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Soubeyre V, Merle L, Jarriault D, Grégoire S, Bretillon L, Acar N, Grosmaitre X, Le Bon AM. Dietary n-3 polyunsaturated fatty acid deficiency alters olfactory mucosa sensitivity in young mice but has no impact on olfactory behavior. Nutr Neurosci 2022:1-14. [PMID: 35694841 DOI: 10.1080/1028415x.2022.2082642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND OBJECTIVE We recently showed that perinatal exposure to diets with unbalanced n-6:n-3 polyunsaturated fatty acid (PUFA) ratios affects the olfactory mucosa (OM) fatty acid composition. To assess the repercussions of these modifications, we investigated the impact of diets unbalanced in n-3 PUFAs on the molecular composition and functionality of the OM in young mice. METHODS After mating, female mice were fed diets either deficient in α-linolenic acid (LOW diet) or supplemented with n-3 long-chain PUFAs (HIGH diet) during the perinatal period. Weaned male offspring were then fed ad libitum with the same experimental diets for 5 weeks. At 8 weeks of age, olfactory behavior tests were performed in young mice. The fatty acid composition of OM and olfactory cilia, as well as the expression of genes involved in different cellular pathways, were analyzed. The electroolfactograms induced by odorant stimuli were recorded to assess the impact of diets on OM functionality. RESULTS AND CONCLUSION Both diets significantly modified the fatty acid profiles of OM and olfactory cilia in young mice. They also induced changes in the expression of genes involved in olfactory signaling and in olfactory neuron maturation. The electroolfactogram amplitudes were reduced in mice fed the LOW diet. Nevertheless, the LOW diet and the HIGH diet did not affect mouse olfactory behavior. Our study demonstrated that consumption of diets deficient in or supplemented with n-3 PUFAs during the perinatal and postweaning periods caused significant changes in young mouse OM. However, these modifications did not impair their olfactory capacities.
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Affiliation(s)
- Vanessa Soubeyre
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS UMR-5203, INSERM U1091, Montpellier, France
| | - Laetitia Merle
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - David Jarriault
- NutriNeuro, UMR 1286 INRAE, Bordeaux INP, Université de Bordeaux, Bordeaux, France
| | - Stéphane Grégoire
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Lionel Bretillon
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Niyazi Acar
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Xavier Grosmaitre
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Anne Marie Le Bon
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
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2
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Ukhanov K, Uytingco C, Green W, Zhang L, Schurmans S, Martens JR. INPP5E controls ciliary localization of phospholipids and the odor response in olfactory sensory neurons. J Cell Sci 2021; 135:jcs.258364. [PMID: 33771931 PMCID: PMC8126451 DOI: 10.1242/jcs.258364] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
The lipid composition of the primary cilia membrane is emerging as a critical regulator of cilia formation, maintenance and function. Here, we show that conditional deletion of the phosphoinositide 5′-phosphatase gene Inpp5e, mutation of which is causative of Joubert syndrome, in terminally developed mouse olfactory sensory neurons (OSNs), leads to a dramatic remodeling of ciliary phospholipids that is accompanied by marked elongation of cilia. Phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2], which is normally restricted to the proximal segment redistributed to the entire length of cilia in Inpp5e knockout mice with a reduction in phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P2] and elevation of phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3] in the dendritic knob. The redistribution of phosphoinositides impaired odor adaptation, resulting in less efficient recovery and altered inactivation kinetics of the odor-evoked electrical response and the odor-induced elevation of cytoplasmic Ca2+. Gene replacement of Inpp5e through adenoviral expression restored the ciliary localization of PI(4,5)P2 and odor response kinetics in OSNs. Our findings support the role of phosphoinositides as a modulator of the odor response and in ciliary biology of native multi-ciliated OSNs. Summary: Cilia of olfactory sensory neurons have a unique lipid composition. Localization of phospholipids is controlled by the INPP5E phosphatase and is involved in modulation of the odor response.
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Affiliation(s)
- Kirill Ukhanov
- University of Florida, Department of Pharmacology and Therapeutics, Gainesville, FL 32603, USA.,University of Florida, Center for Smell and Taste, FL 32610-0267, USA
| | - Cedric Uytingco
- University of Florida, Department of Pharmacology and Therapeutics, Gainesville, FL 32603, USA
| | - Warren Green
- University of Florida, Department of Pharmacology and Therapeutics, Gainesville, FL 32603, USA
| | - Lian Zhang
- University of Florida, Department of Pharmacology and Therapeutics, Gainesville, FL 32603, USA.,University of Florida, Center for Smell and Taste, FL 32610-0267, USA
| | - Stephane Schurmans
- Laboratory of Functional Genetics, GIGA-Molecular Biology of Disease, University of Liège, Liège, Belgium
| | - Jeffrey R Martens
- University of Florida, Department of Pharmacology and Therapeutics, Gainesville, FL 32603, USA.,University of Florida, Center for Smell and Taste, FL 32610-0267, USA
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3
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Camblor-Perujo S, Kononenko NL. Brain-specific functions of the endocytic machinery. FEBS J 2021; 289:2219-2246. [PMID: 33896112 DOI: 10.1111/febs.15897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/29/2021] [Indexed: 12/12/2022]
Abstract
Endocytosis is an essential cellular process required for multiple physiological functions, including communication with the extracellular environment, nutrient uptake, and signaling by the cell surface receptors. In a broad sense, endocytosis is accomplished through either constitutive or ligand-induced invagination of the plasma membrane, which results in the formation of the plasma membrane-retrieved endocytic vesicles, which can either be sent for degradation to the lysosomes or recycled back to the PM. This additional function of endocytosis in membrane retrieval has been adopted by excitable cells, such as neurons, for membrane equilibrium maintenance at synapses. The last two decades were especially productive with respect to the identification of brain-specific functions of the endocytic machinery, which additionally include but not limited to regulation of neuronal differentiation and migration, maintenance of neuron morphology and synaptic plasticity, and prevention of neurotoxic aggregates spreading. In this review, we highlight the current knowledge of brain-specific functions of endocytic machinery with a specific focus on three brain cell types, neuronal progenitor cells, neurons, and glial cells.
