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Clupper M, Gill R, Elsayyid M, Touroutine D, Caplan JL, Tanis JE. Kinesin-2 motors differentially impact biogenesis of extracellular vesicle subpopulations shed from sensory cilia. iScience 2022; 25:105262. [PMID: 36304122 PMCID: PMC9593189 DOI: 10.1016/j.isci.2022.105262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 07/13/2022] [Accepted: 09/26/2022] [Indexed: 01/21/2023] Open
Abstract
Extracellular vesicles (EVs) are bioactive lipid-bilayer enclosed particles released from nearly all cells. One specialized site for EV shedding is the primary cilium. Here, we discover the conserved ion channel CLHM-1 as a ciliary EV cargo. Imaging of EVs released from sensory neuron cilia of Caenorhabditis elegans expressing fluorescently tagged CLHM-1 and TRP polycystin-2 channel PKD-2 shows enrichment of these cargoes in distinct EV subpopulations that are differentially shed in response to mating partner availability. PKD-2 alone is present in EVs shed from the cilium distal tip, whereas CLHM-1 EVs bud from a secondary site(s), including the ciliary base. Heterotrimeric and homodimeric kinesin-2 motors have discrete impacts on PKD-2 and CLHM-1 colocalization in both cilia and EVs. Total loss of kinesin-2 activity decreases shedding of PKD-2 but not CLHM-1 EVs. Our data demonstrate that anterograde intraflagellar transport is required for selective enrichment of protein cargoes into heterogeneous EVs with different signaling potentials.
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Affiliation(s)
- Michael Clupper
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Rachael Gill
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Malek Elsayyid
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Denis Touroutine
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jeffrey L. Caplan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USA
| | - Jessica E. Tanis
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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2
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Ramachandran S, Banerjee N, Bhattacharya R, Lemons ML, Florman J, Lambert CM, Touroutine D, Alexander K, Schoofs L, Alkema MJ, Beets I, Francis MM. A conserved neuropeptide system links head and body motor circuits to enable adaptive behavior. eLife 2021; 10:71747. [PMID: 34766905 PMCID: PMC8626090 DOI: 10.7554/elife.71747] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/11/2021] [Indexed: 01/11/2023] Open
Abstract
Neuromodulators promote adaptive behaviors that are often complex and involve concerted activity changes across circuits that are often not physically connected. It is not well understood how neuromodulatory systems accomplish these tasks. Here, we show that the Caenorhabditis elegans NLP-12 neuropeptide system shapes responses to food availability by modulating the activity of head and body wall motor neurons through alternate G-protein coupled receptor (GPCR) targets, CKR-1 and CKR-2. We show ckr-2 deletion reduces body bend depth during movement under basal conditions. We demonstrate CKR-1 is a functional NLP-12 receptor and define its expression in the nervous system. In contrast to basal locomotion, biased CKR-1 GPCR stimulation of head motor neurons promotes turning during local searching. Deletion of ckr-1 reduces head neuron activity and diminishes turning while specific ckr-1 overexpression or head neuron activation promote turning. Thus, our studies suggest locomotor responses to changing food availability are regulated through conditional NLP-12 stimulation of head or body wall motor circuits.
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Affiliation(s)
- Shankar Ramachandran
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Navonil Banerjee
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Raja Bhattacharya
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Michele L Lemons
- Department of Biological and Physical Sciences, Assumption University, Worcester, United States
| | - Jeremy Florman
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Christopher M Lambert
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Denis Touroutine
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Kellianne Alexander
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Liliane Schoofs
- Department of Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Mark J Alkema
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
| | - Isabel Beets
- Department of Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Michael M Francis
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, United States
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3
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Touroutine D, Tanis JE. A Rapid, SuperSelective Method for Detection of Single Nucleotide Variants in Caenorhabditis elegans. Genetics 2020; 216:343-352. [PMID: 32817008 PMCID: PMC7536863 DOI: 10.1534/genetics.120.303553] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 08/09/2020] [Indexed: 12/30/2022] Open
Abstract
With the widespread use of single nucleotide variants generated through mutagenesis screens and genome editing technologies, there is pressing need for an efficient and low-cost strategy to genotype single nucleotide substitutions. We have developed a rapid and inexpensive method for detection of point mutants through optimization of SuperSelective (SS) primers for end-point PCR in Caenorhabditis elegans Each SS primer consists of a 5' "anchor" that hybridizes to the template, followed by a noncomplementary "bridge," and a "foot" corresponding to the target allele. The foot sequence is short, such that a single mismatch at the terminal 3' nucleotide destabilizes primer binding and prevents extension, enabling discrimination of different alleles. We explored how length and sequence composition of each SS primer segment affected selectivity and efficiency in various genetic contexts in order to develop simple rules for primer design that allow for differentiation between alleles over a broad range of annealing temperatures. Manipulating bridge length affected amplification efficiency, while modifying the foot sequence altered discriminatory power. Changing the anchor position enabled SS primers to be used for genotyping in regions with sequences that are challenging for standard primer design. After defining primer design parameters, we demonstrated the utility of SS primers for genotyping crude C. elegans lysates, suggesting that this approach could also be used for SNP mapping and screening of CRISPR mutants. Further, since SS primers reliably detect point mutations, this method has potential for broad application in all genetic systems.
