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Dermady APC, DeFazio DL, Hensley EM, Ruiz DL, Chavez AD, Iannone SA, Dermady NM, Grandel LV, Hill AS. Neuronal excitability modulates developmental time of Drosophila melanogaster. Dev Biol 2024; 508:38-45. [PMID: 38224932 DOI: 10.1016/j.ydbio.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/17/2024]
Abstract
Developmental time is a fundamental life history trait that affects the reproductive success of animals. Developmental time is known to be regulated by many genes and environmental conditions, yet mechanistic understandings of how various cellular processes influence the developmental timing of an organism are lacking. The nervous system is known to control key processes that affect developmental time, including the release of hormones that signal transitions between developmental stages. Here we show that the excitability of neurons plays a crucial role in modulating developmental time. Genetic manipulation of neuronal excitability in Drosophila melanogaster alters developmental time, which is faster in animals with increased neuronal excitability. We find that selectively modulating the excitability of peptidergic neurons is sufficient to alter developmental time, suggesting the intriguing hypothesis that the impact of neuronal excitability on DT may be at least partially mediated by peptidergic regulation of hormone release. This effect of neuronal excitability on developmental time is seen during embryogenesis and later developmental stages. Observed phenotypic plasticity in the effect of genetically increasing neuronal excitability at different temperatures, a condition also known to modulate excitability, suggests there is an optimal level of neuronal excitability, in terms of shortening DT. Together, our data highlight a novel connection between neuronal excitability and developmental time, with broad implications related to organismal physiology and evolution.
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Affiliation(s)
- Aidan P C Dermady
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Dionna L DeFazio
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Emily M Hensley
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Daniel L Ruiz
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | | | - Sarah A Iannone
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Niall M Dermady
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Lexis V Grandel
- College of the Holy Cross, Department of Biology, Worcester, MA, USA
| | - Alexis S Hill
- College of the Holy Cross, Department of Biology, Worcester, MA, USA.
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2
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Yuan XN, Luo C, Zhao QF, Zhong SY, Hang Q, Dai TM, Pan ZH, Sima YH, Qiu JF, Xu SQ. The clock gene Cryptochrome 1 is involved in the photoresponse of embryonic hatching behavior in Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 114:e22046. [PMID: 37583246 DOI: 10.1002/arch.22046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/17/2023]
Abstract
The hatching of insect eggs is a classic circadian behavior rhythm controlled by the biological clock. Its function is considered to impose a daily rhythm on the embryo, allowing it to hatch within a permissible time window. However, the molecular pathways through which the clock affects embryonic hatching behavior remain unclear. Here, we utilized a clock gene Cryptochrome1 (Cry1) knockout mutant to dissect the pathways by which the circadian clock affects embryonic hatching rhythm in the silkworm. In the Cry1 mutant, the embryo hatching rhythm was disrupted. Under the constant light or constant dark incubation conditions, mutant embryos lost their hatching rhythm, while wild-type embryos hatch exhibiting free-running rhythm. In the light-dark cycle (LD), the hatching rhythm of CRY1-deficient silkworms could not be entrained by the LD photoperiod during the incubation period. The messenger RNA levels and enzymatic activities of Cht and Hel in the mutant embryos were significantly reduced at circadian time 24 (CT24). Transcriptome analysis revealed significant differences in gene expression at CT24 between the Cry1 knockout mutant and the wild-type, with 2616 differentially expressed genes identified. The enriched Gene Ontology pathway includes enzyme activity, energy availability, and protein translation. Short neuropeptide F signaling was reduced in the CT24 embryonic brain of the mutant, the expression of the neuropeptide PTTH was also reduced and the rhythm was lost, which further affects ecdysteroid signaling. Our results suggested that the silkworm circadian clock affects neuropeptide-hormone signaling as well as physiological functions related to hatching, which may regulate the hatching rhythm.
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Affiliation(s)
- Xiao-Nan Yuan
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Cheng Luo
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Qi-Fan Zhao
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Si-Yin Zhong
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Qi Hang
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Tai-Ming Dai
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Zhong-Hua Pan
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Yang-Hu Sima
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Jian-Feng Qiu
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
| | - Shi-Qing Xu
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology & Ecology (IABE), Soochow University, Suzhou, China
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3
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González Segarra AJ, Pontes G, Jourjine N, Del Toro A, Scott K. Hunger- and thirst-sensing neurons modulate a neuroendocrine network to coordinate sugar and water ingestion. eLife 2023; 12:RP88143. [PMID: 37732734 PMCID: PMC10513480 DOI: 10.7554/elife.88143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023] Open
Abstract
Consumption of food and water is tightly regulated by the nervous system to maintain internal nutrient homeostasis. Although generally considered independently, interactions between hunger and thirst drives are important to coordinate competing needs. In Drosophila, four neurons called the interoceptive subesophageal zone neurons (ISNs) respond to intrinsic hunger and thirst signals to oppositely regulate sucrose and water ingestion. Here, we investigate the neural circuit downstream of the ISNs to examine how ingestion is regulated based on internal needs. Utilizing the recently available fly brain connectome, we find that the ISNs synapse with a novel cell-type bilateral T-shaped neuron (BiT) that projects to neuroendocrine centers. In vivo neural manipulations revealed that BiT oppositely regulates sugar and water ingestion. Neuroendocrine cells downstream of ISNs include several peptide-releasing and peptide-sensing neurons, including insulin producing cells (IPCs), crustacean cardioactive peptide (CCAP) neurons, and CCHamide-2 receptor isoform RA (CCHa2R-RA) neurons. These neurons contribute differentially to ingestion of sugar and water, with IPCs and CCAP neurons oppositely regulating sugar and water ingestion, and CCHa2R-RA neurons modulating only water ingestion. Thus, the decision to consume sugar or water occurs via regulation of a broad peptidergic network that integrates internal signals of nutritional state to generate nutrient-specific ingestion.
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Affiliation(s)
| | - Gina Pontes
- University of California, BerkeleyBerkeleyUnited States
| | | | | | - Kristin Scott
- University of California, BerkeleyBerkeleyUnited States
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4
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Lee GG, Zeng K, Duffy CM, Sriharsha Y, Yoo S, Park JH. In vivo characterization of the maturation steps of a pigment dispersing factor neuropeptide precursor in the Drosophila circadian pacemaker neurons. Genetics 2023; 225:iyad118. [PMID: 37364299 PMCID: PMC10471210 DOI: 10.1093/genetics/iyad118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 05/19/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
Pigment dispersing factor (PDF) is a key signaling molecule coordinating the neuronal network associated with the circadian rhythms in Drosophila. The precursor (proPDF) of the mature PDF (mPDF) consists of 2 motifs, a larger PDF-associated peptide (PAP) and PDF. Through cleavage and amidation, the proPDF is predicted to produce cleaved-PAP (cPAP) and mPDF. To delve into the in vivo mechanisms underlying proPDF maturation, we generated various mutations that eliminate putative processing sites and then analyzed the effect of each mutation on the production of cPAP and mPDF by 4 different antibodies in both ectopic and endogenous conditions. We also assessed the knockdown effects of processing enzymes on the proPDF maturation. At the functional level, circadian phenotypes were measured for all mutants and knockdown lines. As results, we confirm the roles of key enzymes and their target residues: Amontillado (Amon) for the cleavage at the consensus dibasic KR site, Silver (Svr) for the removal of C-terminal basic residues from the intermediates, PAP-KR and PDF-GK, derived from proPDF, and PHM (peptidylglycine-α-hydroxylating monooxygenase) for the amidation of PDF. Our results suggest that the C-terminal amidation occurs independently of proPDF cleavage. Moreover, the PAP domain is important for the proPDF trafficking into the secretory vesicles and a close association between cPAP and mPDF following cleavage seems required for their stability within the vesicles. These studies highlight the biological significance of individual processing steps and the roles of the PAP for the stability and function of mPDF which is essential for the circadian clockworks.
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Affiliation(s)
- Gyunghee G Lee
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Kevin Zeng
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Cole M Duffy
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Yadali Sriharsha
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Siuk Yoo
- Department of Life Sciences, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea
| | - Jae H Park
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- Genome Science and Technology Graduate Program, University of Tennessee, Knoxville, TN 37996, USA
- NeuroNET Research Center, University of Tennessee, Knoxville, TN 37996, USA
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5
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González-Segarra AJ, Pontes G, Jourjine N, Del Toro A, Scott K. Hunger- and thirst-sensing neurons modulate a neuroendocrine network to coordinate sugar and water ingestion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.06.535891. [PMID: 37066363 PMCID: PMC10104137 DOI: 10.1101/2023.04.06.535891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Consumption of food and water is tightly regulated by the nervous system to maintain internal nutrient homeostasis. Although generally considered independently, interactions between hunger and thirst drives are important to coordinate competing needs. In Drosophila , four neurons called the Interoceptive Subesophageal zone Neurons (ISNs) respond to intrinsic hunger and thirst signals to oppositely regulate sucrose and water ingestion. Here, we investigate the neural circuit downstream of the ISNs to examine how ingestion is regulated based on internal needs. Utilizing the recently available fly brain connectome, we find that the ISNs synapse with a novel cell type Bilateral T-shaped neuron (BiT) that projects to neuroendocrine centers. In vivo neural manipulations revealed that BiT oppositely regulates sugar and water ingestion. Neuroendocrine cells downstream of ISNs include several peptide-releasing and peptide-sensing neurons, including insulin producing cells (IPC), crustacean cardioactive peptide (CCAP) neurons, and CCHamide-2 receptor isoform RA (CCHa2R-RA) neurons. These neurons contribute differentially to ingestion of sugar and water, with IPCs and CCAP neurons oppositely regulating sugar and water ingestion, and CCHa2R-RA neurons modulating only water ingestion. Thus, the decision to consume sugar or water occurs via regulation of a broad peptidergic network that integrates internal signals of nutritional state to generate nutrient-specific ingestion.
