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Gaspar CJ, Gomes T, Martins JC, Melo MN, Adrain C, Cordeiro TN, Domingos PM. Xport-A functions as a chaperone by stabilizing the first five transmembrane domains of rhodopsin-1. iScience 2023; 26:108309. [PMID: 38025784 PMCID: PMC10663829 DOI: 10.1016/j.isci.2023.108309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 04/21/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Rhodopsin-1 (Rh1), the main photosensitive protein of Drosophila, is a seven-transmembrane domain protein, which is inserted co-translationally in the endoplasmic reticulum (ER) membrane. Biogenesis of Rh1 occurs in the ER, where various chaperones interact with Rh1 to aid in its folding and subsequent transport from the ER to the rhabdomere, the light-sensing organelle of the photoreceptors. Xport-A has been proposed as a chaperone/transport factor for Rh1, but the exact molecular mechanism for Xport-A activity upon Rh1 is unknown. Here, we propose a model where Xport-A functions as a chaperone during the biogenesis of Rh1 in the ER by stabilizing the first five transmembrane domains (TMDs) of Rh1.
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Affiliation(s)
- Catarina J. Gaspar
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
- Membrane Traffic Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
| | - Tiago Gomes
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
| | - Joana C. Martins
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
| | - Manuel N. Melo
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
| | - Colin Adrain
- Membrane Traffic Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
- Patrick G Johnston Centre for Cancer Research, Queen’s University Belfast, 97 Lisburn Road, BT9 7AE Belfast, UK
| | - Tiago N. Cordeiro
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
| | - Pedro M. Domingos
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157 Oeiras, Portugal
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2
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Zhao N, Li N, Wang T. PERK prevents rhodopsin degradation during retinitis pigmentosa by inhibiting IRE1-induced autophagy. J Cell Biol 2023; 222:e202208147. [PMID: 37022709 PMCID: PMC10082367 DOI: 10.1083/jcb.202208147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 04/07/2023] Open
Abstract
Chronic endoplasmic reticulum (ER) stress is the underlying cause of many degenerative diseases, including autosomal dominant retinitis pigmentosa (adRP). In adRP, mutant rhodopsins accumulate and cause ER stress. This destabilizes wild-type rhodopsin and triggers photoreceptor cell degeneration. To reveal the mechanisms by which these mutant rhodopsins exert their dominant-negative effects, we established an in vivo fluorescence reporter system to monitor mutant and wild-type rhodopsin in Drosophila. By performing a genome-wide genetic screen, we found that PERK signaling plays a key role in maintaining rhodopsin homeostasis by attenuating IRE1 activities. Degradation of wild-type rhodopsin is mediated by selective autophagy of ER, which is induced by uncontrolled IRE1/XBP1 signaling and insufficient proteasome activities. Moreover, upregulation of PERK signaling prevents autophagy and suppresses retinal degeneration in the adRP model. These findings establish a pathological role for autophagy in this neurodegenerative condition and indicate that promoting PERK activity could be used to treat ER stress-related neuropathies, including adRP.
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Affiliation(s)
- Ning Zhao
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Ning Li
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Tao Wang
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- College of Biological Sciences, China Agricultural University, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
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3
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Liu D, De Schutter K, Far J, Staes A, Dewettinck K, Quinton L, Gevaert K, Smagghe G. RNAi of Mannosidase-Ia in the Colorado potato beetle and changes in the midgut and peritrophic membrane. PEST MANAGEMENT SCIENCE 2022; 78:5071-5079. [PMID: 36053804 DOI: 10.1002/ps.7145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/03/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND In addition to its role in the digestive system, the peritrophic membrane (PM) provides a physical barrier protecting the intestine from abrasion and against pathogens. Because of its sensitivity to RNA interference (RNAi), the notorious pest insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata), has become a model insect for functional studies. Previously, RNAi-mediated silencing of Mannosidase-Ia (ManIa), a key enzyme in the transition from high-mannose glycan moieties to paucimannose N-glycans, was shown to disrupt the transition from larva to pupa and the metamorphosis into adult beetles. While these effects at the organismal level were interesting in a pest control context, the effects at the organ or tissue level and also immune effects have not been investigated yet. To fill this knowledge gap, we performed an analysis of the midgut and PM in ManIa-silenced insects. RESULTS As marked phenotype, the ManIaRNAi insects, the PM pore size was found to be decreased when compared to the control GFPRNAi insects. These smaller pores are related to the observation of thinner microvilli (Mv) on the epithelial cells of the midgut of ManIaRNAi insects. A midgut and PM proteome study and reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis with a selection of marker genes was performed to characterize the midgut cells and understand their response to the silencing of ManIa. In agreement with the loss of ManIa activity, an accumulation of high-mannose N-glycans was observed in the ManIa-silenced insects. As a pathogen-associated molecular pattern (PAMP), the presence of these glycan structures could trigger the activation of the immune pathways. CONCLUSION The observed decrease in PM pore size could be a response to prevent potential pathogens to access the midgut epithelium. This hypothesis is supported by the strong increase in transcription levels of the anti-fungal peptide drosomycin-like in ManIaRNAi insects, although further research is required to elucidate this possibility. The potential immune response in the midgut and the smaller pore size in the PM shed a light on the function of the PM as a physical barrier and provide evidence for the relation between the Mv and PM. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Dongdong Liu
- Laboratory of Agrozoology, Department Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Kristof De Schutter
- Laboratory of Agrozoology, Department Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, Liège, Belgium
| | - An Staes
- VIB Center for Medical Biotechnology, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Koen Dewettinck
