D3 reporter cell lines to characterize the cellular effects of various competitive and allosteric PDE 4 inhibitors. In addition, we compared the cellular activity of these PDE 4 inhibitors with the in vitro inhibition of full-length PDE 4D3 and a truncated enzyme comprising the PDE 4D3 catalytic domain. Two different groups of PDE 4 inhibitors could be identified. The first group, including competitive inhibitors like roflumilast, cilomilast and piclamilast, shows similar in vitro activity on full-length and truncated PDE 4D3 and comparably low cellular activity. The second group, including the allosteric inhibitors PMNPQ, D159153, and D159404, shows much better inhibition of full-length versus truncated PDE 4D3. In addition, these compounds show high cellular activity. Our data obtained with the prototype PDE 4 inhibitor rolipram show that rolipram has properties intermediate between the two groups. The results imply that these novel PDE 4 reporter cell lines are well-suited for the characterization of the cellular activity of PDE 4 inhibitors and may also support a better understanding of the complex PDE 4 pharmacology.
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Affiliation(s)
- Frank Wunder
- Lead Discovery Wuppertal, Bayer Pharma AG , Pharma Research Center, Aprather Weg 18a, D-42096 Wuppertal, Germany
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33
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Smith HK, Luo L, O’Halloran D, Guo D, Huang XY, Samuel ADT, Hobert O. Defining specificity determinants of cGMP mediated gustatory sensory transduction in Caenorhabditis elegans. Genetics 2013; 194:885-901. [PMID: 23695300 PMCID: PMC3730918 DOI: 10.1534/genetics.113.152660] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 05/18/2013] [Indexed: 12/21/2022] Open
Abstract
Cyclic guanosine monophosphate (cGMP) is a key secondary messenger used in signal transduction in various types of sensory neurons. The importance of cGMP in the ASE gustatory receptor neurons of the nematode Caenorhabditis elegans was deduced by the observation that multiple receptor-type guanylyl cyclases (rGCs), encoded by the gcy genes, and two presently known cyclic nucleotide-gated ion channel subunits, encoded by the tax-2 and tax-4 genes, are essential for ASE-mediated gustatory behavior. We describe here specific mechanistic features of cGMP-mediated signal transduction in the ASE neurons. First, we assess the specificity of the sensory functions of individual rGC proteins. We have previously shown that multiple rGC proteins are expressed in a left/right asymmetric manner in the functionally lateralized ASE neurons and are required to sense distinct salt cues. Through domain swap experiments among three different rGC proteins, we show here that the specificity of individual rGC proteins lies in their extracellular domains and not in their intracellular, signal-transducing domains. Furthermore, we find that rGC proteins are also sufficient to confer salt sensory responses to other neurons. Both findings support the hypothesis that rGC proteins are salt receptor proteins. Second, we identify a novel, likely downstream effector of the rGC proteins in gustatory signal transduction, a previously uncharacterized cyclic nucleotide-gated (CNG) ion channel, encoded by the che-6 locus. che-6 mutants show defects in gustatory sensory transduction that are similar to defects observed in animals lacking the tax-2 and tax-4 CNG channels. In contrast, thermosensory signal transduction, which also requires tax-2 and tax-4, does not require che-6, but requires another CNG, cng-3. We propose that CHE-6 may form together with two other CNG subunits, TAX-2 and TAX-4, a gustatory neuron-specific heteromeric CNG channel complex.