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Affiliation(s)
| | - Natalia L Kononenko
- CECAD Cluster of Excellence, University of Cologne, Germany.,Center for Physiology & Pathophysiology, Medical Faculty, University of Cologne, Germany
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4
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Campos FSO, Piña-Rodrigues FM, Reis A, Atella GC, Mermelstein CS, Allodi S, Cavalcante LA. Lipid Rafts from Olfactory Ensheathing Cells: Molecular Composition and Possible Roles. Cell Mol Neurobiol 2021; 41:525-536. [PMID: 32415577 DOI: 10.1007/s10571-020-00869-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/05/2020] [Indexed: 01/16/2023]
Abstract
Olfactory ensheathing cells (OECs) are specialized glial cells of the olfactory system, believed to play a role in the continuous production of olfactory neurons and ensheathment of their axons. Although OECs are used in therapeutic applications, little is known about the cellular mechanisms underlying their migratory behavior. Recently, we showed that OEC migration is sensitive to ganglioside blockage through A2B5 and Jones antibody in OEC culture. Gangliosides are common components of lipid rafts, where they participate in several cellular mechanisms, including cell migration. Here, we characterized OEC lipid rafts, analyzing the presence of specific proteins and gangliosides that are commonly expressed in motile neural cells, such as young neurons, oligodendrocyte progenitors, and glioma cells. Our results showed that lipid rafts isolated from OECs were enriched in cholesterol, sphingolipids, phosphatidylcholine, caveolin-1, flotillin-1, gangliosides GM1 and 9-O-acetyl GD3, A2B5-recognized gangliosides, CNPase, α-actinin, and β1-integrin. Analysis of the actin cytoskeleton of OECs revealed stress fibers, membrane spikes, ruffled membranes and lamellipodia during cell migration, as well as the distribution of α-actinin in membrane projections. This is the first description of α-actinin and flotillin-1 in lipid rafts isolated from OECs and suggests that, together with β1-integrin and gangliosides, membrane lipid rafts play a role during OEC migration. This study provides new information on the molecular composition of OEC membrane microdomains that can impact on our understanding of the role of OEC lipid rafts under physiological and pathological conditions of the nervous system, including inflammation, hypoxia, aging, neurodegenerative diseases, head trauma, brain tumor, and infection.
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Affiliation(s)
- Fernanda S O Campos
- Laboratório de Neurobiologia do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CCS. Bloco G, Rio de Janeiro, 21941-902, Brazil
- Laboratório de Bioquímica de Lipídeos e Lipoproteínas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Felipe M Piña-Rodrigues
- Laboratório de Neurobiologia do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CCS. Bloco G, Rio de Janeiro, 21941-902, Brazil
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Alice Reis
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Georgia C Atella
- Laboratório de Bioquímica de Lipídeos e Lipoproteínas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Claudia S Mermelstein
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Silvana Allodi
- Laboratório de Neurobiologia do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CCS. Bloco G, Rio de Janeiro, 21941-902, Brazil.
| | - Leny A Cavalcante
- Laboratório de Neurobiologia do Desenvolvimento, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CCS. Bloco G, Rio de Janeiro, 21941-902, Brazil
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5
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A Role for STOML3 in Olfactory Sensory Transduction. eNeuro 2021; 8:ENEURO.0565-20.2021. [PMID: 33637538 PMCID: PMC7986538 DOI: 10.1523/eneuro.0565-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/25/2021] [Accepted: 02/08/2021] [Indexed: 11/24/2022] Open
Abstract
Stomatin-like protein-3 (STOML3) is an integral membrane protein expressed in the cilia of olfactory sensory neurons (OSNs), but its functional role in this cell type has never been addressed. STOML3 is also expressed in dorsal root ganglia neurons, where it has been shown to be required for normal touch sensation. Here, we extended previous results indicating that STOML3 is mainly expressed in the knob and proximal cilia of OSNs. We additionally showed that mice lacking STOML3 have a morphologically normal olfactory epithelium. Because of its presence in the cilia, together with known olfactory transduction components, we hypothesized that STOML3 could be involved in modulating odorant responses in OSNs. To investigate the functional role of STOML3, we performed loose patch recordings from wild-type (WT) and Stoml3 knock-out (KO) OSNs. We found that spontaneous mean firing activity was lower with additional shift in interspike intervals (ISIs) distributions in Stoml3 KOs compared with WT neurons. Moreover, the firing activity in response to stimuli was reduced both in spike number and duration in neurons lacking STOML3 compared with WT neurons. Control experiments suggested that the primary deficit in neurons lacking STOML3 was at the level of transduction and not at the level of action potential generation. We conclude that STOML3 has a physiological role in olfaction, being required for normal sensory encoding by OSNs.
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Abstract
Recent evidence has indicated that caveolins are localized at the base of primary cilia, which are microtubule-based sensory organelles present on the cell surface, and that Caveolin-1 (CAV1) plays important roles in regulating ciliary membrane composition and function. Here we describe methods to analyze the localization and function of CAV1 in primary cilia of cultured mammalian cells. These include methods for culturing and transfecting mammalian cells with a CAV1-encoding plasmid or small interfering RNA (siRNA), analysis of mammalian cells by immunofluorescence microscopy (IFM) with antibodies against ciliary markers and CAV1, as well as methods for analyzing ciliary CAV1 function in siRNA-treated cells by IFM and cell-based signaling assays.
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Sterol targeting drugs reveal life cycle stage-specific differences in trypanosome lipid rafts. Sci Rep 2017; 7:9105. [PMID: 28831063 PMCID: PMC5567337 DOI: 10.1038/s41598-017-08770-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
Cilia play important roles in cell signaling, facilitated by the unique lipid environment of a ciliary membrane containing high concentrations of sterol-rich lipid rafts. The African trypanosome Trypanosoma brucei is a single-celled eukaryote with a single cilium/flagellum. We tested whether flagellar sterol enrichment results from selective flagellar partitioning of specific sterol species or from general enrichment of all sterols. While all sterols are enriched in the flagellum, cholesterol is especially enriched. T. brucei cycles between its mammalian host (bloodstream cell), in which it scavenges cholesterol, and its tsetse fly host (procyclic cell), in which it both scavenges cholesterol and synthesizes ergosterol. We wondered whether the insect and mammalian life cycle stages possess chemically different lipid rafts due to different sterol utilization. Treatment of bloodstream parasites with cholesterol-specific methyl-β-cyclodextrin disrupts both membrane liquid order and localization of a raft-associated ciliary membrane calcium sensor. Treatment with ergosterol-specific amphotericin B does not. The opposite results were observed with ergosterol-rich procyclic cells. Further, these agents have opposite effects on flagellar sterol enrichment and cell metabolism in the two life cycle stages. These findings illuminate differences in the lipid rafts of an organism employing life cycle-specific sterols and have implications for treatment.
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8
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Pedersen LB, Mogensen JB, Christensen ST. Endocytic Control of Cellular Signaling at the Primary Cilium. Trends Biochem Sci 2016; 41:784-797. [DOI: 10.1016/j.tibs.2016.06.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/03/2016] [Accepted: 06/07/2016] [Indexed: 01/20/2023]
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9
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Baumgart S, Jansen F, Bintig W, Kalbe B, Herrmann C, Klumpers F, Köster SD, Scholz P, Rasche S, Dooley R, Metzler-Nolte N, Spehr M, Hatt H, Neuhaus EM. The scaffold protein MUPP1 regulates odorant-mediated signaling in olfactory sensory neurons. J Cell Sci 2014; 127:2518-27. [PMID: 24652834 DOI: 10.1242/jcs.144220] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The olfactory signal transduction cascade transforms odor information into electrical signals by a cAMP-based amplification mechanism. The mechanisms underlying the very precise temporal and spatial organization of the relevant signaling components remains poorly understood. Here, we identify, using co-immunoprecipitation experiments, a macromolecular assembly of signal transduction components in mouse olfactory neurons, organized through MUPP1. Disruption of the PDZ signaling complex, through use of an inhibitory peptide, strongly impaired odor responses and changed the activation kinetics of olfactory sensory neurons. In addition, our experiments demonstrate that termination of the response is dependent on PDZ-based scaffolding. These findings provide new insights into the functional organization, and regulation, of olfactory signal transduction.