- Food Structure and Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Loic Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, Liège, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, Ghent University, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Guy Smagghe
- Laboratory of Agrozoology, Department Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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4
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Sigle LT, Jones M, Novelo M, Ford SA, Urakova N, Lymperopoulos K, Sayre RT, Xi Z, Rasgon JL, McGraw EA. Assessing Aedes aegypti candidate genes during viral infection and Wolbachia-mediated pathogen blocking. INSECT MOLECULAR BIOLOGY 2022; 31:356-368. [PMID: 35112745 PMCID: PMC9081237 DOI: 10.1111/imb.12764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 01/11/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
One approach to control dengue virus transmission is the symbiont Wolbachia, which limits viral infection in mosquitoes. Despite plans for its widespread use in Aedes aegypti, Wolbachia's mode of action remains poorly understood. Many studies suggest that the mechanism is likely multifaceted, involving aspects of immunity, cellular stress and nutritional competition. A previous study from our group used artificial selection to identify a new mosquito candidate gene related to viral blocking; alpha-mannosidase-2a (alpha-Mann-2a) with a predicted role in protein glycosylation. Protein glycosylation pathways tend to be involved in complex host-viral interactions; however, the function of alpha-mannosidases has not been described in mosquito-virus interactions. We examined alpha-Mann-2a expression in response to virus and Wolbachia infections and whether reduced gene expression, caused by RNA interference, affected viral loads. We show that dengue virus (DENV) infection affects the expression of alpha-Mann-2a in a tissue- and time-dependent manner, whereas Wolbachia infection had no effect. In the midgut, DENV prevalence increased following knockdown of alpha-Mann-2a expression in Wolbachia-free mosquitoes, suggesting that alpha-Mann-2a interferes with infection. Expression knockdown had the same effect on the togavirus chikungunya virus, indicating that alpha-Mann-2a may have broad antivirus effects in the midgut. Interestingly, we were unable to knockdown the expression in Wolbachia-infected mosquitoes. We also provide evidence that alpha-Mann-2a may affect the transcriptional level of another gene predicted to be involved in viral blocking and cell adhesion; cadherin87a. These data support the hypothesis that glycosylation and adhesion pathways may broadly be involved in viral infection in Ae. aegypti.
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Affiliation(s)
- Leah T. Sigle
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Matthew Jones
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Mario Novelo
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Suzanne A. Ford
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Nadya Urakova
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | | | | | - Zhiyong Xi
- Department of Microbiology and Molecular GeneticsMichigan State UniversityEast LansingMichiganUSA
| | - Jason L. Rasgon
- Department of Entomology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Elizabeth A. McGraw
- Department of Biology and Center for Infectious Disease DynamicsThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
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5
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Yang Q, De Schutter K, Chen P, Van Damme EJM, Smagghe G. RNAi of the N-glycosylation-related genes confirms their importance in insect development and α-1,6-fucosyltransferase plays a role in the ecdysis event for the hemimetabolous pest insect Nilaparvata lugens. INSECT SCIENCE 2022; 29:91-99. [PMID: 33860636 DOI: 10.1111/1744-7917.12920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/16/2021] [Accepted: 03/13/2021] [Indexed: 06/12/2023]
Abstract
Recently N-glycosylation was found to be required for the postembryonic development and metamorphosis of the holometabolous beetle Tribolium castaneum. However, the role of N-glycosylation in the development of hemimetabolous insects is unknown. To further elucidate the role of N-glycosylation in the development of insects, a functional characterization of the N-glycosylation-related genes (NGRGs) was performed in a model insect for hemimetabolous development, namely the brown planthopper Nilaparvata lugens. In this project, we report the effects of RNAi-mediated silencing of 15 NGRGs on the postembryonic development of N. lugens. Two major observations were made. First, interruption of the early steps of N-glycan processing led to a lethal phenotype during the transition from nymph to adult as was observed in T. castaneum. Second, we report here on an essential function for the α-1,6-fucosyl transferase in the ecdysis event of N. lugens between nymphal instars, since gene-silencing by RNAi led to failure of ecdysis and subsequent mortality of the treated insect.
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Affiliation(s)
- Qun Yang
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
| | - Kristof De Schutter
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
| | - Pengyu Chen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
- Laboratory of Biochemistry and Glycobiology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
| | - Els J M Van Damme
- Laboratory of Biochemistry and Glycobiology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, 9000, Belgium
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6
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Gaspar CJ, Vieira LC, Santos CC, Christianson JC, Jakubec D, Strisovsky K, Adrain C, Domingos PM. EMC is required for biogenesis of Xport-A, an essential chaperone of Rhodopsin-1 and the TRP channel. EMBO Rep 2022; 23:e53210. [PMID: 34918864 PMCID: PMC8728618 DOI: 10.15252/embr.202153210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/26/2021] [Accepted: 11/10/2021] [Indexed: 01/07/2023] Open
Abstract
The ER membrane protein complex (EMC) is required for the biogenesis of a subset of tail anchored (TA) and polytopic membrane proteins, including Rhodopsin-1 (Rh1) and the TRP channel. To understand the physiological implications of EMC-dependent membrane protein biogenesis, we perform a bioinformatic identification of Drosophila TA proteins. From 254 predicted TA proteins, screening in larval eye discs identified two proteins that require EMC for their biogenesis: fan and Xport-A. Fan is required for male fertility in Drosophila and we show that EMC is also required for this process. Xport-A is essential for the biogenesis of both Rh1 and TRP, raising the possibility that disruption of Rh1 and TRP biogenesis in EMC mutants is secondary to the Xport-A defect. We show that EMC is required for Xport-A TMD membrane insertion and that EMC-independent Xport-A mutants rescue Rh1 and TRP biogenesis in EMC mutants. Finally, our work also reveals a role for Xport-A in a glycosylation-dependent triage mechanism during Rh1 biogenesis in the endoplasmic reticulum.