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Affiliation(s)
- Denis Touroutine
- Department of Biological Sciences, University of Delaware, Newark, Delaware 19716
| | - Jessica E Tanis
- Department of Biological Sciences, University of Delaware, Newark, Delaware 19716
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4
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Barbagallo B, Philbrook A, Touroutine D, Banerjee N, Oliver D, Lambert CM, Francis MM. Excitatory neurons sculpt GABAergic neuronal connectivity in the C. elegans motor circuit. Development 2017; 144:1807-1819. [PMID: 28420711 DOI: 10.1242/dev.141911] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 04/03/2017] [Indexed: 11/20/2022]
Abstract
Establishing and maintaining the appropriate number of GABA synapses is key for balancing excitation and inhibition in the nervous system, though we have only a limited understanding of the mechanisms controlling GABA circuit connectivity. Here, we show that disrupting cholinergic innervation of GABAergic neurons in the C. elegans motor circuit alters GABAergic neuron synaptic connectivity. These changes are accompanied by reduced frequency and increased amplitude of GABAergic synaptic events. Acute genetic disruption in early development, during the integration of post-embryonic-born GABAergic neurons into the circuit, produces irreversible effects on GABAergic synaptic connectivity that mimic those produced by chronic manipulations. In contrast, acute genetic disruption of cholinergic signaling in the adult circuit does not reproduce these effects. Our findings reveal that GABAergic signaling is regulated by cholinergic neuronal activity, probably through distinct mechanisms in the developing and mature nervous system.
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Affiliation(s)
- Belinda Barbagallo
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Alison Philbrook
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Denis Touroutine
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Navonil Banerjee
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Devyn Oliver
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Christopher M Lambert
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Michael M Francis
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Kowalski JR, Dube H, Touroutine D, Rush KM, Goodwin PR, Carozza M, Didier Z, Francis MM, Juo P. The Anaphase-Promoting Complex (APC) ubiquitin ligase regulates GABA transmission at the C. elegans neuromuscular junction. Mol Cell Neurosci 2014; 58:62-75. [PMID: 24321454 PMCID: PMC4036811 DOI: 10.1016/j.mcn.2013.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 11/23/2013] [Accepted: 12/02/2013] [Indexed: 01/05/2023] Open
Abstract
Regulation of both excitatory and inhibitory synaptic transmission is critical for proper nervous system function. Aberrant synaptic signaling, including altered excitatory to inhibitory balance, is observed in numerous neurological diseases. The ubiquitin enzyme system controls the abundance of many synaptic proteins and thus plays a key role in regulating synaptic transmission. The Anaphase-Promoting Complex (APC) is a multi-subunit ubiquitin ligase that was originally discovered as a key regulator of protein turnover during the cell cycle. More recently, the APC has been shown to function in postmitotic neurons, where it regulates diverse processes such as synapse development and synaptic transmission at glutamatergic synapses. Here we report that the APC regulates synaptic GABA signaling by acting in motor neurons to control the balance of excitatory (acetylcholine) to inhibitory (GABA) transmission at the Caenorhabditis elegans neuromuscular junction (NMJ). Loss-of-function mutants in multiple APC subunits have increased muscle excitation at the NMJ; this phenotype is rescued by expression of the missing subunit in GABA neurons. Quantitative imaging and electrophysiological analyses indicate that APC mutants have decreased GABA release but normal cholinergic transmission. Consistent with this, APC mutants exhibit convulsions in a seizure assay sensitive to reductions in GABA signaling. Previous studies in other systems showed that the APC can negatively regulate the levels of the active zone protein SYD-2 Liprin-α. Similarly, we found that SYD-2 accumulates in APC mutants at GABAergic presynaptic sites. Finally, we found that the APC subunit EMB-27 CDC16 can localize to presynapses in GABA neurons. Together, our data suggest a model in which the APC acts at GABAergic presynapses to promote GABA release and inhibit muscle excitation. These findings are the first evidence that the APC regulates transmission at inhibitory synapses and have implications for understanding nervous system pathologies, such as epilepsy, that are characterized by misregulated GABA signaling.