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Affiliation(s)
- Sabrina Baumgart
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Fabian Jansen
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Willem Bintig
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Benjamin Kalbe
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Christian Herrmann
- Physical Chemistry I, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Fabian Klumpers
- Physical Chemistry I, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - S David Köster
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Paul Scholz
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Sebastian Rasche
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Ruth Dooley
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Nils Metzler-Nolte
- Chair of Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Worringer Weg 1, 52074 Aachen, Germany
| | - Hanns Hatt
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Eva M Neuhaus
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany Pharmacology and Toxicology, University Hospital Jena, Drakendorfer Weg 1, 07743 Jena, Germany
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10
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Meyer D, Voigt A, Widmayer P, Borth H, Huebner S, Breit A, Marschall S, de Angelis MH, Boehm U, Meyerhof W, Gudermann T, Boekhoff I. Expression of Tas1 taste receptors in mammalian spermatozoa: functional role of Tas1r1 in regulating basal Ca²⁺ and cAMP concentrations in spermatozoa. PLoS One 2012; 7:e32354. [PMID: 22427794 PMCID: PMC3303551 DOI: 10.1371/journal.pone.0032354] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 01/25/2012] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND During their transit through the female genital tract, sperm have to recognize and discriminate numerous chemical compounds. However, our current knowledge of the molecular identity of appropriate chemosensory receptor proteins in sperm is still rudimentary. Considering that members of the Tas1r family of taste receptors are able to discriminate between a broad diversity of hydrophilic chemosensory substances, the expression of taste receptors in mammalian spermatozoa was examined. METHODOLOGY/PRINCIPAL FINDINGS The present manuscript documents that Tas1r1 and Tas1r3, which form the functional receptor for monosodium glutamate (umami) in taste buds on the tongue, are expressed in murine and human spermatozoa, where their localization is restricted to distinct segments of the flagellum and the acrosomal cap of the sperm head. Employing a Tas1r1-deficient mCherry reporter mouse strain, we found that Tas1r1 gene deletion resulted in spermatogenic abnormalities. In addition, a significant increase in spontaneous acrosomal reaction was observed in Tas1r1 null mutant sperm whereas acrosomal secretion triggered by isolated zona pellucida or the Ca²⁺ ionophore A23187 was not different from wild-type spermatozoa. Remarkably, cytosolic Ca²⁺ levels in freshly isolated Tas1r1-deficient sperm were significantly higher compared to wild-type cells. Moreover, a significantly higher basal cAMP concentration was detected in freshly isolated Tas1r1-deficient epididymal spermatozoa, whereas upon inhibition of phosphodiesterase or sperm capacitation, the amount of cAMP was not different between both genotypes. CONCLUSIONS/SIGNIFICANCE Since Ca²⁺ and cAMP control fundamental processes during the sequential process of fertilization, we propose that the identified taste receptors and coupled signaling cascades keep sperm in a chronically quiescent state until they arrive in the vicinity of the egg - either by constitutive receptor activity and/or by tonic receptor activation by gradients of diverse chemical compounds in different compartments of the female reproductive tract.
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MESH Headings
- Animals
- Blotting, Western
- Calcium/metabolism
- Cyclic AMP/metabolism
- Female
- Gene Expression
- Humans
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Male
- Mice
- Mice, 129 Strain
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Microscopy, Confocal
- Models, Biological
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Sperm Head/metabolism
- Spermatozoa/metabolism
- Testis/cytology
- Testis/metabolism
- Red Fluorescent Protein
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Affiliation(s)
- Dorke Meyer
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Anja Voigt
- German Institute of Nutrition,
Potsdam-Rehbruecke, Germany
- Institute for Neural Signal Transduction,
Center for Molecular Neurobiology, Hamburg, Germany
| | - Patricia Widmayer
- Institute of Physiology, University of
Hohenheim, Stuttgart, Germany
| | - Heike Borth
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Sandra Huebner
- German Institute of Nutrition,
Potsdam-Rehbruecke, Germany
| | - Andreas Breit
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Susan Marschall
- Institute of Experimental Genetics,
Helmholtz-Zentrum, Munich, Germany
| | | | - Ulrich Boehm
- Institute for Neural Signal Transduction,
Center for Molecular Neurobiology, Hamburg, Germany
| | | | - Thomas Gudermann
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Ingrid Boekhoff
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
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Interaction abolishment between mutant caveolin-1Δ62–100 and ABCA1 reduces HDL-mediated cellular cholesterol efflux. Biochem Biophys Res Commun 2011; 414:337-43. [DOI: 10.1016/j.bbrc.2011.09.070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 09/14/2011] [Indexed: 11/18/2022]
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12
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Endo D, Yamamoto Y, Yamaguchi-Yamada M, Nakamuta N, Taniguchi K. Localization of eNOS in the olfactory epithelium of the rat. J Vet Med Sci 2010; 73:423-30. [PMID: 21068516 DOI: 10.1292/jvms.10-0353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) is a free radical and produced from L-arginine by nitric oxide synthase (NOS). Since NO is recently suggested to be involved in olfactory perception, the expression of eNOS, an isoform of NOS, was examined in the rat olfactory epithelium. The activity of NADPH-diaphorase was also examined as a marker of NOS. In the dorsomedial region of the nasal cavity, intensely positive reactions for NADPH-diaphorase were observed in the entire cytoplasm of sensory cells (olfactory cells). By immunohistochemistry, intensely positive reactions for eNOS were also found in the dorsomedial region of the nasal cavity. These reactions were observed on the free border of the olfactory epithelium. By immunoelectron microscopy, positive reactions for eNOS were found in the cilia of olfactory cells. In addition, in situ hybridization analysis of the olfactory epithelium revealed the expression of eNOS mRNA in the olfactory cells. These results indicate the presence of eNOS in the olfactory cells of the rat, and differential expression of eNOS in the olfactory epithelium depending on the regions of the nasal cavity. In addition, NO produced by eNOS may be involved in olfactory perception in the cilia of olfactory cells.