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Affiliation(s)
| | - Gina Pontes
- University of California, Berkeley, United States
- present address: IBBEA, CONICET-UBA, Buenos Aires, Argentina
| | - Nicholas Jourjine
- University of California, Berkeley, United States
- present address: Harvard University, Cambridge, United States
| | - Alexander Del Toro
- University of California, Berkeley, United States
- present address: Brown University, Rhode Island, United States
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6
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Fritzsche S, Hunnekuhl VS. Cell-specific expression and individual function of prohormone convertase PC1/3 in Tribolium larval growth highlights major evolutionary changes between beetle and fly neuroendocrine systems. EvoDevo 2021; 12:9. [PMID: 34187565 PMCID: PMC8244231 DOI: 10.1186/s13227-021-00179-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 06/14/2021] [Indexed: 11/15/2022] Open
Abstract
Background The insect neuroendocrine system acts in the regulation of physiology, development and growth. Molecular evolution of this system hence has the potential to allow for major biological differences between insect groups. Two prohormone convertases, PC1/3 and PC2, are found in animals and both function in the processing of neuropeptide precursors in the vertebrate neurosecretory pathway. Whereas PC2-function is conserved between the fly Drosophila and vertebrates, ancestral PC1/3 was lost in the fly lineage and has not been functionally studied in any protostome. Results In order to understand its original functions and the changes accompanying the gene loss in the fly, we investigated PC1/3 and PC2 expression and function in the beetle Tribolium castaneum. We found that PC2 is broadly expressed in the nervous system, whereas surprisingly, PC1/3 expression is restricted to specific cell groups in the posterior brain and suboesophageal ganglion. Both proteases have parallel but non-redundant functions in adult beetles’ viability and fertility. Female infertility following RNAi is caused by a failure to deposit sufficient yolk to the developing oocytes. Larval RNAi against PC2 produced moulting defects where the larvae were not able to shed their old cuticle. This ecdysis phenotype was also observed in a small subset of PC1/3 knockdown larvae and was strongest in a double knockdown. Unexpectedly, most PC1/3-RNAi larvae showed strongly reduced growth, but went through larval moults despite minimal to zero weight gain. Conclusions The cell type-specific expression of PC1/3 and its essential requirement for larval growth highlight the important role of this gene within the insect neuroendocrine system. Genomic conservation in most insect groups suggests that it has a comparable individual function in other insects as well, which has been replaced by alternative mechanisms in flies. Supplementary Information The online version contains supplementary material available at 10.1186/s13227-021-00179-w.
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Affiliation(s)
- Sonja Fritzsche
- Johann-Friedrich-Blumenbach Institute, GZMB, Göttingen University, Göttingen, Germany
| | - Vera S Hunnekuhl
- Johann-Friedrich-Blumenbach Institute, GZMB, Göttingen University, Göttingen, Germany.
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7
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Pauls D, Hamarat Y, Trufasu L, Schendzielorz TM, Gramlich G, Kahnt J, Vanselow JT, Schlosser A, Wegener C. Drosophila carboxypeptidase D (SILVER) is a key enzyme in neuropeptide processing required to maintain locomotor activity levels and survival rate. Eur J Neurosci 2019; 50:3502-3519. [PMID: 31309630 DOI: 10.1111/ejn.14516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/19/2019] [Accepted: 07/05/2019] [Indexed: 11/27/2022]
Abstract
Neuropeptides are processed from larger preproproteins by a dedicated set of enzymes. The molecular and biochemical mechanisms underlying preproprotein processing and the functional importance of processing enzymes are well-characterised in mammals, but little studied outside this group. In contrast to mammals, Drosophila melanogaster lacks a gene for carboxypeptidase E (CPE), a key enzyme for mammalian peptide processing. By combining peptidomics and neurogenetics, we addressed the role of carboxypeptidase D (dCPD) in global neuropeptide processing and selected peptide-regulated behaviours in Drosophila. We found that a deficiency in dCPD results in C-terminally extended peptides across the peptidome, suggesting that dCPD took over CPE function in the fruit fly. dCPD is widely expressed throughout the nervous system, including peptidergic neurons in the mushroom body and neuroendocrine cells expressing adipokinetic hormone. Conditional hypomorphic mutation in the dCPD-encoding gene silver in the larva causes lethality, and leads to deficits in starvation-induced hyperactivity and appetitive gustatory preference, as well as to reduced viability and activity levels in adults. A phylogenomic analysis suggests that loss of CPE is not common to insects, but only occurred in Hymenoptera and Diptera. Our results show that dCPD is a key enzyme for neuropeptide processing and peptide-regulated behaviour in Drosophila. dCPD thus appears as a suitable target to genetically shut down total neuropeptide production in peptidergic neurons. The persistent occurrence of CPD in insect genomes may point to important further CPD functions beyond neuropeptide processing which cannot be fulfilled by CPE.
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Affiliation(s)
- Dennis Pauls
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Yasin Hamarat
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany.,'Santaka' Valley I Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Luisa Trufasu
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Tim M Schendzielorz
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Gertrud Gramlich
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jörg Kahnt
- Max-Planck-Institute of Terrestrial Microbiology, Marburg, Germany
| | - Jens T Vanselow
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Christian Wegener
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
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8
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Christie AE, Stanhope ME, Gandler HI, Lameyer TJ, Pascual MG, Shea DN, Yu A, Dickinson PS, Hull JJ. Molecular characterization of putative neuropeptide, amine, diffusible gas and small molecule transmitter biosynthetic enzymes in the eyestalk ganglia of the American lobster, Homarus americanus. INVERTEBRATE NEUROSCIENCE 2018; 18:12. [PMID: 30276482 DOI: 10.1007/s10158-018-0216-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/21/2018] [Indexed: 02/03/2023]
Abstract
The American lobster, Homarus americanus, is a model for investigating the neuromodulatory control of physiology and behavior. Prior studies have shown that multiple classes of chemicals serve as locally released/circulating neuromodulators/neurotransmitters in this species. Interestingly, while many neuroactive compounds are known from Homarus, little work has focused on identifying/characterizing the enzymes responsible for their biosynthesis, despite the fact that these enzymes are key components for regulating neuromodulation/neurotransmission. Here, an eyestalk ganglia-specific transcriptome was mined for transcripts encoding enzymes involved in neuropeptide, amine, diffusible gas and small molecule transmitter biosynthesis. Using known Drosophila melanogaster proteins as templates, transcripts encoding putative Homarus homologs of peptide precursor processing (signal peptide peptidase, prohormone processing protease and carboxypeptidase) and immature peptide modifying (glutaminyl cyclase, tyrosylprotein sulfotransferase, protein disulfide isomerase, peptidylglycine-α-hydroxylating monooxygenase and peptidyl-α-hydroxyglycine-α-amidating lyase) enzymes were identified in the eyestalk assembly. Similarly, transcripts encoding full complements of the enzymes responsible for dopamine [tryptophan-phenylalanine hydroxylase (TPH), tyrosine hydroxylase and DOPA decarboxylase (DDC)], octopamine (TPH, tyrosine decarboxylase and tyramine β-hydroxylase), serotonin (TPH or tryptophan hydroxylase and DDC) and histamine (histidine decarboxylase) biosynthesis were identified from the eyestalk ganglia, as were those responsible for the generation of the gases nitric oxide (nitric oxide synthase) and carbon monoxide (heme oxygenase), and the small molecule transmitters acetylcholine (choline acetyltransferase), glutamate (glutaminase) and GABA (glutamic acid decarboxylase). The presence and identity of the transcriptome-derived transcripts were confirmed using RT-PCR. The data presented here provide a foundation for future gene-based studies of neuromodulatory control at the level of neurotransmitter/modulator biosynthesis in Homarus.
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Affiliation(s)
- Andrew E Christie
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI, 96822, USA.
| | - Meredith E Stanhope
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME, 04011, USA
| | - Helen I Gandler
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME, 04011, USA
| | - Tess J Lameyer
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME, 04011, USA
| | - Micah G Pascual
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI, 96822, USA
| | - Devlin N Shea
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME, 04011, USA
| | - Andy Yu
- Békésy Laboratory of Neurobiology, Pacific Biosciences Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI, 96822, USA
| | - Patsy S Dickinson
- Department of Biology, Bowdoin College, 6500 College Station, Brunswick, ME, 04011, USA
| | - J Joe Hull
- Pest Management and Biocontrol Research Unit, US Arid Land Agricultural Research Center, USDA Agricultural Research Services, Maricopa, AZ, 85138, USA
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9
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Aittomäki S, Valanne S, Lehtinen T, Matikainen S, Nyman TA, Rämet M, Pesu M. Proprotein convertase Furin1 expression in the Drosophila fat body is essential for a normal antimicrobial peptide response and bacterial host defense. FASEB J 2017; 31:4770-4782. [PMID: 28705811 DOI: 10.1096/fj.201700296r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/27/2017] [Indexed: 01/17/2023]
Abstract
Invading pathogens provoke robust innate immune responses in Dipteran insects, such as Drosophila melanogaster In a systemic bacterial infection, a humoral response is induced in the fat body. Gram-positive bacteria trigger the Toll signaling pathway, whereas gram-negative bacterial infections are signaled via the immune deficiency (IMD) pathway. We show here that the RNA interference-mediated silencing of Furin1-a member of the proprotein convertase enzyme family-specifically in the fat body, results in a reduction in the expression of antimicrobial peptides. This, in turn, compromises the survival of adult fruit flies in systemic infections that are caused by both gram-positive and -negative bacteria. Furin1 plays a nonredundant role in the regulation of immune responses, as silencing of Furin2, the other member of the enzyme family, had no effect on survival or the expression of antimicrobial peptides upon a systemic infection. Furin1 does not directly affect the Toll or IMD signaling pathways, but the reduced expression of Furin1 up-regulates stress response factors in the fat body. We also demonstrate that Furin1 is a negative regulator of the Janus kinase/signal transducer and activator of transcription signaling pathway, which is implicated in stress responses in the fly. In summary, our data identify Furin1 as a novel regulator of humoral immunity and cellular stress responses in Drosophila-Aittomäki, S., Valanne, S., Lehtinen, T., Matikainen, S., Nyman, T. A., Rämet, M., Pesu, M. Proprotein convertase Furin1 expression in the Drosophila fat body is essential for a normal antimicrobial peptide response and bacterial host defense.
