1
|
Junkunlo K, Söderhäll K, Söderhäll I. A transcription factor glial cell missing (Gcm) in the freshwater crayfish Pacifastacus leniusculus. Dev Comp Immunol 2020; 113:103782. [PMID: 32679114 DOI: 10.1016/j.dci.2020.103782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/26/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
The transcription factor glial cell missing, Gcm, is known to be an important protein in the determination of glial cell fate as well as embryonic plasmatocyte differentiation in Drosophila melanogaster. So far, no function for Gcm in crustaceans has been reported. In this study, we show the cDNA sequence of a Gcm homologue in the freshwater crayfish Pacifastacus leniusculus. The P. leniusculus Gcm transcript is expressed exclusively in brain and nervous tissue, and by in situ hybridization we show that the expression is restricted to a small number of large cells with morphology similar to neurosecretory cells. Furthermore, we show that the expression of Gcm coincides with the expression of a Repo homologue, that is induced in expression by Gcm in Drosophila. Moreover, the Gcm transcript is increased shortly and transiently after injection of cystamine, a substance that inhibits transglutaminase and also strongly affects the movement behavior of crayfish. This finding of Gcm transcripts in a subpopulation of brain cells in very low numbers may enable more detailed studies about Gcm in adult crustaceans.
Collapse
Affiliation(s)
- Kingkamon Junkunlo
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18 A, SE752 36, Uppsala, Sweden
| | - Kenneth Söderhäll
- Science for Life Laboratory, Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, 752 36, Uppsala, Sweden
| | - Irene Söderhäll
- Science for Life Laboratory, Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, 752 36, Uppsala, Sweden.
| |
Collapse
|
2
|
Banerjee N, Bhattacharya R, Gorczyca M, Collins KM, Francis MM. Local neuropeptide signaling modulates serotonergic transmission to shape the temporal organization of C. elegans egg-laying behavior. PLoS Genet 2017; 13:e1006697. [PMID: 28384151 PMCID: PMC5398689 DOI: 10.1371/journal.pgen.1006697] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/20/2017] [Accepted: 03/15/2017] [Indexed: 11/18/2022] Open
Abstract
Animal behaviors are often composed of distinct alternating behavioral states. Neuromodulatory signals are thought to be critical for establishing stable behavioral states and for orchestrating transitions between them. However, we have only a limited understanding of how neuromodulatory systems act in vivo to alter circuit performance and shape behavior. To address these questions, we have investigated neuromodulatory signaling in the context of Caenorhabditis elegans egg-laying. Egg-laying activity cycles between discrete states-short bursts of egg deposition (active phases) that alternate with prolonged quiescent periods (inactive phases). Here using genetic, pharmacological and optogenetic approaches for cell-specific activation and inhibition, we show that a group of neurosecretory cells (uv1) located in close spatial proximity to the egg-laying neuromusculature direct the temporal organization of egg-laying by prolonging the duration of inactive phases. We demonstrate that the modulatory effects of the uv1 cells are mediated by peptides encoded by the nlp-7 and flp-11 genes that act locally to inhibit circuit activity, primarily by inhibiting vesicular release of serotonin from HSN motor neurons. This peptidergic inhibition is achieved, at least in part, by reducing synaptic vesicle abundance in the HSN motor neurons. By linking the in vivo actions of specific neuropeptide signaling systems with the generation of stable behavioral outcomes, our study reveals how cycles of neuromodulation emanating from non-neuronal cells can fundamentally shape the organization of a behavioral program.