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Affiliation(s)
- Daisuke Endo
- Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
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Castillo K, Restrepo D, Bacigalupo J. Cellular and molecular Ca2+ microdomains in olfactory cilia support low signaling amplification of odor transduction. Eur J Neurosci 2010; 32:932-8. [PMID: 20849528 DOI: 10.1111/j.1460-9568.2010.07393.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Signal transduction depends critically on the spatial localization of protein constituents. A key question in odor transduction is whether chemotransduction proteins organize into discrete molecular complexes throughout olfactory cilia or distribute homogeneously along the ciliary membrane. Our recordings of Ca(2+) changes in individual cilia with unprecedented spatial and temporal resolution, by the use of two-photon microscopy, provide solid evidence for Ca(2+) microdomains (transducisomes). Dissociated frog olfactory neurons were preloaded with caged-cAMP and fluo-4 acetoxymethyl ester probe Ca(2+) indicator. Ca(2+) influx through cyclic nucleotide-gated (CNG) channels was evoked by uniformly photoreleasing cAMP, while ciliary Ca(2+) was measured. Discrete fluorescence events were clearly resolved. Events were missing in the absence of external Ca(2+) , consistent with the absence of internal Ca(2+) sources. Fluorescence events at individual microdomains resembled single-CNG channel fluctuations in shape, mean duration and kinetics, indicating that transducisomes typically contain one to three CNG channels. Inhibiting the Na(+) /Ca(2+) exchanger or the Ca(2+) -ATPase prolonged the decay of evoked intraciliary Ca(2+) transients, supporting the participation of both transporters in ciliary Ca(2+) clearance, and suggesting that both molecules localize close to the CNG channel. Chemosensory transducisomes provide a physical basis for the low amplification and for the linearity of odor responses at low odor concentrations.
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Affiliation(s)
- Karen Castillo
- Department of Biology, Faculty of Sciences, University of Chile, Santiago, Las Palmeras 3525, Nuñoa, Santiago 7800024
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14
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Lobasso S, Lopalco P, Angelini R, Baronio M, Fanizzi FP, Babudri F, Corcelli A. Lipidomic Analysis of Porcine Olfactory Epithelial Membranes and Cilia. Lipids 2010; 45:593-602. [DOI: 10.1007/s11745-010-3432-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 05/06/2010] [Indexed: 11/29/2022]
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15
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Tao B, Bu S, Yang Z, Siroky B, Kappes JC, Kispert A, Guay-Woodford LM. Cystin localizes to primary cilia via membrane microdomains and a targeting motif. J Am Soc Nephrol 2009; 20:2570-80. [PMID: 19850956 DOI: 10.1681/asn.2009020188] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Primary cilia are dynamic, complex structures that contain >500 proteins, including several related to polycystic kidney disease. How these proteins target to cilia and assemble is unknown. We previously identified Cys1 as the gene responsible for disease in Cys1(cpk) mice, a mouse model of autosomal recessive polycystic kidney disease; this gene encodes cystin, a 145-amino acid cilium-associated protein. Here, we characterized the localization of cystin in the embryonic kidney and liver, in isolated renal collecting ducts, and in an inner medullary collecting duct mouse cell line. Because endogenous levels of cystin expression are low, we generated inner medullary collecting duct cell lines that stably express enhanced green fluorescence protein-tagged constructs of wild-type cystin or various truncation mutants. We determined that cystin is myristoylated at its G2 residue and that N-myristoylated cystin fractionates with membrane microdomains. Furthermore, the N-myristoylation signal is necessary but not sufficient to target cystin to the primary cilium. Analysis of deletion and chimeric constructs identified an AxEGG motif that is necessary to target and retain cystin in the cilium. Derangement of these localization motifs may lead to cystic kidney disease.
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Affiliation(s)
- Binli Tao
- Departments of Medicine and Genetics, University of Alabama at Birmingham, 720 20th Street South, Birmingham, AL 35294, USA
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16
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Mayer U, Küller A, Daiber PC, Neudorf I, Warnken U, Schnölzer M, Frings S, Möhrlen F. The proteome of rat olfactory sensory cilia. Proteomics 2009; 9:322-34. [PMID: 19086097 DOI: 10.1002/pmic.200800149] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Olfactory sensory neurons expose to the inhaled air chemosensory cilia which bind odorants and operate as transduction organelles. Odorant receptors in the ciliary membrane activate a transduction cascade which uses cAMP and Ca(2+) for sensory signaling in the ciliary lumen. Although the canonical transduction pathway is well established, molecular components for more complex aspects of sensory transduction, like adaptation, regulation, and termination of the receptor response have not been systematically identified. Moreover, open questions in olfactory physiology include how the cilia exchange solutes with the surrounding mucus, assemble their highly polarized set of proteins, and cope with noxious substances in the ambient air. A specific ciliary proteome would promote research efforts in all of these fields. We have improved a method to detach cilia from rat olfactory sensory neurons and have isolated a preparation specifically enriched in ciliary membrane proteins. Using LC-ESI-MS/MS analysis, we identified 377 proteins which constitute the olfactory cilia proteome. These proteins represent a comprehensive data set for olfactory research since more than 80% can be attributed to the characteristic functions of olfactory sensory neurons and their cilia: signal processing, protein targeting, neurogenesis, solute transport, and cytoprotection. Organellar proteomics thus yielded decisive information about the diverse physiological functions of a sensory organelle.
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Affiliation(s)
- Ulrich Mayer
- Department of Molecular Physiology, Institute of Zoology, University of Heidelberg, Heidelberg, Germany
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17
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Jenkins PM, McEwen DP, Martens JR. Olfactory cilia: linking sensory cilia function and human disease. Chem Senses 2009; 34:451-64. [PMID: 19406873 DOI: 10.1093/chemse/bjp020] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The olfactory system gives us an awareness of our immediate environment by allowing us to detect airborne stimuli. The components necessary for detection of these odorants are compartmentalized in the cilia of olfactory sensory neurons. Cilia are microtubule-based organelles, which can be found projecting from the surface of almost any mammalian cell, and are critical for proper olfactory function. Mislocalization of ciliary proteins and/or the loss of cilia cause impaired olfactory function, which is now recognized as a clinical manifestation of a broad class of human diseases, termed ciliopathies. Future work investigating the mechanisms of olfactory cilia function will provide us important new information regarding the pathogenesis of human sensory perception diseases.
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Affiliation(s)
- Paul M Jenkins
- Department of Pharmacology, University of Michigan, 1301 MSRB III, Ann Arbor, MI 48109-5632, USA
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18
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Kleene SJ. The electrochemical basis of odor transduction in vertebrate olfactory cilia. Chem Senses 2008; 33:839-59. [PMID: 18703537 DOI: 10.1093/chemse/bjn048] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Most vertebrate olfactory receptor neurons share a common G-protein-coupled pathway for transducing the binding of odorant into depolarization. The depolarization involves 2 currents: an influx of cations (including Ca2+) through cyclic nucleotide-gated channels and a secondary efflux of Cl- through Ca2+-gated Cl- channels. The relation between stimulus strength and receptor current shows positive cooperativity that is attributed to the channel properties. This cooperativity amplifies the responses to sufficiently strong stimuli but reduces sensitivity and dynamic range. The odor response is transient, and prolonged or repeated stimulation causes adaptation and desensitization. At least 10 mechanisms may contribute to termination of the response; several of these result from an increase in intraciliary Ca2+. It is not known to what extent regulation of ionic concentrations in the cilium depends on the dendrite and soma. Although many of the major mechanisms have been identified, odor transduction is not well understood at a quantitative level.