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Affiliation(s)
- Saara Aittomäki
- Immunoregulation Group, University of Tampere, Tampere, Finland.,BioMediTech Institute, University of Tampere, Tampere, Finland
| | - Susanna Valanne
- BioMediTech Institute, University of Tampere, Tampere, Finland.,Experimental Immunology Group, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
| | - Tapio Lehtinen
- Immunoregulation Group, University of Tampere, Tampere, Finland.,BioMediTech Institute, University of Tampere, Tampere, Finland
| | | | - Tuula A Nyman
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Mika Rämet
- BioMediTech Institute, University of Tampere, Tampere, Finland.,Experimental Immunology Group, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.,PEDEGO Research Unit, Medical Research Center Oulu, and.,Department of Children and Adolescents, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Marko Pesu
- Immunoregulation Group, University of Tampere, Tampere, Finland .,BioMediTech Institute, University of Tampere, Tampere, Finland.,Department of Dermatology, Tampere University Hospital, Tampere, Finland
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10
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Ordan E, Volk T. Amontillado is required for Drosophila Slit processing and for tendon-mediated muscle patterning. Biol Open 2016; 5:1530-1534. [PMID: 27628033 PMCID: PMC5087687 DOI: 10.1242/bio.020636] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Slit cleavage into N-terminal and C-terminal polypeptides is essential for restricting the range of Slit activity. Although the Slit cleavage site has been characterized previously and is evolutionally conserved, the identity of the protease that cleaves Slit remains elusive. Our previous analysis indicated that Slit cleavage is essential to immobilize the active Slit-N at the tendon cell surfaces, mediating the arrest of muscle elongation. In an attempt to identify the protease required for Slit cleavage we performed an RNAi-based assay in the ectoderm and followed the process of elongation of the lateral transverse muscles toward tendon cells. The screen led to the identification of the Drosophila homolog of pheromone convertase 2 (PC2), Amontillado (Amon), as an essential protease for Slit cleavage. Further analysis indicated that Slit mobility on SDS polyacrylamide gel electrophoresis (SDS-PAGE) is slightly up-shifted in amon mutants, and its conventional cleavage into the Slit-N and Slit-C polypeptides is attenuated. Consistent with the requirement for amon to promote Slit cleavage and membrane immobilization of Slit-N, the muscle phenotype of amon mutant embryos was rescued by co-expressing a membrane-bound form of full-length Slit lacking the cleavage site and knocked into the slit locus. The identification of a novel protease component essential for Slit processing may represent an additional regulatory step in the Slit signaling pathway. Summary: The Drosophila homolog of pheromone convertase 2 (PC2), amontillado (Amon), is shown to contribute to Slit processing and further cleavage into an N-Slit, essential for Slit activity in directing muscle patterning.
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Affiliation(s)
- Elly Ordan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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11
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Sfaxi F, Scamuffa N, Lalou C, Ma J, Metrakos P, Siegfried G, Ragg H, Bikfalvi A, Calvo F, Khatib AM. Repression of liver colorectal metastasis by the serpin Spn4A a naturally occurring inhibitor of the constitutive secretory proprotein convertases. Oncotarget 2015; 5:4195-210. [PMID: 24961901 PMCID: PMC4147316 DOI: 10.18632/oncotarget.1966] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Liver is the most common site of metastasis from colorectal cancers, and liver of patients with liver colorectal metastasis have abnormal levels of the proprotein convertases (PCs). These proteases are involved in the activation and/or expression of various colon cancer-related mediators, making them promising targets in colorectal liver metastasis therapy. Here, we revealed that the serpin Spn4 from Drosophila melanogaster inhibits the activity of all the PCs found in the constitutive secretory pathway and represses the metastatic potential of the colon cancer cells HT-29 and CT-26. In these cells, Spn4A inhibited the processing of the PCs substrates IGF-1R and PDGF-A that associated their reduced anchorage-independent growth, invasiveness and survival in response to apoptotic agents. In vivo, Spn4A-expressing tumor cells showed repressed subcutaneous tumor development and liver metastases formation in response to their intrasplenic inoculation. In these cells Spn4A induced the expression of molecules with anti-metastatic functions and inhibited expression of pro-tumorigenic molecules. Taken together, our findings identify Spn4A as the only endogenous inhibitor of all the constitutive secretory pathway PCs, which is able to repress the metastatic potential of colon cancer cells. These results suggest the potential use of Spn4A and/or derivates as a useful adduct colorectal liver metastasis prevention.
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Affiliation(s)
- Fatma Sfaxi
- Université Bordeaux 1, LAMC, Talence, France; INSERM, UMR 1029, F-33405 Talence, France
| | | | | | | | | | | | | | | | | | - Abdel-Majid Khatib
- Université Bordeaux 1, LAMC, Talence, France; INSERM, UMR 1029, F-33405 Talence, France
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12
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Diao F, Ironfield H, Luan H, Diao F, Shropshire WC, Ewer J, Marr E, Potter CJ, Landgraf M, White BH. Plug-and-play genetic access to drosophila cell types using exchangeable exon cassettes. Cell Rep 2015; 10:1410-21. [PMID: 25732830 PMCID: PMC4373654 DOI: 10.1016/j.celrep.2015.01.059] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/06/2015] [Accepted: 01/27/2015] [Indexed: 12/27/2022] Open
Abstract
Genetically encoded effectors are important tools for probing cellular function in living animals, but improved methods for directing their expression to specific cell types are required. Here, we introduce a simple, versatile method for achieving cell-type-specific expression of transgenes that leverages the untapped potential of "coding introns" (i.e., introns between coding exons). Our method couples the expression of a transgene to that of a native gene expressed in the cells of interest using intronically inserted "plug-and-play" cassettes (called "Trojan exons") that carry a splice acceptor site followed by the coding sequences of T2A peptide and an effector transgene. We demonstrate the efficacy of this approach in Drosophila using lines containing suitable MiMIC (Minos-mediated integration cassette) transposons and a palette of Trojan exons capable of expressing a range of commonly used transcription factors. We also introduce an exchangeable, MiMIC-like Trojan exon construct that can be targeted to coding introns using the Crispr/Cas system.
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Affiliation(s)
- Fengqiu Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Holly Ironfield
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Haojiang Luan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Feici Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - William C Shropshire
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - John Ewer
- Centro Interdisciplinario de Neurociencia, Universidad de Valparaiso, Pasaje Harrington 287, Playa Ancha, Valparaiso, Chile
| | - Elizabeth Marr
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Christopher J Potter
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Benjamin H White
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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13
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Kim YJ, Igiesuorobo O, Ramos CI, Bao H, Zhang B, Serpe M. Prodomain removal enables neto to stabilize glutamate receptors at the Drosophila neuromuscular junction. PLoS Genet 2015; 11:e1004988. [PMID: 25723514 PMCID: PMC4344203 DOI: 10.1371/journal.pgen.1004988] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/06/2015] [Indexed: 11/24/2022] Open
Abstract
Stabilization of neurotransmitter receptors at postsynaptic specializations is a key step in the assembly of functional synapses. Drosophila Neto (Neuropillin and Tolloid-like protein) is an essential auxiliary subunit of ionotropic glutamate receptor (iGluR) complexes required for the iGluRs clustering at the neuromuscular junction (NMJ). Here we show that optimal levels of Neto are crucial for stabilization of iGluRs at synaptic sites and proper NMJ development. Genetic manipulations of Neto levels shifted iGluRs distribution to extrajunctional locations. Perturbations in Neto levels also produced small NMJs with reduced synaptic transmission, but only Neto-depleted NMJs showed diminished postsynaptic components. Drosophila Neto contains an inhibitory prodomain that is processed by Furin1-mediated limited proteolysis. neto null mutants rescued with a Neto variant that cannot be processed have severely impaired NMJs and reduced iGluRs synaptic clusters. Unprocessed Neto retains the ability to engage iGluRs in vivo and to form complexes with normal synaptic transmission. However, Neto prodomain must be removed to enable iGluRs synaptic stabilization and proper postsynaptic differentiation. Synapse development is initiated by genetic programs, but is coordinated by neuronal activity, by communication between the pre- and postsynaptic compartments, and by cellular signals that integrate the status of the whole organisms and its developmental progression. The molecular mechanisms underlining these processes are poorly understood. In particular, how neurotransmitter receptors are recruited and stabilized at central synapses remain the subject of intense research. The Drosophila NMJ is a glutamatergic synapse similar in composition and physiology with mammalian central excitatory synapses. Like mammals, Drosophila utilizes auxiliary subunit(s) to modulate the formation and function of glutamatergic synapses. We have previously reported that Neto is an auxiliary protein essential for functional glutamate receptors and for organization of postsynaptic specializations. Here we report that synapse assembly and NMJ development are exquisitely sensitive to postsynaptic Neto levels. Furthermore, we show that Neto activity is controlled by Furin-type proteases, which regulate the processing and maturation of many developmentally important proteins, from growth factors and neuropeptides to extracellular matrix components. Such concerted control may serve to coordinate synapse assembly with synapse growth and developmental progression.
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Affiliation(s)
- Young-Jun Kim
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Oghomwen Igiesuorobo
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Cathy I. Ramos
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Hong Bao
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Mihaela Serpe
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
- * E-mail:
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14
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Hadžić T, Park D, Abruzzi KC, Yang L, Trigg JS, Rohs R, Rosbash M, Taghert PH. Genome-wide features of neuroendocrine regulation in Drosophila by the basic helix-loop-helix transcription factor DIMMED. Nucleic Acids Res 2015; 43:2199-215. [PMID: 25634895 PMCID: PMC4344488 DOI: 10.1093/nar/gku1377] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Neuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The dimmed (DIMM) basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMM's activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile. By this combined approach, we showed that DIMM binds to conserved E-boxes in enhancers of 212 genes whose expression is enriched in DIMM-expressing NE cells. DIMM binds preferentially to certain E-boxes within first introns of specific gene isoforms. Statistical machine learning revealed that flanking regions of putative DIMM binding sites contribute to its DNA binding specificity. DIMM's transcriptional repertoire features at least 20 LDCV constituents. In addition, DIMM notably targets the pro-secretory transcription factor, creb-A, but significantly, DIMM does not target any neuropeptide genes. DIMM therefore prescribes the scale of secretory activity in NE neurons, by a systematic control of both proximal and distal points in the regulated secretory pathway.
