scholarly journals Identification of genes required for apical protein trafficking in Drosophila photoreceptor cells

2019 ◽  
Author(s):  
Azadeh Laffafian ◽  
Ulrich Tepass
Keyword(s):  
Protein Trafficking ◽  
Apical Membrane ◽  
Vesicle Trafficking ◽  
Retinal Disease ◽  
Photoreceptor Cells ◽  
Fruit Fly ◽  
Light Sensing ◽  
Human Orthologs ◽  
Apical Trafficking ◽  
Drosophila Photoreceptor

AbstractDrosophila photoreceptor cells (PRCs) are highly polarized epithelial cells. Their apical membrane is further subdivided into the stalk membrane and the light-sensing rhabdomere. The photo-pigment Rhodopsin1 (Rh1) localizes to the rhabdomere, whereas the apical determinant Crumbs (Crb) is enriched at the stalk membrane. The proteoglycan Eyes shut (Eys) is secreted through the apical membrane into an inter-rhabdomeral space. Rh1, Crb, and Eys are essential for PRC development, normal vision, and PRC survival. Human orthologs of all three proteins have been linked to retinal degenerative diseases. Here, we describe an RNAi-based screen examining the importance of approximately 240 trafficking-related genes in apical trafficking of Eys, Rh1, and Crb. We found 28 genes that have an effect on the localization and/or levels of these apical proteins and analyzed several factors in more detail. We show that the Arf GEF protein Sec71 is required for biosynthetic traffic of both apical and basolateral proteins, that the exocyst complex and the microtubule-based motor proteins dynein and kinesin promote the secretion of Eys and Rh1, and that Syntaxin 7/Avalanche controls the endocytosis of Rh1, Eys, and Crb.Article summeryPhotoreceptor cells (PRCs) rely on polarized vesicle trafficking to deliver key secreted and transmembrane proteins to their correct locations. Failure to do so causes defects in PRC development, function, and survival leading to retinal disease. Using the fruit fly Drosophila as a model we have identified 28 genes that are required for the trafficking of the three apical proteins Rhodopsin 1, Crumbs, and Eyes Shut. Human homologs of all three genes are associated with retinal degeneration. We characterized several genes to reveal novel mechanisms of vesicle trafficking in photoreceptor cells at different points in the biosynthetic or endocytotic pathways.

scholarly journals Retinitis pigmentosa is associated with shifts in the gut microbiome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oksana Kutsyr ◽  
Lucía Maestre-Carballa ◽  
Mónica Lluesma-Gomez ◽  
Manuel Martinez-Garcia ◽  
Nicolás Cuenca ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Gut Microbiome ◽  
Functional Decline ◽  
Retinal Disease ◽  
Photoreceptor Cells ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Sequencing Data ◽  
Alpha And Beta Diversity ◽  
Potential Biomarker

AbstractThe gut microbiome is known to influence the pathogenesis and progression of neurodegenerative diseases. However, there has been relatively little focus upon the implications of the gut microbiome in retinal diseases such as retinitis pigmentosa (RP). Here, we investigated changes in gut microbiome composition linked to RP, by assessing both retinal degeneration and gut microbiome in the rd10 mouse model of RP as compared to control C57BL/6J mice. In rd10 mice, retinal responsiveness to flashlight stimuli and visual acuity were deteriorated with respect to observed in age-matched control mice. This functional decline in dystrophic animals was accompanied by photoreceptor loss, morphologic anomalies in photoreceptor cells and retinal reactive gliosis. Furthermore, 16S rRNA gene amplicon sequencing data showed a microbial gut dysbiosis with differences in alpha and beta diversity at the genera, species and amplicon sequence variants (ASV) levels between dystrophic and control mice. Remarkably, four fairly common ASV in healthy gut microbiome belonging to Rikenella spp., Muribaculaceace spp., Prevotellaceae UCG-001 spp., and Bacilli spp. were absent in the gut microbiome of retinal disease mice, while Bacteroides caecimuris was significantly enriched in mice with RP. The results indicate that retinal degenerative changes in RP are linked to relevant gut microbiome changes. The findings suggest that microbiome shifting could be considered as potential biomarker and therapeutic target for retinal degenerative diseases.

scholarly journals TRP and the PDZ Protein, Inad, Form the Core Complex Required for Retention of the Signalplex in Drosophila Photoreceptor Cells

2000 ◽  
Vol 150 (6) ◽  
pp. 1411-1422 ◽  
Author(s):  
Hong-Sheng Li ◽  
Craig Montell
Keyword(s):  
Transient Receptor Potential ◽  
Direct Interaction ◽  
Light Response ◽  
Receptor Potential ◽  
Photoreceptor Cells ◽  
Macromolecular Complex ◽  
Pdz Domains ◽  
The Core ◽  
Transient Receptor ◽  
Drosophila Photoreceptor