Collapse
Affiliation(s)
- Navonil Banerjee
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA United States of America
| | - Raja Bhattacharya
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA United States of America
| | - Michael Gorczyca
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA United States of America
| | - Kevin M. Collins
- Department of Biology, University of Miami, Coral Gables, FL United States of America
| | - Michael M. Francis
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA United States of America
| |
Collapse
|
3
|
Pérez-Rodríguez R, Oliván AM, Roncero C, Morón-Oset J, González MP, Oset-Gasque MJ. Glutamate triggers neurosecretion and apoptosis in bovine chromaffin cells through a mechanism involving NO production by neuronal NO synthase activation. Free Radic Biol Med 2014; 69:390-402. [PMID: 24486340 DOI: 10.1016/j.freeradbiomed.2014.01.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 11/30/2022]
Abstract
Previous work from our group stated that nitric oxide (NO), via cytokines, induces apoptosis in chromaffin cells by a mechanism involving iNOS, nNOS, and NF-κB. In this paper the involvement of glutamate as a possible intracellular trigger of neurosecretion and NO-mediated apoptosis has been evaluated. We show that chromaffin cells express different ionotropic and metabotropic glutamate receptors, this exerting different effects on the regulation of basal and glutamate-induced catecholamine secretion, via NO/cGMP. In addition, we studied the effects of endogenously generated NO, both basal and glutamate-stimulated, on apoptosis of chromaffin cells. Our results show that glutamate agonists are able to induce cell death and apoptosis in bovine chromaffin cells, parallel to an increase in NO production. Such effects were reversed by NOS inhibitors and glutamate receptor antagonists. Under basal conditions, iNOS inhibitors did not have any effect on apoptosis, whereas nNOS inhibitors induced apoptosis, indicating a neuroprotective effect of constitutive nNOS-generated NO. In contrast, glutamate-induced apoptosis was strongly reversed by nNOS inhibitors and weakly by iNOS inhibitors, thus indicating nNOS involvement in glutamate-mediated apoptosis. These results were confirmed by the fact that nNOS expression, but not iNOS, is specifically activated by glutamate. Finally, our results suggest the participation of PKG, PKA, PKC, and MAPK pathways in glutamate-mediated nNOS activation in chromaffin cells and point out the involvement of both PKA and PKC signaling pathways in the apoptotic effect of glutamate.
Collapse
Affiliation(s)
- R Pérez-Rodríguez
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain
| | - A M Oliván
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain
| | - C Roncero
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain
| | - J Morón-Oset
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain
| | - M P González
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain
| | - M J Oset-Gasque
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Complutense University of Madrid, E-28040 Madrid, Spain.
| |
Collapse
|
4
|
Tangprasittipap A, Chouwdee S, Phiwsaiya K, Laiphrom S, Senapin S, Flegel TW, Sritunyalucksana K. Structure and expression of a shrimp prohormone convertase 2. Gen Comp Endocrinol 2012; 178:185-93. [PMID: 22634957 DOI: 10.1016/j.ygcen.2012.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 05/01/2012] [Accepted: 05/10/2012] [Indexed: 11/17/2022]
Abstract
Although many crustacean neuroendocrine hormones have been reported, the enzymes responsible for post-translational modification of neuroendocrine hormones have rarely been characterized. A prohormone convertase 2 (PC2)-like enzyme has been isolated from the optic lobe of the giant tiger shrimp, Penaeus monodon and referred as PmPC2. The full length cDNA sequence of PmPC2 has been identified and found to resemble evolutionarily conserved PC2 enzymes of vertebrates and invertebrates. PmPC2 was expressed in all larval developmental stages and in neuroendrocrine cells in the adult optic lobe. Its expression was found to be negatively related with shrimp body weight by qPCR (P<0.05). Immunohistochemistry results using an anti-rPmPC2 antibody with adult shrimp revealed high staining intensity in specific neurosecretory cells including the sinus gland, the organ of Hanström (also referred to as the medullar terminalis X-organ) and the organ of Bellonci (also referred to as the sensory or X-organ). By using the yeast two hybrid technique, PmPC2 was found to bind with P. monodon hyperglycemic hormone (Pem-CHH1) that plays an important role in glucose metabolism. Since PmPC2 is a subtilisin-like serine proteinase, it is expected to cleave the synthetic substrate, pyr-RTKR-MCA, but the expressed recombinant catalytic domain of PmPC2 (rPmPC2-cat) showed no enzymatic activity as expected. In vivo injection of dsRNA-PmPC2 resulted in reduced transcripts for both PmPC2 and Pem-CHH1 on day 3 post injection, but there was no accompanying reduction of glucose level in the hemolymph. Taken together, PmPC2 localization, expression and activity suggest that it has a function(s) in the shrimp neuroendrocrine system and that it may not only activate Pem-CHH1 but also affect its expression. However, there is no obvious explanation for the negative correlation between PmPC2 expression level and shrimp body weight.
