1
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Saeki Y, Hosoi A, Nishioka M, Fukuda J, Sasaki Y, Yajima S, Ito S. Involvement of G-protein alpha subunit in soybean cyst nematode chemotaxis. Biochem Biophys Res Commun 2024; 735:150830. [PMID: 39423572 DOI: 10.1016/j.bbrc.2024.150830] [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: 10/10/2024] [Accepted: 10/11/2024] [Indexed: 10/21/2024]
Abstract
The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a significant agricultural pest that causes extensive damage to soybean production worldwide. Second-stage juveniles (J2s) of the SCN migrate through the soil and infest the roots of host plants in response to certain chemical substances secreted from the host roots. Therefore, controlling SCN chemotaxis could be an effective strategy for its management. In the present study, we identified the Hg-gpa-3d gene, which encodes the G protein alpha subunit, as a key regulator of SCN chemotaxis. Gene silencing of Hg-gpa-3d reduced the attraction of SCN J2s to host roots, as well as to nitrate ions, a chemoattractant recognized through a mechanism different from that of host recognition. However, silencing of Hg-gpa-3d did not affect avoidance behavior towards unpleasant temperatures or stylet protrusion. These results suggest that Hg-gpa-3d is a crucial gene in the regulation of SCN chemotaxis and provide new insights into the chemotactic mechanisms of the SCN.
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Affiliation(s)
- Yasumasa Saeki
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Akito Hosoi
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Mizuki Nishioka
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Junta Fukuda
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Yasuyuki Sasaki
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Shunsuke Yajima
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Shinsaku Ito
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan.
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2
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Campagna CM, McMahon H, Nechipurenko I. The G protein alpha chaperone and guanine-nucleotide exchange factor RIC-8 regulates cilia morphogenesis in Caenorhabditis elegans sensory neurons. PLoS Genet 2023; 19:e1011015. [PMID: 37910589 PMCID: PMC10642896 DOI: 10.1371/journal.pgen.1011015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/13/2023] [Accepted: 10/12/2023] [Indexed: 11/03/2023] Open
Abstract
Heterotrimeric G (αβγ) proteins are canonical transducers of G-protein-coupled receptor (GPCR) signaling and play critical roles in communication between cells and their environment. Many GPCRs and heterotrimeric G proteins localize to primary cilia and modulate cilia morphology via mechanisms that are not well understood. Here, we show that RIC-8, a cytosolic guanine nucleotide exchange factor (GEF) and chaperone for Gα protein subunits, shapes cilia membrane morphology in a subset of Caenorhabditis elegans sensory neurons. Consistent with its role in ciliogenesis, C. elegans RIC-8 localizes to cilia in different sensory neuron types. Using domain mutagenesis, we demonstrate that while the GEF function alone is not sufficient, both the GEF and Gα-interacting chaperone motifs of RIC-8 are required for its role in cilia morphogenesis. We identify ODR-3 as the RIC-8 Gα client and demonstrate that RIC-8 functions in the same genetic pathway with another component of the non-canonical G protein signaling AGS-3 to shape cilia morphology. Notably, despite defects in AWC cilia morphology, ags-3 null mutants exhibit normal chemotaxis toward benzaldehyde unlike odr-3 mutant animals. Collectively, our findings describe a novel function for the evolutionarily conserved protein RIC-8 and non-canonical RIC-8-AGS-3-ODR-3 signaling in cilia morphogenesis and uncouple Gα ODR-3 functions in ciliogenesis and olfaction.
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Affiliation(s)
- Christina M. Campagna
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
| | - Hayley McMahon
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
| | - Inna Nechipurenko
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
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3
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Campagna CM, McMahon H, Nechipurenko I. The G protein alpha Chaperone and Guanine-Nucleotide Exchange Factor RIC-8 Regulates Cilia Morphogenesis in Caenorhabditis elegans Sensory Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.25.554856. [PMID: 37662329 PMCID: PMC10473713 DOI: 10.1101/2023.08.25.554856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Heterotrimeric G (αβγ) proteins are canonical transducers of G-protein-coupled receptor (GPCR) signaling and play critical roles in communication between cells and their environment. Many GPCRs and heterotrimeric G proteins localize to primary cilia and modulate cilia morphology via mechanisms that are not well understood. Here, we show that RIC-8, a cytosolic guanine nucleotide exchange factor (GEF) and chaperone for Gα protein subunits, shapes cilia membrane morphology in a subset of Caenorhabditis elegans sensory neurons. Consistent with its role in ciliogenesis, C. elegans RIC-8 localizes to cilia in different sensory neuron types. Using domain mutagenesis, we demonstrate that while the GEF function alone is not sufficient, both the GEF and Gα-interacting chaperone motifs of RIC-8 are required for its role in cilia morphogenesis. We identify ODR-3 as the RIC-8 Gα client and demonstrate that RIC-8 functions in the same genetic pathway with another component of the non-canonical G protein signaling AGS-3 to shape cilia morphology. Notably, despite severe defects in AWC cilia morphology, ags-3 null mutants exhibit normal chemotaxis toward benzaldehyde unlike odr-3 mutant animals. Collectively, our findings describe a novel function for the evolutionarily conserved protein RIC-8 and non-canonical RIC-8-AGS-3-ODR-3 signaling in cilia morphogenesis and uncouple Gα ODR-3 functions in ciliogenesis and olfaction.
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Affiliation(s)
- Christina M. Campagna
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
| | - Hayley McMahon
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
| | - Inna Nechipurenko
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, United States of America
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4
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Wu N, Chen YA, Zhu Q, Son CH, Gu KZ, Zou CG, Wu QY, Ma YC. The EGL-30 pathway regulates experience-dependent aversive behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa. Biochem Biophys Res Commun 2023; 642:107-112. [PMID: 36566561 DOI: 10.1016/j.bbrc.2022.12.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Avoidance of harmful substances is survival strategy used cross invertebrates and vertebrates. For example, the nematode Caenorhabditis elegans evolves a sufficient avoidance response to pathogenic bacteria. Despite G protein has been found to exert neural plasticity for avoidance behaviours in C. elegans, the function of Gi/o and Gq subunit signalling in experience-dependent aversive behaviour remains unclear. In this study, we show that EGL-30/Gq coupled with EGL-8/UNC-13 regulates aversive behaviour of C. elegans to pathogenic bacterium Pseudomonas aeruginosa PA01 via acetylcholine and its receptor nAChR. Pyocyanin, a toxin secreted from P. aeruginosa, acts as a signal molecule to trigger aversive behaviour. ODR-3 and ODR-7 in AWA and AWC neurons function as upstream of EGL-30 to induce experience-dependent aversive behaviour to P. aeruginosa, respectively. These results suggested that a novel signalling pathway to regulate a behavioural response.
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Affiliation(s)
- Nan Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Yu-An Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qian Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cai-Hua Son
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Kun-Ze Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Cheng-Gang Zou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China
| | - Qin-Yi Wu
- Yunnan Provincial Key Laboratory of Molecular Biology for Sinomedicine, Yunnan University of Chinese Medicine, Kunming, 650500, Yunnan, China.
| | - Yi-Cheng Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, Yunnan, 650091, China.
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5
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Nicoletti M, Luchetti N, Chiodo L, Loppini A, Folli V, Ruocco G, Filippi S. Modeling of olfactory transduction in AWC ON neuron via coupled electrical-calcium dynamics. Biomol Concepts 2023; 14:bmc-2022-0035. [PMID: 37574865 DOI: 10.1515/bmc-2022-0035] [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: 06/20/2023] [Accepted: 07/28/2023] [Indexed: 08/15/2023] Open
Abstract
Amphid wing "C" (AWC) neurons are among the most important and studied neurons of the nematode Caenorhabditis elegans. In this work, we unify the existing electrical and intracellular calcium dynamics descriptions to obtain a biophysically accurate model of olfactory transduction in AWCON neurons. We study the membrane voltage and the intracellular calcium dynamics at different exposure times and odorant concentrations to grasp a complete picture of AWCON functioning. Moreover, we investigate the complex cascade of biochemical processes that allow AWC activation upon odor removal. We analyze the behavior of the different components of the models and, by suppressing them selectively, we extrapolate their contribution to the overall neuron response and study the resilience of the dynamical system. Our results are all in agreement with the available experimental data. Therefore, we provide an accurate mathematical and biophysical model for studying olfactory signal processing in C. elegans.
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Affiliation(s)
- Martina Nicoletti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Nicole Luchetti
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
| | | | - Viola Folli
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
- D-tails s.r.l., Via di Torre Rossa 66, 00165, Rome, Italy
| | - Giancarlo Ruocco
- Center for Life Nano- & Neuro-Science (CLN2S@Sapienza), Italian Institute of Technology, Rome, Italy
| | - Simonetta Filippi
- Department of Engineering, Campus Bio-Medico University, Rome, Italy
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), Florence, Italy
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6
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Li Y, Ren Q, Bo T, Mo M, Liu Y. AWA and ASH Homologous Sensing Genes of Meloidogyne incognita Contribute to the Tomato Infection Process. Pathogens 2022; 11:pathogens11111322. [PMID: 36365073 PMCID: PMC9693415 DOI: 10.3390/pathogens11111322] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/12/2022] Open
Abstract
The AWA neurons of Caenorhabditis elegans mainly perceive volatile attractive odors, while the ASH neurons perceive pH, penetration, nociception, odor tropism, etc. The perceptual neurons of Meloidogyne incognita have been little studied. The number of infestations around and within tomato roots was significantly reduced after RNA interference for high-homology genes in AWA and ASH neurons compared between M. incognita and C. elegans. Through in situ hybridization, we further determined the expression and localization of the homologous genes Mi-odr-10 and Mi-gpa-6 in M. incognita. In this study, we found that M. incognita has neuronal sensing pathways similar to AWA and ASH perception of C. elegans for sensing chemical signals from tomato roots. Silencing the homologous genes in these pathways could affect the nematode perception and infestation of tomato root systems. The results contribute to elucidating the process of the plant host perception of M. incognita.