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Affiliation(s)
- Steven J Kleene
- Department of Cancer and Cell Biology, University of Cincinnati, PO Box 670667, 231 Albert Sabin Way, Cincinnati, OH 45267-0667, USA.
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19
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McEwen DP, Jenkins PM, Martens JR. Olfactory cilia: our direct neuronal connection to the external world. Curr Top Dev Biol 2008; 85:333-70. [PMID: 19147011 DOI: 10.1016/s0070-2153(08)00812-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An organism's awareness of its surroundings is dependent on sensory function. As antennas to our external environment, cilia are involved in fundamental biological processes such as olfaction, photoreception, and touch. The olfactory system has adapted this organelle for its unique sensory function and optimized it for detection of external stimuli. The elongated and tapering structure of olfactory cilia and their organization into an overlapping meshwork bathed by the nasal mucosa is optimized to enhance odor absorption and detection. As many as 15-30 nonmotile, sensory cilia on dendritic endings of single olfactory sensory neurons (OSNs) compartmentalize signaling molecules necessary for odor detection allowing for efficient and spatially confined responses to sensory stimuli. Although the loss of olfactory cilia or deletion of selected components of the olfactory signaling cascade leads to anosmia, the mechanisms of ciliogenesis and the selected enrichment of signaling molecules remain poorly understood. Much of our current knowledge is the result of elegant electron microscopy studies describing the structure and organization of the olfactory epithelium and cilia. New genetic and cell biological approaches, which compliment these early studies, show promise in elucidating the mechanisms of olfactory cilia assembly, maintenance, and compartmentalization. Importantly, emerging evidence suggests that olfactory dysfunction represents a previously unrecognized clinical manifestation of multiple ciliary disorders. Future work investigating the mechanisms of olfactory dysfunction combining both clinical studies with basic science research will provide us important new information regarding the pathogenesis of human sensory perception diseases.
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Affiliation(s)
- Dyke P McEwen
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-5632, USA
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20
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Klimmeck D, Mayer U, Ungerer N, Warnken U, Schnölzer M, Frings S, Möhrlen F. Calcium-signaling networks in olfactory receptor neurons. Neuroscience 2007; 151:901-12. [PMID: 18155848 DOI: 10.1016/j.neuroscience.2007.11.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/31/2007] [Accepted: 11/16/2007] [Indexed: 01/03/2023]
Abstract
The olfactory neuroepithelium represents a unique interface between the brain and the external environment. Olfactory function comprises a distinct set of molecular tasks: sensory signal transduction, cytoprotection and adult neurogenesis. A multitude of biochemical studies has revealed the central role of Ca(2+) signaling in the function of olfactory receptor neurons (ORNs). We set out to establish Ca(2+)-dependent signaling networks in ORN cilia by proteomic analysis. We subjected a ciliary membrane preparation to Ca(2+)/calmodulin-affinity chromatography using mild detergent conditions in order to maintain functional protein complexes involved in olfactory Ca(2+) signaling. Thus, calmodulin serves as a valuable tool to gain access to novel Ca(2+)-regulated protein complexes. Tandem mass spectrometry (nanoscale liquid-chromatography-electrospray injection) identified 123 distinct proteins. Ninety-seven proteins (79%) could be assigned to specific olfactory functions, including 32 to sensory signal transduction and 40 to cytoprotection. We point out novel perspectives for research on the Ca(2+)-signaling networks in the olfactory system of the rat.
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Affiliation(s)
- D Klimmeck
- Department of Molecular Physiology, Institute of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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21
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Arenas-Mena C, Wong KSY, Arandi-Forosani N. Ciliary band gene expression patterns in the embryo and trochophore larva of an indirectly developing polychaete. Gene Expr Patterns 2007; 7:544-9. [PMID: 17350349 DOI: 10.1016/j.modgep.2007.01.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 01/25/2007] [Accepted: 01/30/2007] [Indexed: 11/26/2022]
Abstract
The trochophore larvae of indirectly developing spiralians have ciliary bands with motor and feeding functions. The preoral prototroch ciliary band is the first differentiating organ in annelid and mollusk embryos. Here we report the expression of several ciliary band markers during embryogenesis and early larval stages of the indirectly developing polychaete Hydroides elegans. Genes with similarity to caveolin, beta-tubulin, alpha-tubulin, and tektin are expressed in the eight primary prototroch precursors, 1q(221) and 1q(212). Blastomeres 1q(221) and 1q(212) locate at the same equatorial latitude after the complementary asymmetric division of their 1q(22) and 1q(21) precursors. In addition, caveolin and alpha-tubulin are expressed in the metatroch and adoral ciliary zone. Caveolin is expressed in foregut ciliated cells, and alpha-tubulin is expressed in apical tuft ciliated cells. The expression of a beta-thymosin homolog is restricted to 1q(122) and 1q(121) blastomeres, which locate just above and in close association with the eight primary prototroch cells 1q(221) and 1q(212). In addition, the beta-thymosin homolog has a transient expression in the hindgut and apical zone. The expression of all these genes provides a landmark for the early specification of ciliary bands and other ciliated organs.
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Affiliation(s)
- Cesar Arenas-Mena
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-4614, USA.
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22
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Cooper DMF, Crossthwaite AJ. Higher-order organization and regulation of adenylyl cyclases. Trends Pharmacol Sci 2006; 27:426-31. [PMID: 16820220 DOI: 10.1016/j.tips.2006.06.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 04/26/2006] [Accepted: 06/16/2006] [Indexed: 11/26/2022]
Abstract
There is increasing awareness of the compartmentalization of cAMP signalling--the means by which cAMP levels change in discrete domains of the cell with discrete local consequences. Current developments in understanding the organization of adenylyl cyclases in the plasma membrane are illuminating how the earliest part of cAMP compartmentalization could occur. This review focuses on recent findings regarding three levels of adenylyl cyclase organization--oligomerization, positioning to lipid rafts and participation in multiprotein signalling complexes. This organization, coupled with the role of scaffolding proteins in arranging the downstream effectors of cAMP, helps to identify complexes that greatly facilitate the translation of enzyme activation into local consequences.
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Affiliation(s)
- Dermot M F Cooper
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK.