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Affiliation(s)
- Catarina J Gaspar
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB‐NOVA)OeirasPortugal
- Membrane Traffic LabInstituto Gulbenkian de Ciência (IGC)OeirasPortugal
| | - Lígia C Vieira
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB‐NOVA)OeirasPortugal
- Present address:
Center for Genomics and Systems BiologyNew York University Abu DhabiAbu DhabiUnited Arab Emirates
| | - Cristiana C Santos
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB‐NOVA)OeirasPortugal
| | - John C Christianson
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal SciencesBotnar Research CentreUniversity of OxfordOxfordUK
| | - David Jakubec
- Institute of Organic Chemistry and BiochemistryCzech Academy of SciencesPragueCzech Republic
| | - Kvido Strisovsky
- Institute of Organic Chemistry and BiochemistryCzech Academy of SciencesPragueCzech Republic
| | - Colin Adrain
- Membrane Traffic LabInstituto Gulbenkian de Ciência (IGC)OeirasPortugal
- Patrick G Johnston Centre for Cancer ResearchQueen’s UniversityBelfastUK
| | - Pedro M Domingos
- Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa (ITQB‐NOVA)OeirasPortugal
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7
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Courtland JL, Bradshaw TWA, Waitt G, Soderblom EJ, Ho T, Rajab A, Vancini R, Kim IH, Soderling SH. Genetic disruption of WASHC4 drives endo-lysosomal dysfunction and cognitive-movement impairments in mice and humans. eLife 2021; 10:e61590. [PMID: 33749590 PMCID: PMC7984842 DOI: 10.7554/elife.61590] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 02/09/2021] [Indexed: 12/12/2022] Open
Abstract
Mutation of the Wiskott-Aldrich syndrome protein and SCAR homology (WASH) complex subunit, SWIP, is implicated in human intellectual disability, but the cellular etiology of this association is unknown. We identify the neuronal WASH complex proteome, revealing a network of endosomal proteins. To uncover how dysfunction of endosomal SWIP leads to disease, we generate a mouse model of the human WASHC4c.3056C>G mutation. Quantitative spatial proteomics analysis of SWIPP1019R mouse brain reveals that this mutation destabilizes the WASH complex and uncovers significant perturbations in both endosomal and lysosomal pathways. Cellular and histological analyses confirm that SWIPP1019R results in endo-lysosomal disruption and uncover indicators of neurodegeneration. We find that SWIPP1019R not only impacts cognition, but also causes significant progressive motor deficits in mice. A retrospective analysis of SWIPP1019R patients reveals similar movement deficits in humans. Combined, these findings support the model that WASH complex destabilization, resulting from SWIPP1019R, drives cognitive and motor impairments via endo-lysosomal dysfunction in the brain.
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Affiliation(s)
- Jamie L Courtland
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Tyler WA Bradshaw
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Greg Waitt
- Proteomics and Metabolomics Shared Resource, Duke University School of MedicineDurhamUnited States
| | - Erik J Soderblom
- Proteomics and Metabolomics Shared Resource, Duke University School of MedicineDurhamUnited States
- Department of Cell Biology, Duke University School of MedicineDurhamUnited States
| | - Tricia Ho
- Proteomics and Metabolomics Shared Resource, Duke University School of MedicineDurhamUnited States
| | - Anna Rajab
- Burjeel Hospital, VPS HealthcareMuscatOman
| | - Ricardo Vancini
- Department of Pathology, Duke University School of MedicineDurhamUnited States
| | - Il Hwan Kim
- Department of Cell Biology, Duke University School of MedicineDurhamUnited States
- Department of Anatomy and Neurobiology, University of Tennessee Heath Science CenterMemphisUnited States
| | - Scott H Soderling
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
- Department of Cell Biology, Duke University School of MedicineDurhamUnited States
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8
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Functional analysis of glycosylation using Drosophila melanogaster. Glycoconj J 2019; 37:1-14. [DOI: 10.1007/s10719-019-09892-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/13/2019] [Accepted: 09/25/2019] [Indexed: 12/15/2022]
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9
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Tjondro HC, Loke I, Chatterjee S, Thaysen-Andersen M. Human protein paucimannosylation: cues from the eukaryotic kingdoms. Biol Rev Camb Philos Soc 2019; 94:2068-2100. [PMID: 31410980 DOI: 10.1111/brv.12548] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 07/10/2019] [Accepted: 07/17/2019] [Indexed: 12/11/2022]
Abstract
Paucimannosidic proteins (PMPs) are bioactive glycoproteins carrying truncated α- or β-mannosyl-terminating asparagine (N)-linked glycans widely reported across the eukaryotic domain. Our understanding of human PMPs remains limited, despite findings documenting their existence and association with human disease glycobiology. This review comprehensively surveys the structures, biosynthetic routes and functions of PMPs across the eukaryotic kingdoms with the aim of synthesising an improved understanding on the role of protein paucimannosylation in human health and diseases. Convincing biochemical, glycoanalytical and biological data detail a vast structural heterogeneity and fascinating tissue- and subcellular-specific expression of PMPs within invertebrates and plants, often comprising multi-α1,3/6-fucosylation and β1,2-xylosylation amongst other glycan modifications and