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Affiliation(s)
- Tarik Hadžić
- Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Dongkook Park
- Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Katharine C Abruzzi
- Howard Hughes Medical Institute, National Center for Behavioral Genomics, Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Lin Yang
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Jennifer S Trigg
- Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Remo Rohs
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Michael Rosbash
- Howard Hughes Medical Institute, National Center for Behavioral Genomics, Department of Biology, Brandeis University, Waltham, MA 02454, USA
| | - Paul H Taghert
- Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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Neuronal remodeling during metamorphosis is regulated by the alan shepard (shep) gene in Drosophila melanogaster. Genetics 2014; 197:1267-83. [PMID: 24931409 DOI: 10.1534/genetics.114.166181] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peptidergic neurons are a group of neuronal cells that synthesize and secrete peptides to regulate a variety of biological processes. To identify genes controlling the development and function of peptidergic neurons, we conducted a screen of 545 splice-trap lines and identified 28 loci that drove expression in peptidergic neurons when crossed to a GFP reporter transgene. Among these lines, an insertion in the alan shepard (shep) gene drove expression specifically in most peptidergic neurons. shep transcripts and SHEP proteins were detected primarily and broadly in the central nervous system (CNS) in embryos, and this expression continued into the adult stage. Loss of shep resulted in late pupal lethality, reduced adult life span, wing expansion defects, uncoordinated adult locomotor activities, rejection of males by virgin females, and reduced neuropil area and reduced levels of multiple presynaptic markers throughout the adult CNS. Examination of the bursicon neurons in shep mutant pharate adults revealed smaller somata and fewer axonal branches and boutons, and all of these cellular phenotypes were fully rescued by expression of the most abundant wild-type shep isoform. In contrast to shep mutant animals at the pharate adult stage, shep mutant larvae displayed normal bursicon neuron morphologies. Similarly, shep mutant adults were uncoordinated and weak, while shep mutant larvae displayed largely, although not entirely, normal locomotor behavior. Thus, shep played an important role in the metamorphic development of many neurons.
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16
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Pauls D, Chen J, Reiher W, Vanselow JT, Schlosser A, Kahnt J, Wegener C. Peptidomics and processing of regulatory peptides in the fruit fly Drosophila. EUPA OPEN PROTEOMICS 2014. [DOI: 10.1016/j.euprot.2014.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Redondo BB, Bunz M, Halder P, Sadanandappa MK, Mühlbauer B, Erwin F, Hofbauer A, Rodrigues V, VijayRaghavan K, Ramaswami M, Rieger D, Wegener C, Förster C, Buchner E. Identification and structural characterization of interneurons of the Drosophila brain by monoclonal antibodies of the würzburg hybridoma library. PLoS One 2013; 8:e75420. [PMID: 24069413 PMCID: PMC3775750 DOI: 10.1371/journal.pone.0075420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 08/11/2013] [Indexed: 11/19/2022] Open
Abstract
Several novel synaptic proteins have been identified by monoclonal antibodies (mAbs) of the Würzburg hybridoma library generated against homogenized Drosophila brains, e.g. cysteine string protein, synapse-associated protein of 47 kDa, and Bruchpilot. However, at present no routine technique exists to identify the antigens of mAbs of our library that label only a small number of cells in the brain. Yet these antibodies can be used to reproducibly label and thereby identify these cells by immunohistochemical staining. Here we describe the staining patterns in the Drosophila brain for ten mAbs of the Würzburg hybridoma library. Besides revealing the neuroanatomical structure and distribution of ten different sets of cells we compare the staining patterns with those of antibodies against known antigens and GFP expression patterns driven by selected Gal4 lines employing regulatory sequences of neuronal genes. We present examples where our antibodies apparently stain the same cells in different Gal4 lines suggesting that the corresponding regulatory sequences can be exploited by the split-Gal4 technique for transgene expression exclusively in these cells. The detection of Gal4 expression in cells labeled by mAbs may also help in the identification of the antigens recognized by the antibodies which then in addition to their value for neuroanatomy will represent important tools for the characterization of the antigens. Implications and future strategies for the identification of the antigens are discussed.
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Affiliation(s)
| | - Melanie Bunz
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Partho Halder
- Institute of Clinical Neurobiology, University of Würzburg, Würzburg, Germany
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Madhumala K. Sadanandappa
- Institute of Clinical Neurobiology, University of Würzburg, Würzburg, Germany
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Barbara Mühlbauer
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Felix Erwin
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Alois Hofbauer
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Veronica Rodrigues
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - K. VijayRaghavan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Mani Ramaswami
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Dirk Rieger
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christian Wegener
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Charlotte Förster
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Erich Buchner
- Institute of Clinical Neurobiology, University of Würzburg, Würzburg, Germany
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
- * E-mail:
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18
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19
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Wegener C, Herbert H, Kahnt J, Bender M, Rhea JM. Deficiency of prohormone convertase dPC2 (AMONTILLADO) results in impaired production of bioactive neuropeptide hormones in Drosophila. J Neurochem 2011; 118:581-95. [PMID: 21138435 DOI: 10.1111/j.1471-4159.2010.07130.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Christian Wegener
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.
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20
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Rhea JM, Wegener C, Bender M. The proprotein convertase encoded by amontillado (amon) is required in Drosophila corpora cardiaca endocrine cells producing the glucose regulatory hormone AKH. PLoS Genet 2010; 6:e1000967. [PMID: 20523747 PMCID: PMC2877730 DOI: 10.1371/journal.pgen.1000967] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 04/21/2010] [Indexed: 12/01/2022] Open
Abstract
Peptide hormones are potent signaling molecules that coordinate animal physiology, behavior, and development. A key step in activation of these peptide signals is their proteolytic processing from propeptide precursors by a family of proteases, the subtilisin-like proprotein convertases (PCs). Here, we report the functional dissection of amontillado (amon), which encodes the Drosophila homolog of the mammalian PC2 protein, using cell-type specific inactivation and rescue experiments, and we show that amon is required in the islet-like adipokinetic hormone (AKH)–producing cells that regulate sugar homeostasis. In Drosophila, AKH acts analogously to vertebrate glucagon to increase circulating sugar levels from energy stores, while insulin-like peptides (DILPs) act to decrease sugar levels. amon mutant larvae have significantly reduced hemolymph sugar levels, and thus phenocopy larvae where the AKH–producing cells in the corpora cardiaca have been ablated. Reduction of amon expression in these cells via cell-specific RNA inactivation also results in larvae with reduced sugar levels while expression of amon in AKH cells in an amon mutant background rescues hypoglycemia. Hypoglycemia in larvae resulting from amon RNA inactivation in the AKH cells can be rescued by global expression of the akh gene. Finally, mass spectrometric profiling shows that the production of mature AKH is inhibited in amon mutants. Our data indicate that amon function in the AKH cells is necessary to maintain normal sugar homeostasis, that amon functions upstream of akh, and that loss of mature AKH is correlated with loss of amon activity. These observations indicate that the AKH propeptide is a proteolytic target of the amon proprotein convertase and provide evidence for a conserved role of PC2 in processing metabolic peptide hormones. Peptide hormones are important signaling molecules that coordinate physiology, behavior, and development. A key step in production of peptide hormones is the proteolytic cleavage of larger inactive precursors by prohormone convertases (PCs). Studies in a variety of organisms, including humans, have shown that deficiencies in PC genes lead to complex and detrimental changes. We used fruitfly genetics to dissect the function of Drosophila PC2, encoded by the amon gene, in the regulation of carbohydrate metabolism. We found that amon is expressed in endocrine cells of the corpora cardiaca that produce the sugar-mobilizing adipokinetic hormone (AKH), a functional analog of vertebrate glucagon. Previous studies suggest that the AKH–producing cells are homologs of the glucagon-producing islet alpha-cells in the pancreas. We found that flies with amon deficiency had significantly reduced hemolymph (insect “blood”) sugar levels. Using cell-type specific inactivation and rescue experiments, we show that amon expression in the AKH cells is necessary and sufficient for normal sugar regulation. We also demonstrate that AKH production is inhibited in amon mutants. Our results indicate that amon is necessary to maintain normal hemolymph sugar levels by activating AKH and suggest a conservation of PC2 function in processing peptide hormones between flies and mammals.
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Affiliation(s)
- Jeanne M. Rhea
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Christian Wegener
- Emmy Noether Neuropeptide Group, Department of Animal Physiology, Philipps University, Marburg, Germany
| | - Michael Bender
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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21
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The proprotein convertase amontillado (amon) is required during Drosophila pupal development. Dev Biol 2009; 333:48-56. [PMID: 19559693 DOI: 10.1016/j.ydbio.2009.06.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 05/13/2009] [Accepted: 06/17/2009] [Indexed: 11/20/2022]
Abstract
Peptide hormones governing many developmental processes are generated via endoproteolysis of inactive precursor molecules by a family of subtilisin-like proprotein convertases (SPCs). We previously identified mutations in the Drosophila amontillado (amon) gene, a homolog of the vertebrate neuroendocrine-specific Prohormone Convertase 2 (PC2) gene, and showed that amon is required during embryogenesis, early larval development, and larval molting. Here, we define amon requirements during later developmental stages using a conditional rescue system and find that amon is required during pupal development for head eversion, leg and wing disc extension, and abdominal differentiation. Immuno-localization experiments show that amon protein is expressed in a subset of central nervous system cells but does not co-localize with peptide hormones known to elicit molting behavior, suggesting the involvement of novel regulatory peptides in this process. The amon protein is expressed in neuronal cells that innervate the corpus allatum and corpora cardiaca of the ring gland, an endocrine organ which is the release site for many key hormonal signals. Expression of amon in a subset of these cell types using the GAL4/UAS system in an amon mutant background partially rescues larval molting and growth. Our results show that amon is required for pupal development and identify a subset of neuronal cell types in which amon function is sufficient to rescue developmental progression and growth defects shown by amon mutants. The results are consistent with a model that the amon protein acts to proteolytically process a diverse suite of peptide hormones that coordinate larval and pupal growth and development.