Collapse
Affiliation(s)
- Amornrat Tangprasittipap
- Shrimp-Virus Interaction Laboratory (ASVI), National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani 12120, Thailand
| | | | | | | | | | | | | |
Collapse
|
5
|
Rybina OI, Zaĭtsev AA, Roshchina NV, Pasiukova EG. [Neuroendocrine system in Drosophila melanogaster lifespan control]. Adv Gerontol 2010; 23:518-526. [PMID: 21510072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Drosophila is used as a model organism to review the mechanisms of neuroendocrine system involvement in lifespan control. The role of neuron specific expression of genes participating in antioxidative system in lifespan control is described. Data on endocrine function of the nervous system in lifespan control are discussed. The participation of genes involved in the regulation of nervous system development and function in lifespan control is contemplated. Based on the data available, hypotheses considering assembly of neurons as the lifespan limiting tissue and (or) the tissue providing regulation of lifespan via systemic effects on other cell types are evaluated.
Collapse
|
6
|
|
7
|
Abstract
OBJECTIVE To identify new genes required for neurosecretory control of aging in C. elegans. METHODS In view of the importance of nervous system in aging regulation, we performed the screen for genes involved in the aging regulation from genetic loci encoding synaptic proteins by lifespan assay and accumulation of lipofuscin autofluorescence. We further investigated the dauer formation phenotypes of their corresponding mutants and whether they were possibly up-regulated by the insulin-like signaling pathway. RESULTS The genetic loci of unc-10, syd-2, hlb-1, dlk-1, mkk-4, scd-2, snb-1, ric-4, nrx-1, unc-13, sbt-1 and unc-64 might be involved in the aging control. In addition, functions of unc-10, syd-2, hlb-1, dlk-1, mkk-4, scd-2, snb-1, ric-4 and nrx-1 in regulating aging may be opposite to those of unc-13, sbt-1 and unc-64. The intestinal autofluorescence assay further indicated that the identified long-lived and short-lived mutants were actually due to the suppressed or accelerated aging. Among the identified genes, syd-2, hlb-1, mkk-4, scd-2, snb-1, ric-4 and unc-64 were also involved in the control of dauer formation. Moreover, daf-2 mutation positively regulated the expression of syd-2 and hlb-1, and negatively regulated the expression of mkk-4, nrx-1, ric-4, sbt-1, rpm-1, unc-10, dlk-1 and unc-13. The daf-16 mutation positively regulated the expression of syd-2 and hlb-1, and negatively regulated the expression of mkk-4, nrx-1, sbt-1, rpm-1, unc-10, dlk-1 and unc-13. CONCLUSION These data suggest the possibly important status of the synaptic transmission to the animal's life-span control machinery, as well as the dauer formation control.
Collapse
Affiliation(s)
- Lu-Lu Shen
- Department of Genetics and Developmental Biology, Southeast University, Nanjing, 210009 China
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Nanjing, 210009 China
| | - Yang Wang
- Department of Genetics and Developmental Biology, Southeast University, Nanjing, 210009 China
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Nanjing, 210009 China
| | - Da-Yong Wang
- Department of Genetics and Developmental Biology, Southeast University, Nanjing, 210009 China
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Nanjing, 210009 China
| |
Collapse
|
8
|
Herrero P, Magariños M, Molina I, Benito J, Dorado B, Turiégano E, Canal I, Torroja L. Squeeze involvement in the specification of Drosophila leucokinergic neurons: Different regulatory mechanisms endow the same neuropeptide selection. Mech Dev 2007; 124:427-40. [PMID: 17442544 DOI: 10.1016/j.mod.2007.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 02/14/2007] [Accepted: 03/01/2007] [Indexed: 11/20/2022]
Abstract
One of the most widely studied phenomena in the establishment of neuronal identity is the determination of neurosecretory phenotype, in which cell-type-specific combinatorial codes direct distinct neurotransmitter or neuropeptide selection. However, neuronal types from divergent lineages may adopt the same neurosecretory phenotype, and it is unclear whether different classes of neurons use different or similar components to regulate shared features of neuronal identity. We have addressed this question by analyzing how differentiation of the Drosophila larval leucokinergic system, which is comprised of only four types of neurons, is regulated by factors known to affect expression of the FMRFamide neuropeptide. We show that all leucokinergic cells express the transcription factor Squeeze (Sqz). However, based on the effect on LK expression of loss- and gain-of-function mutations, we can describe three types of Lk regulation. In the brain LHLK cells, both Sqz and Apterous (Ap) are required for LK expression, but surprisingly, high levels of either Sqz or Ap alone are sufficient to restore LK expression in these neurons. In the suboesophageal SELK cells, Sqz, but not Ap, is required for LK expression. In the abdominal ABLK neurons, inhibition of retrograde axonal transport reduces LK expression, and although sqz is dispensable for LK expression in these cells, it can induce ectopic leucokinergic ABLK-like cells when over-expressed. Thus, Sqz appears to be a regulatory factor for neuropeptidergic identity common to all leucokinergic cells, whose function in different cell types is regulated by cell-specific factors.