non-glycan substitutions e.g. O-methylation. Vertebrates and protists express less-heterogeneous PMPs typically only comprising variable core fucosylation of bi- and trimannosylchitobiose core glycans. In particular, the Manα1,6Manβ1,4GlcNAc(α1,6Fuc)β1,4GlcNAcβAsn glycan (M2F) decorates various human neutrophil proteins reportedly displaying bioactivity and structural integrity demonstrating that they are not degradation products. Less-truncated paucimannosidic glycans (e.g. M3F) are characteristic glycosylation features of proteins expressed by human cancer and stem cells. Concertedly, these observations suggest the involvement of human PMPs in processes related to innate immunity, tumorigenesis and cellular differentiation. The absence of human PMPs in diverse bodily fluids studied under many (patho)physiological conditions suggests extravascular residence and points to localised functions of PMPs in peripheral tissues. Absence of PMPs in Fungi indicates that paucimannosylation is common, but not universally conserved, in eukaryotes. Relative to human PMPs, the expression of PMPs in plants, invertebrates and protists is more tissue-wide and constitutive yet, similar to their human counterparts, PMP expression remains regulated by the physiology of the producing organism and PMPs evidently serve essential functions in development, cell-cell communication and host-pathogen/symbiont interactions. In most PMP-producing organisms, including humans, the N-acetyl-β-hexosaminidase isoenzymes and linkage-specific α-mannosidases are glycoside hydrolases critical for generating PMPs via N-acetylglucosaminyltransferase I (GnT-I)-dependent and GnT-I-independent truncation pathways. However, the identity and structure of many species-specific PMPs in eukaryotes, their biosynthetic routes, strong tissue- and development-specific expression, and diverse functions are still elusive. Deep exploration of these PMP features involving, for example, the characterisation of endogenous PMP-recognising lectins across a variety of healthy and N-acetyl-β-hexosaminidase-deficient human tissue types and identification of microbial adhesins reactive to human PMPs, are amongst the many tasks required for enhanced insight into the glycobiology of human PMPs. In conclusion, the literature supports the notion that PMPs are significant, yet still heavily under-studied biomolecules in human glycobiology that serve essential functions and create structural heterogeneity not dissimilar to other human N-glycoprotein types. Human PMPs should therefore be recognised as bioactive glycoproteins that are distinctly different from the canonical N-glycoprotein classes and which warrant a more dedicated focus in glycobiological research.
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Affiliation(s)
- Harry C Tjondro
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Ian Loke
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.,Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Sayantani Chatterjee
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Morten Thaysen-Andersen
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
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10
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Xiong L, Zhang L, Yang Y, Li N, Lai W, Wang F, Zhu X, Wang T. ER complex proteins are required for rhodopsin biosynthesis and photoreceptor survival in Drosophila and mice. Cell Death Differ 2019; 27:646-661. [PMID: 31263175 PMCID: PMC7206144 DOI: 10.1038/s41418-019-0378-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/17/2022] Open
Abstract
Defective rhodopsin homeostasis is one of the major causes of retinal degeneration, including the disease Retinitis pigmentosa. To identify cellular factors required for the biosynthesis of rhodopsin, we performed a genome-wide genetic screen in Drosophila for mutants with reduced levels of rhodopsin. We isolated loss-of-function alleles in endoplasmic reticulum membrane protein complex 3 (emc3), emc5, and emc6, each of which exhibited defective phototransduction and photoreceptor cell degeneration. EMC3, EMC5, and EMC6 were essential for rhodopsin synthesis independent of the ER associated degradation (ERAD) pathway, which eliminates misfolded proteins. We generated null mutations for all EMC subunits, and further demonstrated that different EMC subunits play roles in different cellular functions. Conditional knockout of the Emc3 gene in mice led to mislocalization of rhodopsin protein and death of cone and rod photoreceptor cells. These data indicate conserved roles for EMC subunits in maintaining rhodopsin homeostasis and photoreceptor function, and suggest that retinal degeneration may also be caused by defects in early biosynthesis of rhodopsin.
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Affiliation(s)
- Liangyao Xiong
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing, 100871, China.,National Institute of Biological Sciences, Beijing, 102206, China
| | - Lin Zhang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610072, China
| | - Yeming Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610072, China
| | - Na Li
- Southwest Jiaotong University, Chengdu, Sichuan, China
| | - Wenjia Lai
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Fengchao Wang
- National Institute of Biological Sciences, Beijing, 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100871, China
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610072, China. .,Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China. .,Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, China. .,Department of Ophthalmology, First People's Hospital of Shangqiu, Shangqiu, Henan, China.
