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Skouloudaki K, Papadopoulos DK, Tomancak P, Knust E. The apical protein Apnoia interacts with Crumbs to regulate tracheal growth and inflation. PLoS Genet 2019; 15:e1007852. [PMID: 30645584 PMCID: PMC6333334 DOI: 10.1371/journal.pgen.1007852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/25/2018] [Indexed: 12/21/2022] Open
Abstract
Most organs of multicellular organisms are built from epithelial tubes. To exert their functions, tubes rely on apico-basal polarity, on junctions, which form a barrier to separate the inside from the outside, and on a proper lumen, required for gas or liquid transport. Here we identify apnoia (apn), a novel Drosophila gene required for tracheal tube elongation and lumen stability at larval stages. Larvae lacking Apn show abnormal tracheal inflation and twisted airway tubes, but no obvious defects in early steps of tracheal maturation. apn encodes a transmembrane protein, primarily expressed in the tracheae, which exerts its function by controlling the localization of Crumbs (Crb), an evolutionarily conserved apical determinant. Apn physically interacts with Crb to control its localization and maintenance at the apical membrane of developing airways. In apn mutant tracheal cells, Crb fails to localize apically and is trapped in retromer-positive vesicles. Consistent with the role of Crb in apical membrane growth, RNAi-mediated knockdown of Crb results in decreased apical surface growth of tracheal cells and impaired axial elongation of the dorsal trunk. We conclude that Apn is a novel regulator of tracheal tube expansion in larval tracheae, the function of which is mediated by Crb.
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Affiliation(s)
- Kassiani Skouloudaki
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EK); (KS)
| | | | - Pavel Tomancak
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Elisabeth Knust
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EK); (KS)
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52
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Lund VK, Madsen KL, Kjaerulff O. Drosophila Rab2 controls endosome-lysosome fusion and LAMP delivery to late endosomes. Autophagy 2018; 14:1520-1542. [PMID: 29940804 PMCID: PMC6135592 DOI: 10.1080/15548627.2018.1458170] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Rab2 is a conserved Rab GTPase with a well-established role in secretory pathway function and phagocytosis. Here we demonstrate that Drosophila Rab2 is recruited to late endosomal membranes, where it controls the fusion of LAMP-containing biosynthetic carriers and lysosomes to late endosomes. In contrast, the lysosomal GTPase Gie/Arl8 is only required for late endosome-lysosome fusion, but not for the delivery of LAMP to the endocytic pathway. We also find that Rab2 is required for the fusion of autophagosomes to the endolysosomal pathway, but not for the biogenesis of lysosome-related organelles. Surprisingly, Rab2 does not rely on HOPS-mediated vesicular fusion for recruitment to late endosomal membranes. Our work suggests that Drosophila Rab2 is a central regulator of the endolysosomal and macroautophagic/autophagic pathways by controlling the major heterotypic fusion processes at the late endosome.
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Affiliation(s)
- Viktor Karlovich Lund
- a Department of Neuroscience, The Faculty of Health Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Kenneth Lindegaard Madsen
- a Department of Neuroscience, The Faculty of Health Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Ole Kjaerulff
- a Department of Neuroscience, The Faculty of Health Sciences , University of Copenhagen , Copenhagen , Denmark
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53
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Kovacs L, Chao-Chu J, Schneider S, Gottardo M, Tzolovsky G, Dzhindzhev NS, Riparbelli MG, Callaini G, Glover DM. Gorab is a Golgi protein required for structure and duplication of Drosophila centrioles. Nat Genet 2018; 50:1021-1031. [PMID: 29892014 PMCID: PMC6097609 DOI: 10.1038/s41588-018-0149-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 04/17/2018] [Indexed: 11/09/2022]
Abstract
We demonstrate that a Drosophila Golgi protein, Gorab, is present not only in the trans-Golgi but also in the centriole cartwheel where, complexed to Sas6, it is required for centriole duplication. In addition to centriole defects, flies lacking Gorab are uncoordinated due to defects in sensory cilia, which lose their nine-fold symmetry. We demonstrate the separation of centriole and Golgi functions of Drosophila Gorab in two ways: first, we have created Gorab variants that are unable to localize to trans-Golgi but can still rescue the centriole and cilia defects of gorab null flies; second, we show that expression of C-terminally tagged Gorab disrupts Golgi functions in cytokinesis of male meiosis, a dominant phenotype overcome by mutations preventing Golgi targeting. Our findings suggest that during animal evolution, a Golgi protein has arisen with a second, apparently independent, role in centriole duplication.
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Affiliation(s)
| | - Jennifer Chao-Chu
- University of Cambridge, Cambridge, UK
- The University of Hong Kong, Hong Kong, China
| | | | - Marco Gottardo
- University of Siena, Siena, Italy
- Alexander von Humboldt Foundation Fellow, Center for Molecular Medicine and Institute for Biochemistry of the University of Cologne, Cologne, Germany
| | - George Tzolovsky
- University of Cambridge, Cambridge, UK
- Carl Zeiss Microscopy Ltd, ZEISS Group, Cambridge, UK
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54
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Neuman SD, Bashirullah A. Hobbit regulates intracellular trafficking to drive insulin-dependent growth during Drosophila development. Development 2018; 145:dev161356. [PMID: 29891564 PMCID: PMC6031322 DOI: 10.1242/dev.161356] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/08/2018] [Indexed: 12/17/2022]
Abstract
All animals must coordinate growth rate and timing of maturation to reach the appropriate final size. Here, we describe hobbit, a novel and conserved gene identified in a forward genetic screen for Drosophila animals with small body size. hobbit is highly conserved throughout eukaryotes, but its function remains unknown. We demonstrate that hobbit mutant animals have systemic growth defects because they fail to secrete insulin. Other regulated secretion events also fail in hobbit mutant animals, including mucin-like 'glue' protein secretion from the larval salivary glands. hobbit mutant salivary glands produce glue-containing secretory granules that are reduced in size. Importantly, secretory granules in hobbit mutant cells lack essential membrane fusion machinery required for exocytosis, including Synaptotagmin 1 and the SNARE SNAP-24. These membrane fusion proteins instead accumulate inside enlarged late endosomes. Surprisingly, however, the Hobbit protein localizes to the endoplasmic reticulum. Our results suggest that Hobbit regulates a novel step in intracellular trafficking of membrane fusion proteins. Our studies also suggest that genetic control of body size, as a measure of insulin secretion, is a sensitive functional readout of the secretory machinery.