The light response in Drosophila photoreceptor cells is mediated by a series of proteins that assemble into a macromolecular complex referred to as the signalplex. The central player in the signalplex is inactivation no afterpotential D (INAD), a protein consisting of a tandem array of five PDZ domains. At least seven proteins bind INAD, including the transient receptor potential (TRP) channel, which depends on INAD for localization to the phototransducing organelle, the rhabdomere. However, the determinants required for localization of INAD are not known. In this work, we showed that INAD was required for retention rather than targeting of TRP to the rhabdomeres. In addition, we demonstrated that TRP bound to INAD through the COOH terminus, and this interaction was required for localization of INAD. Other proteins that depend on INAD for localization, phospholipase C and protein kinase C, also mislocalized. However, elimination of any other member of the signalplex had no impact on the spatial distribution of INAD. A direct interaction between TRP and INAD did not appear to have a role in the photoresponse independent of localization of multiple signaling components. Rather, the primary function of the TRP/ INAD complex is to form the core unit required for localization of the signalplex to the rhabdomeres.

scholarly journals Balancing the Photoreceptor Proteome: Proteostasis Network Therapeutics for Inherited Retinal Disease

Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 557 ◽  
Author(s):  
Siebren Faber ◽  
Ronald Roepman
Keyword(s):  
Retinal Disease ◽  
Protein Accumulation ◽  
Retinal Diseases ◽  
High Turnover ◽  
Protein Balance ◽  
Light Sensing ◽  
Outer Segments ◽  
Inherited Retinal Disease ◽  
Tremendous Amount ◽  
Therapeutic Compounds

The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.

scholarly journals A LINE-1 insertion situated in the promoter of IMPG2 is associated with autosomal recessive progressive retinal atrophy in Lhasa Apso dogs

BMC Genetics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Rebekkah J. Hitti-Malin ◽  
Louise M. Burmeister ◽  
Sally L. Ricketts ◽  
Thomas W. Lewis ◽  
Louise Pettitt ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Retinal Disease ◽  
Photoreceptor Cells ◽  
Causal Variant ◽  
Sequencing Analysis ◽  
Sequencing Data ◽  
Progressive Retinal Atrophy ◽  
Dna Test ◽  
A Genome ◽  
The Uk

Abstract Background Canine progressive retinal atrophies are a group of hereditary retinal degenerations in dogs characterised by depletion of photoreceptor cells in the retina, which ultimately leads to blindness. PRA in the Lhasa Apso (LA) dog has not previously been clinically characterised or described in the literature, but owners in the UK are advised to have their dog examined through the British Veterinary Association/ Kennel Club/ International Sheep Dog Society (BVA/KC/ISDS) eye scheme annually, and similar schemes that are in operation in other countries. After the exclusion of 25 previously reported canine retinal mutations in LA PRA-affected dogs, we sought to identify the genetic cause of PRA in this breed. Results Analysis of whole-exome sequencing data of three PRA-affected LA and three LA without signs of PRA did not identify any exonic or splice site variants, suggesting the causal variant was non-exonic. We subsequently undertook a genome-wide association study (GWAS), which identified a 1.3 Mb disease-associated region on canine chromosome 33, followed by whole-genome sequencing analysis that revealed a long interspersed element-1 (LINE-1) insertion upstream of the IMPG2 gene. IMPG2 has previously been implicated in human retinal disease; however, until now no canine PRAs have been associated with this gene. The identification of this PRA-associated variant has enabled the development of a DNA test for this form of PRA in the breed, here termed PRA4 to distinguish it from other forms of PRA described in other breeds. This test has been used to determine the genotypes of over 900 LA dogs. A large cohort of genotyped dogs was used to estimate the allele frequency as between 0.07–0.1 in the UK LA population. Conclusions Through the use of GWAS and subsequent sequencing of a PRA case, we have identified a LINE-1 insertion in the retinal candidate gene IMPG2 that is associated with a form of PRA in the LA dog. Validation of this variant in 447 dogs of 123 breeds determined it was private to LA dogs. We envisage that, over time, the developed DNA test will offer breeders the opportunity to avoid producing dogs affected with this form of PRA.

A role for the extracellular domain of Crumbs in morphogenesis of Drosophila photoreceptor cells

2009 ◽  
Vol 88 (12) ◽  
pp. 765-777 ◽  
Author(s):  
Mélisande Richard ◽  
Nadine Muschalik ◽  
Ferdi Grawe ◽  
Susann Özüyaman ◽  
Elisabeth Knust
Keyword(s):  
Photoreceptor Cells ◽  
Extracellular Domain ◽  
Drosophila Photoreceptor

scholarly journals The Abl/Enabled signaling pathway regulates Golgi architecture in Drosophila photoreceptor neurons

2014 ◽  
Vol 25 (19) ◽  
pp. 2993-3005 ◽  
Author(s):  
Ramakrishnan Kannan ◽  
Irina Kuzina ◽  
Stephen Wincovitch ◽  
Stephanie H. Nowotarski ◽  
Edward Giniger
Keyword(s):  
Cell Signaling ◽  
Signaling Pathway ◽  
Protein Trafficking ◽  
Adaptor Protein ◽  
Loss Of Function ◽  
Abl Tyrosine Kinase ◽  
Upstream Regulator ◽  
Basal Portion ◽  
Photoreceptor Neurons ◽  
Drosophila Photoreceptor