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Affiliation(s)
- Jennifer R Kowalski
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208 USA.
| | - Hitesh Dube
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208 USA.
| | - Denis Touroutine
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Kristen M Rush
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208 USA.
| | - Patricia R Goodwin
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Marc Carozza
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208 USA.
| | - Zachary Didier
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208 USA.
| | - Michael M Francis
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Peter Juo
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
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Sancar F, Touroutine D, Gao S, Oh HJ, Gendrel M, Bessereau JL, Kim H, Zhen M, Richmond JE. The dystrophin-associated protein complex maintains muscle excitability by regulating Ca(2+)-dependent K(+) (BK) channel localization. J Biol Chem 2011; 286:33501-10. [PMID: 21795674 PMCID: PMC3190934 DOI: 10.1074/jbc.m111.227678] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 07/07/2011] [Indexed: 11/06/2022] Open
Abstract
The dystrophin-associated protein complex (DAPC) consists of several transmembrane and intracellular scaffolding elements that have been implicated in maintaining the structure and morphology of the vertebrate neuromuscular junction (NMJ). Genetic linkage analysis has identified loss-of-function mutations in DAPC genes that give rise to degenerative muscular dystrophies. Although much is known about the involvement of the DAPC in maintaining muscle integrity, less is known about the precise contribution of the DAPC in cell signaling events. To better characterize the functional role of the DAPC at the NMJ, we used electrophysiology, immunohistochemistry, and fluorescent labeling to directly assess cholinergic synaptic transmission, ion channel localization, and muscle excitability in loss-of-function (lf) mutants of Caenorhabditis elegans DAPC homologues. We found that all DAPC mutants consistently display mislocalization of the Ca(2+)-gated K(+) channel, SLO-1, in muscle cells, while ionotropic acetylcholine receptor (AChR) expression and localization at the NMJ remained unaltered. Synaptic cholinergic signaling was also not significantly impacted across DAPC(lf) mutants. Consistent with these findings and the postsynaptic mislocalization of SLO-1, we observed an increase in muscle excitability downstream of cholinergic signaling. Based on our results, we conclude that the DAPC is not involved in regulating AChR architecture at the NMJ, but rather functions to control muscle excitability, in an activity-dependent manner, through the proper localization of SLO-1 channels.
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Affiliation(s)
- Feyza Sancar
- From the Department of Biological Sciences, University of Illinois-Chicago, Chicago, Illinois 60607
| | - Denis Touroutine
- the Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Shangbang Gao
- the Samuel Lunenfeld Research Institute, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | - Hyun J. Oh
- the Department of Cell Biology and Anatomy, Rosalind Franklin University of Science and Medicine, North Chicago, Illinois 60064
| | - Marie Gendrel
- the Biology Department, Institut de Biologie de l'Ecole Normale Superieure, F-75005 Paris, France
| | - Jean-Louis Bessereau
- the Biology Department, Institut de Biologie de l'Ecole Normale Superieure, F-75005 Paris, France
- the Inserm, Unite 1024, F-75005 Paris, France, and
- the Centre National de la Recherche Scientifique, Unit e Mixte de Recherche 8197, F-75005 Paris, France
| | - Hongkyun Kim
- the Department of Cell Biology and Anatomy, Rosalind Franklin University of Science and Medicine, North Chicago, Illinois 60064
| | - Mei Zhen
- the Samuel Lunenfeld Research Institute, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | - Janet E. Richmond
- From the Department of Biological Sciences, University of Illinois-Chicago, Chicago, Illinois 60607
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7
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Gracheva EO, Burdina AO, Touroutine D, Berthelot-Grosjean M, Parekh H, Richmond JE. Tomosyn negatively regulates CAPS-dependent peptide release at Caenorhabditis elegans synapses. J Neurosci 2007; 27:10176-84. [PMID: 17881523 PMCID: PMC3874420 DOI: 10.1523/jneurosci.2339-07.2007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The syntaxin-interacting protein tomosyn is thought to be a key regulator of exocytosis, although its precise mechanism of action has yet to be elucidated. Here we examined the role of tomosyn in peptide secretion in Caenorhabditis elegans tomosyn (tom-1) mutants. Ultrastructural analysis of tom-1 mutants revealed a 50% reduction in presynaptic dense-core vesicles (DCVs) corresponding to enhanced neuropeptide release. Conversely, overexpression of TOM-1 led to an accumulation of DCVs. Together, these data provide the first in vivo evidence that TOM-1 negatively regulates DCV exocytosis. In C. elegans, neuropeptide release is promoted by the calcium-dependent activator protein for secretion (CAPS) homolog UNC-31. To test for a genetic interaction between tomosyn and CAPS, we generated tom-1;unc-31 double mutants. Loss of TOM-1 suppressed the behavioral, electrophysiological, and DCV ultrastructural phenotypes of unc-31 mutants, indicating that TOM-1 antagonizes UNC-31-dependent DCV release. Because unc-31 mutants exhibit synaptic transmission defects, we postulated that loss of DCV release in these mutants and the subsequent suppression by tom-1 mutants could simply reflect alterations in synaptic activity, rather than direct regulation of DCV release. To distinguish between these two possibilities, we analyzed C. elegans Rim mutants (unc-10), which have a comparable reduction in synaptic transmission to unc-31 mutants, specifically attributed to defects in synaptic vesicle (SV) exocytosis. Based on this analysis, we conclude that the changes in DCV release in tom-1 and unc-31 mutants reflect direct effects of TOM-1 and UNC-31 on DCV exocytosis, rather than altered SV release.