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Affiliation(s)
| | | | | | | | - Yajun Liu
- Correspondence: ; Tel.: +86-871-65031093
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7
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Arrestin-mediated desensitization enables intraneuronal olfactory discrimination in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2022; 119:e2116957119. [PMID: 35878038 PMCID: PMC9351366 DOI: 10.1073/pnas.2116957119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In the mammalian olfactory system, cross-talk between olfactory signals is minimized through physical isolation: individual neurons express one or few olfactory receptors among those encoded in the genome. Physical isolation allows for segregation of stimuli during signal transduction; however, in the nematode worm Caenorhabditis elegans, ∼1,300 olfactory receptors are primarily expressed in only 32 neurons, precluding this strategy. Here, we report genetic and behavioral evidence that β-arrestin-mediated desensitization of olfactory receptors, working downstream of the kinase GRK-1, enables discrimination between intraneuronal olfactory stimuli. Our findings suggest that C. elegans exploits β-arrestin desensitization to maximize responsiveness to novel odors, allowing for behaviorally appropriate responses to olfactory stimuli despite the large number of olfactory receptors signaling in single cells. This represents a fundamentally different solution to the problem of olfactory discrimination than that which evolved in mammals, allowing for economical use of a limited number of sensory neurons.
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8
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Khan M, Hartmann AH, O’Donnell MP, Piccione M, Pandey A, Chao PH, Dwyer ND, Bargmann CI, Sengupta P. Context-dependent reversal of odorant preference is driven by inversion of the response in a single sensory neuron type. PLoS Biol 2022; 20:e3001677. [PMID: 35696430 PMCID: PMC9232122 DOI: 10.1371/journal.pbio.3001677] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 06/24/2022] [Accepted: 05/16/2022] [Indexed: 11/18/2022] Open
Abstract
The valence and salience of individual odorants are modulated by an animal’s innate preferences, learned associations, and internal state, as well as by the context of odorant presentation. The mechanisms underlying context-dependent flexibility in odor valence are not fully understood. Here, we show that the behavioral response of Caenorhabditis elegans to bacterially produced medium-chain alcohols switches from attraction to avoidance when presented in the background of a subset of additional attractive chemicals. This context-dependent reversal of odorant preference is driven by cell-autonomous inversion of the response to these alcohols in the single AWC olfactory neuron pair. We find that while medium-chain alcohols inhibit the AWC olfactory neurons to drive attraction, these alcohols instead activate AWC to promote avoidance when presented in the background of a second AWC-sensed odorant. We show that these opposing responses are driven via engagement of distinct odorant-directed signal transduction pathways within AWC. Our results indicate that context-dependent recruitment of alternative intracellular signaling pathways within a single sensory neuron type conveys opposite hedonic valences, thereby providing a robust mechanism for odorant encoding and discrimination at the periphery.
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Affiliation(s)
- Munzareen Khan
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Anna H. Hartmann
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Michael P. O’Donnell
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Madeline Piccione
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Anjali Pandey
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Pin-Hao Chao
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Noelle D. Dwyer
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | | | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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9
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Zaroubi L, Ozugergin I, Mastronardi K, Imfeld A, Law C, Gélinas Y, Piekny A, Findlay BL. The Ubiquitous Soil Terpene Geosmin Acts as a Warning Chemical. Appl Environ Microbiol 2022; 88:e0009322. [PMID: 35323022 PMCID: PMC9004350 DOI: 10.1128/aem.00093-22] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/26/2022] [Indexed: 12/29/2022] Open
Abstract
Known as the smell of earth after rain, geosmin is an odorous terpene detectable by humans at picomolar concentrations. Geosmin production is heavily conserved in actinobacteria, myxobacteria, cyanobacteria, and some fungi, but its biological activity is poorly understood. We theorized that geosmin was an aposematic signal used to indicate the unpalatability of toxin-producing microbes, discouraging predation by eukaryotes. Consistent with this hypothesis, we found that geosmin altered the behavior of the bacteriophagous nematode Caenorhabditis elegans on agar plates in the absence of bacteria. Normal movement was restored in mutant worms lacking differentiated ASE (amphid neurons, single ciliated endings) neurons, suggesting that geosmin is a taste detected by the nematodal gustatory system. In a predation assay, geosmin and the related terpene 2-methylisoborneol reduced grazing on the bacterium Streptomyces coelicolor. Predation was restored by the removal of both terpene biosynthetic pathways or the introduction of C. elegans that lacked differentiated ASE taste neurons, leading to the apparent death of both bacteria and worms. While geosmin and 2-methylisoborneol appeared to be nontoxic, grazing triggered bacterial sporulation and the production of actinorhodin, a pigment coproduced with a number of toxic metabolites. In this system, geosmin thus appears to act as a warning signal indicating the unpalatability of its producers and reducing predation in a manner that benefits predator and prey. This suggests that molecular signaling may affect microbial predator-prey interactions in a manner similar to that of the well-studied visual markers of poisonous animal prey. IMPORTANCE One of the key chemicals that give soil its earthy aroma, geosmin is a frequent water contaminant produced by a range of unrelated microbes. Many animals, including humans, are able to detect geosmin at minute concentrations, but the benefit that this compound provides to its producing organisms is poorly understood. We found that geosmin repelled the bacterial predator Caenorhabditis elegans in the absence of bacteria and reduced contact between the worms and the geosmin-producing bacterium Streptomyces coelicolor in a predation assay. While geosmin itself appears to be nontoxic to C. elegans, these bacteria make a wide range of toxic metabolites, and grazing on them harmed the worms. In this system, geosmin thus appears to indicate unpalatable bacteria, reducing predation and benefiting both predator and prey. Aposematic signals are well known in animals, and this work suggests that metabolites may play a similar role in the microbial world.
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Affiliation(s)
- Liana Zaroubi
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Québec, Canada
| | - Imge Ozugergin
- Department of Biology, Concordia University, Montreal, Québec, Canada
| | | | - Anic Imfeld
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Québec, Canada
| | - Chris Law
- Department of Biology, Concordia University, Montreal, Québec, Canada
| | - Yves Gélinas
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Québec, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, Québec, Canada
| | - Brandon L. Findlay
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Québec, Canada
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10
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A single chemosensory GPCR is required for a concentration-dependent behavioral switching in C. elegans. Curr Biol 2021; 32:398-411.e4. [PMID: 34906353 DOI: 10.1016/j.cub.2021.11.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/15/2021] [Accepted: 11/12/2021] [Indexed: 12/19/2022]
Abstract
Animals detect and discriminate countless environmental chemicals for their well-being and survival. Although a single chemical can trigger opposing behavioral responses depending on its concentration, the mechanisms underlying such a concentration-dependent switching remain poorly understood. Here, we show that C. elegans exhibits either attraction or avoidance of the bacteria-derived volatile chemical dimethyl trisulfide (DMTS) depending on its concentration. This behavioral switching is mediated by two different types of chemosensory neurons, both of which express the DMTS-sensitive seven-transmembrane G protein-coupled receptor (GPCR) SRI-14. These two sensory neurons share downstream interneurons that process and translate DMTS signals via distinct glutamate receptors to generate the appropriate behavioral outcome. Thus, our results present one mechanism by which an animal connects two distinct types of chemosensory neurons detecting a common ligand to alternate downstream circuitry, thus efficiently switching between specific behavioral programs based on ligand concentration.
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11
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Cheng H, Liu Y, Xue Y, Shao J, Tan Z, Liu S, Duan S, Kang L. Molecular Strategies for Intensity-Dependent Olfactory Processing in Caenorhabditis elegans. Front Mol Neurosci 2021; 14:748214. [PMID: 34803606 PMCID: PMC8600271 DOI: 10.3389/fnmol.2021.748214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Various odorants trigger complex animal behaviors across species in both quality- and quantity-dependent manners. However, how the intensity of olfactory input is encoded remains largely unknown. Here we report that isoamyl alcohol (IAA) induces bi-directional currents through a Gα- guanylate cyclase (GC)- cGMP signaling pathway in Caenorhabditis elegans olfactory neuron amphid wing “C” cell (AWC), while two opposite cGMP signaling pathways are responsible for odor-sensing in olfactory neuron amphid wing “B” cell (AWB): (1) a depolarizing Gα (GPA-3)- phosphodiesterase (PDE) – cGMP pathway which can be activated by low concentrations of isoamyl alcohol (IAA), and (2) a hyperpolarizing Gα (ODR-3)- GC- cGMP pathway sensing high concentrations of IAA. Besides, IAA induces Gα (ODR-3)-TRPV(OSM-9)-dependent currents in amphid wing “A” cell (AWA) and amphid neuron “H” cell with single ciliated sensory ending (ASH) neurons with different thresholds. Our results demonstrate that an elaborate combination of multiple signaling machineries encode the intensity of olfactory input, shedding light on understanding the molecular strategies on sensory transduction.
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Affiliation(s)
- Hankui Cheng
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yu Liu
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yadan Xue
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiajie Shao
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhibing Tan
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyan Liu
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.,Department of Neurology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lijun Kang
- Department of Neurobiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
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12
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Matei IV, Samukange VNC, Bunu G, Toren D, Ghenea S, Tacutu R. Knock-down of odr-3 and ife-2 additively extends lifespan and healthspan in C. elegans. Aging (Albany NY) 2021; 13:21040-21065. [PMID: 34506301 PMCID: PMC8457566 DOI: 10.18632/aging.203518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/24/2021] [Indexed: 01/04/2023]
Abstract
Genetic manipulations can ameliorate the aging process and extend the lifespan of model organisms. The aim of this research was to identify novel genetic interventions that promote both lifespan and healthspan, by combining the effects of multiple longevity-associated gene inactivations in C. elegans. For this, the individual and combined effects of the odr-3 mutation and of ife-2 and cku-70 knock-downs were studied, both in the wild type and daf-16 mutant backgrounds. We found that besides increasing the lifespan of wild type animals, the knock-down of ife-2 (starting at L4) also extends the lifespan and healthspan of long-lived odr-3 mutants. In the daf-16 background, ife-2 and odr-3 impairment exert opposing effects individually, while the daf-16; odr-3; ife-2 deficient animals show a similar lifespan and healthspan as daf-16, suggesting that the odr-3 and ife-2 effector outcomes converge downstream of DAF-16. By contrast, cku-70 knock-down did not extend the lifespan of single or double odr-3; ife-2 inactivated animals, and was slightly deleterious to healthspan. In conclusion, we report that impairment of odr-3 and ife-2 increases lifespan and healthspan in an additive and synergistic manner, respectively, and that this result is not improved by further knocking-down cku-70.