Collapse
Affiliation(s)
- Pilar Herrero
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E 28049 Madrid, Spain.
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Abstract
The rat PC12 variant cell line, A35C, lacks regulated secretory organelles due to a selective transcriptional block. Hence, A35C may provide clues about the mechanisms that underlie control of neurosecretion. We used mRNA microarray profiling to examine gene expression in A35C. Genes for regulated secretory proteins were down-regulated, while other membrane trafficking pathways were unaffected. A subset of genes repressed in A35C contain binding sites for the neuronal transcriptional repressor, RE1-silencing transcription factor (REST), and REST is expressed in A35C but not normal PC12 cells. Blocking the activity of REST in A35C using a dominant-negative construct induced the reappearance of mRNAs for synaptophysin, chromogranin A, synaptotagmin IV and the beta3 subunit of the voltage-gated sodium channel (Scn3b), all of which contain RE1 sites in their genes. In the case of Scn3b, the corresponding protein was also re-expressed. Granule and synaptic vesicle proteins were not re-expressed at the protein level, despite reactivation of their mRNA, suggesting the existence of additional post-transcriptional control for these proteins. Our work identifies one of the mechanisms underlying the phenotype of neurosecretory-deficient neuroendocrine cells, and begins to define the critical components that determine a key aspect of the neuroendocrine phenotype.
Collapse
Affiliation(s)
- Alena Pance
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | |
Collapse
|
10
|
Bruce AW, Krejcí A, Ooi L, Deuchars J, Wood IC, Dolezal V, Buckley NJ. The transcriptional repressor REST is a critical regulator of the neurosecretory phenotype. J Neurochem 2006; 98:1828-40. [PMID: 16945103 DOI: 10.1111/j.1471-4159.2006.04010.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [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: 01/01/2023]
Abstract
Release of distinct cellular cargoes in response to specific stimuli is a process fundamental to all higher eukaryotes and controlled by the regulated secretory pathway (RSP). However, the mechanism by which genes involved in the RSP are selectively expressed, leading to the establishment and appropriate functioning of regulated secretion remaining largely unknown. Using the rat pheochromocytoma cell line PC12, we provide evidence that, by controlling expression of many genes involved in the RSP, the transcriptional repressor REST can regulate this pathway and hence the neurosecretory phenotype. Introduction of REST transgenes into PC12 cells leads to the repression of many genes, the products of which are involved in regulated secretion. Moreover, chromatin immunoprecipitation assays show that many of the repressed genes recruit the recombinant REST protein to RE1 sites within their promoters and abrogation of REST function leads to reactivation of these transcripts. In addition to the observed transcriptional effects, PC12 cells expressing REST have fewer secretory granules and a reduction in the ability to store and release noradrenaline. Furthermore, an important trigger for synaptic release, influx of calcium through voltage-operated calcium channels, is compromised. This is the first demonstration of a transcription factor that directly controls expression of many major components of the RSP and provides further insight into the function of REST.