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, 102206, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100871, China.
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11
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Zhao H, Wang J, Wang T. The V-ATPase V1 subunit A1 is required for rhodopsin anterograde trafficking in Drosophila. Mol Biol Cell 2018; 29:1640-1651. [PMID: 29742016 PMCID: PMC6080656 DOI: 10.1091/mbc.e17-09-0546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Synthesis and maturation of the light sensor, rhodopsin, are critical for the maintenance of light sensitivity and for photoreceptor homeostasis. In Drosophila, the main rhodopsin, Rh1, is synthesized in the endoplasmic reticulum and transported to the rhabdomere through the secretory pathway. In an unbiased genetic screen for factors involved in rhodopsin homeostasis, we identified mutations in vha68-1, which encodes the vacuolar proton-translocating ATPase (V-ATPase) catalytic subunit A isoform 1 of the V1 component. Loss of vha68-1 in photoreceptor cells disrupted post-Golgi anterograde trafficking of Rh1, reduced light sensitivity, increased secretory vesicle pH, and resulted in incomplete Rh1 deglycosylation. In addition, vha68-1 was required for activity-independent photoreceptor cell survival. Importantly, vha68-1 mutants exhibited phenotypes similar to those exhibited by mutations in the V0 component of V-ATPase, vha100-1. These data demonstrate that the V1 and V0 components of V-ATPase play key roles in post-Golgi trafficking of Rh1 and that Drosophila may represent an important animal model system for studying diseases associated with V-ATPase dysfunction.
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Affiliation(s)
- Haifang Zhao
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,National Institute of Biological Sciences, Beijing 102206, China
| | - Jing Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing 102206, China
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12
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Hall H, Medina P, Cooper DA, Escobedo SE, Rounds J, Brennan KJ, Vincent C, Miura P, Doerge R, Weake VM. Transcriptome profiling of aging Drosophila photoreceptors reveals gene expression trends that correlate with visual senescence. BMC Genomics 2017; 18:894. [PMID: 29162050 PMCID: PMC5698953 DOI: 10.1186/s12864-017-4304-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/14/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Aging is associated with functional decline of neurons and increased incidence of both neurodegenerative and ocular disease. Photoreceptor neurons in Drosophila melanogaster provide a powerful model for studying the molecular changes involved in functional senescence of neurons since decreased visual behavior precedes retinal degeneration. Here, we sought to identify gene expression changes and the genomic features of differentially regulated genes in photoreceptors that contribute to visual senescence. RESULTS To identify gene expression changes that could lead to visual senescence, we characterized the aging transcriptome of Drosophila sensory neurons highly enriched for photoreceptors. We profiled the nuclear transcriptome of genetically-labeled photoreceptors over a 40 day time course and identified increased expression of genes involved in stress and DNA damage response, and decreased expression of genes required for neuronal function. We further show that combinations of promoter motifs robustly identify age-regulated genes, suggesting that transcription factors are important in driving expression changes in aging photoreceptors. However, long, highly expressed and heavily spliced genes are also more likely to be downregulated with age, indicating that other mechanisms could contribute to expression changes at these genes. Lastly, we identify that circular RNAs (circRNAs) strongly increase during aging in photoreceptors. CONCLUSIONS Overall, we identified changes in gene expression in aging Drosophila photoreceptors that could account for visual senescence. Further, we show that genomic features predict these age-related changes, suggesting potential mechanisms that could be targeted to slow the rate of age-associated visual decline.
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Affiliation(s)
- Hana Hall
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Patrick Medina
- Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA
| | - Daphne A Cooper
- Department of Biology, University of Nevada, Reno, NV, 89557, USA
| | - Spencer E Escobedo
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jeremiah Rounds
- Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA
| | - Kaelan J Brennan
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | | | - Pedro Miura
- Department of Biology, University of Nevada, Reno, NV, 89557, USA
| | | | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA. .,Purdue University Center for Cancer Research, Purdue University, West Lafayette, 47907, USA.
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13
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Walski T, De Schutter K, Van Damme EJM, Smagghe G. Diversity and functions of protein glycosylation in insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 83:21-34. [PMID: 28232040 DOI: 10.1016/j.ibmb.2017.02.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 01/27/2017] [Accepted: 02/10/2017] [Indexed: 05/28/2023]
Abstract
The majority of proteins is modified with carbohydrate structures. This modification, called glycosylation, was shown to be crucial for protein folding, stability and subcellular location, as well as protein-protein interactions, recognition and signaling. Protein glycosylation is involved in multiple physiological processes, including embryonic development, growth, circadian rhythms, cell attachment as well as maintenance of organ structure, immunity and fertility. Although the general principles of glycosylation are similar among eukaryotic organisms, insects synthesize a distinct repertoire of glycan structures compared to plants and vertebrates. Consequently, a number of unique insect glycans mediate functions specific to this class of invertebrates. For instance, the core α1,3-fucosylation of N-glycans is absent in vertebrates, while in insects this modification is crucial for the development of wings and the nervous system. At present, most of the data on insect glycobiology comes from research in Drosophila. Yet, progressively more information on the glycan structures and the importance of glycosylation in other insects like beetles, caterpillars, aphids and bees is becoming available. This review gives a summary of the current knowledge and recent progress related to glycan diversity and function(s) of protein glycosylation in insects. We focus on N- and O-glycosylation, their synthesis, physiological role(s), as well as the molecular and biochemical basis of these processes.