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Affiliation(s)
- Ioan Valentin Matei
- Systems Biology of Aging Group, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | | | - Gabriela Bunu
- Systems Biology of Aging Group, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Dmitri Toren
- Systems Biology of Aging Group, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Simona Ghenea
- Systems Biology of Aging Group, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Robi Tacutu
- Systems Biology of Aging Group, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
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13
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Khanna A, Sellegounder D, Kumar J, Chamoli M, Vargas M, Chinta SJ, Rane A, Nelson C, Peiris TH, Brem R, Andersen J, Lithgow G, Kapahi P. Trimethylamine modulates dauer formation, neurodegeneration, and lifespan through tyra-3/daf-11 signaling in Caenorhabditis elegans. Aging Cell 2021; 20:e13351. [PMID: 33819374 PMCID: PMC8135002 DOI: 10.1111/acel.13351] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 11/27/2022] Open
Abstract
In the nematode Caenorhabditis elegans, signals derived from bacteria in the diet, the animal's major nutrient source, can modulate both behavior and healthspan. Here we describe a dual role for trimethylamine (TMA), a human gut flora metabolite, which acts as a nutrient signal and a neurotoxin. TMA and its associated metabolites are produced by the human gut microbiome and have been suggested to serve as risk biomarkers for diabetes and cardiovascular diseases. We demonstrate that the tyramine receptor TYRA-3, a conserved G protein-coupled receptor (GPCR), is required to sense TMA and mediate its responses. TMA activates guanylyl cyclase DAF-11 signaling through TYRA-3 in amphid neurons (ASK) and ciliated neurons (BAG) to mediate food-sensing behavior. Bacterial mutants deficient in TMA production enhance dauer formation, extend lifespan, and are less preferred as a food source. Increased levels of TMA lead to neural damage in models of Parkinson's disease and shorten lifespan. Our results reveal conserved signaling pathways modulated by TMA in C. elegans that are likely to be relevant for its effects in mammalian systems.
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Affiliation(s)
- Amit Khanna
- Buck Institute for Research on Aging Novato CA USA
- Dovetail Genomics LLC Scotts Valley CA USA
| | | | | | | | | | - Shankar J. Chinta
- Buck Institute for Research on Aging Novato CA USA
- Touro University California Vallejo CA USA
| | - Anand Rane
- Buck Institute for Research on Aging Novato CA USA
| | | | | | - Rachel Brem
- Buck Institute for Research on Aging Novato CA USA
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14
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Ferkey DM, Sengupta P, L’Etoile ND. Chemosensory signal transduction in Caenorhabditis elegans. Genetics 2021; 217:iyab004. [PMID: 33693646 PMCID: PMC8045692 DOI: 10.1093/genetics/iyab004] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Chemosensory neurons translate perception of external chemical cues, including odorants, tastants, and pheromones, into information that drives attraction or avoidance motor programs. In the laboratory, robust behavioral assays, coupled with powerful genetic, molecular and optical tools, have made Caenorhabditis elegans an ideal experimental system in which to dissect the contributions of individual genes and neurons to ethologically relevant chemosensory behaviors. Here, we review current knowledge of the neurons, signal transduction molecules and regulatory mechanisms that underlie the response of C. elegans to chemicals, including pheromones. The majority of identified molecules and pathways share remarkable homology with sensory mechanisms in other organisms. With the development of new tools and technologies, we anticipate that continued study of chemosensory signal transduction and processing in C. elegans will yield additional new insights into the mechanisms by which this animal is able to detect and discriminate among thousands of chemical cues with a limited sensory neuron repertoire.
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Affiliation(s)
- Denise M Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Noelle D L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
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15
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Kundu A, Jaiswal N, Bhat CG, Phani V, Chatterjee M, Dash M, Rao U, Somvanshi VS. Expression of various odorant-response defective (odr) genes in the entomopathogenic nematode Heterorhabditis bacteriophora (Nematoda: Heterorhabditidae). GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Wolf T, Perez A, Harris G. Glutamatergic transmission regulates locomotory behavior on a food patch in C. elegans. MICROPUBLICATION BIOLOGY 2020; 2020:10.17912/micropub.biology.000332. [PMID: 33274320 PMCID: PMC7704250 DOI: 10.17912/micropub.biology.000332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Trevor Wolf
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012
| | - Ariana Perez
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012
| | - Gareth Harris
- Biology Program, 1 University Drive, California State University Channel Islands, Camarillo, Ca, 93012,
Correspondence to: Gareth Harris ()
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17
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Jia R, Zhang J, Jia K. Neuroendocrine regulation of fat metabolism by autophagy gene atg-18 in C. elegans dauer larvae. FEBS Open Bio 2019; 9:1623-1631. [PMID: 31368651 PMCID: PMC6722879 DOI: 10.1002/2211-5463.12708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2019] [Accepted: 07/31/2019] [Indexed: 12/21/2022] Open
Abstract
In environments with limited food and high population density, Caenorhabditis elegans larvae may enter the dauer stage, in which metabolism is shifted to fat accumulation to allow larvae to survive for months without food. Mutations in the insulin‐like receptor gene daf‐2 force C. elegans to constitutively form dauer larva at higher temperature. It has been reported that autophagy is required for fat accumulation in daf‐2 dauer larva. However, the mechanism underlying this process remains unknown. Here, we report that autophagy gene atg‐18 acts in a cell nonautonomous manner in neurons and intestinal cells to mediate the influence of daf‐2 signaling on fat metabolism. Moreover, ATG‐18 in chemosensory neurons plays a vital role in this metabolic process. Finally, we report that neuronal ATG‐18 functions through neurotransmitters to control fat storage in daf‐2 dauers, which suggests an essential role of autophagy in the neuroendocrine regulation of fat metabolism by insulin‐like signaling.
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Affiliation(s)
- Ray Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
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18
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Iwanir S, Ruach R, Itskovits E, Pritz CO, Bokman E, Zaslaver A. Irrational behavior in C. elegans arises from asymmetric modulatory effects within single sensory neurons. Nat Commun 2019; 10:3202. [PMID: 31324786 PMCID: PMC6642097 DOI: 10.1038/s41467-019-11163-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 06/20/2019] [Indexed: 12/19/2022] Open
Abstract
C. elegans worms exhibit a natural chemotaxis towards food cues. This provides a potential platform to study the interactions between stimulus valence and innate behavioral preferences. Here we perform a comprehensive set of choice assays to measure worms' relative preference towards various attractants. Surprisingly, we find that when facing a combination of choices, worms' preferences do not always follow value-based hierarchy. In fact, the innate chemotaxis behavior in worms robustly violates key rationality paradigms of transitivity, independence of irrelevant alternatives and regularity. These violations arise due to asymmetric modulatory effects between the presented options. Functional analysis of the entire chemosensory system at a single-neuron resolution, coupled with analyses of mutants, defective in individual neurons, reveals that these asymmetric effects originate in specific sensory neurons.
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Affiliation(s)
- Shachar Iwanir
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Rotem Ruach
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Eyal Itskovits
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Christian O Pritz
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Eduard Bokman
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Alon Zaslaver
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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19
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Chute CD, DiLoreto EM, Zhang YK, Reilly DK, Rayes D, Coyle VL, Choi HJ, Alkema MJ, Schroeder FC, Srinivasan J. Co-option of neurotransmitter signaling for inter-organismal communication in C. elegans. Nat Commun 2019; 10:3186. [PMID: 31320626 PMCID: PMC6639374 DOI: 10.1038/s41467-019-11240-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 06/28/2019] [Indexed: 12/22/2022] Open
Abstract
Biogenic amine neurotransmitters play a central role in metazoan biology, and both their chemical structures and cognate receptors are evolutionarily conserved. Their primary roles are in cell-to-cell signaling, as biogenic amines are not normally recruited for communication between separate individuals. Here, we show that in the nematode C. elegans, a neurotransmitter-sensing G protein-coupled receptor, TYRA-2, is required for avoidance responses to osas#9, an ascaroside pheromone that incorporates the neurotransmitter, octopamine. Neuronal ablation, cell-specific genetic rescue, and calcium imaging show that tyra-2 expression in the nociceptive neuron, ASH, is necessary and sufficient to induce osas#9 avoidance. Ectopic expression in the AWA neuron, which is generally associated with attractive responses, reverses the response to osas#9, resulting in attraction instead of avoidance behavior, confirming that TYRA-2 partakes in the sensing of osas#9. The TYRA-2/osas#9 signaling system represents an inter-organismal communication channel that evolved via co-option of a neurotransmitter and its cognate receptor.
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Affiliation(s)
- Christopher D Chute
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA
- BioHelix Corporation, Beverly, MA, 01915, USA
| | - Elizabeth M DiLoreto
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA
| | - Ying K Zhang
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Douglas K Reilly
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA
| | - Diego Rayes
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (CONICET), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, B8000, Argentina
| | - Veronica L Coyle
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA
- AbbVie, Cambridge, MA, 02139, USA
| | - Hee June Choi
- Biomedical Engineering Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA
| | - Mark J Alkema
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Jagan Srinivasan
- Biology and Biotechnology Department, Worcester Polytechnic Institute, Worcester, MA, 01605, USA.
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20
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Shivakumara TN, Dutta TK, Chaudhary S, von Reuss SH, Williamson VM, Rao U. Homologs of Caenorhabditis elegans Chemosensory Genes Have Roles in Behavior and Chemotaxis in the Root-Knot Nematode Meloidogyne incognita. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:876-887. [PMID: 30759351 DOI: 10.1094/mpmi-08-18-0226-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nematode chemosensation is a vital component of their host-seeking behavior. The globally important phytonematode Meloidogyne incognita perceives and responds (via sensory organs such as amphids and phasmids) differentially to various chemical cues emanating from the rhizosphere during the course of host finding. However, compared with the free-living worm Caenorhabditis elegans, the molecular intricacies behind the plant nematode chemotaxis are a yet-unexploited territory. In the present study, four putative chemosensory genes of M. incognita, namely, Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 were molecularly characterized. Mi-odr-1 mRNA was found to be expressed in the cell bodies of amphidial neurons and phasmids of M. incognita. Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 transcripts were highly expressed in early life stages of M. incognita, consistent with a role of these genes in host recognition. Functional characterization of Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 via RNA interference revealed behavioral defects in M. incognita and perturbed attraction to host roots in Pluronic gel medium. Knockdown of Mi-odr-1, Mi-odr-3, Mi-tax-2, and Mi-tax-4 resulted in defective chemotaxis of M. incognita to various volatile compounds (alcohol, ketone, aromatic compound, ester, thiazole, pyrazine), nonvolatiles of plant origin (carbohydrate, phytohormone, organic acid, amino acid, phenolic), and host root exudates in an agar-Pluronic gel-based assay plate. In addition, ascaroside-mediated signaling was impeded by downregulation of chemosensory genes. This new information that behavioral response in M. incognita is modulated by specific olfactory genes can be extended to understand chemotaxis in other nematodes.