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23
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Levin AM, Coroneus JG, Cocco MJ, Weiss GA. Exploring the interaction between the protein kinase A catalytic subunit and caveolin-1 scaffolding domain with shotgun scanning, oligomer complementation, NMR, and docking. Protein Sci 2006; 15:478-86. [PMID: 16452625 PMCID: PMC2249769 DOI: 10.1110/ps.051911706] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The techniques of phage-displayed homolog shotgun scanning, oligomer complementation, NMR secondary structure analysis, and computational docking provide a complementary suite of tools for dissecting protein-protein interactions. Focusing these tools on the interaction between the catalytic sub-unit of protein kinase A (PKAcat) and caveolin-1 scaffolding domain (CSD) reveals the first structural model for the interaction. Homolog shotgun scanning varied each CSD residue as either a wild-type or a homologous amino acid. Wild-type to homolog ratios from 116 different homologous CSD variants identified side-chain functional groups responsible for precise contacts with PKAcat. Structural analysis by NMR assigned an alpha-helical conformation to the central residues 84- 97 of CSD. The extensive mutagenesis data and NMR secondary structure information provided constraints for developing a model for the PKAcat-CSD interaction. Addition of synthetic CSD to phage-displayed CSD resulted in oligomer complementation, or enhanced binding to PKAcat. Together with previous experiments examining the interaction between CSD and endothelial nitric oxide synthase (eNOS), the results suggest a general oligomerization-dependent enhancement of binding between signal transducing enzymes and caveolin-1.
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Affiliation(s)
- Aron M Levin
- Department of Chemistry, University of California, Irvine, CA 92697, USA
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24
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Witt M, Hummel T. Vomeronasal versus olfactory epithelium: is there a cellular basis for human vomeronasal perception? INTERNATIONAL REVIEW OF CYTOLOGY 2006; 248:209-59. [PMID: 16487792 DOI: 10.1016/s0074-7696(06)48004-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The vomeronasal organ (VNO) constitutes an accessory olfactory organ that receives chemical stimuli, pheromones, which elicit behavioral, reproductive, or neuroendocrine responses among individuals of the same species. In many macrosmatic animals, the morphological substrate constitutes a separate organ system consisting of a vomeronasal duct (ductus vomeronasalis, VND), equipped with chemosensory cells, and a vomeronasal nerve (nervus vomeronasalis, VNN) conducting information into the accessory olfactory bulb (AOB) in the central nervous system (CNS). Recent data require that the long-accepted dual functionality of a main olfactory system and the VNO be reexamined, since all species without a VNO are nevertheless sexually active, and species possessing a VNO also can sense other than "vomeronasal" stimuli via the vomeronasal epithelium (VNE). The human case constitutes a borderline situation, as its embryonic VNO anlage exerts a developmental track common to most macrosmatics, but later typical structures such as the VNN, AOB, and probably most of the chemoreceptor cells within the still existent VND are lost. This review also presents recent information on the VND including immunohistochemical expression of neuronal markers, intermediate filaments, lectins, integrins, caveolin, CD44, and aquaporins. Further, we will address the issue of human pheromone candidates.
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Affiliation(s)
- Martin Witt
- Department of Anatomy, University of Technology Dresden, Dresden, Germany
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25
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Elsaesser R, Montani G, Tirindelli R, Paysan J. Phosphatidyl-inositide signalling proteins in a novel class of sensory cells in the mammalian olfactory epithelium. Eur J Neurosci 2005; 21:2692-700. [PMID: 15926917 DOI: 10.1111/j.1460-9568.2005.04108.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ciliated sensory neurons, supporting cells and basal stem cells represent major cellular components of the main olfactory epithelium in mammals. Here we describe a novel class of sensory cells in the olfactory neuroepithelium. The cells express phospholipase C beta-2 (PLC beta2), transient receptor potential channels 6 (TRPC6) and inositol 3, 4, 5-trisphosphate receptors type III (InsP3R-III). Unlike ciliated olfactory neurons, they express neither olfactory marker protein nor centrin, adenylyl cyclase or cyclic nucleotide-gated cation channels. Typical components of the cytoskeleton of microvilli, ezrin and actin are found co-localized with PLC beta2 and TRPC6 in apical protrusions of the cells. In Ca2+-imaging experiments, the cells responded to odours. They express neuronal marker proteins and possess an axon-like process, but following bulbectomy the cells do not degenerate. Our results suggest a novel class of microvillous secondary chemosensory cells in the mammalian olfactory system. These cells, which utilize phosphatidyl-inositides in signal transduction, represent about 5% of all olfactory cells. Their abundance indicates that they play an important role in stimulus-dependent functions and/or the regeneration of the olfactory system.
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Affiliation(s)
- Rebecca Elsaesser
- Institute of General Zoology and Animal Physiology, Friedrich-Schiller-University, D-07743 Jena, Germany.
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26
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YU TUNTZU, McINTYRE JEREMYC, BOSE SOMAC, HARDIN DEBRA, OWEN MICHAELC, McCLINTOCK TIMOTHYS. Differentially expressed transcripts from phenotypically identified olfactory sensory neurons. J Comp Neurol 2005; 483:251-62. [PMID: 15682396 PMCID: PMC2967457 DOI: 10.1002/cne.20429] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In comparing purified mouse olfactory sensory neurons (OSNs) with neighboring cells, we identified 54 differentially expressed transcripts. One-third of the transcripts encode proteins with no known function, but the others have functions that correlate with challenges faced by OSNs. The OSNs expressed a diversity of signaling protein genes, including stomatin (Epb7.2), S100A5, Ddit3, Sirt2, CD81, Sdc2, Omp, and Ptpla. The elaboration of dendrites, cilia, and axons that places OSNs in contact with diverse cell types and signals presumably also requires large investments in cytoskeletal-associated proteins, lipid biosynthesis, and energy production. Several of the genes encode proteins that participate in these biological processes, including ATP5g3, Ndufa9, Sqrdl, Mdh1, Got1, beta-2 tubulin, Capza1, Bin3, Tom1, Acl6, and similar to O-MACS. Three transcripts had restricted expression patterns. Similar to O-MACS and Gstm2 had zonally restricted expression patterns in OSNs and sustentacular cells but not in Bowman's glands, suggesting that zonality can be differentially regulated by cell type. The mosaic expression pattern of S100A5 in approximately 70% of OSNs predicts that it is coexpressed with a subset of odorant receptors. We captured four abundant transcripts, Cyp2a4, similar to Cyp2g1, Gstm2, and Cbr2, that encode xenobiotic metabolizing enzymes expressed by sustentacular cells or Bowman's glands, reinforcing the interpretation that clearance of xenobiotic compounds is a major function of these cells. Within the olfactory epithelium, Cbr2 is a new anatomical marker for sustentacular cells. We also discovered that Reg3g is a marker for respiratory epithelium.