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22
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Künnapuu J, Björkgren I, Shimmi O. The Drosophila DPP signal is produced by cleavage of its proprotein at evolutionary diversified furin-recognition sites. Proc Natl Acad Sci U S A 2009; 106:8501-6. [PMID: 19433798 PMCID: PMC2689000 DOI: 10.1073/pnas.0809885106] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Indexed: 11/18/2022] Open
Abstract
Maturation of bone morphogenetic proteins (BMPs) requires cleavage of their precursor proteins by furin-type proprotein convertases. Here, we find that cleavage sites of the BMP2/4/decapentaplegic (DPP) subfamily have been evolutionary diversified and can be categorized into 4 different types. Cnidaria BMP2/4/DPP is considered to be a prototype containing only 1 furin site. Bilateria BMP2/4/DPP acquired an additional cleavage site with either the combination of minimal-optimal or optimal-optimal furin sites. DPPs belonging to Diptera, such as Drosophila and mosquito, and Lepidoptera of silkworm contain a third cleavage site between the 2 optimal furin sites. We studied how the 3 furin sites (FSI-III) of Drosophila DPP coordinate maturation of ligands and contribute to signals in vivo. Combining mutational analysis of furin-recognition sites and RNAi experiments, we found that the Drosophila DPP precursor is initially cleaved at an upstream furin-recognition site (FSII), with consequent cleavages at 2 furin sites (FSI and FSIII). Both Dfurin1 and Dfurin2 are involved in the processing of DPP proproteins. Biochemical and genetic analyses using cleavage mutants of DPP suggest the first cleavage at FSII to be critical and sufficient for long-range DPP signaling. Our data suggest that the Drosophila DPP precursor is cleaved in a different manner from vertebrate BMP4 even though they are functional orthologs. This indicates that the furin-cleavage sites in BMP2/4/DPP precursors are tolerant to mutations acquired through evolution and have adapted to different systems in diversified species.
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Affiliation(s)
- Jaana Künnapuu
- Institute of Biotechnology, University of Helsinki, P.O. Box 56 Viikinkaari 9, 00014, Helsinki, Finland
| | - Ida Björkgren
- Institute of Biotechnology, University of Helsinki, P.O. Box 56 Viikinkaari 9, 00014, Helsinki, Finland
| | - Osamu Shimmi
- Institute of Biotechnology, University of Helsinki, P.O. Box 56 Viikinkaari 9, 00014, Helsinki, Finland
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23
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Abstract
We used non-invasive muscle imaging to study the onset of motor activity and emergence of coordinated movement in Drosophila embryos. Earliest movements are myogenic, and neurally controlled muscle contractions first appear with the onset of bursting activity 17 hours after egg laying. Initial episodes of activity are poorly organised and coordinated crawling sequences only begin to appear after a further hour of bursting. Thus, network performance improves during this first period of activity. The embryo continues to exhibit bursts of crawling-like sequences until shortly before hatching, while other reflexes also mature. Bursting does not begin as a reflex response to sensory input but appears to reflect the onset of spontaneous activity in the motor network. It does not require GABA-mediated transmission, and, by using a light-activated channel to excite the network, we demonstrate activity-dependent depression that may cause burst termination.
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Affiliation(s)
- Sarah Crisp
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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24
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Pereanu W, Spindler S, Im E, Buu N, Hartenstein V. The emergence of patterned movement during late embryogenesis of Drosophila. Dev Neurobiol 2007; 67:1669-85. [PMID: 17577205 DOI: 10.1002/dneu.20538] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Larval behavioral patterns arise in a gradual fashion during late embryogenesis as the innervation of the somatic musculature and connectivity within the central nervous system develops. In this paper, we describe in a quantitative manner the maturation of behavioral patterns. Early movements are locally restricted "twitches" of the body wall, involving single segments or parts of segments. These twitches occur at a low frequency and have low amplitude, reflecting weak muscle contractions. Towards later stages twitches increase in frequency and amplitude and become integrated into coordinated movements of multiple segments. Most noticeable among these is the peristaltic wave of longitudinal segmental contractions by which the larva moves forward or backward. Besides becoming more complex as development proceeds, embryonic movements also acquire a pronounced rhythm. Thus, late embryonic movements occur in bursts, with phases of frequent movement separated by phases of no movement at all; early movements show no such periodicity. These data will serve as a baseline for future studies that address the function of embryonic lethal genes controlling neuronal connectivity and larval behavior. We have analyzed behavioral abnormalities in two embryonic lethal mutations with severe neural defects, tailless (tll), which lacks the protocerebrum, and glial cells missing (gcm), in which glial cells are absent. Our results reveal prominent alterations in embryonic motility for both of these mutations, indicating that the protocerebrum and glial cells play a crucial role in the neural mechanism controlling larval movement in Drosophila.
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Affiliation(s)
- Wayne Pereanu
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, California 90095, USA
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25
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Husson SJ, Clynen E, Baggerman G, Janssen T, Schoofs L. Defective processing of neuropeptide precursors in Caenorhabditis elegans lacking proprotein convertase 2 (KPC-2/EGL-3): mutant analysis by mass spectrometry. J Neurochem 2006; 98:1999-2012. [PMID: 16945111 DOI: 10.1111/j.1471-4159.2006.04014.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biologically active peptides are synthesized as larger inactive proprotein peptide precursors which are processed by the concerted action of a cascade of enzymes. Among the proprotein convertases, PC2 is widely expressed in neuro-endocrine tissues and has been proposed to be the major convertase involved in the biosynthesis of neuropeptides. In this study, we have examined the role of the Caenorhabditis elegans orthologue PC2/EGL-3 in the processing of proprotein peptide precursors. We recently isolated and identified 60 endogenous peptides in the nematode C. elegans by two-dimensional nanoscale liquid chromatography - quadrupole time-of-flight tandem mass spectrometry. In the present study, we compare the peptide profile of different C. elegans strains, including PC2/EGL-3 mutants. For this purpose, we used an offline approach in which HPLC fractions are analysed by a matrix-assisted laser desorption ionisation - time of flight mass spectrometer. This differential peptidomic approach unambiguously provides evidence for the role of PC2/EGL-3 in the processing of FMRFamide-like peptide (FLP) precursors and neuropeptide-like protein (NLP) precursors in nematodes.
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Affiliation(s)
- Steven J Husson
- Laboratory of Developmental Physiology, Genomics and Proteomics, Katholieke Universiteit Leuven, Leuven, Belgium.
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26
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Gauthier SA, Hewes RS. Transcriptional regulation of neuropeptide and peptide hormone expression by the Drosophila dimmed and cryptocephal genes. ACTA ACUST UNITED AC 2006; 209:1803-15. [PMID: 16651547 DOI: 10.1242/jeb.02202] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The regulation of neuropeptide and peptide hormone gene expression is essential for the development and function of neuroendocrine cells in integrated physiological networks. In insects, a decline in circulating ecdysteroids triggers the activation of a neuroendocrine system to stimulate ecdysis, the behaviors used to shed the old cuticle at the culmination of each molt. Here we show that two evolutionarily conserved transcription factor genes, the basic helix-loop-helix (bHLH) gene dimmed (dimm) and the basic-leucine zipper (bZIP) gene cryptocephal (crc), control expression of diverse neuropeptides and peptide hormones in Drosophila. Central nervous system expression of three neuropeptide genes, Dromyosuppressin, FMRFamide-related and Leucokinin, is activated by dimm. Expression of Ecdysis triggering hormone (ETH) in the endocrine Inka cells requires crc; homozygous crc mutant larvae display markedly reduced ETH levels and corresponding defects in ecdysis. crc activates ETH expression though a 382 bp enhancer, which completely recapitulates the ETH expression pattern. The enhancer contains two evolutionarily conserved regions, and both are imperfect matches to recognition elements for activating transcription factor-4 (ATF-4), the vertebrate ortholog of the CRC protein and an important intermediate in cellular responses to endoplasmic reticulum stress. These regions also contain a putative ecdysteroid response element and a predicted binding site for the products of the E74 ecdysone response gene. These results suggest that convergence between ATF-related signaling and an important intracellular steroid response pathway may contribute to the neuroendocrine regulation of insect molting.
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Affiliation(s)
- Sebastien A Gauthier
- Department of Zoology, Stephenson Research and Technology Center, University of Oklahoma, Norman, OK 73019, USA.
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27
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Sidyelyeva G, Baker NE, Fricker LD. Characterization of the molecular basis of the Drosophila mutations in carboxypeptidase D. Effect on enzyme activity and expression. J Biol Chem 2006; 281:13844-13852. [PMID: 16556608 DOI: 10.1074/jbc.m513499200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carboxypeptidase D (CPD) functions in the processing of proteins and peptides in the secretory pathway. Drosophila CPD is encoded by the silver gene (svr), which is differentially spliced to produce long transmembrane protein forms with three metallocarboxypeptidase (CP)-like domains and short soluble forms with a single CP domain. Many svr mutants have been reported, but the precise molecular defects have not been previously determined. In the present study, three mutant lines were characterized. svr (PG33) mutants do not survive past the early larval stage. These mutants have a P-element insertion within exon 1B upstream of the initiation ATG, which greatly reduces mRNA levels of all forms of CPD. Both svr (1) and svr (poi) mutants are viable, with a silvery body color and pointed wings. The wing shape is generally similar between these two mutants, although svr (poi) mutants have smaller wings. The svr (1) gene has a three-nucleotide deletion in exon 6, removing a leucine in a region of the protein predicted to function as a folding domain for the second CP-like domain. svr (poi) has a 1072-bp duplication of the gene that introduces a stop codon into the open reading frame, causing the truncation of the protein in the middle of the second CP-like domain. Both deletions eliminate enzyme activity of the second CP-like domain and appear to cause the misfolding of the protein. This greatly reduces the levels of the long forms of CPD protein but do not affect the levels of the short forms. Taken together, these findings suggest that lethal and viable svr alleles differ in which protein forms are affected. Flies that retain the short form are viable, whereas flies that are missing all forms of CPD do not survive past the early larval stages.