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Affiliation(s)
- Heidi K. Smith
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, New York 10032
| | - Linjiao Luo
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138
| | - Damien O’Halloran
- Department of Biological Sciences and Institute for Neuroscience, George Washington University, Washington DC, 20037
| | - Dagang Guo
- Department of Physiology, Cornell University Weill Medical College, New York, New York 10065
| | - Xin-Yun Huang
- Department of Physiology, Cornell University Weill Medical College, New York, New York 10065
| | - Aravinthan D. T. Samuel
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138
| | - Oliver Hobert
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, New York 10032
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138
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34
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Wojtyniak M, Brear AG, O'Halloran DM, Sengupta P. Cell- and subunit-specific mechanisms of CNG channel ciliary trafficking and localization in C. elegans. J Cell Sci 2013; 126:4381-95. [PMID: 23886944 DOI: 10.1242/jcs.127274] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Primary cilia are ubiquitous sensory organelles that concentrate transmembrane signaling proteins essential for sensing environmental cues. Mislocalization of crucial ciliary signaling proteins, such as the tetrameric cyclic nucleotide-gated (CNG) channels, can lead to cellular dysfunction and disease. Although several cis- and trans-acting factors required for ciliary protein trafficking and localization have been identified, whether these mechanisms act in a protein- and cell-specific manner is largely unknown. Here, we show that CNG channel subunits can be localized to discrete ciliary compartments in individual sensory neurons in C. elegans, suggesting that channel composition is heterogeneous across the cilium. We demonstrate that ciliary localization of CNG channel subunits is interdependent on different channel subunits in specific cells, and identify sequences required for efficient ciliary targeting and localization of the TAX-2 CNGB and TAX-4 CNGA subunits. Using a candidate gene approach, we show that Inversin, transition zone proteins, intraflagellar transport motors and a MYND-domain protein are required to traffic and/or localize CNG channel subunits in both a cell- and channel subunit-specific manner. We further find that TAX-2 and TAX-4 are relatively immobile in specific sensory cilia subcompartments, suggesting that these proteins undergo minimal turnover in these domains in mature cilia. Our results uncover unexpected diversity in the mechanisms that traffic and localize CNG channel subunits to cilia both within and across cell types, highlighting the essential contribution of this process to cellular functions.
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Affiliation(s)
- Martin Wojtyniak
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
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35
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Barry J, Gu C. Coupling mechanical forces to electrical signaling: molecular motors and the intracellular transport of ion channels. Neuroscientist 2013; 19:145-59. [PMID: 22910031 PMCID: PMC3625366 DOI: 10.1177/1073858412456088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Proper localization of various ion channels is fundamental to neuronal functions, including postsynaptic potential plasticity, dendritic integration, action potential initiation and propagation, and neurotransmitter release. Microtubule-based forward transport mediated by kinesin motors plays a key role in placing ion channel proteins to correct subcellular compartments. PDZ- and coiled-coil-domain proteins function as adaptor proteins linking ionotropic glutamate and GABA receptors to various kinesin motors, respectively. Recent studies show that several voltage-gated ion channel/transporter proteins directly bind to kinesins during forward transport. Three major regulatory mechanisms underlying intracellular transport of ion channels are also revealed. These studies contribute to understanding how mechanical forces are coupled to electrical signaling and illuminating pathogenic mechanisms in neurodegenerative diseases.
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Affiliation(s)
- Joshua Barry
- The Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Chen Gu
- The Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA
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36
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Dauner K, Lissmann J, Jeridi S, Frings S, Möhrlen F. Expression patterns of anoctamin 1 and anoctamin 2 chloride channels in the mammalian nose. Cell Tissue Res 2012; 347:327-41. [PMID: 22314846 DOI: 10.1007/s00441-012-1324-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 01/09/2012] [Indexed: 02/01/2023]
Abstract
Calcium-activated chloride channels are expressed in chemosensory neurons of the nose and contribute to secretory processes and sensory signal transduction. These channels are thought to be members of the family of anoctamins (alternative name: TMEM16 proteins), which are opened by micromolar concentrations of intracellular Ca(2+). Two family members,ANO 1 (TMEM16A) and ANO 2 (TMEM16B), are expressed in the various sensory and respiratory tissues of the nose.We have examined the tissue specificity and sub-cellular localization of these channels in the nasal respiratory epithelium and in the five chemosensory organs of the nose: the main olfactory epithelium, the septal organ of Masera, the vomeronasal organ, the Grueneberg ganglion and the trigeminal system. We have found that the two channels show mutually exclusive expression patterns. ANO 1 is present in the apical membranes of various secretory epithelia in which it is co-localized with the water channel aquaporin 5. It has also been detected in acinar cells and duct cells of subepithelial glands and in the supporting cells of sensory epithelia. In contrast, ANO 2 expression is restricted to chemosensory neurons in which it has been detected in microvillar and ciliary surface structures. The different expression patterns of ANO 1 and ANO 2 have been observed in the olfactory, vomeronasal and respiratory epithelia. No expression has been detected in the Grueneberg ganglion or trigeminal sensory fibers. On the basis of this differential expression, we derive the main functional features of ANO 1 and ANO 2 chloride channels in the nose and suggest their significance for nasal physiology.