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Affiliation(s)
- Tomasz Walski
- Department of Crop Protection, Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Department of Molecular Biotechnology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
| | - Kristof De Schutter
- Department of Crop Protection, Ghent University, Coupure Links 653, 9000 Ghent, Belgium; Department of Molecular Biotechnology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
| | - Els J M Van Damme
- Department of Molecular Biotechnology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
| | - Guy Smagghe
- Department of Crop Protection, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
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Light-Driven Processes Control Both Rhodopsin Maturation and Recycling in Mosquito Photoreceptors. J Neurosci 2016; 36:11051-11058. [PMID: 27798185 DOI: 10.1523/jneurosci.1754-16.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/07/2016] [Indexed: 11/21/2022] Open
Abstract
Many invertebrates carry out a daily cycle of shedding and rebuilding of the photoreceptor's photosensitive rhabdomeric membranes. The mosquito Aedes aegypti shows a robust response, losing nearly all Aaop1 rhodopsin from the rhabdomeric membranes during the shedding process at dawn. Here, we made use of Aaop1 antibodies capable of distinguishing newly synthesized, glycosylated rhodopsin from mature nonglycosylated rhodopsin to characterize the fate of Aaop1 during the shedding and rebuilding processes. The rhabdomeric rhodopsin is moved into large cytoplasmic vesicles at dawn and is subsequently degraded during the standard 12 h daytime period. The endocytosed rhodopsin is trafficked back to the photosensitive membranes if animals are shifted back to dark conditions during the morning hours. During the daytime period, small vesicles containing newly synthesized and glycosylated Aaop1 rhodopsin accumulate within the cytoplasm. At dusk, these vesicles are lost as the newly synthesized Aaop1 is converted to the nonglycosylated form and deposited in the rhabdomeres. We demonstrate that light acts though a novel signaling pathway to block rhodopsin maturation, thus inhibiting the deglycosylation and rhabdomeric targeting of newly synthesized Aaop1 rhodopsin. Therefore, light controls two cellular processes responsible for the daily renewal of rhodopsin: rhodopsin endocytosis at dawn and inhibition of rhodopsin maturation until dusk. SIGNIFICANCE STATEMENT Organisms use multiple strategies to maximize visual capabilities in different light conditions. Many invertebrates show a daily cycle of shedding the photoreceptor's rhabdomeric membranes at dawn and rebuilding these during the following night. We show here that the Aedes aegypti mosquito possesses two distinct light-driven cellular signaling processes for modulating rhodopsin content during this cycle. One of these, endocytosis of rhabdomeric rhodopsin, has been described previously. The second, a light-activated cellular pathway acting to inhibit the anterograde movement of newly synthesized rhodopsin, is revealed here for the first time. The discovery of this cellular signaling pathway controlling a G-protein-coupled receptor is of broad interest due to the prominent role of this receptor family across all areas of neuroscience.
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15
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Protein N-glycosylation and N-glycan trimming are required for postembryonic development of the pest beetle Tribolium castaneum. Sci Rep 2016; 6:35151. [PMID: 27731363 PMCID: PMC5059678 DOI: 10.1038/srep35151] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/26/2016] [Indexed: 11/09/2022] Open
Abstract
In holometabolous insects the transition from larva to adult requires a complete body reorganization and relies on N-glycosylated proteins. N-glycosylation is an important posttranslational modification that influences protein activity but its impact on the metamorphosis has not been studied yet. Here we used the red flour beetle, Tribolium castaneum, to perform a first comprehensive study on the involvement of the protein N-glycosylation pathway in metamorphosis. The transcript levels for genes encoding N-glycan processing enzymes increased during later developmental stages and, in turn, transition from larva to adult coincided with an enrichment of more extensively modified paucimannose glycans, including fucosylated ones. Blockage of N-glycan attachment resulted in larval mortality, while RNAi of α-glucosidases involved in early N-glycan trimming and quality control disrupted the larva to pupa transition. Additionally, simultaneous knockdown of multiple genes responsible for N-glycan processing towards paucimannose structures revealed their novel roles in pupal appendage formation and adult eclosion. Our findings revealed that, next to hormonal control, insect post-embryonic development and metamorphosis depend on protein N-glycan attachment and efficient N-glycan processing. Consequently, disruption of these processes could be an effective new approach for insect control.
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16
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Chow CY, Kelsey KJP, Wolfner MF, Clark AG. Candidate genetic modifiers of retinitis pigmentosa identified by exploiting natural variation in Drosophila. Hum Mol Genet 2015; 25:651-9. [PMID: 26662796 DOI: 10.1093/hmg/ddv502] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/07/2015] [Indexed: 01/10/2023] Open
Abstract
Individuals carrying the same pathogenic mutation can present with a broad range of disease outcomes. While some of this variation arises from environmental factors, it is increasingly recognized that the background genetic variation of each individual can have a profound effect on the expressivity of a pathogenic mutation. In order to understand this background effect on disease-causing mutations, studies need to be performed across a wide range of backgrounds. Recent advancements in model organism biology allow us to test mutations across genetically diverse backgrounds and identify the genes that influence the expressivity of a mutation. In this study, we used the Drosophila Genetic Reference Panel, a collection of ∼200 wild-derived strains, to test the variability of the retinal phenotype of the Rh1(G69D) Drosophila model of retinitis pigmentosa (RP). We found that the Rh1(G69D) retinal phenotype is quite a variable quantitative phenotype. To identify the genes driving this extensive phenotypic variation, we performed a genome-wide association study. We identified 106 candidate genes, including 14 high-priority candidates. Functional testing by RNAi indicates that 10/13 top candidates tested influence the expressivity of Rh1(G69D). The human orthologs of the candidate genes have not previously been implicated as RP modifiers and their functions are diverse, including roles in endoplasmic reticulum stress, apoptosis and retinal degeneration and development. This study demonstrates the utility of studying a pathogenic mutation across a wide range of genetic backgrounds. These candidate modifiers provide new avenues of inquiry that may reveal new RP disease mechanisms and therapies.