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Affiliation(s)
- Galyna Sidyelyeva
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Nicholas E Baker
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461.
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28
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Reichhart JM. Tip of another iceberg: Drosophila serpins. Trends Cell Biol 2005; 15:659-65. [PMID: 16260136 DOI: 10.1016/j.tcb.2005.10.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 08/05/2005] [Accepted: 10/03/2005] [Indexed: 11/20/2022]
Abstract
Serpins are serine protease inhibitors with a conserved structure that have been identified in nearly all species and act as suicide substrates by binding covalently to their target proteases. Serpins regulate various physiological processes and defence mechanisms. In humans, several serpin mutations are linked to diseases. The genome of Drosophila melanogaster encodes 29 serpins and even more serine proteases. To date, three serpins have been investigated in detail. Spn27A controls the Toll pathway during early development and is involved in defence reactions in adult flies. SPN42DaA is an inhibitor of furin, a subtilisin-like convertase that is required for pro-protein maturation. Spn43Ac controls the Toll pathway during the immune response. In each case, Drosophila genetics has shed new light on the function of these serine protease inhibitors.
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Affiliation(s)
- Jean-Marc Reichhart
- Institut de Biologie Moléculaire et Cellulaire, UPR 9022 du CNRS, 15 rue Rene Descartes, F67084 Strasbourg Cedex, France.
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29
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Clermont A, Wedde M, Seitz V, Podsiadlowski L, Lenze D, Hummel M, Vilcinskas A. Cloning and expression of an inhibitor of microbial metalloproteinases from insects contributing to innate immunity. Biochem J 2005; 382:315-22. [PMID: 15115439 PMCID: PMC1133944 DOI: 10.1042/bj20031923] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Revised: 04/22/2004] [Accepted: 04/28/2004] [Indexed: 11/17/2022]
Abstract
The first IMPI (inhibitor of metalloproteinases from insects) was identified in the greater wax moth, Galleria mellonella [Wedde, Weise, Kopacek, Franke and Vilcinskas (1998) Eur. J. Biochem. 255, 535-543]. Here we report cloning and expression of a cDNA coding for this IMPI. The IMPI mRNA was identified among the induced transcripts from a subtractive and suppressive PCR analysis after bacterial challenge of G. mellonella larvae. Induced expression of the IMPI during a humoral immune response was confirmed by real-time PCR, which documented up to 500 times higher amounts of IMPI mRNA in immunized larvae in comparison with untreated ones. The IMPI sequence shares no similarity with those of tissue inhibitors of metalloproteinases or other natural inhibitors of metalloproteinases, and the recombinant IMPI specifically inhibits thermolysin-like metalloproteinases, but not matrix metalloproteinases. These results support the hypothesis that the IMPI represents a novel type of immune-related protein which is induced and processed during the G. mellonella humoral immune response to inactivate pathogen-associated thermolysin-like metalloproteinases.
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Affiliation(s)
- Anja Clermont
- Institute of Pathology, Benjamin-Franklin-Hospital, Free University of Berlin, Hindenburgdamm 30, 12200 Berlin, Germany.
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30
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Oley M, Letzel MC, Ragg H. Inhibition of furin by serpin Spn4A from Drosophila melanogaster. FEBS Lett 2005; 577:165-9. [PMID: 15527779 DOI: 10.1016/j.febslet.2004.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 09/20/2004] [Accepted: 10/01/2004] [Indexed: 11/17/2022]
Abstract
The serpin gene Spn4 from Drosophila melanogaster encodes multiple isoforms with alternative reactive site loops (RSL). Here, we show that isoform Spn4A inhibits human furin with an apparent kassoc of 5.5 x 10(6) M(-1) s(-1). The serpin forms SDS-stable complexes with the enzyme and the RSL of Spn4A is cleaved C-terminally to the sequence -Arg-Arg-Lys-Arg/ in accord with the recognition/cleavage site of furin. Immunofluorescence studies show that Spn4A is localized in the endoplasmic reticulum (ER), suggesting that the inhibitor is an interesting tool for investigating the cellular mechanisms regulating furin and for the design of agents controlling prohormone convertases.
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Affiliation(s)
- Mareke Oley
- Department of Biotechnology, Faculty of Technology, University of Bielefeld, D-33501 Bielefeld, Germany
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31
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Ogiwara K, Shinohara M, Takahashi T. Expression of proprotein convertase 2 mRNA in the ovarian follicles of the medaka, Oryzias latipes. Gene 2004; 337:79-89. [PMID: 15276204 DOI: 10.1016/j.gene.2004.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 03/29/2004] [Accepted: 04/13/2004] [Indexed: 12/01/2022]
Abstract
Proprotein convertases (PCs) are enzymes responsible for processing the precursors of many bioactive peptides in vertebrates and invertebrates. In the present study, a cDNA for proprotein convertase 2 (PC2) was cloned for the first time from a fish. The clone, which was isolated from the ovary of the medaka, Oryzias latipes, by a combination of RT-PCR cloning and 5'- and 3'-rapid amplification of cDNA ends, codes for a protein of 641 amino acid residues highly homologous to other vertebrate PC2. The medaka preproPC2 consists of a signal sequence, a propeptide with sites for autocatalytic activation, a Kex2-like catalytic domain, and a P-domain. The catalytic triad residues (Asp-169, His-210, and Ser-386) were all conserved. Northern blot analysis revealed that PC2 was expressed in the brain, ovary, and kidney of the fish. The size of PC2 mRNA expressed in the ovary was 2.3 kb, whereas those of the brain and kidney were 2.8 kb. This size difference was attributed to the lack of an approximately 300-bp nucleotide sequence just before the poly(A)+ tail of the ovarian PC2 mRNA. Ovarian expression of the PC2 gene was found in the medaka but not in the mouse, and therefore further analysis was conducted for the fish ovary. The greatest expression of PC2 mRNA in the oocytes of small growing follicles in the mature medaka was demonstrated by Northern blotting, RT-PCR and in situ hybridization analysis. These results suggest that PC2 may play a role in the processing of proproteins and/or pro-hormones expressed in the growing oocytes.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Male
- Molecular Sequence Data
- Oryzias/genetics
- Ovarian Follicle/enzymology
- Ovarian Follicle/growth & development
- Ovarian Follicle/metabolism
- Proprotein Convertase 2/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- Katsueki Ogiwara
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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32
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Rozan L, Krysan DJ, Rockwell NC, Fuller RS. Plasticity of Extended Subsites Facilitates Divergent Substrate Recognition by Kex2 and Furin. J Biol Chem 2004; 279:35656-63. [PMID: 15159396 DOI: 10.1074/jbc.m405362200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yeast Kex2 and human furin are subtilisin-related proprotein convertases that function in the late secretory pathway and exhibit similar though distinguishable patterns of substrate recognition. Although both enzymes prefer Arg at P(1) and basic residues at P(2), the two differ in recognition of P(4) and P(6) residues. To probe P(4) and P(6) recognition by Kex2p, furin-like substitutions were made in the putative S(4) and S(6) subsites of Kex2. T252D and Q283E mutations were introduced to increase the preference for Arg at P(4) and P(6), respectively. Glu(255) was replaced with Ile to limit recognition of P(4) Arg. The effects of putative S(4) and S(6) mutations were determined by examining the cleavage by purified mutant enzymes of a series of fluorogenic substrates with systematic changes in P(4) and/or P(6). Whereas wild Kex2 exhibited little preference type for Arg at P(6), the T252D mutant and T252D/Q283E double mutant exhibited clear interactions with P(6) Arg. Moreover, the T252D and T252D/Q283E substitutions altered the influence of the P(6) residue on P(4) recognition. We infer that cross-talk between S(4) and S(6), not seen in furin, allows wild type and mutant forms of Kex2 to adapt their subsites for altered modes of recognition. This apparent plasticity may allow the subsites to rearrange their local environment to interact with different substrates in a productive manner. E255I-Kex2 exhibited significantly decreased recognition of P(4) Arg in a tetrapeptide substrate with Lys at P(1), although the general pattern of selectivity for aliphatic residues at P(4) remained unchanged.
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Affiliation(s)
- Laura Rozan
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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33
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Richer MJ, Keays CA, Waterhouse J, Minhas J, Hashimoto C, Jean F. The Spn4 gene of Drosophila encodes a potent furin-directed secretory pathway serpin. Proc Natl Acad Sci U S A 2004; 101:10560-5. [PMID: 15247425 PMCID: PMC489976 DOI: 10.1073/pnas.0401406101] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Proprotein convertases (PCs) are an important class of host-cell serine endoproteases implicated in many physiological and pathological processes. Owing to their expanding roles in the proteolytic events required for generating infectious microbial pathogens and for tumor growth and invasiveness, there is increasing interest in identifying endogenous PC inhibitors. Here we report the identification of Spn4A, a previously uncharacterized secretory pathway serine protease inhibitor (serpin) from Drosophila melanogaster that contains a consensus furin cleavage site, -Arg(P4)-Arg-Lys-Arg(P1) downsream-, in its reactive site loop (RSL). Our biochemical and kinetics analysis revealed that recombinant Spn4A inhibits human furin (K(i), 13 pM; k(ass), 3.2 x 10(7) M(-1) x s(-1)) and Drosophila PC2 (K(i), 3.5 nM; k(ass), 9.2 x 10(4) M(-1) x s(-1)) by a slow-binding mechanism characteristic of serpin molecules and forms a kinetically trapped SDS-stable complex with each enzyme. For both PCs, the stoichiometry of inhibition by Spn4A is nearly 1, which is characteristic of known physiological serpin-protease interactions. Mass analysis of furin-Spn4A reaction products identified the actual reactive site center of Spn4A to be -Arg(P4)-Arg-Lys-Arg(P1)-downstream-. Moreover, we demonstrate that Spn4A's highly effective PC inhibition properties are critically dependent on the unusual length of its RSL, which is composed of 18 aa instead of the typical 17-residue RSL found in most other inhibitory serpins. The identification of Spn4A, the most potent and effective natural serpin of PCs identified to date, suggests that Spn4A could be a prototype of endogenous serpins involved in the precise regulation of PC-dependent proteolytic cleavage events in the secretory pathway of eukaryotic cells.