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Affiliation(s)
- Kristin Dauner
- Department of Molecular Physiology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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37
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Nache V, Zimmer T, Wongsamitkul N, Schmauder R, Kusch J, Reinhardt L, Bönigk W, Seifert R, Biskup C, Schwede F, Benndorf K. Differential regulation by cyclic nucleotides of the CNGA4 and CNGB1b subunits in olfactory cyclic nucleotide-gated channels. Sci Signal 2012; 5:ra48. [PMID: 22786723 DOI: 10.1126/scisignal.2003110] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Olfactory cyclic nucleotide-gated (CNG) ion channels are essential contributors to signal transduction of olfactory sensory neurons. The activity of the channels is controlled by the cyclic nucleotides guanosine 3',5'-monophosphate (cGMP) and adenosine 3',5'-monophosphate (cAMP). The olfactory CNG channels are composed of two CNGA2 subunits, one CNGA4 and one CNGB1b subunit, each containing a cyclic nucleotide-binding domain. Using patch-clamp fluorometry, we measured ligand binding and channel activation simultaneously and showed that cGMP activated olfactory CNG channels not only by binding to the two CNGA2 subunits but also by binding to the CNGA4 subunit. In a channel in which the CNGA2 subunits were compromised for ligand binding, cGMP binding to CNGA4 was sufficient to partly activate the channel. In contrast, in heterotetrameric channels, the CNGB1b subunit did not bind cGMP, but channels with this subunit showed activation by cAMP. Thus, the modulatory subunits participate actively in translating ligand binding to activation of heterotetrameric olfactory CNG channels and enable the channels to differentiate between cyclic nucleotides.
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Affiliation(s)
- Vasilica Nache
- Institute of Physiology II, University Hospital Jena, Friedrich-Schiller-University Jena, D-07740 Jena, Germany
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Podda MV, Leone L, Piacentini R, Cocco S, Mezzogori D, D'Ascenzo M, Grassi C. Expression of olfactory-type cyclic nucleotide-gated channels in rat cortical astrocytes. Glia 2012; 60:1391-405. [PMID: 22653779 DOI: 10.1002/glia.22360] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 05/03/2012] [Indexed: 12/31/2022]
Abstract
Cyclic nucleotide-gated (CNG) channels are nonselective cation channels activated by cyclic AMP (cAMP) or cyclic GMP (cGMP). They were originally identified in retinal and olfactory receptors, but evidence has also emerged for their expression in several mammalian brain areas. Because cGMP and cAMP control important aspects of glial cell physiology, we wondered whether CNG channels are expressed in astrocytes, the most functionally relevant glial cells in the CNS. Immunoblot and immunofluorescence experiments demonstrated expression of the CNG channel olfactory-type A subunit, CNGA2, in cultured rat cortical astrocytes. In patch-clamp experiments, currents elicited in these cells by voltage ramps from -100 to +100 mV in the presence of the cGMP analogue, dB-cGMP, were significantly reduced by the CNG channel blockers, L-cis-diltiazem (LCD) and Cd(2+) . The reversal potentials of the LCD- and Cd(2+) -sensitive currents were more positive than that of K(+) , as expected for a mixed cation current. Noninactivating, voltage-independent currents were also elicited by extracellular application of the membrane permeant cGMP analogue, 8-Br-cGMP. These effects were blocked by LCD and were mimicked by natriuretic peptide receptor activation and inhibition of phosphodiesterase activity. Voltage-independent, LCD-sensitive currents were also elicited by 8-Br-cGMP in astrocytes of hippocampal and neocortical brain slices. Immunohistochemistry confirmed a broad distribution of CNG channels in astrocytes of the rat forebrain, midbrain, and hindbrain. These findings suggest that CNG channels are downstream targets of cyclic nucleotides in astrocytes, and they may be involved in the glial-mediated regulation of CNS functions under physiological and pathological conditions.