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Affiliation(s)
| | - Tushar K Dutta
- 1 Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India
| | - Sonam Chaudhary
- 1 Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India
| | - Stephan H von Reuss
- 2 Institute of Chemistry, University of Neuchâtel, Neuchâtel, Avenue de Bellevaux 51, Switzerland
| | - Valerie M Williamson
- 3 Department of Plant Pathology, University of California, Davis, CA 95616, U.S.A
| | - Uma Rao
- 1 Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India
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21
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Bryant AS, Hallem EA. Terror in the dirt: Sensory determinants of host seeking in soil-transmitted mammalian-parasitic nematodes. Int J Parasitol Drugs Drug Resist 2018; 8:496-510. [PMID: 30396862 PMCID: PMC6287541 DOI: 10.1016/j.ijpddr.2018.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 12/12/2022]
Abstract
Infection with gastrointestinal parasitic nematodes is a major cause of chronic morbidity and economic burden around the world, particularly in low-resource settings. Some parasitic nematode species, including the human-parasitic threadworm Strongyloides stercoralis and human-parasitic hookworms in the genera Ancylostoma and Necator, feature a soil-dwelling infective larval stage that seeks out hosts for infection using a variety of host-emitted sensory cues. Here, we review our current understanding of the behavioral responses of soil-dwelling infective larvae to host-emitted sensory cues, and the molecular and cellular mechanisms that mediate these responses. We also discuss the development of methods for transgenesis and CRISPR/Cas9-mediated targeted mutagenesis in Strongyloides stercoralis and the closely related rat parasite Strongyloides ratti. These methods have established S. stercoralis and S. ratti as genetic model systems for gastrointestinal parasitic nematodes and are enabling more detailed investigations into the neural mechanisms that underlie the sensory-driven behaviors of this medically and economically important class of parasites.
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Affiliation(s)
- Astra S Bryant
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA.
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22
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G Proteins and GPCRs in C. elegans Development: A Story of Mutual Infidelity. J Dev Biol 2018; 6:jdb6040028. [PMID: 30477278 PMCID: PMC6316442 DOI: 10.3390/jdb6040028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 11/15/2018] [Accepted: 11/22/2018] [Indexed: 12/14/2022] Open
Abstract
Many vital processes during C. elegans development, especially the establishment and maintenance of cell polarity in embryogenesis, are controlled by complex signaling pathways. G protein-coupled receptors (GPCRs), such as the four Frizzled family Wnt receptors, are linchpins in regulating and orchestrating several of these mechanisms. However, despite being GPCRs, which usually couple to G proteins, these receptors do not seem to activate classical heterotrimeric G protein-mediated signaling cascades. The view on signaling during embryogenesis is further complicated by the fact that heterotrimeric G proteins do play essential roles in cell polarity during embryogenesis, but their activity is modulated in a predominantly GPCR-independent manner via G protein regulators such as GEFs GAPs and GDIs. Further, the triggered downstream effectors are not typical. Only very few GPCR-dependent and G protein-mediated signaling pathways have been unambiguously defined in this context. This unusual and highly intriguing concept of separating GPCR function and G-protein activity, which is not restricted to embryogenesis in C. elegans but can also be found in other organisms, allows for essential and multi-faceted ways of regulating cellular communication and response. Although its relevance cannot be debated, its impact is still poorly discussed, and C. elegans is an ideal model to understand the underlying principles.
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23
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Assaying sensory ciliopathies using calcium biosensor expression in zebrafish ciliated olfactory neurons. Cilia 2018; 7:2. [PMID: 29568513 PMCID: PMC5856005 DOI: 10.1186/s13630-018-0056-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/22/2018] [Indexed: 12/12/2022] Open
Abstract
Background Primary cilia mediate signal transduction by acting as an organizing scaffold for receptors, signalling proteins and ion channels. Ciliated olfactory sensory neurons (OSNs) organize olfactory receptors and ion channels on cilia and generate a calcium influx as a primary signal in odourant detection. In the zebrafish olfactory placode, ciliated OSNs and microvillus OSNs constitute the major OSN cell types with distinct odourant sensitivity. Methods Using transgenic expression of the calcium biosensor GCaMP5 in OSNs, we analysed sensory cilia-dependent odour responses in live zebrafish, at individual cell resolution. oval/ift88 mutant and ift172 knockdown zebrafish were compared with wild-type siblings to establish ciliated OSN sensitivity to different classes of odourants. Results oval/ift88 mutant and ift172 knockdown zebrafish showed fewer and severely shortened OSN cilia without a reduction in OSN number. The fraction of responding OSNs and response amplitudes to bile acids and food odour, both sensed by ciliated OSNs, were significantly reduced in ift88 mutants and ift172-deficient embryos, while the amino acids responses were not significantly changed. Conclusions Our approach presents a quantitative model for studying sensory cilia signalling using zebrafish OSNs. Our results also implicate ift172-deficiency as a novel cause of hyposmia, a reduced sense of smell, highlighting the value of directly assaying sensory cilia signalling in vivo and supporting the idea that hyposmia can be used as a diagnostic indicator of ciliopathies. Electronic supplementary material The online version of this article (10.1186/s13630-018-0056-1) contains supplementary material, which is available to authorized users.
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24
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Jean F, Pilgrim D. Coordinating the uncoordinated: UNC119 trafficking in cilia. Eur J Cell Biol 2017; 96:643-652. [PMID: 28935136 DOI: 10.1016/j.ejcb.2017.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/29/2022] Open
Abstract
Constructing the distinct subcellular environment of the cilium relies in a large part upon intraflagellar transport (IFT) proteins, which traffic cargo both to and within the cilium. However, evidence from the last 10 years suggests that IFT alone is not sufficient to generate the ciliary environment. One essential factor is UNC119, which interacts with known IFT molecular switches to transport ciliary cargos. Despite its apparent importance in ciliary trafficking though, human UNC119 mutations have only rarely been associated with diseases commonly linked with ciliopathies. This review will outline the trafficking pathways required for constructing the cilium by highlighting UNC119's role and the complexities involved in ciliary trafficking. Finally, despite important roles for UNC119 in cilia, UNC119 proteins also interact with non-ciliary proteins to affect other cellular processes.
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25
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Igual Gil C, Jarius M, von Kries JP, Rohlfing AK. Neuronal Chemosensation and Osmotic Stress Response Converge in the Regulation of aqp-8 in C. elegans. Front Physiol 2017. [PMID: 28649202 PMCID: PMC5465262 DOI: 10.3389/fphys.2017.00380] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Aquaporins occupy an essential role in sustaining the salt/water balance in various cells types and tissues. Here, we present new insights into aqp-8 expression and regulation in Caenorhabditis elegans. We show, that upon exposure to osmotic stress, aqp-8 exhibits a distinct expression pattern within the excretory cell compared to other C. elegans aquaporins expressed. This expression is correlated to the osmolarity of the surrounding medium and can be activated physiologically by osmotic stress or genetically in mutants with constitutively active osmotic stress response. In addition, we found aqp-8 expression to be constitutively active in the TRPV channel mutant osm-9(ok1677). In a genome-wide RNAi screen we identified additional regulators of aqp-8. Many of these regulators are connected to chemosensation by the amphid neurons, e.g., odr-10 and gpa-6, and act as suppressors of aqp-8 expression. We postulate from our results, that aqp-8 plays an important role in sustaining the salt/water balance during a secondary response to hyper-osmotic stress. Upon its activation aqp-8 promotes vesicle docking to the lumen of the excretory cell and thereby enhances the ability to secrete water and transport osmotic active substances or waste products caused by protein damage. In summary, aqp-8 expression and function is tightly regulated by a network consisting of the osmotic stress response, neuronal chemosensation as well as the response to protein damage. These new insights in maintaining the salt/water balance in C. elegans will help to reveal the complex homeostasis network preserved throughout species.
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Affiliation(s)
- Carla Igual Gil
- Zoophysiology, Institute for Biochemistry and Biology, University PotsdamPotsdam, Germany
| | - Mirko Jarius
- Zoophysiology, Institute for Biochemistry and Biology, University PotsdamPotsdam, Germany
| | - Jens P von Kries
- Leibniz-Institut für Molekulare Pharmakologie (FMP)Berlin, Germany
| | - Anne-Katrin Rohlfing
- Zoophysiology, Institute for Biochemistry and Biology, University PotsdamPotsdam, Germany
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26
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Minnerly J, Zhang J, Parker T, Kaul T, Jia K. The cell non-autonomous function of ATG-18 is essential for neuroendocrine regulation of Caenorhabditis elegans lifespan. PLoS Genet 2017; 13:e1006764. [PMID: 28557996 PMCID: PMC5469504 DOI: 10.1371/journal.pgen.1006764] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 06/13/2017] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Dietary restriction (DR) and reduced insulin growth factor (IGF) signaling extend lifespan in Caenorhabditis elegans and other eukaryotic organisms. Autophagy, an evolutionarily conserved lysosomal degradation pathway, has emerged as a central pathway regulated by various longevity signals including DR and IGF signaling in promoting longevity in a variety of eukaryotic organisms. However, the mechanism remains unclear. Here we show that the autophagy protein ATG-18 acts cell non-autonomously in neuronal and intestinal tissues to maintain C. elegans wildtype lifespan and to respond to DR and IGF-mediated longevity signaling. Moreover, ATG-18 activity in chemosensory neurons that are involved in food detection sufficiently mediates the effect of these longevity pathways. Additionally, ATG-18-mediated cell non-autonomous signaling depends on the release of neurotransmitters and neuropeptides. Interestingly, our data suggest that neuronal and intestinal ATG-18 acts in parallel and converges on unidentified neurons that secrete neuropeptides to regulate C. elegans lifespan through the transcription factor DAF-16/FOXO in response to reduced IGF signaling.