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Affiliation(s)
- Martin J Richer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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34
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Park D, Han M, Kim YC, Han KA, Taghert PH. Ap-let neurons--a peptidergic circuit potentially controlling ecdysial behavior in Drosophila. Dev Biol 2004; 269:95-108. [PMID: 15081360 DOI: 10.1016/j.ydbio.2004.01.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Revised: 01/14/2004] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
Here we describe a novel set of peptidergic neurons conserved throughout all developmental stages in the Drosophila central nervous system (CNS). We show that a small complement of 28 apterous-expressing cells (Ap-let neurons) in the ventral nerve cord (VNC) of Drosophila larvae co-express numerous gene products. The products include the neuroendocrine-specific bHLH regulator called Dimmed (Dimm), four neuropeptide biosynthetic enzymes (PC2, Fur1, PAL2, and PHM), and a specific dopamine receptor subtype (dDA1). For the PC2, Fur1, and PAL2 enzymes, and for the dDA1 receptor, this neuronal pattern represents the vast majority of their total expression in the VNC. In addition, while Dimm and PHM are present in the peritracheal Inka cells in larvae, pupae, and adults, Ap, PC2, Fur1, PAL2, and dDA1 are not. PC2, PAL2, and DA1 receptor expression were all controlled by both dimm and ap. Previous genetic analysis of animals deficient in PC2 revealed an abnormal larval ecdysis phenotype. Together, these data support the hypothesis that the small cohort of Ap-let interneurons regulates larval ecdysis behavior by secretion of an unidentified amidated peptide(s). This hypothesis further predicts that the production of the Ap-let neuropeptide(s) is dependent on each of four specific enzymes, and that a certain aspect(s) of its production and/or release is regulated by dopamine input.
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Affiliation(s)
- Dongkook Park
- Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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35
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Caldwell JC, Miller MM, Wing S, Soll DR, Eberl DF. Dynamic analysis of larval locomotion in Drosophila chordotonal organ mutants. Proc Natl Acad Sci U S A 2003; 100:16053-8. [PMID: 14673076 PMCID: PMC307691 DOI: 10.1073/pnas.2535546100] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Accepted: 10/09/2003] [Indexed: 11/18/2022] Open
Abstract
Rhythmic movements, such as peristaltic contraction, are initiated by output from central pattern generator (CPG) networks in the CNS. These oscillatory networks elicit locomotion in the absence of external sensory or descending inputs, but CPG circuits produce more directed and behaviorally relevant movement via peripheral nervous system (PNS) input. Drosophila melanogaster larval locomotion results from patterned muscle contractions moving stereotypically along the body segments, but without PNS feedback, contraction of body segments is uncoordinated. We have dissected the role of a subset of mechanosensory neurons in the larval PNS, the chordotonal organs (chos), in providing sensory feedback to the locomotor CPG circuit with dias (Dynamic Image Analysis System) software. We analyzed mutants carrying cho mutations including atonal, a cho proneural gene, beethoven, a cho cilia class mutant, smetana and touch-insensitive larva B, two axonemal mutants, and 5D10, a weak cho mutant. All cho mutants have defects in gross path morphology compared to controls. These mutants exhibit increased frequency and duration of turning (decision-making) and reduced duration of linear locomotion. Furthermore, cho mutants affect locomotor parameters, including reduced average speed, direction change, and persistence. Dias analysis of peristaltic waves indicates that mutants exhibit reduced average speed, positive flow and negative flow, and increased stride period. Thus, cho sensilla are major proprioceptive components that underlie touch sensitivity, locomotion, and peristaltic contraction by providing sensory feedback to the locomotor CPG circuit in larvae.
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Affiliation(s)
- Jason C Caldwell
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
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36
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Landgraf M, Jeffrey V, Fujioka M, Jaynes JB, Bate M. Embryonic origins of a motor system: motor dendrites form a myotopic map in Drosophila. PLoS Biol 2003; 1:E41. [PMID: 14624243 PMCID: PMC261881 DOI: 10.1371/journal.pbio.0000041] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 08/25/2003] [Indexed: 11/19/2022] Open
Abstract
The organisational principles of locomotor networks are less well understood than those of many sensory systems, where in-growing axon terminals form a central map of peripheral characteristics. Using the neuromuscular system of the Drosophila embryo as a model and retrograde tracing and genetic methods, we have uncovered principles underlying the organisation of the motor system. We find that dendritic arbors of motor neurons, rather than their cell bodies, are partitioned into domains to form a myotopic map, which represents centrally the distribution of body wall muscles peripherally. While muscles are segmental, the myotopic map is parasegmental in organisation. It forms by an active process of dendritic growth independent of the presence of target muscles, proper differentiation of glial cells, or (in its initial partitioning) competitive interactions between adjacent dendritic domains. The arrangement of motor neuron dendrites into a myotopic map represents a first layer of organisation in the motor system. This is likely to be mirrored, at least in part, by endings of higher-order neurons from central pattern-generating circuits, which converge onto the motor neuron dendrites. These findings will greatly simplify the task of understanding how a locomotor system is assembled. Our results suggest that the cues that organise the myotopic map may be laid down early in development as the embryo subdivides into parasegmental units.
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Affiliation(s)
- Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom.
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37
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Taylor CAM, Winther AME, Siviter RJ, Shirras AD, Isaac RE, Nässel DR. Identification of a proctolin preprohormone gene (Proct) ofDrosophila melanogaster: Expression and predicted prohormone processing. ACTA ACUST UNITED AC 2003; 58:379-91. [PMID: 14750150 DOI: 10.1002/neu.10301] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Proctolin was the first insect neuropeptide to be sequenced and has been the subject of many physiological and pharmacological studies in insects and crustaceans. We have identified a Drosophila gene (CG7105, Proct) encoding a precursor protein containing the neuropeptide proctolin (RYLPT). In situ hybridization with a riboprobe to the Proct gene revealed a distribution of transcript in neurons of the larval central nervous system (CNS) matching that seen with antiserum to proctolin. An antiserum raised to a sequence in the precursor downstream of proctolin labeled the same neurons as those seen with the antiproctolin antisera. The predicted protein encoded by Proct has a single copy of the RYLPT sequence that directly follows the predicted signal peptidase cleavage point and precedes a consensus recognition site for a furinlike processing endoprotease. Ectopic expression of Proct in the CNS and midgut via the GAL4-UAS system, using an Actin5C-GAL4 driver, confirmed that the predicted preproproctolin can be processed to generate immunoreactive proctolin peptide. Pupae over-expressing Proct displayed a 14% increase in heart rate, providing evidence in support of a cardioacceleratory endocrine function for proctolin in Drosophila. The distribution of proctolin suggests roles as a neuromodulator in motoneurons and interneurons, and as a neurohormone that could be released from brain neurosecretory cells with terminations in the ring gland.
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38
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Czyzyk TA, Morgan DJ, Peng B, Zhang J, Karantzas A, Arai M, Pintar JE. Targeted mutagenesis of processing enzymes and regulators: Implications for development and physiology. J Neurosci Res 2003; 74:446-55. [PMID: 14598321 DOI: 10.1002/jnr.10792] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Traci A Czyzyk
- Department of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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39
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Affiliation(s)
- Paul H Taghert
- Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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40
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Lesage G, Guimond J, Boileau G. trans-Complementation assay establishes the role of proregion hydrophobic amino acid residues in the biosynthesis of Saccharomyces cerevisiae Kex2p endoprotease. Yeast 2003; 20:397-406. [PMID: 12673623 DOI: 10.1002/yea.972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proregion of Saccharomyces cerevisiae endoprotease Kex2p is essential for the biosynthesis of an active enzyme. It has been suggested that the proregion acts in the endoplasmic reticulum to catalyse folding of the enzyme. To identify amino acid residues important for proregion function, we used an in vivo system in which the Kex2p proregion can act in trans to activate a Kex2p enzyme synthesized without its proregion. Activation of Kex2p by wild-type and mutated proregions revealed the essential role of hydrophobic residues F(37), V(39) and F(70) in enzyme activation. Further exploration of the role of these residues by in vitro inhibition of Kex2p activity by its proregion indicated that they are essential to form the proregion/enzyme bimolecular complex. In contrast, basic residues K(108) and R(109), located in the C-terminus of the proregion, are not involved in complex formation but are necessary for the biosynthesis of an active enzyme.
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Affiliation(s)
- Guillaume Lesage
- Département de Biochimie, Université de Montréal, Montréal (Québec) H3C 3J7, Canada
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41
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Jacob TC, Kaplan JM. The EGL-21 carboxypeptidase E facilitates acetylcholine release at Caenorhabditis elegans neuromuscular junctions. J Neurosci 2003; 23:2122-30. [PMID: 12657671 PMCID: PMC6742027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Proneuropeptides are packaged into dense-core vesicles in which they are processed into active peptides by copackaged enzymes. Proprotein convertases (PCs) cleave precursors after dibasic residues, and carboxypeptidases remove basic residues from the C terminals. We show here that the Caenorhabditis elegans egl-21 gene encodes a protein that is very similar to carboxypeptidase E (CPE) and is broadly expressed in the nervous system. Mutants lacking either egl-21 CPE or egl-3, which encodes the C. elegans ortholog of PC type 2 (PC2), were defective for processing endogenously expressed FMRFamide (Phe-Met-Arg-Phe-NH2)-related peptides (FaRPs). Mutants lacking the unc-104 kinesin motor protein were defective for anterograde movement of dense-core vesicle components, including egl-3 PC2, egl-21 CPE, and FaRPs. We provide evidence that egl-3 PC2 and egl-21 CPE mutants have diminished acetylcholine release at neuromuscular junctions (NMJs). Taken together, these results suggest that egl-21 CPE and egl-3 PC2 process endogenous neuropeptides that facilitate acetylcholine release at C. elegans NMJs.