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Affiliation(s)
- Maria Vittoria Podda
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
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Lopez-Jimenez ME, González JC, Lizasoain I, Sánchez-Prieto J, Hernández-Guijo JM, Torres M. Functional cGMP-gated channels in cerebellar granule cells. J Cell Physiol 2012; 227:2252-63. [PMID: 21809342 DOI: 10.1002/jcp.22964] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cyclic nucleotide-gated channels (CNGCs) are important transducers of external signals in sensory processes. These channels are ubiquitously expressed in a variety of neurons, and are necessary to transduce signals for growth cone guidance and plasticity. Here, we demonstrate that the CNGC subunits (CNGA1 and CNGB1, presumably the 1b isoform) are expressed in rat cerebellar granule cells and that they combine to form functional channels. The expression of the mRNAs that encode these proteins is maximal after 7 days in cell culture, when the channels are expressed at synapses and co-localize with the synaptic marker synapsin I. These ligand-gated channels are functional and can be blocked by Mg(2+) or L-cis-diltiazem. Moreover, channel opening in response to increases in intracellular cGMP results in Ca(2+) entry into the cell. Chronic blockade (96 h) of these channels with L-cis-diltiazem significantly decreases the number of functional boutons, as determined by their capacity to load and unload the styryl dye FM1-43 when stimulated. Moreover, the unloading kinetics is modified from a biphasic to a monophasic profile in a subset of synaptic boutons. These channels are also expressed in early developmental stages, both in the soma and in emerging processes, and CNGA1 can be detected in growth cones. Pharmacological blockade of these channels with L-cis-diltiazem causes an overall change in growth cone morphology, impairing the formation of lamellipodia between filopodia and increasing the number of filopodia. J
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Affiliation(s)
- Ma Elena Lopez-Jimenez
- Facultad de Veterinaria, Departamento de Bioquímica, Universidad Complutense, Madrid, Spain
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40
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Pask GM, Jones PL, Rützler M, Rinker DC, Zwiebel LJ. Heteromeric Anopheline odorant receptors exhibit distinct channel properties. PLoS One 2011; 6:e28774. [PMID: 22174894 PMCID: PMC3235152 DOI: 10.1371/journal.pone.0028774] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 11/15/2011] [Indexed: 11/30/2022] Open
Abstract
Background Insect odorant receptors (ORs) function as odorant-gated ion channels consisting of a conventional, odorant-binding OR and the Orco coreceptor. While Orco can function as a homomeric ion channel, the role(s) of the conventional OR in heteromeric OR complexes has largely focused only on odorant recognition. Results To investigate other roles of odorant-binding ORs, we have employed patch clamp electrophysiology to investigate the properties of the channel pore of several OR complexes formed by a range of different odorant-specific Anopheles gambiae ORs (AgOrs) each paired with AgOrco. These studies reveal significant differences in cation permeability and ruthenium red susceptibility among different AgOr complexes. Conclusions With observable differences in channel function, the data support a model in which the odorant-binding OR also affects the channel pore. The variable effect contributed by the conventional OR on the conductive properties of odorant-gated sensory channels adds additional complexity to insect olfactory signaling, with differences in odor coding beginning with ORs on the periphery of the olfactory system.