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Affiliation(s)
- Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Thomas Parker
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Tiffany Kaul
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
- * E-mail:
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Hussey R, Stieglitz J, Mesgarzadeh J, Locke TT, Zhang YK, Schroeder FC, Srinivasan S. Pheromone-sensing neurons regulate peripheral lipid metabolism in Caenorhabditis elegans. PLoS Genet 2017; 13:e1006806. [PMID: 28545126 PMCID: PMC5456406 DOI: 10.1371/journal.pgen.1006806] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 06/02/2017] [Accepted: 05/05/2017] [Indexed: 12/03/2022] Open
Abstract
It is now established that the central nervous system plays an important role in regulating whole body metabolism and energy balance. However, the extent to which sensory systems relay environmental information to modulate metabolic events in peripheral tissues has remained poorly understood. In addition, it has been challenging to map the molecular mechanisms underlying discrete sensory modalities with respect to their role in lipid metabolism. In previous work our lab has identified instructive roles for serotonin signaling as a surrogate for food availability, as well as oxygen sensing, in the control of whole body metabolism. In this study, we now identify a role for a pair of pheromone-sensing neurons in regulating fat metabolism in C. elegans, which has emerged as a tractable and highly informative model to study the neurobiology of metabolism. A genetic screen revealed that GPA-3, a member of the Gα family of G proteins, regulates body fat content in the intestine, the major metabolic organ for C. elegans. Genetic and reconstitution studies revealed that the potent body fat phenotype of gpa-3 null mutants is controlled from a pair of neurons called ADL(L/R). We show that cAMP functions as the second messenger in the ADL neurons, and regulates body fat stores via the neurotransmitter acetylcholine, from downstream neurons. We find that the pheromone ascr#3, which is detected by the ADL neurons, regulates body fat stores in a GPA-3-dependent manner. We define here a third sensory modality, pheromone sensing, as a major regulator of body fat metabolism. The pheromone ascr#3 is an indicator of population density, thus we hypothesize that pheromone sensing provides a salient 'denominator' to evaluate the amount of food available within a population and to accordingly adjust metabolic rate and body fat levels. The central nervous system plays a vital role in regulating whole body metabolism and energy balance. However, the precise cellular, genetic and molecular mechanisms underlying these effects remain a major unsolved mystery. C. elegans has emerged as a tractable and highly informative model to study the neurobiology of metabolism. Previously, we have identified instructive roles for serotonin signaling as a surrogate for food availability, as well as oxygen sensing, in the control of whole body metabolism. In our current study we have identified a role for a pair of pheromone-sensing neurons in regulating fat metabolism in C. elegans. cAMP acts as a second messenger in these neurons, and regulates body fat stores via acetylcholine signaling in the nervous system. We find that the population-density-sensing pheromone detected by these neurons regulates body fat stores. Together, we define a third sensory modality, population density sensing, as a major regulator of body fat metabolism.
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Affiliation(s)
- Rosalind Hussey
- Department of Molecular Medicine and Department of Neuroscience, The Scripps Research Institute, La Jolla, California, United States of America
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Jon Stieglitz
- Kellogg School of Science and Technology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Jaleh Mesgarzadeh
- Department of Molecular Medicine and Department of Neuroscience, The Scripps Research Institute, La Jolla, California, United States of America
- Department of Biology, University of California, San Diego, La Jolla, California, United States of America
| | - Tiffany T. Locke
- Department of Biology, University of California, San Diego, La Jolla, California, United States of America
| | - Ying K. Zhang
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States of America
| | - Frank C. Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States of America
| | - Supriya Srinivasan
- Department of Molecular Medicine and Department of Neuroscience, The Scripps Research Institute, La Jolla, California, United States of America
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Zhang C, Zhao N, Chen Y, Zhang D, Yan J, Zou W, Zhang K, Huang X. The Signaling Pathway of Caenorhabditis elegans Mediates Chemotaxis Response to the Attractant 2-Heptanone in a Trojan Horse-like Pathogenesis. J Biol Chem 2016; 291:23618-23627. [PMID: 27660389 DOI: 10.1074/jbc.m116.741132] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 11/06/2022] Open
Abstract
The nematode Caenorhabditis elegans exhibits behavioral responses to a wide range of odorants associated with food and pathogens. A previous study described a Trojan Horse-like strategy of pathogenesis whereby the bacterium Bacillus nematocida B16 emits the volatile organic compound 2-heptanone to trap C. elegans for successful infection. Here, we further explored the receptor for 2-heptanone as well as the pathway involved in signal transduction in C. elegans Our experiments showed that 2-heptanone sensing depended on the function of AWC neurons and a GPCR encoded by str-2 Consistent with the above observation, the HEK293 cells expressing STR-2 on their surfaces showed a transient elevation in intracellular Ca2+ levels after 2-heptanone applications. After combining the assays of RNA interference and gene mutants, we also identified the Gα subunits and their downstream components in the olfactory signal cascade that are necessary for responding to 2-heptanone, including Gα subunits of egl-30 and gpa-3, phospholipase C of plc-1and egl-8, and the calcium channel of cmk-1 and cal-1. Our work demonstrates for the first time that an integrated signaling pathway for 2-heptanone response in C. elegans involves recognition by GPCR STR-2, activation by Gα subunits of egl-30/gpa-3 and transfer to the PLC pathway, indicating that a potentially novel olfactory pathway exists in AWC neurons. Meanwhile, since 2-heptanone, a metabolite from the pathogenic bacterium B. nematocida B16, can be sensed by C. elegans and thus strongly attract its host, our current work also suggested coevolution between the pathogenic microorganism and the chemosensory system in C. elegans.
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Affiliation(s)
- Chunmei Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Ninghui Zhao
- Neurosurgery of the Second Hospital affiliated with Kunming Medical University, Kunming 650101, China, and
| | - Yao Chen
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Donghua Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Jinyuan Yan
- Center Laboratory of the Second Hospital affiliated with Kunming Medical University, Kunming 650101, China
| | - Wei Zou
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Keqin Zhang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China
| | - Xiaowei Huang
- From the State Key Lab for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan 650091, China,
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Campbell JC, Polan-Couillard LF, Chin-Sang ID, Bendena WG. NPR-9, a Galanin-Like G-Protein Coupled Receptor, and GLR-1 Regulate Interneuronal Circuitry Underlying Multisensory Integration of Environmental Cues in Caenorhabditis elegans. PLoS Genet 2016; 12:e1006050. [PMID: 27223098 PMCID: PMC4880332 DOI: 10.1371/journal.pgen.1006050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 04/21/2016] [Indexed: 11/27/2022] Open
Abstract
C. elegans inhabit environments that require detection of diverse stimuli to modulate locomotion in order to avoid unfavourable conditions. In a mammalian context, a failure to appropriately integrate environmental signals can lead to Parkinson’s, Alzheimer’s, and epilepsy. Provided that the circuitry underlying mammalian sensory integration can be prohibitively complex, we analyzed nematode behavioral responses in differing environmental contexts to evaluate the regulation of context dependent circuit reconfiguration and sensorimotor control. Our work has added to the complexity of a known parallel circuit, mediated by interneurons AVA and AIB, that integrates sensory cues and is responsible for the initiation of backwards locomotion. Our analysis of the galanin-like G-protein coupled receptor NPR-9 in C. elegans revealed that upregulation of galanin signaling impedes the integration of sensory evoked neuronal signals. Although the expression pattern of npr-9 is limited to AIB, upregulation of the receptor appears to impede AIB and AVA circuits to broadly prevent backwards locomotion, i.e. reversals, suggesting that these two pathways functionally interact. Galanin signaling similarly plays a broadly inhibitory role in mammalian models. Moreover, our identification of a mutant, which rarely initiates backwards movement, allowed us to interrogate locomotory mechanisms underlying chemotaxis. In support of the pirouette model of chemotaxis, organisms that did not exhibit reversal behavior were unable to navigate towards an attractant peak. We also assessed ionotropic glutamate receptor GLR-1 cell-specifically within AIB and determined that GLR-1 fine-tunes AIB activity to modify locomotion following reversal events. Our research highlights that signal integration underlying the initiation and fine-tuning of backwards locomotion is AIB and NPR-9 dependent, and has demonstrated the suitability of C. elegans for analysis of multisensory integration and sensorimotor control. Multiple environmental cues are sensed by an organism in order to coordinate behavioral responses. Consequently, organisms must be able to simultaneously detect and integrate multiple external stimuli in order to appropriately modify their behavior. Identifying the unique circuits mediating the response to individual stimuli and points of overlap is essential to understanding how multiple signals can be integrated for a coordinated behavioral response. In order to analyze individual circuits, we have used the model organism C. elegans. We have identified that a C. elegans neuropeptide receptor (NPR-9) and a glutamate receptor (GLR-1) function in a single interneuron to play a broad regulatory role in multiple neural circuits. Our research has identified that interneuron AIB is involved in the integration of signals from numerous sensory neurons. Moreover, regulation of AIB via a neuropeptide receptor (NPR-9) and a glutamate receptor (GLR-1) coordinates AIB activity in the context of multisensory integration. Long-range chemotaxis behavior, in which an organism alters locomotory patterns based on odorant sensation, is also regulated by NPR-9. Our analysis indicates that reversals, and thus the pirouette model, are sufficient for chemotaxis.
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Affiliation(s)
- Jason C. Campbell
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
| | | | - Ian D. Chin-Sang
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
| | - William G. Bendena
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
- Centre for Neuroscience, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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30
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Maruyama IN. Receptor Guanylyl Cyclases in Sensory Processing. Front Endocrinol (Lausanne) 2016; 7:173. [PMID: 28123378 PMCID: PMC5225109 DOI: 10.3389/fendo.2016.00173] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 12/28/2016] [Indexed: 11/18/2022] Open
Abstract
Invertebrate models have generated many new insights into transmembrane signaling by cell-surface receptors. This review focuses on receptor guanylyl cyclases (rGCs) and describes recent advances in understanding their roles in sensory processing in the nematode, Caenorhabditis elegans. A complete analysis of the C. elegans genome elucidated 27 rGCs, an unusually large number compared with mammalian genomes, which encode 7 rGCs. Most C. elegans rGCs are expressed in sensory neurons and play roles in sensory processing, including gustation, thermosensation, olfaction, and phototransduction, among others. Recent studies have found that by producing a second messenger, guanosine 3',5'-cyclic monophosphate, some rGCs act as direct sensor molecules for ions and temperatures, while others relay signals from G protein-coupled receptors. Interestingly, genetic and biochemical analyses of rGCs provide the first example of an obligate heterodimeric rGC. Based on recent structural studies of rGCs in mammals and other organisms, molecular mechanisms underlying activation of rGCs are also discussed in this review.