Collapse
Affiliation(s)
- Alexander W Bruce
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| | | | | | | | | | | | | |
Collapse
|
11
|
Pan J, Luk C, Kent G, Cutz E, Yeger H. Pulmonary neuroendocrine cells, airway innervation, and smooth muscle are altered in Cftr null mice. Am J Respir Cell Mol Biol 2006; 35:320-6. [PMID: 16614351 PMCID: PMC2643285 DOI: 10.1165/rcmb.2005-0468oc] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [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: 11/24/2022] Open
Abstract
The amine- and peptide-producing pulmonary neuroendocrine cells (PNEC) are widely distributed within the airway mucosa of mammalian lung as solitary cells and innervated clusters, neuroepithelial bodies (NEB), which function as airway O2 sensors. These cells express Cftr and hence could play a role in the pathophysiology of cystic fibrosis (CF) lung disease. We performed confocal microscopy and morphometric analysis on lung sections from Cftr-/- (null), Cftr+/+, and Cftr+/- (control) mice at developmental stages E20, P5, P9, and P30 to determine the distribution, frequency, and innervation of PNEC/NEB, innervation and cell mass of airway smooth muscle, and neuromuscular junctions using synaptic vesicle protein 2, smooth muscle actin, and synaptophysin markers, respectively. The mean number of PNEC/NEB in Cftr-/- mice was significantly reduced compared with control mice at E20, whereas comparable or increased numbers were observed postnatally. NEB cells in Cftr null mice showed a significant reduction in intracorpuscular nerve endings compared with control mice, which is consistent with an intrinsic abnormality of the PNEC system. The airways of Cftr-/- mice showed reduced density (approximately 20-30%) of smooth muscle innervation, decreased mean airway smooth muscle mass (approximately 35%), and reduced density (approximately 20%) of nerve endings compared with control mice. We conclude that the airways of Cftr-/- mice exhibit heretofore unappreciated structural alterations affecting cellular and neural components of the PNEC system and airway smooth muscle and its innervation resulting in blunted O2 sensing and reduced airway tonus. Cftr could play a role in the development of the PNEC system, lung innervation, and airway smooth muscle.
Collapse
Affiliation(s)
- Jie Pan
- Division of Pathology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
12
|
van de Stolpe A, Slycke AJ, Reinders MO, Zomer AWM, Goodenough S, Behl C, Seasholtz AF, van der Saag PT. Estrogen receptor (ER)-mediated transcriptional regulation of the human corticotropin-releasing hormone-binding protein promoter: differential effects of ERalpha and ERbeta. Mol Endocrinol 2004; 18:2908-23. [PMID: 15345745 DOI: 10.1210/me.2003-0446] [Citation(s) in RCA: 37] [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: 11/19/2022] Open
Abstract
CRH-binding protein (CRH-BP) regulates activation of the hypothalamic-pituitary-adrenal (HPA) axis by binding and inhibiting CRH. We investigated for the first time transcriptional regulation of the human CRH-BP promoter using transient transfections. Estrogen receptors (ERs) contributed to ligand-independent constitutive activation of the promoter, whereas in the presence of estradiol ERalpha induced and ERbeta repressed promoter activity in a dose-dependent manner. TNFalpha inhibited promoter induction by ERalpha in the absence and presence of estradiol. Three ERE half-sites in the CRH-BP promoter bound ERalpha and ERbeta in an EMSA, and disruption of ERE half-sites by site-directed mutagenesis abolished ligand-independent induction by ERalpha and ERbeta and promoter enhancement by estradiol-activated ERalpha. Repression by estradiol/ERbeta was unaffected by disruption of ERE half-sites, activating protein 1, cAMP response element, GATA, or nuclear factor kappaB sites, and reversed to promoter induction by estrogen antagonists, tamoxifen and ICI 182,780, suggesting corepressor involvement. In hypothalamic GT1-7 cells, Western blotting demonstrated rapid induction of endogenous CRH-BP expression by estradiol-bound ER, which was inhibited by TNFalpha. We propose a model in which ERs maintain basal CRH-BP expression in pituitary and neurosecretory cells, whereas in the presence of ERalpha estrogen enhances CRH-BP transcription, causing down-regulation of the HPA axis, and nuclear factor kappaB-activating cytokines activate the HPA axis by inhibiting ERalpha.