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Affiliation(s)
- Clement Y Chow
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA and Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Keegan J P Kelsey
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA and
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA and
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA and
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17
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TRP and Rhodopsin Transport Depends on Dual XPORT ER Chaperones Encoded by an Operon. Cell Rep 2015; 13:573-584. [PMID: 26456832 DOI: 10.1016/j.celrep.2015.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/30/2015] [Accepted: 09/04/2015] [Indexed: 11/24/2022] Open
Abstract
TRP channels and G protein-coupled receptors (GPCRs) play critical roles in sensory reception. However, the identities of the chaperones that assist GPCRs in translocating from the endoplasmic reticulum (ER) are limited, and TRP ER chaperones are virtually unknown. The one exception for TRPs is Drosophila XPORT. Here, we show that the xport locus is bicistronic and encodes unrelated transmembrane proteins, which enable the signaling proteins that initiate and culminate phototransduction, rhodopsin 1 (Rh1) and TRP, to traffic to the plasma membrane. XPORT-A and XPORT-B are ER proteins, and loss of either has a profound impact on TRP and Rh1 targeting to the light-sensing compartment of photoreceptor cells. XPORT-B complexed in vivo with the Drosophila homolog of the mammalian HSP70 protein, GRP78/BiP, which, in turn, associated with Rh1. Our work highlights a coordinated network of chaperones required for the biosynthesis of the TRP channel and rhodopsin in Drosophila photoreceptor cells.
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18
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Ma Y, Li J, Yu H, Wang L, Lu T, Pan C, Han Y, Zhang D, Yue W. Association of chromosome 5q21.3 polymorphisms with the exploratory eye movement dysfunction in schizophrenia. Sci Rep 2015; 5:10299. [PMID: 26242244 PMCID: PMC4533163 DOI: 10.1038/srep10299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/07/2015] [Indexed: 11/09/2022] Open
Abstract
Schizophrenia patients show abnormalities in many eye movement tasks. Among them, exploratory eye movements (EEM) dysfunction seems to be specific to schizophrenia. However the mechanism of EEM disturbances in schizophrenia patients remains elusive. We investigate the relationship between EEM and single nucleotide polymorphisms (SNPs) or genes to identify susceptibility loci for EEM in schizophrenia. We firstly performed EEM test, then performed a genome-wide association study (GWAS) and gene-based association study of EEM in 128 individuals with schizophrenia and 143 healthy control subjects. Comparing to healthy controls, schizophrenia patients show significant decrease in NEF (22.99 ± 3.96 vs. 26.02 ± 5.72, P <0.001), TESL (368.78 ± 123.57 vs. 603.12 ± 178.63, P <0.001), MESL (16.86 ± 5.27 vs. 24.42 ± 6.46, P <0.001), RSS (8.22 ± 1.56 vs. 10.92 ± 1.09, P <0.001), and CSS (5.06 ± 0.97 vs. 6.64 ± 0.87, P <0.001). Five SNPs of the MAN2A1, at 5q21.3, were associated with EEM abnormalities (deceased CSS) and satisfied the criteria of GWAS significance threshold. One is localized near 5'-UTR (rs17450784) and four are in intron (rs1438663, rs17162094, rs6877440 and rs10067856) of the gene. Our findings suggest that the identified loci may control the schizophrenia-related quantitative EEM trait. And the identified gene, associated with the EEM phenotype, may lead to new insights into the etiology of schizophrenia.