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Affiliation(s)
- Ichiro N. Maruyama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- *Correspondence: Ichiro N. Maruyama,
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31
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DLK-1/p38 MAP Kinase Signaling Controls Cilium Length by Regulating RAB-5 Mediated Endocytosis in Caenorhabditis elegans. PLoS Genet 2015; 11:e1005733. [PMID: 26657059 PMCID: PMC4686109 DOI: 10.1371/journal.pgen.1005733] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 11/19/2015] [Indexed: 01/11/2023] Open
Abstract
Cilia are sensory organelles present on almost all vertebrate cells. Cilium length is constant, but varies between cell types, indicating that cilium length is regulated. How this is achieved is unclear, but protein transport in cilia (intraflagellar transport, IFT) plays an important role. Several studies indicate that cilium length and function can be modulated by environmental cues. As a model, we study a C. elegans mutant that carries a dominant active G protein α subunit (gpa-3QL), resulting in altered IFT and short cilia. In a screen for suppressors of the gpa-3QL short cilium phenotype, we identified uev-3, which encodes an E2 ubiquitin-conjugating enzyme variant that acts in a MAP kinase pathway. Mutation of two other components of this pathway, dual leucine zipper-bearing MAPKKK DLK-1 and p38 MAPK PMK-3, also suppress the gpa-3QL short cilium phenotype. However, this suppression seems not to be caused by changes in IFT. The DLK-1/p38 pathway regulates several processes, including microtubule stability and endocytosis. We found that reducing endocytosis by mutating rabx-5 or rme-6, RAB-5 GEFs, or the clathrin heavy chain, suppresses gpa-3QL. In addition, gpa-3QL animals showed reduced levels of two GFP-tagged proteins involved in endocytosis, RAB-5 and DPY-23, whereas pmk-3 mutant animals showed accumulation of GFP-tagged RAB-5. Together our results reveal a new role for the DLK-1/p38 MAPK pathway in control of cilium length by regulating RAB-5 mediated endocytosis. Cells detect cues in their environment using many different receptor and channel proteins, most of which localize to the plasma membrane of the cell. Some of these receptors and channels localize to a specialized sensory organelle, the primary cilium, that extends from the cell like a small antenna. Almost all cells of the human body have one or more cilia. Defects in cilium structure or function have been implicated in many diseases. Many studies have shown that the length of cilia is regulated and can be modulated by environmental signals. Several genes have been identified that function in cilium length regulation and it is clear that transport of proteins inside the cilium plays an important role. Here, we identify several genes of a MAP kinase cascade that modulate the length of cilia of the nematode Caenorhabditis elegans. Interestingly, this regulation seems not to be mediated by the transport system in the cilia, but by modulation of endocytosis. Our results suggest that regulated delivery and removal of proteins and/or lipids at the base of the cilium contributes to the regulation of cilium length.
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Krishnan A, Mustafa A, Almén MS, Fredriksson R, Williams MJ, Schiöth HB. Evolutionary hierarchy of vertebrate-like heterotrimeric G protein families. Mol Phylogenet Evol 2015; 91:27-40. [DOI: 10.1016/j.ympev.2015.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
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Sowa JN, Mutlu AS, Xia F, Wang MC. Olfaction Modulates Reproductive Plasticity through Neuroendocrine Signaling in Caenorhabditis elegans. Curr Biol 2015; 25:2284-9. [PMID: 26279229 DOI: 10.1016/j.cub.2015.07.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/07/2015] [Accepted: 07/09/2015] [Indexed: 11/26/2022]
Abstract
Reproductive plasticity describes the ability of organisms to adjust parameters such as volume, rate, or timing of progeny production in order to maximize successful reproduction under different environmental conditions. Reproductive plasticity in response to environmental variation has been observed in a wide range of animals; however, the mechanisms involved in translating environmental cues into reproductive outcomes remain unknown. Here, we show that olfaction modulates reproductive timing and senescence through neuroendocrine signaling in Caenorhabditis elegans. On their preferred diet, worms demonstrate an increased rate of reproduction and an early onset of reproductive aging. Perception of the preferred diet's odor by AWB olfactory neurons elicits these adjustments by increasing germline proliferation, and optogenetic stimulation of AWB neurons is sufficient to accelerate reproductive timing in the absence of dietary inputs. Furthermore, AWB neurons act through neuropeptide signaling to regulate reproductive rate and senescence. These findings reveal a neuroendocrine nexus linking olfactory sensation and reproduction in response to environmental variation and indicate the significance of olfaction in the regulation of reproductive decline during aging.
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Affiliation(s)
- Jessica N Sowa
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ayse Sena Mutlu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng C Wang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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Meisel JD, Panda O, Mahanti P, Schroeder FC, Kim DH. Chemosensation of bacterial secondary metabolites modulates neuroendocrine signaling and behavior of C. elegans. Cell 2015; 159:267-80. [PMID: 25303524 DOI: 10.1016/j.cell.2014.09.011] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 07/03/2014] [Accepted: 09/03/2014] [Indexed: 11/30/2022]
Abstract
Discrimination between pathogenic and beneficial microbes is essential for host organism immunity and homeostasis. Here, we show that chemosensory detection of two secondary metabolites produced by Pseudomonas aeruginosa modulates a neuroendocrine signaling pathway that promotes avoidance behavior in the simple animal host Caenorhabditis elegans. Secondary metabolites phenazine-1-carboxamide and pyochelin activate a G-protein-signaling pathway in the ASJ chemosensory neuron pair that induces expression of the neuromodulator DAF-7/TGF-β. DAF-7, in turn, activates a canonical TGF-β signaling pathway in adjacent interneurons to modulate aerotaxis behavior and promote avoidance of pathogenic P. aeruginosa. Our data provide a chemical, genetic, and neuronal basis for how the behavior and physiology of a simple animal host can be modified by the microbial environment and suggest that secondary metabolites produced by microbes may provide environmental cues that contribute to pathogen recognition and host survival.
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Affiliation(s)
- Joshua D Meisel
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Oishika Panda
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Parag Mahanti
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Frank C Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Dennis H Kim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Tehseen M, Dumancic M, Briggs L, Wang J, Berna A, Anderson A, Trowell S. Functional coupling of a nematode chemoreceptor to the yeast pheromone response pathway. PLoS One 2014; 9:e111429. [PMID: 25415379 PMCID: PMC4240545 DOI: 10.1371/journal.pone.0111429] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/25/2014] [Indexed: 12/22/2022] Open
Abstract
Sequencing of the Caenorhabditis elegans genome revealed sequences encoding more than 1,000 G-protein coupled receptors, hundreds of which may respond to volatile organic ligands. To understand how the worm's simple olfactory system can sense its chemical environment there is a need to characterise a representative selection of these receptors but only very few receptors have been linked to a specific volatile ligand. We therefore set out to design a yeast expression system for assigning ligands to nematode chemoreceptors. We showed that while a model receptor ODR-10 binds to C. elegans Gα subunits ODR-3 and GPA-3 it cannot bind to yeast Gα. However, chimaeras between the nematode and yeast Gα subunits bound to both ODR-10 and the yeast Gβγ subunits. FIG2 was shown to be a superior MAP-dependent promoter for reporter expression. We replaced the endogenous Gα subunit (GPA1) of the Saccharomyces cerevisiae (ste2Δ sst2Δ far1Δ) triple mutant ("Cyb") with a Gpa1/ODR-3 chimaera and introduced ODR-10 as a model nematode GPCR. This strain showed concentration-dependent activation of the yeast MAP kinase pathway in the presence of diacetyl, the first time that the native form of a nematode chemoreceptor has been functionally expressed in yeast. This is an important step towards en masse de-orphaning of C. elegans chemoreceptors.
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Affiliation(s)
- Muhammad Tehseen
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Mira Dumancic
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Lyndall Briggs
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Jian Wang
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Amalia Berna
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Alisha Anderson
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
| | - Stephen Trowell
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, PO Box 1700, Canberra, ACT 2601, Australia
- * E-mail:
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Abstract
Food is critical for survival. Many animals, including the nematode Caenorhabditis elegans, use sensorimotor systems to detect and locate preferred food sources. However, the signaling mechanisms underlying food-choice behaviors are poorly understood. Here, we characterize the molecular signaling that regulates recognition and preference between different food odors in C. elegans. We show that the major olfactory sensory neurons, AWB and AWC, play essential roles in this behavior. A canonical Gα-protein, together with guanylate cyclases and cGMP-gated channels, is needed for the recognition of food odors. The food-odor-evoked signal is transmitted via glutamatergic neurotransmission from AWC and through AMPA and kainate-like glutamate receptor subunits. In contrast, peptidergic signaling is required to generate preference between different food odors while being dispensable for the recognition of the odors. We show that this regulation is achieved by the neuropeptide NLP-9 produced in AWB, which acts with its putative receptor NPR-18, and by the neuropeptide NLP-1 produced in AWC. In addition, another set of sensory neurons inhibits food-odor preference. These mechanistic logics, together with a previously mapped neural circuit underlying food-odor preference, provide a functional network linking sensory response, transduction, and downstream receptors to process complex olfactory information and generate the appropriate behavioral decision essential for survival.