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Affiliation(s)
| | | | | | | | | | - TIMOTHY S. McCLINTOCK
- Correspondence to: Timothy S. McClintock, Louis Boyarsky Professor of Physiology, Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY 40536-0298.
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27
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Brady JD, Rich TC, Le X, Stafford K, Fowler CJ, Lynch L, Karpen JW, Brown RL, Martens JR. Functional role of lipid raft microdomains in cyclic nucleotide-gated channel activation. Mol Pharmacol 2004; 65:503-11. [PMID: 14978228 DOI: 10.1124/mol.65.3.503] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) channels are the primary targets of light- and odorant-induced signaling in photoreceptors and olfactory sensory neurons. Compartmentalized cyclic nucleotide signaling is necessary to ensure rapid and efficient activation of these nonselective cation channels. However, relatively little is known about the subcellular localization of CNG channels or the mechanisms of their membrane partitioning. Lipid raft domains are specialized membrane microdomains rich in cholesterol and sphingolipids that have been implicated in the organization of many membrane-associated signaling pathways. Herein, we report that the alpha subunit of the olfactory CNG channel, CNGA2, associates with lipid rafts in heterologous expression systems and in rat olfactory epithelium. However, CNGA2 does not directly bind caveolin, and its membrane localization overlaps only slightly with that of caveolin at the surface of human embryonic kidney (HEK) 293 cells. To test for a possible functional role of lipid raft association, we treated HEK 293 cells with the cholesterol-depleting agent, methyl-beta-cyclodextrin. Cholesterol depletion abolished prostaglandin E1-stimulated CNGA2 channel activity in intact cells. Recordings from membrane patches excised from CNGA2-expressing HEK 293 cells revealed that cholesterol depletion dramatically reduced the apparent affinity of homomeric CNGA2 channels for cAMP but only slightly reduced the maximal current. Our results show that olfactory CNG channels target to lipid rafts and that disruption of lipid raft microdomains dramatically alters the function of CNGA2 channels.
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Affiliation(s)
- James D Brady
- Dept of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098, USA
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28
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Reisert J, Bauer PJ, Yau KW, Frings S. The Ca-activated Cl channel and its control in rat olfactory receptor neurons. J Gen Physiol 2003; 122:349-63. [PMID: 12939394 PMCID: PMC2234486 DOI: 10.1085/jgp.200308888] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Odorants activate sensory transduction in olfactory receptor neurons (ORNs) via a cAMP-signaling cascade, which results in the opening of nonselective, cyclic nucleotide-gated (CNG) channels. The consequent Ca2+ influx through CNG channels activates Cl channels, which serve to amplify the transduction signal. We investigate here some general properties of this Ca-activated Cl channel in rat, as well as its functional interplay with the CNG channel, by using inside-out membrane patches excised from ORN dendritic knobs/cilia. At physiological concentrations of external divalent cations, the maximally activated Cl current was approximately 30 times as large as the CNG current. The Cl channels on an excised patch could be activated by Ca2+ flux through the CNG channels opened by cAMP. The magnitude of the Cl current depended on the strength of Ca buffering in the bath solution, suggesting that the CNG and Cl channels were probably not organized as constituents of a local transducisome complex. Likewise, Cl channels and the Na/Ca exchanger, which extrudes Ca2+, appear to be spatially segregated. Based on the theory of buffered Ca2+ diffusion, we determined the Ca2+ diffusion coefficient and calculated that the CNG and Cl channel densities on the membrane were approximately 8 and 62 micro m-2, respectively. These densities, together with the Ca2+ diffusion coefficient, demonstrate that a given Cl channel is activated by Ca2+ originating from multiple CNG channels, thus allowing low-noise amplification of the olfactory receptor current.
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Affiliation(s)
- Johannes Reisert
- Institut für Biologische Informationsverarbeitung, Frorschungszentrum Jülich, 52425 Jülich, Germany.
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29
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Abstract
Olfactory receptors lead lives of exclusivity and privilege, the monarchs of fiefdoms organized solely to carry out their instructions. Each olfactory sensory neuron expresses one allele of one of approximately 1000 olfactory receptor genes. It is thought that olfactory receptor diversity is critical for the ability of animals to detect many thousands of odorants, but supporting functional evidence has been difficult to obtain because olfactory receptors expressed in heterologous cells are typically retained in the endoplasmic reticulum. The membrane trafficking entitlements enjoyed by olfactory receptors appear to be available only in mature olfactory sensory neurons. Evidence is accumulating that cell-type-specific accessory proteins regulate first the exit of olfactory receptors from the endoplasmic reticulum, and then the trafficking of olfactory receptors from post-Golgi compartments to the plasma membrane of the olfactory cilia where the receptors gain access to odorants. Critical olfactory receptor accessory proteins are known only in the nematode Caenorhabditis elegans, where the absence of a novel protein called ODR-4 or a clathrin adaptor, UNC-101, interferes with proper trafficking. Similar functional specificity also occurs in a parallel chemosensory system, the mammalian vomeronasal organ. Trafficking of the V2R type of vomeronasal receptors is mediated by a vomeronasal-specific family of major histocompatibility complex proteins. Removal of olfactory receptors from the plasma membrane may be regulated in a more conventional fashion because odor stimulation has been linked to receptor phosphorylation, to the function of G-protein coupled receptor kinase 3, and to an increase in vesicles retrieved from the plasma membrane.
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30
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Elliott MH, Fliesler SJ, Ghalayini AJ. Cholesterol-dependent association of caveolin-1 with the transducin alpha subunit in bovine photoreceptor rod outer segments: disruption by cyclodextrin and guanosine 5'-O-(3-thiotriphosphate). Biochemistry 2003; 42:7892-903. [PMID: 12834341 DOI: 10.1021/bi027162n] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Evidence suggests that caveolins, 21-24 kDa cholesterol-binding proteins that generally reside in specialized detergent-resistant membrane microdomains, act as signaling scaffolds. Detergent-resistant membranes isolated from rod outer segments (ROS) have been previously shown to contain the photoreceptor G-protein, transducin. In this report we show, by subcellular fractionation, that caveolin-1 is an authentic component of purified ROS. We demonstrate that caveolin-1 in ROS almost exclusively resides in low-buoyant-density, cholesterol-rich, detergent-resistant membranes that can be disrupted by cholesterol depletion using methyl-beta-cyclodextrin (MCD). Cholesterol depletion was also observed to extract a pool of transducin alpha (Talpha) from ROS membranes. Immunoprecipitation with anti-caveolin-1 revealed the association of Talpha in the absence of Tbetagamma. Treatment of ROS with MCD resulted in a 2-fold decrease in recovery of Talpha in anti-caveolin-1 immunoprecipitates. This interaction was also completely disrupted when ROS were exposed to light in the presence of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS), a nonhydrolyzable GTP analogue. In addition, caveolin-1/Talpha association in the immune complex was disrupted by a peptide based on the primary sequence of the caveolin-1 scaffolding domain. Finally, we confirm the colocalization of caveolin-1 and Talpha in photoreceptors by immunofluorescence microscopy. These results strongly suggest that the association between Talpha and caveolin-1 occurs in cholesterol-rich, detergent-resistant membranes and is likely to be dependent upon the activation state of Talpha.