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Affiliation(s)
- Gregory M. Pask
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Patrick L. Jones
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Michael Rützler
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- The Water and Salt Research Center, Institute of Anatomy, University of Aarhus, Aarhus C, Denmark
| | - David C. Rinker
- Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Laurence J. Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pharmacology, Centers for Molecular Neuroscience and Human Genetics Research, Institutes of Chemical Biology and Global Health and Program in Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
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41
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Billig GM, Pál B, Fidzinski P, Jentsch TJ. Ca2+-activated Cl− currents are dispensable for olfaction. Nat Neurosci 2011; 14:763-9. [PMID: 21516098 DOI: 10.1038/nn.2821] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 03/30/2011] [Indexed: 11/09/2022]
Abstract
Canonical olfactory signal transduction involves the activation of cyclic AMP-activated cation channels that depolarize the cilia of receptor neurons and raise intracellular calcium. Calcium then activates Cl(-) currents that may be up to tenfold larger than cation currents and are believed to powerfully amplify the response. We identified Anoctamin2 (Ano2, also known as TMEM16B) as the ciliary Ca(2+)-activated Cl(-) channel of olfactory receptor neurons. Ano2 is expressed in the main olfactory epithelium (MOE) and in the vomeronasal organ (VNO), which also expresses the related Ano1 channel. Disruption of Ano2 in mice virtually abolished Ca(2+)-activated Cl(-) currents in the MOE and VNO. Ano2 disruption reduced fluid-phase electro-olfactogram responses by only ∼40%, did not change air-phase electro-olfactograms and did not reduce performance in olfactory behavioral tasks. In contrast with the current view, cyclic nucleotide-gated cation channels do not need a boost by Cl(-) channels to achieve near-physiological levels of olfaction.
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Affiliation(s)
- Gwendolyn M Billig
- Leibniz-Institut für Molekulare Pharmakologie (FMP)/Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
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Kusch J, Zimmer T, Holschuh J, Biskup C, Schulz E, Nache V, Benndorf K. Role of the S4-S5 linker in CNG channel activation. Biophys J 2011; 99:2488-96. [PMID: 20959089 DOI: 10.1016/j.bpj.2010.07.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 06/22/2010] [Accepted: 07/19/2010] [Indexed: 10/18/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) channels mediate sensory signal transduction in retinal and olfactory cells. The channels are activated by the binding of cyclic nucleotides to a cyclic nucleotide-binding domain (CNBD) in the C-terminus that is located at the intracellular side. The molecular events translating the ligand binding to the pore opening are still unknown. We investigated the role of the S4-S5 linker in the activation process by quantifying its interaction with other intracellular regions. To this end, we constructed chimeric channels in which the N-terminus, the S4-S5 linker, the C-linker, and the CNBD of the retinal CNGA1 subunit were systematically replaced by the respective regions of the olfactory CNGA2 subunit. Macroscopic concentration-response relations were analyzed, yielding the apparent affinity to cGMP and the Hill coefficient. The degree of functional coupling of intracellular regions in the activation gating was determined by thermodynamic double-mutant cycle analysis. We observed that all four intracellular regions, including the relatively short S4-S5 linker, are involved in controlling the apparent affinity of the channel to cGMP and, moreover, in determining the degree of cooperativity between the subunits, as derived from the Hill coefficient. The interaction energies reveal an interaction of the S4-S5 linker with both the N-terminus and the C-linker, but no interaction with the CNBD.
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Affiliation(s)
- Jana Kusch
- Universitätsklinikum Jena, Institut für Physiologie II, Germany
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43
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Odorant Detection and Discrimination in the Olfactory System. LECTURE NOTES IN ELECTRICAL ENGINEERING 2011. [DOI: 10.1007/978-94-007-1324-6_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Cukkemane A, Seifert R, Kaupp UB. Cooperative and uncooperative cyclic-nucleotide-gated ion channels. Trends Biochem Sci 2010; 36:55-64. [PMID: 20729090 DOI: 10.1016/j.tibs.2010.07.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/06/2010] [Accepted: 07/14/2010] [Indexed: 12/31/2022]
Abstract
Ion channels gated by cyclic nucleotides serve multiple functions in sensory signaling in diverse cell types ranging from neurons to sperm. Newly discovered members from bacteria and marine invertebrates provide a wealth of structural and functional information on this channel family. A hallmark of classical tetrameric cyclic-nucleotide-gated channels is their cooperative activation by binding of several ligands. By contrast, the new members seem to be uncooperative, and binding of a single ligand molecule suffices to open these channels. These new findings provide a fresh look at the mechanism of allosteric activation of ion channels.