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Affiliation(s)
- Tija C Jacob
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California 94720, USA
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Rayburn LYM, Gooding HC, Choksi SP, Maloney D, Kidd AR, Siekhaus DE, Bender M. amontillado, the Drosophila homolog of the prohormone processing protease PC2, is required during embryogenesis and early larval development. Genetics 2003; 163:227-37. [PMID: 12586710 PMCID: PMC1462398 DOI: 10.1093/genetics/163.1.227] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Biosynthesis of most peptide hormones and neuropeptides requires proteolytic excision of the active peptide from inactive proprotein precursors, an activity carried out by subtilisin-like proprotein convertases (SPCs) in constitutive or regulated secretory pathways. The Drosophila amontillado (amon) gene encodes a homolog of the mammalian PC2 protein, an SPC that functions in the regulated secretory pathway in neuroendocrine tissues. We have identified amon mutants by isolating ethylmethanesulfonate (EMS)-induced lethal and visible mutations that define two complementation groups in the amon interval at 97D1 of the third chromosome. DNA sequencing identified the amon complementation group and the DNA sequence change for each of the nine amon alleles isolated. amon mutants display partial embryonic lethality, are defective in larval growth, and arrest during the first to second instar larval molt. Mutant larvae can be rescued by heat-shock-induced expression of the amon protein. Rescued larvae arrest at the subsequent larval molt, suggesting that amon is also required for the second to third instar larval molt. Our data indicate that the amon proprotein convertase is required during embryogenesis and larval development in Drosophila and support the hypothesis that AMON acts to proteolytically process peptide hormones that regulate hatching, larval growth, and larval ecdysis.
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Affiliation(s)
- Lowell Y M Rayburn
- Department of Genetics, The University of Georgia, Athens, Georgia 30602-7223, USA
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43
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Rockwell NC, Krysan DJ, Komiyama T, Fuller RS. Precursor processing by kex2/furin proteases. Chem Rev 2002; 102:4525-48. [PMID: 12475200 DOI: 10.1021/cr010168i] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nathan C Rockwell
- Department of Biological Chemistry, University of Michigan Medical Center, Room 5413 Med Sci I, 1301 East Catherine, Ann Arbor Michigan 48109, USA
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Andrews HK, Zhang YQ, Trotta N, Broadie K. Drosophila sec10 is required for hormone secretion but not general exocytosis or neurotransmission. Traffic 2002; 3:906-21. [PMID: 12453153 DOI: 10.1034/j.1600-0854.2002.31206.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The sec6/8, or exocyst, complex is implicated in trafficking of secretory vesicles to fusion sites in the plasma membrane. Genetic analyses have been done primarily in yeast, where mutation of the eight protein subunits similarly disrupts polarized vesicle fusion. The goal of this study was to assay the sec6/8 complex in Drosophila, and specifically to test its widely hypothesized functions in synaptogenesis and neurotransmission. We used a transgenic RNAi approach to remove the most highly conserved complex component, Drosophila sec10 (dSec10). Ubiquitous dSec10 RNAi resulted in early postembryonic lethality, demonstrating that dSec10 is essential. Surprisingly, tissue-specific dSec10 RNAi revealed no essential requirement in nervous system, musculature, gut or epidermis. Assays of polarized secretion in all these tissues failed to reveal any role for dSec10. In particular, the neuromuscular synapse showed no defects in morphogenesis or vesicle trafficking/fusion underlying neurotransmission. The essential requirement for dSec10 was restricted to the ring gland, the Drosophila organ specialized for endocrine function. The developmental arrest of dSec10 RNAi animals was partially rescued by feeding ecdysone, suggesting dSec10 mediates steroid hormone secretion. We conclude that dSec10 has no detectable role in most forms of polarized trafficking/exocytosis, including neurotransmission, but rather is essential for endocrine secretion.
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Affiliation(s)
- Hillary K Andrews
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA
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Meng X, Wahlström G, Immonen T, Kolmer M, Tirronen M, Predel R, Kalkkinen N, Heino TI, Sariola H, Roos C. The Drosophila hugin gene codes for myostimulatory and ecdysis-modifying neuropeptides. Mech Dev 2002; 117:5-13. [PMID: 12204246 DOI: 10.1016/s0925-4773(02)00175-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In a genomic screen we isolated the Drosophila gene hugin (hug, cytology 87C1-2) by cross-hybridisation to a human glial cell line-derived neurotrophic factor cDNA. Upon cDNA sequence analysis and in vitro expression assays, the hugin gene was found to encode a signal peptide containing proprotein that was further processed in Schneider-2 cells into peptides similar to known neuropeptides. Two of the peptides were similar to FXPRL-amides (pyrokinins) and to the ecdysis-triggering hormone, respectively. The former displayed myostimulatory activity in a bioassay on the cockroach hyperneural muscle preparation, as well as in the Drosophila heart muscle assay. Hugin is expressed during the later half of embryogenesis and during larval stages in a subgroup of neurosecretory cells of the suboesophageal ganglion. Ubiquitous ectopic hugin expression resulted in larval death predominantly at or shortly after ecdysis from second to third instar, suggesting that at least one of the posttranslational cleavage products affects molting of the larva by interfering with the regulation of ecdysis.
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Affiliation(s)
- Xiaojuan Meng
- Developmental Biology Program, Institute of Biotechnology, Viikki Biocenter, PB 56, FIN-00014 University of Helsinki, Finland
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Kovaleva ES, Yakovlev AG, Masler EP, Chitwood DJ. Human proprotein convertase 2 homologue from a plant nematode: cloning, characterization, and comparison with other species. FASEB J 2002; 16:1099-101. [PMID: 12039853 DOI: 10.1096/fj.01-0940fje] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Proprotein convertases (PCs) are evolutionarily conserved enzymes responsible for processing the precursors of many bioactive peptides in mammals. The invertebrate homologues of PC2 play important roles during development that makes the enzyme a good target for practical applications in pest management. Screening of a plant nematode Heterodera glycines cDNA library resulted in isolation of a full-length clone encoding a PC2-like precursor. The deduced protein (74.2 kD) exhibits strong amino acid homology to all known PC2s, including human, and shares the main structural characteristics: signal peptide; prosegment; catalytic domain, with D/H/S catalytic triad, PC2-specific residues, and 7B2 binding sites; P domain (with RRGDT pentapeptide); and carboxyl terminus. Comparative analysis of PC2s from 15 species discloses the presence of an insert in the catalytic domain unique to nematodes. Expression of PC2-like mRNA found in eggs and juveniles was undetectable in adult stages of H. glycines. Nucleotide analysis reveals distinctive differences in base composition and codon usage between H. glycines and Caenorhabditis elegans PC2s. The H. glycines cDNA clone encoding PC2 is the first one isolated from plant-parasitic nematodes.
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Affiliation(s)
- Elena S Kovaleva
- Nematology Laboratory, USDA, ARS/PSI, Beltsville, Maryland 20705-2350, USA.
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Abstract
Pro-hormone convertases PC1 and PC2 perform endoproteolytic cleavages of precursors in peptide-containing secretory granules. PC1 and PC2 are soluble, secreted with bioactive peptides. Evolutionarily related PCs have membrane tethers, not secreted. We tethered PC1 to the transmembrane-cytoplasmic domains (CD) of a granule enzyme (peptidylglycine-alpha-amidating monooxygenase; PAM) and Golgi-localized PC8. The tethered PC1 is far more stable to elevated temperature and denaturants than soluble PC1, and more active. Both tethers allow PC1 to visit the cell surface transiently, cleaving soluble molecules outside the cell. Both membrane-bound PC1 chimeras cleave membrane PAM into soluble active fragments when PAM is expressed on adjacent cells.
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Affiliation(s)
- Angela Bruzzaniti
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Abstract
Locomotion depends on the integration of sensory information with the activity of central circuitry, which generates patterned discharges in motor nerves to appropriate muscles. Isolated central networks generate fictive locomotor rhythms (recorded in the absence of movement), indicating that the fundamental pattern of motor output depends on the intrinsic connectivity and electrical properties of these central circuits. Sensory inputs are required to modify the pattern of motor activity in response to the actual circumstances of real movement. A central issue for our understanding of how locomotor circuits are specified and assembled is the extent to which sensory inputs are required as such systems develop. Here we describe the effects of eliminating sensory function and structure on the development of the peristaltic motor pattern of Drosophila embryos and larvae. We infer that the circuitry for peristaltic crawling develops in the complete absence of sensory input; however, the integration of this circuitry into actual patterns of locomotion requires additional information from the sensory system. In the absence of sensory inputs, the polarity of movement is deranged, and backward peristaltic waves predominate at the expense of forward peristalsis.
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Steiner DF. The Prohormone Convertases and Precursor Processing in Protein Biosynthesis. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1874-6047(02)80008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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50
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Kass J, Jacob TC, Kim P, Kaplan JM. The EGL-3 proprotein convertase regulates mechanosensory responses of Caenorhabditis elegans. J Neurosci 2001; 21:9265-72. [PMID: 11717360 PMCID: PMC6763909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Neuroactive peptides are packaged as proproteins into dense core vesicles or secretory granules, where they are cleaved at dibasic residues by copackaged proprotein convertases. We show here that the Caenorhabditis elegans egl-3 gene encodes a protein that is 57% identical to mouse proprotein convertase type 2 (PC2), and we provide evidence that this convertase regulates mechanosensory responses. Nose touch sensitivity (mediated by ASH sensory neurons) is defective in mutants lacking GLR-1 glutamate receptors (GluRs); however, mutations eliminating the egl-3 PC2 restored nose touch sensitivity to glr-1 GluR mutants. By contrast, body touch sensitivity (mediated by the touch cells) is greatly diminished in egl-3 PC2 mutants. Taken together, these results suggest that egl-3 PC2-processed peptides normally regulate the responsiveness of C. elegans to mechanical stimuli.
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Affiliation(s)
- J Kass
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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