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Affiliation(s)
- Michael H Elliott
- Dean A. McGee Eye Institute, Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
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31
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Affiliation(s)
- Pingsheng Liu
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas 75235-9039, USA
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32
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Reversible translocation and activity-dependent localization of the calcium-myristoyl switch protein VILIP-1 to different membrane compartments in living hippocampal neurons. J Neurosci 2002. [PMID: 12196554 DOI: 10.1523/jneurosci.22-17-07331.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Visinin-like protein-1 (VILIP-1) belongs to the family of neuronal calcium sensor (NCS) proteins, a neuronal subfamily of EF-hand [corrected] calcium-binding proteins that are myristoylated at their N termini. NCS proteins are discussed to play roles in calcium-dependent signal transduction of physiological and pathological processes in the CNS. The calcium-dependent membrane association, the so-called calcium-myristoyl switch, localizes NCS proteins to a distinct cellular signaling compartment and thus may be a critical mechanism for the coordinated regulation of signaling cascades. To study whether the biochemically defined calcium-myristoyl switch of NCS proteins can occur in living neuronal cells, the reversible and stimulus-dependent translocation of green fluorescent protein (GFP)-tagged VILIP-1 to subcellular targets was examined by fluorescence microscopy in transfected cell lines and hippocampal primary neurons. In transiently transfected NG108-15 and COS-7 cells, a translocation of diffusely distributed VILIP-1-GFP but not of myristoylation-deficient VILIP-1-GFP to the plasma membrane and to intracellular targets, such as Golgi membranes, occurred after raising the intracellular calcium concentration with a calcium ionophore. The observed calcium-dependent localization was completely reversed after depletion of intracellular calcium by EGTA. Interestingly, a fast and reversible translocation of VILIP-1-GFP and translocation of endogenous VILIP-1 to specialized membrane structures was also observed after a depolarizing stimulus or activation of glutamate receptors in hippocampal neurons. These results show for the first time the reversibility and stimulus-dependent occurrence of the calcium-myristoyl switch in living neurons, suggesting a physiological role as a signaling mechanism of NCS proteins, enabling them to activate specific targets localized in distinct membrane compartments.
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Stomatin-related olfactory protein, SRO, specifically expressed in the murine olfactory sensory neurons. J Neurosci 2002. [PMID: 12122055 DOI: 10.1523/jneurosci.22-14-05931.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We identified a stomatin-related olfactory protein (SRO) that is specifically expressed in olfactory sensory neurons (OSNs). The mouse sro gene encodes a polypeptide of 287 amino acids with a calculated molecular weight of 32 kDa. SRO shares 82% sequence similarity with the murine stomatin, 78% with Caenorhabditis elegans MEC-2, and 77% with C. elegans UNC-1. Unlike other stomatin-family genes, the sro transcript was present only in OSNs of the main olfactory epithelium. No sro expression was seen in vomeronasal neurons. SRO was abundant in most apical dendrites of OSNs, including olfactory cilia. Immunoprecipitation revealed that SRO associates with adenylyl cyclase type III and caveolin-1 in the low-density membrane fraction of olfactory cilia. Furthermore, anti-SRO antibodies stimulated cAMP production in fractionated cilia membrane. SRO may play a crucial role in modulating odorant signals in the lipid rafts of olfactory cilia.
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Liou JY, Deng WG, Gilroy DW, Shyue SK, Wu KK. Colocalization and interaction of cyclooxygenase-2 with caveolin-1 in human fibroblasts. J Biol Chem 2001; 276:34975-82. [PMID: 11432874 DOI: 10.1074/jbc.m105946200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Results from our previous study suggest that cyclooxygenase-2 (COX-2) induced by phorbol 12-myristate 13-acetate (PMA) may be localized to caveolae-like structures (Liou, J.-Y., Shyue, S.-K., Tsai, M.-J., Chung, C.-L., Chu, K.-Y., and Wu, K. K. (2000) J. Biol. Chem. 275, 15314-15320). In this study, we determined subcellular localization of COX-2 and caveolin-1 by confocal microscopy. COX-2 in human foreskin fibroblasts stimulated by PMA (100 nm) or interleukin-1beta (1 ng/ml) for 6 h was localized to plasma membrane in addition to endoplasmic reticulum and nuclear envelope. Caveolin-1 was localized to plasma membrane, and image overlay showed colocalization of COX-2 with caveolin-1. This was confirmed by the presence of COX-2 and caveolin-1 in the detergent-insoluble membrane fraction of cells stimulated by PMA. Immunoprecipitation showed complex formation of COX-2 with caveolin-1 in a time-dependent manner. A larger quantity of COX-2 was complexed with caveolin-1 in PMA-treated than in interleukin-1beta-treated cells. Purified COX-2 complexed with glutathione S-transferase-fused caveolin-1, which was not inhibited by the scaffolding domain peptide. Caveolin-1-bound COX-2 was catalytically active, and its activity was not inhibited by the scaffolding domain peptide. These results suggest that COX-2 induced by PMA and interleukin-1beta is colocalized with caveolin-1 in the segregated caveolae compartment. Because caveolae are rich in signaling molecules, this COX-2 compartment may play an important role in diverse pathophysiological processes.
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Affiliation(s)
- J Y Liou
- Vascular Biology Research Center and Division of Hematology, University of Texas-Houston Medical School, Houston, Texas 77030, USA
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Byrne S, Cheent A, Dimond J, Fisher G, Ockleford CD. Immunocytochemical localization of a caveolin-1 isoform in human term extra-embryonic membranes using confocal laser scanning microscopy: implications for the complexity of the materno-fetal junction. Placenta 2001; 22:499-510. [PMID: 11440537 DOI: 10.1053/plac.2001.0697] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This immunochemical, immunocytochemical, histological and ultrastructural study demonstrates the presence of caveolin 1 in a number of locations in term human extra-embryonic membranes. Strong expression was observed in fetal blood vessel endothelial cells of chorionic villi (cv) and in cv, amniotic and chorionic plate mesenchymal cells, but weak expression was characteristic of trophoblast. Expression in the amniotic epithelium indicated a stronger association with apical as opposed to baso-lateral membranes. Strong immunoreactivity in the thin lining layer of the maternal blood space of the basal plate was a surprising finding. Previously defined as trophoblast, we argue that this is at least partly endothelium based on this new histological, ultrastructural and immunocytochemical data.
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Affiliation(s)
- S Byrne
- Advanced Light Microscope Facility, Department of Pre-Clinical Sciences, Leicester Warwick Medical School, University Road, Leicester, LE1 9HN, UK
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