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Affiliation(s)
- Abhishek Cukkemane
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Leung YK, Du J, Huang Y, Yao X. Cyclic nucleotide-gated channels contribute to thromboxane A2-induced contraction of rat small mesenteric arteries. PLoS One 2010; 5:e11098. [PMID: 20559420 PMCID: PMC2885410 DOI: 10.1371/journal.pone.0011098] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Accepted: 05/18/2010] [Indexed: 11/18/2022] Open
Abstract
Background Thromboxane A2 (TxA2)-induced smooth muscle contraction has been implicated in cardiovascular, renal and respiratory diseases. This contraction can be partly attributed to TxA2-induced Ca2+ influx, which resulted in vascular contraction via Ca2+-calmodulin-MLCK pathway. This study aims to identify the channels that mediate TxA2-induced Ca2+ influx in vascular smooth muscle cells. Methodology/Principal Findings Application of U-46619, a thromboxane A2 mimic, resulted in a constriction in endothelium-denuded small mesenteric artery segments. The constriction relies on the presence of extracellular Ca2+, because removal of extracellular Ca2+ abolished the constriction. This constriction was partially inhibited by an L-type Ca2+ channel inhibitor nifedipine (0.5–1 µM). The remaining component was inhibited by L-cis-diltiazem, a selective inhibitor for CNG channels, in a dose-dependent manner. Another CNG channel blocker LY83583 [6-(phenylamino)-5,8-quinolinedione] had similar effect. In the primary cultured smooth muscle cells derived from rat aorta, application of U46619 (100 nM) induced a rise in cytosolic Ca2+ ([Ca2+]i), which was inhibited by L-cis-diltiazem. Immunoblot experiments confirmed the presence of CNGA2 protein in vascular smooth muscle cells. Conclusions/Significance These data suggest a functional role of CNG channels in U-46619-induced Ca2+ influx and contraction of smooth muscle cells.
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Affiliation(s)
- Yuk Ki Leung
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Juan Du
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Physiology, Anhui Medical University, He Fei, China
| | - Yu Huang
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
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Olfactory signalling in vertebrates and insects: differences and commonalities. Nat Rev Neurosci 2010; 11:188-200. [DOI: 10.1038/nrn2789] [Citation(s) in RCA: 373] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rasche S, Toetter B, Adler J, Tschapek A, Doerner JF, Kurtenbach S, Hatt H, Meyer H, Warscheid B, Neuhaus EM. Tmem16b is specifically expressed in the cilia of olfactory sensory neurons. Chem Senses 2010; 35:239-45. [PMID: 20100788 DOI: 10.1093/chemse/bjq007] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Calcium-activated chloride channels (CaCCs) are involved in many physiological processes, including sensory signal transduction, but only little is known to date about their structure and function. We performed a proteome analysis of the olfactory epithelium (OE) membrane proteome and identified so far uncharacterized membrane proteins as candidate channels. One of the most abundant membrane proteins in olfactory sensory neurons (OSNs) was Tmem16b, a member of a recently identified family of CaCCs. In addition to former studies performed on Tmem16b, we show here that Tmem16b expression is highly specific for the OE, in contrast to the closely related Tmem16a, which shows a broad expression pattern in secretory epithelial cells. Native Tmem16b is localized in the cilia of the OSNs, which is in agreement with previous electrophysiological recordings.