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Affiliation(s)
- Elena O Gracheva
- Department of Biological Sciences, Science and Engineering Labs, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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Gracheva EO, Burdina AO, Touroutine D, Berthelot-Grosjean M, Parekh H, Richmond JE. Tomosyn negatively regulates both synaptic transmitter and neuropeptide release at the C. elegans neuromuscular junction. J Physiol 2007; 585:705-9. [PMID: 17627987 PMCID: PMC2375516 DOI: 10.1113/jphysiol.2007.138321] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The SNARE proteins, syntaxin, SNAP-25 and synaptobrevin form a tertiary complex essential for vesicle fusion. Proteins that influence SNARE complex assembly are therefore likely to be important regulators of fusion events. In this study we have focused on tomosyn, a highly conserved, neuronally enriched, syntaxin-binding protein that has been implicated in the regulation of vesicle exocytosis. To directly test the role of tomosyn in neurosecretion we analysed loss-of-function mutants in the single Caenorhabditis elegans tomosyn gene, tom-1. These mutants exhibit enhanced synaptic transmission based on electrophysiological analysis of neuromuscular junction activity. This phenotype is the result of increased synaptic vesicle priming. In addition, we present evidence that tom-1 mutants also exhibit enhanced peptide release from dense core vesicles. These results indicate that tomosyn negatively regulates secretion for both vesicle types, possibly through a common mechanism, interfering with SNARE complex formation, thereby inhibiting vesicle fusion.
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Affiliation(s)
- Elena O Gracheva
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
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Touroutine D, Fox RM, Von Stetina SE, Burdina A, Miller DM, Richmond JE. acr-16 encodes an essential subunit of the levamisole-resistant nicotinic receptor at the Caenorhabditis elegans neuromuscular junction. J Biol Chem 2005; 280:27013-21. [PMID: 15917232 DOI: 10.1074/jbc.m502818200] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Caenorhabditis elegans neuromuscular junction (NMJ) contains three pharmacologically distinct ionotropic receptors: gamma-aminobutyric acid receptors, levamisole-sensitive nicotinic receptors, and levamisole-insensitive nicotinic receptors. The subunit compositions of the gamma-aminobutyric acid- and levamisole-sensitive receptors have been elucidated, but the levamisole-insensitive acetylcholine receptor is uncharacterized. To determine which of the approximately 40 putative nicotinic receptor subunit genes in the C. elegans genome encodes the levamisole-resistant receptor, we utilized MAPCeL, a microarray profiling strategy. Of seven nicotinic receptor subunit transcripts found to be enriched in muscle, five encode the levamisole receptor subunits, leaving two candidates for the levamisole-insensitive receptor: acr-8 and acr-16. Electrophysiological analysis of the acr-16 deletion mutant showed that the levamisole-insensitive muscle acetylcholine current was eliminated, whereas deletion of acr-8 had no effect. These data suggest that ACR-16, like its closest vertebrate homolog, the nicotinic receptor alpha7-subunit, may form homomeric receptors in vivo. Genetic ablation of both the levamisole-sensitive receptor and acr-16 abolished all cholinergic synaptic currents at the NMJ and severely impaired C. elegans locomotion. Therefore, ACR-16-containing receptors account for all non-levamisole-sensitive nicotinic synaptic signaling at the C. elegans NMJ. The determination of subunit composition for all three C. elegans body wall muscle ionotropic receptors provides a critical foundation for future research at this tractable model synapse.
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Affiliation(s)
- Denis Touroutine
- Department of Biology, University of Illinois, Chicago, Illinois 60607, USA
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