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37
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The olfactory signal transduction for attractive odorants in Caenorhabditis elegans. Biotechnol Adv 2014; 32:290-5. [DOI: 10.1016/j.biotechadv.2013.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/14/2013] [Accepted: 10/28/2013] [Indexed: 11/20/2022]
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Olofsson B. The olfactory neuron AWC promotes avoidance of normally palatable food following chronic dietary restriction. ACTA ACUST UNITED AC 2014; 217:1790-8. [PMID: 24577446 PMCID: PMC4020945 DOI: 10.1242/jeb.099929] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Changes in metabolic state alter foraging behavior and food preference in animals. Here, I show that normally attractive food becomes repulsive to Caenorhabditis elegans if animals are chronically undernourished as a result of alimentary tract defects. This behavioral plasticity is achieved in two ways: increased food leaving and induction of aversive behavior towards food. A particularly strong food avoider is defective in the chitin synthase that makes the pharyngeal lining. Food avoidance induced by underfeeding is mediated by cGMP signaling in the olfactory neurons AWC and AWB, and the gustatory neurons ASJ and ASK. Food avoidance is enhanced by increased population density and is reduced if the animals are unable to correctly interpret their nutritional state as a result of defects in the AMP kinase or TOR/S6kinase pathways. The TGF-β/DBL-1 pathway suppresses food avoidance and the cellular basis for this is distinct from its role in aversive olfactory learning of harmful food. This study suggests that nutritional state feedback via nutrient sensors, population size and olfactory neurons guides food preference in C. elegans.
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Affiliation(s)
- Birgitta Olofsson
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
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Brechbühl J, Moine F, Broillet MC. Mouse Grueneberg ganglion neurons share molecular and functional features with C. elegans amphid neurons. Front Behav Neurosci 2013; 7:193. [PMID: 24367309 PMCID: PMC3856774 DOI: 10.3389/fnbeh.2013.00193] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/20/2013] [Indexed: 01/29/2023] Open
Abstract
The mouse Grueneberg ganglion (GG) is an olfactory subsystem located at the tip of the nose close to the entry of the naris. It comprises neurons that are both sensitive to cold temperature and play an important role in the detection of alarm pheromones (APs). This chemical modality may be essential for species survival. Interestingly, GG neurons display an atypical mammalian olfactory morphology with neurons bearing deeply invaginated cilia mostly covered by ensheathing glial cells. We had previously noticed their morphological resemblance with the chemosensory amphid neurons found in the anterior region of the head of Caenorhabditis elegans (C. elegans). We demonstrate here further molecular and functional similarities. Thus, we found an orthologous expression of molecular signaling elements that was furthermore restricted to similar specific subcellular localizations. Calcium imaging also revealed a ligand selectivity for the methylated thiazole odorants that amphid neurons are known to detect. Cellular responses from GG neurons evoked by chemical or temperature stimuli were also partially cGMP-dependent. In addition, we found that, although behaviors depending on temperature sensing in the mouse, such as huddling and thermotaxis did not implicate the GG, the thermosensitivity modulated the chemosensitivity at the level of single GG neurons. Thus, the striking similarities with the chemosensory amphid neurons of C. elegans conferred to the mouse GG neurons unique multimodal sensory properties.
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Affiliation(s)
- Julien Brechbühl
- Department of Pharmacology and Toxicology, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Fabian Moine
- Department of Pharmacology and Toxicology, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Marie-Christine Broillet
- Department of Pharmacology and Toxicology, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
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Broekhuis JR, Rademakers S, Burghoorn J, Jansen G. SQL-1, homologue of the Golgi protein GMAP210, modulates intraflagellar transport in C. elegans. J Cell Sci 2013; 126:1785-95. [PMID: 23444385 DOI: 10.1242/jcs.116640] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Primary cilia are microtubule-based organelles that have important sensory functions. For their function, cilia rely on the delivery of specific proteins, both by intracellular trafficking and intraflagellar transport (IFT). In the cilia of Caenorhabditis elegans, anterograde IFT is mediated by kinesin-II and OSM-3. Previously, we have shown that expression of a dominant active G protein α subunit (GPA-3QL) in amphid channel neurons affects the coordination of kinesin-II and OSM-3 and also affects cilia length, suggesting that environmental signals can modulate these processes. Here, we show that loss-of-function of sql-1 (suppressor of gpa-3QL 1), which encodes the homologue of the mammalian Golgi protein GMAP210, suppresses the gpa-3QL cilia length phenotype. SQL-1 localizes to the Golgi apparatus, where it contributes to maintaining Golgi organization. Loss of sql-1 by itself does not affect cilia length, whereas overexpression of sql-1 results in longer cilia. Using live imaging of fluorescently tagged IFT proteins, we show that in sql-1 mutants OSM-3 moves faster, kinesin-II moves slower and that some complex A and B proteins move at an intermediate velocity, while others move at the same velocity as OSM-3. This indicates that mutation of sql-1 destabilizes the IFT complex. Finally, we show that simultaneous inactivation of sql-1 and activation of gpa-3QL affects the velocity of OSM-3. In summary, we show that in C. elegans the Golgin protein SQL-1 plays an important role in maintaining the stability of the IFT complex.
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Affiliation(s)
- Joost R Broekhuis
- Department of Cell Biology, Erasmus MC, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
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Investigating the Relationship between Topology and Evolution in a Dynamic Nematode Odor Genetic Network. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2012; 2012:548081. [PMID: 23056995 PMCID: PMC3465961 DOI: 10.1155/2012/548081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/06/2012] [Accepted: 08/29/2012] [Indexed: 11/17/2022]
Abstract
The relationship between biological network architectures and evolution is unclear. Within the phylum nematoda olfaction represents a critical survival tool. For nematodes, olfaction contributes to multiple processes including the finding of food, hosts, and reproductive partners, making developmental decisions, and evading predators. Here we examine a dynamic nematode odor genetic network to investigate how divergence, diversity, and contribution are shaped by network topology. Our findings describe connectivity frameworks and characteristics that correlate with molecular evolution and contribution across the olfactory network. Our data helps guide the development of a robust evolutionary description of the nematode odor network that may eventually aid in the prediction of interactive and functional qualities of novel nodes.
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42
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Constantine R, Zhang H, Gerstner CD, Frederick JM, Baehr W. Uncoordinated (UNC)119: coordinating the trafficking of myristoylated proteins. Vision Res 2012; 75:26-32. [PMID: 23000199 DOI: 10.1016/j.visres.2012.08.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 01/06/2023]
Abstract
The mechanism by which myristoylated proteins are targeted to specific subcellular membrane compartments is poorly understood. Two novel acyl-binding proteins, UNC119A and UNC119B, have been shown recently to function as chaperones/co-factors in the transport of myristoylated G protein α-subunits and src-type tyrosine kinases. UNC119 polypeptides feature an immunoglobulin-like β-sandwich fold that forms a hydrophobic pocket capable of binding lauroyl (C12) and myristoyl (C14) side chains. UNC119A in rod photoreceptors facilitates the transfer of transducin α subunits (Tα) from inner segment to outer segment membranes by forming an intermediate diffusible UNC119-Tα complex. Similar complexes are formed in other sensory neurons, as the G proteins ODR-3 and GPA-13 in Caenorhabditis elegans unc-119 mutants traffic inappropriately. UNC119B knockdown in IMCD3 cells prevents trafficking ofmyristoylated nephrocystin-3 (NPHP3), a protein associated with nephronophthisis, to cilia. Further, UNC119A was shown to transport myristoylated src-type tyrosine kinases to cell membranes and to affect T-cell receptor (TCR) and interleukin-5 receptor (IL-5R) activities. These interactions establish UNC119 polypeptides as novel lipid-binding chaperones with specificity for a diverse subset of myristoylated proteins.
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Affiliation(s)
- Ryan Constantine
- Graduate Program in Neuroscience, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
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43
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Yoshida K, Hirotsu T, Tagawa T, Oda S, Wakabayashi T, Iino Y, Ishihara T. Odour concentration-dependent olfactory preference change in C. elegans. Nat Commun 2012; 3:739. [PMID: 22415830 DOI: 10.1038/ncomms1750] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/14/2012] [Indexed: 01/28/2023] Open
Abstract
The same odorant can induce attractive or repulsive responses depending on its concentration in various animals including humans. However, little is understood about the neuronal basis of this behavioural phenomenon. Here we show that Caenorhabditis elegans avoids high concentrations of odorants that are attractive at low concentrations. Behavioural analyses and computer simulation reveal that the odour concentration-dependent behaviour is primarily generated by klinokinesis, a behavioural strategy in C. elegans. Genetic analyses and lesion experiments show that distinct combinations of sensory neurons function at different concentrations of the odorant; AWC and ASH sensory neurons have critical roles for attraction to or avoidance of the odorant, respectively. Moreover, we found that AWC neurons respond to only lower concentrations of the odorant, whereas ASH neurons respond to only higher concentrations of odorant. Hence, our study suggests that odour concentration coding in C. elegans mostly conforms to the labelled-line principle where distinct neurons respond to distinct stimuli.
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Affiliation(s)
- Kazushi Yoshida
- Department of Biophysics and Biochemistry, Graduate School of Sciences, The University of Tokyo, 113-0032, Japan
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O'Halloran DM, Hamilton OS, Lee JI, Gallegos M, L'Etoile ND. Changes in cGMP levels affect the localization of EGL-4 in AWC in Caenorhabditis elegans. PLoS One 2012; 7:e31614. [PMID: 22319638 PMCID: PMC3272044 DOI: 10.1371/journal.pone.0031614] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 01/10/2012] [Indexed: 02/06/2023] Open
Abstract
The Protein Kinase G, EGL-4, is required within the C. elegans AWC sensory neurons to promote olfactory adaptation. After prolonged stimulation of these neurons, EGL-4 translocates from the cytosol to the nuclei of the AWC. This nuclear translocation event is both necessary and sufficient for adaptation of the AWC neuron to odor. A cGMP binding motif within EGL-4 and the Gα protein ODR-3 are both required for this translocation event, while loss of the guanylyl cyclase ODR-1 was shown to result in constitutively nuclear localization of EGL-4. However, the molecular changes that are integrated over time to produce a stably adapted response in the AWC are unknown. Here we show that odor-induced fluctuations in cGMP levels in the adult cilia may be responsible in part for sending EGL-4 into the AWC nucleus to produce long-term adaptation. We found that reductions in cGMP that result from mutations in the genes encoding the cilia-localized guanylyl cyclases ODR-1 and DAF-11 result in constitutively nuclear EGL-4 even in naive animals. Conversely, increases in cGMP levels that result from mutations in cGMP phosphodiesterases block EGL-4 nuclear entry even after prolonged odor exposure. Expression of a single phosphodiesterase in adult, naive animals was sufficient to modestly increase the number of animals with nuclear EGL-4. Further, coincident acute treatment of animals with odor and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) decreased the number of animals with nuclear EGL-4. These data suggest that reducing cGMP levels in AWC is necessary and even partially sufficient for nuclear translocation of EGL-4 and adaptation as a result of prolonged odor exposure. Our genetic analysis and chemical treatment of C. elegans further indicate that cilia morphology, as defined by fluorescent microscopic observation of the sensory endings, may allow for odor-induced fluctuations in cGMP levels and this fluctuation may be responsible for sending EGL-4 into the AWC nucleus.