The Golgi apparatus is optimized separately in different tissues for efficient protein trafficking, but we know little of how cell signaling shapes this organelle. We now find that the Abl tyrosine kinase signaling pathway controls the architecture of the Golgi complex in Drosophila photoreceptor (PR) neurons. The Abl effector, Enabled (Ena), selectively labels the cis-Golgi in developing PRs. Overexpression or loss of function of Ena increases the number of cis- and trans-Golgi cisternae per cell, and Ena overexpression also redistributes Golgi to the most basal portion of the cell soma. Loss of Abl or its upstream regulator, the adaptor protein Disabled, lead to the same alterations of Golgi as does overexpression of Ena. The increase in Golgi number in Abl mutants arises in part from increased frequency of Golgi fission events and a decrease in fusions, as revealed by live imaging. Finally, we demonstrate that the effects of Abl signaling on Golgi are mediated via regulation of the actin cytoskeleton. Together, these data reveal a direct link between cell signaling and Golgi architecture. Moreover, they raise the possibility that some of the effects of Abl signaling may arise, in part, from alterations of protein trafficking and secretion.

scholarly journals Essential function of Drosophila Sec6 in apical exocytosis of epithelial photoreceptor cells

2005 ◽  
Vol 169 (4) ◽  
pp. 635-646 ◽  
Author(s):  
Slobodan Beronja ◽  
Patrick Laprise ◽  
Ophelia Papoulas ◽  
Milena Pellikka ◽  
John Sisson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Transport ◽  
Basolateral Membrane ◽  
Photoreceptor Cells ◽  
Secretory Vesicles ◽  
Membrane Domains ◽  
Animal Cells ◽  
Light Sensing ◽  
Membrane Growth ◽  
Essential Function

Polarized exocytosis plays a major role in development and cell differentiation but the mechanisms that target exocytosis to specific membrane domains in animal cells are still poorly understood. We characterized Drosophila Sec6, a component of the exocyst complex that is believed to tether secretory vesicles to specific plasma membrane sites. sec6 mutations cause cell lethality and disrupt plasma membrane growth. In developing photoreceptor cells (PRCs), Sec6 but not Sec5 or Sec8 shows accumulation at adherens junctions. In late PRCs, Sec6, Sec5, and Sec8 colocalize at the rhabdomere, the light sensing subdomain of the apical membrane. PRCs with reduced Sec6 function accumulate secretory vesicles and fail to transport proteins to the rhabdomere, but show normal localization of proteins to the apical stalk membrane and the basolateral membrane. Furthermore, we show that Rab11 forms a complex with Sec5 and that Sec5 interacts with Sec6 suggesting that the exocyst is a Rab11 effector that facilitates protein transport to the apical rhabdomere in Drosophila PRCs.

scholarly journals Proteomics of protein trafficking by in vivo tissue-specific labeling

2020 ◽  
Author(s):  
Ilia A. Droujinine ◽  
Dan Wang ◽  
Yanhui Hu ◽  
Namrata D. Udeshi ◽  
Luye Mu ◽  
...  
Keyword(s):  
Protein Trafficking ◽  
Large Scale ◽  
Fat Body ◽  
Secreted Proteins ◽  
Intracellular Protein ◽  
Quantitative Mass Spectrometry ◽  
Subcellular Compartment ◽  
Human Orthologs ◽  
Identification And Characterization

AbstractSecreted interorgan communication factors encode key regulators of homeostasis. However, long-standing questions surround their origins/destinations, mechanisms of interactions, and the number of proteins involved. Progress has been hindered by the lack of methodologies for these factors’ large-scale identification and characterization, as conventional approaches cannot identify low-abundance factors and the origins and destinations of secreted proteins. We established an in vivo platform to investigate secreted protein trafficking between organs proteome-wide, whereby engineered promiscuous biotin ligase BirA*G3 (a relative of TurboID) biotinylates all proteins in a subcellular compartment of one tissue, and biotinylated proteins are affinity-enriched and identified from distal organs using quantitative mass spectrometry. Using this platform, we identified 51 putative muscle-secreted proteins from heads and 269 fat body-secreted proteins from legs/muscles, of which 60-70% have human orthologs. We demonstrate, in particular, that conserved fat body-derived novel interorgan communication factors CG31326, CG2145, and CG4332 promote muscle activity. Our results indicate that the communication network of secreted proteins is vast, and we identified systemic functions for a number of these factors. This approach is widely applicable to studies in interorgan, local and intracellular protein trafficking networks, non-conventional secretion, and to mammalian systems, under healthy or diseased states.One Sentence SummaryWe developed an in vivo platform to investigate protein trafficking between organs proteome-wide, provide a resource for interorgan communication factors, and determined conserved adipokines that affect muscles.

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