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Affiliation(s)
- Yuanlin Ma
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Jun Li
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Hao Yu
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China [3] School of Life Sciences, Tsinghua University, Beijing 100084, China [4] Peking University-Tsinghua University Joint Center for Life Sciences, Beijing 100871, China
| | - Lifang Wang
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Tianlan Lu
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Chao Pan
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Yonghua Han
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Dai Zhang
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China [3] School of Life Sciences, Tsinghua University, Beijing 100084, China [4] Peking University-Tsinghua University Joint Center for Life Sciences, Beijing 100871, China [5] PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - Weihua Yue
- 1] Institute of Mental Health, The Sixth Hospital, Peking University, Beijing 100191, China [2] Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
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19
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Chow CY, Avila FW, Clark AG, Wolfner MF. Induction of excessive endoplasmic reticulum stress in the Drosophila male accessory gland results in infertility. PLoS One 2015; 10:e0119386. [PMID: 25742606 PMCID: PMC4350844 DOI: 10.1371/journal.pone.0119386] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/30/2015] [Indexed: 12/11/2022] Open
Abstract
Endoplasmic reticulum (ER) stress occurs when misfolded proteins accumulate in the lumen of the ER. A cell responds to ER stress with the unfolded protein response (UPR), a complex program of transcriptional and translational changes aimed at clearing misfolded proteins. Secretory tissues and cells are particularly well adapted to respond to ER stress because their function requires high protein production and secretory load. The insect male accessory gland (AG) is a secretory tissue involved in male fertility. The AG secretes many seminal fluid proteins (SFPs) essential for male reproduction. Among adult Drosophila tissues, we find that genes upregulated by ER stress are most highly expressed in the AG, suggesting that the AG is already undergoing high levels of ER stress due to its normal secretory functions. We hypothesized that induction of excessive ER stress in the AG above basal levels, would perturb normal function and provide a genetic tool for studying AG and SFP biology. To test this, we genetically induced excessive ER stress in the AG by conditional 1) expression of a misfolded protein or 2) knockdown of the UPR regulatory protein, BiP. Both genetic manipulations induced excessive ER stress in the AG, as indicated by the increase in Xbp1 splicing, a marker of ER stress. Both models resulted in a large decrease in or loss of SFP production and male infertility. Sperm production, motility, and transfer appeared unaffected. The induction of strong ER stress in the insect male AG may provide a simple way for studying or manipulating male fertility, as it eliminates AG function while preserving sperm production.
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Affiliation(s)
- Clement Y. Chow
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Frank W. Avila
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Andrew G. Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Mariana F. Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
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20
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Dragosits M, Yan S, Razzazi-Fazeli E, Wilson IBH, Rendic D. Enzymatic properties and subtle differences in the substrate specificity of phylogenetically distinct invertebrate N-glycan processing hexosaminidases. Glycobiology 2014; 25:448-64. [PMID: 25488985 PMCID: PMC4339880 DOI: 10.1093/glycob/cwu132] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Fused lobes (FDL) hexosaminidases are the most recently genetically defined glycosidases involved in the biosynthesis of N-glycans in invertebrates, and their narrow specificity is essential for the generation of paucimannosidic N-glycans in insects. In this study, we explored the potential of FDL hexosaminidases in the utilization of different artificial and natural substrates, both as purified, native compounds or generated in vitro using various relevant glycosyltransferases. In addition to the already-known FDL enzyme from Drosophila melanogaster, we now have identified and characterized the Apis mellifera FDL homolog. The enzymatic properties of the soluble forms of the affinity-purified insect FDL enzymes, expressed in both yeast and insect cells, were compared with those of the phylogenetically distinct recombinant Caenorhabditis elegans FDL-like enzymes and the N-acetylgalactosamine (GalNAc)-specific Caenorhabditis hexosaminidase HEX-4. In tests with a range of substrates, including natural N-glycans, we show that the invertebrate FDL(-like) enzymes are highly specific for N-acetylglucosamine attached to the α1,3-mannose, but under extreme conditions also remove other terminal GalNAc and N-acetylglucosamine residues. Recombinant FDL also proved useful in the analysis of complex mixtures of N-glycans originating from wild-type and mutant Caenorhabditis strains, thereby aiding isomeric definition of paucimannosidic and hybrid N-glycans in this organism. Furthermore, differences in activity and specificity were shown for two site-directed mutants of Drosophila FDL, compatible with the high structural similarity of chitinolytic and N-glycan degrading exohexosaminidases in insects. Our studies are another indication for the variety of structural and function aspects in the GH20 hexosaminidase family important for both catabolism and biosynthesis of glycoconjugates in eukaryotes.
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Affiliation(s)
- Martin Dragosits
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Shi Yan
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna
| | | | - Iain B H Wilson
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna
| | - Dubravko Rendic
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna
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21
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Rosenbaum EE, Vasiljevic E, Cleland SC, Flores C, Colley NJ. The Gos28 SNARE protein mediates intra-Golgi transport of rhodopsin and is required for photoreceptor survival. J Biol Chem 2014; 289:32392-409. [PMID: 25261468 PMCID: PMC4239595 DOI: 10.1074/jbc.m114.585166] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/24/2014] [Indexed: 11/06/2022] Open
Abstract
SNARE proteins play indispensable roles in membrane fusion events in many cellular processes, including synaptic transmission and protein trafficking. Here, we characterize the Golgi SNARE protein, Gos28, and its role in rhodopsin (Rh1) transport through Drosophila photoreceptors. Mutations in gos28 lead to defective Rh1 trafficking and retinal degeneration. We have pinpointed a role for Gos28 in the intra-Golgi transport of Rh1, downstream from α-mannosidase-II in the medial- Golgi. We have confirmed the necessity of key residues in Gos28's SNARE motif and demonstrate that its transmembrane domain is not required for vesicle fusion, consistent with Gos28 functioning as a t-SNARE for Rh1 transport. Finally, we show that human Gos28 rescues both the Rh1 trafficking defects and retinal degeneration in Drosophila gos28 mutants, demonstrating the functional conservation of these proteins. Our results identify Gos28 as an essential SNARE protein in Drosophila photoreceptors and provide mechanistic insights into the role of SNAREs in neurodegenerative disease.
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Affiliation(s)
- Erica E Rosenbaum
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Eva Vasiljevic
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Spencer C Cleland
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Carlos Flores
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Nansi Jo Colley
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
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