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Affiliation(s)
- Damien M O'Halloran
- Center for Neuroscience, University of California Davis, Davis, California, United States of America.
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Zhang H, Constantine R, Vorobiev S, Chen Y, Seetharaman J, Huang YJ, Xiao R, Montelione GT, Gerstner CD, Davis MW, Inana G, Whitby FG, Jorgensen EM, Hill CP, Tong L, Baehr W. UNC119 is required for G protein trafficking in sensory neurons. Nat Neurosci 2011; 14:874-80. [PMID: 21642972 DOI: 10.1038/nn.2835] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Indexed: 12/20/2022]
Abstract
UNC119 is widely expressed among vertebrates and other phyla. We found that UNC119 recognized the acylated N terminus of the rod photoreceptor transducin α (Tα) subunit and Caenorhabditis elegans G proteins ODR-3 and GPA-13. The crystal structure of human UNC119 at 1.95-Å resolution revealed an immunoglobulin-like β-sandwich fold. Pulldowns and isothermal titration calorimetry revealed a tight interaction between UNC119 and acylated Gα peptides. The structure of co-crystals of UNC119 with an acylated Tα N-terminal peptide at 2.0 Å revealed that the lipid chain is buried deeply into UNC119's hydrophobic cavity. UNC119 bound Tα-GTP, inhibiting its GTPase activity, thereby providing a stable UNC119-Tα-GTP complex capable of diffusing from the inner segment back to the outer segment after light-induced translocation. UNC119 deletion in both mouse and C. elegans led to G protein mislocalization. Thus, UNC119 is a Gα subunit cofactor essential for G protein trafficking in sensory cilia.
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Affiliation(s)
- Houbin Zhang
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, USA
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Chen L, Fu Y, Ren M, Xiao B, Rubin CS. A RasGRP, C. elegans RGEF-1b, couples external stimuli to behavior by activating LET-60 (Ras) in sensory neurons. Neuron 2011; 70:51-65. [PMID: 21482356 PMCID: PMC3081643 DOI: 10.1016/j.neuron.2011.02.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2011] [Indexed: 11/17/2022]
Abstract
RasGRPs, which load GTP onto Ras and Rap1, are expressed in vertebrate and invertebrate neurons. The functions, regulation, and mechanisms of action of neuronal RasGRPs are unknown. Here, we show how C. elegans RGEF-1b, a prototypical neuronal RasGRP, regulates a critical behavior. Chemotaxis to volatile odorants was disrupted in RGEF-1b-deficient (rgef-1⁻/⁻) animals and wild-type animals expressing dominant-negative RGEF-1b in AWC sensory neurons. AWC-specific expression of RGEF-1b-GFP restored chemotaxis in rgef-1⁻/⁻ mutants. Signals disseminated by RGEF-1b in AWC neurons activated a LET-60 (Ras)-MPK-1 (ERK) signaling cascade. Other RGEF-1b and LET-60 effectors were dispensable for chemotaxis. A bifunctional C1 domain controlled intracellular targeting and catalytic activity of RGEF-1b and was essential for sensory signaling in vivo. Chemotaxis was unaffected when Ca²+-binding EF hands and a conserved phosphorylation site of RGEF-1b were inactivated. Diacylglycerol-activated RGEF-1b links external stimuli (odorants) to behavior (chemotaxis) by activating the LET-60-MPK-1 pathway in specific neurons.
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Affiliation(s)
- Lu Chen
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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47
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Liao C, Gock A, Michie M, Morton B, Anderson A, Trowell S. Behavioural and genetic evidence for C. elegans' ability to detect volatile chemicals associated with explosives. PLoS One 2010; 5:e12615. [PMID: 20830309 PMCID: PMC2935383 DOI: 10.1371/journal.pone.0012615] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 08/13/2010] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives. METHODOLOGY/PRINCIPAL FINDINGS We assayed C. elegans for chemotactic responses to chemical vapours of explosives and compounds associated with explosives. C. elegans failed to respond to many of the explosive materials themselves but showed strong chemotaxis with a number of compounds associated with commercial or homemade explosives. Genetic mutant strains were used to identify the likely neuronal location of a putative receptor responding to cyclohexanone, which is a contaminant of some compounded explosives, and to identify the specific transduction pathway involved. Upper limits on the sensitivity of the nematode were calculated. A sensory adaptation protocol was used to estimate the receptive range of the receptor. CONCLUSIONS/SIGNIFICANCE The results suggest that C. elegans may be a convenient source of highly sensitive, narrowly tuned receptors to detect a range of explosive-associated volatiles.
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Affiliation(s)
- Chunyan Liao
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
| | - Andrew Gock
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
| | - Michelle Michie
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
| | - Bethany Morton
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
| | - Alisha Anderson
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
| | - Stephen Trowell
- CSIRO Entomology and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory, Australia
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Burghoorn J, Dekkers MPJ, Rademakers S, de Jong T, Willemsen R, Swoboda P, Jansen G. Dauer pheromone and G-protein signaling modulate the coordination of intraflagellar transport kinesin motor proteins in C. elegans. J Cell Sci 2010; 123:2077-84. [PMID: 20501698 DOI: 10.1242/jcs.062885] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cilia length and function are dynamically regulated by modulation of intraflagellar transport (IFT). The cilia of C. elegans amphid channel neurons provide an excellent model to study this process, since they use two different kinesins for anterograde transport: kinesin-II and OSM-3 kinesin together in the cilia middle segments, but only OSM-3 in the distal segments. To address whether sensory signaling modulates the coordination of the kinesins, we studied IFT protein motility in gpa-3 mutant animals, since dominant active mutation of this sensory Galpha protein GPA-3QL) affects cilia length. In addition, we examined animals exposed to dauer pheromone, since dauer formation, which involves gpa-3, induces changes in cilia morphology. Live imaging of fluorescently tagged IFT proteins showed that in gpa-3 mutants and in larvae exposed to dauer pheromone, kinesin-II speed is decreased and OSM-3 speed is increased, whereas structural IFT proteins move at an intermediate speed. These results indicate that mutation of gpa-3 and exposure to dauer pheromone partially uncouple the two kinesins. We propose a model in which GPA-3-regulated docking of kinesin-II and/or OSM-3 determines entry of IFT particles into the cilia subdomains, allowing structural and functional plasticity of cilia in response to environmental cues.
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Affiliation(s)
- Jan Burghoorn
- Department of Cell Biology and Genetics, Erasmus MC, Rotterdam, the Netherlands
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Nuclear entry of a cGMP-dependent kinase converts transient into long-lasting olfactory adaptation. Proc Natl Acad Sci U S A 2010; 107:6016-21. [PMID: 20220099 DOI: 10.1073/pnas.1000866107] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To navigate a complex and changing environment, an animal's sensory neurons must continually adapt to persistent cues while remaining responsive to novel stimuli. Long-term exposure to an inherently attractive odor causes Caenorhabditis elegans to ignore that odor, a process termed odor adaptation. Odor adaptation is likely to begin within the sensory neuron, because it requires factors that act within these cells at the time of odor exposure. The process by which an olfactory sensory neuron makes a decisive shift over time from a receptive state to a lasting unresponsive one remains obscure. In C. elegans, adaptation to odors sensed by the AWC pair of olfactory neurons requires the cGMP-dependent protein kinase EGL-4. Using a fully functional, GFP-tagged EGL-4, we show here that prolonged odor exposure sends EGL-4 into the nucleus of the stimulated AWC neuron. This odor-induced nuclear translocation correlates temporally with the stable dampening of chemotaxis that is indicative of long-term adaptation. Long-term adaptation requires cGMP binding residues as well as an active EGL-4 kinase. We show here that EGL-4 nuclear accumulation is both necessary and sufficient to induce long-lasting odor adaptation. After it is in the AWC nucleus, EGL-4 decreases the animal's responsiveness to AWC-sensed odors by acting downstream of the primary sensory transduction. Thus, the EGL-4 protein kinase acts as a sensor that integrates odor signaling over time, and its nuclear translocation is an instructive switch that allows the animal to ignore persistent odors.
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Caenorhabditis elegans TRPV channels function in a modality-specific pathway to regulate response to aberrant sensory signaling. Genetics 2010; 185:233-44. [PMID: 20176974 DOI: 10.1534/genetics.110.115188] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Olfaction and some forms of taste (including bitter) are mediated by G protein-coupled signal transduction pathways. Olfactory and gustatory ligands bind to chemosensory G protein-coupled receptors (GPCRs) in specialized sensory cells to activate intracellular signal transduction cascades. G protein-coupled receptor kinases (GRKs) are negative regulators of signaling that specifically phosphorylate activated GPCRs to terminate signaling. Although loss of GRK function usually results in enhanced cellular signaling, Caenorhabditis elegans lacking GRK-2 function are not hypersensitive to chemosensory stimuli. Instead, grk-2 mutant animals do not chemotax toward attractive olfactory stimuli or avoid aversive tastes and smells. We show here that loss-of-function mutations in the transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 selectively restore grk-2 behavioral avoidance of bitter tastants, revealing modality-specific mechanisms for TRPV channel function in the regulation of C. elegans chemosensation. Additionally, a single amino acid point mutation in OCR-2 that disrupts TRPV channel-mediated gene expression, but does not decrease channel function in chemosensory primary signal transduction, also restores grk-2 bitter taste avoidance. Thus, loss of GRK-2 function may lead to changes in gene expression, via OSM-9/OCR-2, to selectively alter the levels of signaling components that transduce or regulate bitter taste responses. Our results suggest a novel mechanism and multiple modality-specific pathways that sensory cells employ in response to aberrant signal transduction.
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