Collapse
|
13
|
Cai T, Fukushige T, Notkins AL, Krause M. Insulinoma-Associated Protein IA-2, a Vesicle Transmembrane Protein, Genetically Interacts with UNC-31/CAPS and Affects Neurosecretion in Caenorhabditis elegans. J Neurosci 2004; 24:3115-24. [PMID: 15044551 PMCID: PMC6729843 DOI: 10.1523/jneurosci.0101-04.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
IA-2 (insulinoma-associated protein 2), a major autoantigen in type 1 diabetes, is a receptor-tyrosine phosphatase-like protein associated with the membrane of secretory granules of neural and endocrine-specific cells. Loss of IA-2 activity in the mouse results in reduced insulin release and additional phenotypes, consistent with a general effect on neurosecretion and hormone release. To gain further insight into the cellular mechanisms of IA-2 function, we have studied the Caenorhabditis elegans homolog, CeIA-2 encoded by the ida-1 gene. Using two independent putative null alleles of ida-1, we demonstrate that animals lacking CeIA-2 activity are viable and exhibit subtle defects. Genetic studies of mutants in ida-1 and several genes involved in neurosecretory vesicle cargo release and signaling highlight two roles for CeIA-2. First, CeIA-2 has a specific and novel genetic interaction with UNC-31/CAPS, a protein that has been shown in other systems to regulate dense-core vesicle cargo release. Second, loss of CeIA-2 activity enhances weak alleles in the insulin-like signaling pathway. These results suggest that CeIA-2 may be an important factor in dense-core vesicle cargo release with parallels to insulin signaling in mammals.
Collapse
Affiliation(s)
- Tao Cai
- Experimental Medicine Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | |
Collapse
|
14
|
Sørensen JB, Nagy G, Varoqueaux F, Nehring RB, Brose N, Wilson MC, Neher E. Differential control of the releasable vesicle pools by SNAP-25 splice variants and SNAP-23. Cell 2003; 114:75-86. [PMID: 12859899 DOI: 10.1016/s0092-8674(03)00477-x] [Citation(s) in RCA: 264] [Impact Index Per Article: 12.6] [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: 10/26/2022]
Abstract
The SNARE complex, consisting of synaptobrevin, syntaxin, and SNAP-25, is essential for calcium-triggered exocytosis in neurosecretory cells. Little is known, however, about how developmentally regulated isoforms and other cognate SNARE components regulate vesicular fusion. To address this question, we examined neuroexocytosis from chromaffin cells of Snap25 null mice rescued by the two splice variants SNAP-25a and SNAP-25b and the ubiquitously expressed homolog SNAP-23. In the absence of SNAP-25, vesicle docking persisted, but primed vesicle pools were empty and fast calcium-triggered release abolished. Single vesicular fusion events showed normal characteristics, except for a shorter duration of the fusion pore. Overexpression of SNAP-25a, SNAP-25b, and SNAP-23 resulted in three distinct phenotypes; SNAP-25b induced larger primed vesicle pools than SNAP-25a, whereas SNAP-23 did not support a standing pool of primed vesicles. We conclude that three alternative SNARE components support exocytosis, but they differ in their ability to stabilize vesicles in the primed state.
Collapse
Affiliation(s)
- Jakob B Sørensen
- Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
| | | | | | | | | | | | | |
Collapse
|
15
|
Malosio ML, Benfante R, Racchetti G, Borgonovo B, Rosa P, Meldolesi J. Neurosecretory cells without neurosecretion: evidence of an independently regulated trait of the cell phenotype. J Physiol 1999; 520 Pt 1:43-52. [PMID: 10517799 PMCID: PMC2269568 DOI: 10.1111/j.1469-7793.1999.t01-1-00043.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Neurosecretion competence is a fundamental property that enables differentiated neurones and professional neurosecretory cells to store neurotransmitters and hormones in specialized organelles, the synaptic-like vesicles and dense granules, and to release them by regulated exocytosis. In our laboratory, the study of rat phaeochromocytoma (PC12) clones that fail to express the above organelles or any other components involved in neurosecretion, whilst maintaining most of the general markers of the parental population, has served to demonstrate that this trait is controlled independently from the rest of the phenotype. The present review focuses on recent advances in elucidating the molecular mechanisms governing neurosecretion competence. Moreover, the opportunities that such neurosecretion-defective PC12 clones offer for the investigation of new aspects of regulated exocytosis and the localization of its components are summarized.
Collapse
Affiliation(s)
- M L Malosio
- DIBIT, Department of Neurosciences, San Raffaele Institute, Department of Pharmacology, B. Ceccarelli Neurobiology Centre, University of Milan, 20132 Milan, Italy
| | | | | | | | | | | |
Collapse
|