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Affiliation(s)
- Sebastian Rasche
- NeuroScience Research Center, Charité, Universitätsmedizin Berlin, 10117 Berlin, Germany
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Waldeck C, Vocke K, Ungerer N, Frings S, Möhrlen F. Activation and desensitization of the olfactory cAMP-gated transduction channel: identification of functional modules. ACTA ACUST UNITED AC 2009; 134:397-408. [PMID: 19822638 PMCID: PMC2768803 DOI: 10.1085/jgp.200910296] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Olfactory receptor neurons respond to odor stimulation with a receptor potential that results from the successive activation of cyclic AMP (cAMP)-gated, Ca2+-permeable channels and Ca2+-activated chloride channels. The cAMP-gated channels open at micromolar concentrations of their ligand and are subject to a Ca2+-dependent feedback inhibition by calmodulin. Attempts to understand the operation of these channels have been hampered by the fact that the channel protein is composed of three different subunits, CNGA2, CNGA4, and CNGB1b. Here, we explore the individual role that each subunit plays in the gating process. Using site-directed mutagenesis and patch clamp analysis, we identify three functional modules that govern channel operation: a module that opens the channel, a module that stabilizes the open state at low cAMP concentrations, and a module that mediates rapid Ca2+-dependent feedback inhibition. Each subunit could be assigned to one of these functions that, together, define the gating logic of the olfactory transduction channel.
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Affiliation(s)
- Clemens Waldeck
- Department of Molecular Physiology, University of Heidelberg, 69120 Heidelberg, Germany
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Abstract
The mammalian olfactory system senses an almost unlimited number of chemical stimuli and initiates a process of neural recognition that influences nearly every aspect of life. This review examines the organizational principles underlying the recognition of olfactory stimuli. The olfactory system is composed of a number of distinct subsystems that can be distinguished by the location of their sensory neurons in the nasal cavity, the receptors they use to detect chemosensory stimuli, the signaling mechanisms they employ to transduce those stimuli, and their axonal projections to specific regions of the olfactory forebrain. An integrative approach that includes gene targeting methods, optical and electrophysiological recording, and behavioral analysis has helped to elucidate the functional significance of this subsystem organization for the sense of smell.
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Affiliation(s)
- Steven D Munger
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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50
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Triguero D, Sancho M, García-Flores M, García-Pascual A. Presence of cyclic nucleotide-gated channels in the rat urethra and their involvement in nerve-mediated nitrergic relaxation. Am J Physiol Renal Physiol 2009; 297:F1353-60. [PMID: 19710238 DOI: 10.1152/ajprenal.00403.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have addressed the distribution of cGMP-gated channels (CNG) in the rat urethra for the first time, as well as their putative role in mediating of the relaxation elicited by electrical field stimulation of nitrergic nerves. Functional studies have shown that specifically blocking CNG with L-cis-diltiazem leads to the rapid inhibition of urethral relaxation induced either by nitric oxide (NO) released by the nerves or by soluble guanylate cyclase activated with YC-1. By contrast, nerve-mediated noradrenergic contractions were only slowly and mildly reduced by L-cis-diltiazem. This effect was mimicked by lower concentrations of the D-diltiazem isomer, probably due to the nonspecific inhibition of voltage-dependent calcium channels. However, D-diltiazem did not affect relaxation responses. The expression of heteromeric retinal-like CNGA1 channels was demonstrated by conventional PCR on mRNA from the rat urethra. These channels were located in a subpopulation of intramuscular interstitial cells of Cajal (ICC) as well as in smooth muscle cells, although they were less abundant in the latter. CNG channels could not be visualized in any nervous structure within the urethral wall, in agreement with the emerging view that a subset of ICC serves as a target for NO. These channels could provide a suitable ionic mechanism to associate the changes in cytosolic calcium with the activation of the nitric NO-cGMP pathway and relaxation although the precise mechanisms involved remain to be elucidated.
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Affiliation(s)
- Domingo Triguero
- Department of Physiology, Veterinary School, Complutense University, Madrid, Spain.
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