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Affiliation(s)
- Sarah D Neuman
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Arash Bashirullah
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI 53706, USA
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55
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Riedel F, Galindo A, Muschalik N, Munro S. The two TRAPP complexes of metazoans have distinct roles and act on different Rab GTPases. J Cell Biol 2017; 217:601-617. [PMID: 29273580 PMCID: PMC5800803 DOI: 10.1083/jcb.201705068] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 10/19/2017] [Accepted: 11/27/2017] [Indexed: 12/03/2022] Open
Abstract
In yeast, the TRAPP complexes activate Rab1 with TRAPPII also activating Rab11, but less is known about the two TRAPPs in metazoans. Riedel et al. show that in Drosophila melanogaster, TRAPPIII is an essential Rab1 activator, and TRAPPII activates Rab1 and Rab11 and becomes essential when an unrelated Rab11 activator is deleted. Originally identified in yeast, transport protein particle (TRAPP) complexes are Rab GTPase exchange factors that share a core set of subunits. TRAPPs were initially found to act on Ypt1, the yeast orthologue of Rab1, but recent studies have found that yeast TRAPPII can also activate the Rab11 orthologues Ypt31/32. Mammals have two TRAPP complexes, but their role is less clear, and they contain subunits that are not found in the yeast complexes but are essential for cell growth. To investigate TRAPP function in metazoans, we show that Drosophila melanogaster have two TRAPP complexes similar to those in mammals and that both activate Rab1, whereas one, TRAPPII, also activates Rab11. TRAPPII is not essential but becomes so in the absence of the gene parcas that encodes the Drosophila orthologue of the SH3BP5 family of Rab11 guanine nucleotide exchange factors (GEFs). Thus, in metazoans, Rab1 activation requires TRAPP subunits not found in yeast, and Rab11 activation is shared by TRAPPII and an unrelated GEF that is metazoan specific.
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Affiliation(s)
- Falko Riedel
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Antonio Galindo
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Nadine Muschalik
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Sean Munro
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
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56
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Abstract
Tango1 enables ER-to-Golgi trafficking of large proteins. We show here that loss of Tango1, in addition to disrupting protein secretion and ER/Golgi morphology, causes ER stress and defects in cell shape. We find that the previously observed dependence of smaller cargos on Tango1 is a secondary effect. If large cargos like Dumpy, which we identify as a Tango1 cargo, are removed from the cell, nonbulky proteins reenter the secretory pathway. Removal of blocking cargo also restores cell morphology and attenuates the ER-stress response. Thus, failures in the secretion of nonbulky proteins, ER stress, and defective cell morphology are secondary consequences of bulky cargo retention. By contrast, ER/Golgi defects in Tango1-depleted cells persist in the absence of bulky cargo, showing that they are due to a secretion-independent function of Tango1. Therefore, maintenance of ER/Golgi architecture and bulky cargo transport are the primary functions for Tango1.
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57
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Lőrincz P, Mauvezin C, Juhász G. Exploring Autophagy in Drosophila. Cells 2017; 6:cells6030022. [PMID: 28704946 PMCID: PMC5617968 DOI: 10.3390/cells6030022] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 07/06/2017] [Accepted: 07/08/2017] [Indexed: 12/11/2022] Open
Abstract
Autophagy is a catabolic process in eukaryotic cells promoting bulk or selective degradation of cellular components within lysosomes. In recent decades, several model systems were utilized to dissect the molecular machinery of autophagy and to identify the impact of this cellular “self-eating” process on various physiological and pathological processes. Here we briefly discuss the advantages and limitations of using the fruit fly Drosophila melanogaster, a popular model in cell and developmental biology, to apprehend the main pathway of autophagy in a complete animal.
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Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, H-1117 Budapest, Hungary.
| | - Caroline Mauvezin
- Catalan Institute of Oncology-IDIBELL, Laboratory of Cancer Metabolism (LMC), Hospital Duran i Reynals, 08908 Barcelona, Spain.
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, H-1117 Budapest, Hungary.
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, H-6726 Szeged, Hungary.
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58
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Lőrincz P, Tóth S, Benkő P, Lakatos Z, Boda A, Glatz G, Zobel M, Bisi S, Hegedűs K, Takáts S, Scita G, Juhász G. Rab2 promotes autophagic and endocytic lysosomal degradation. J Cell Biol 2017; 216:1937-1947. [PMID: 28483915 PMCID: PMC5496615 DOI: 10.1083/jcb.201611027] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/24/2017] [Accepted: 04/21/2017] [Indexed: 11/22/2022] Open
Abstract
Rab7 promotes fusion of autophagosomes and late endosomes with lysosomes. Lőrincz et al. show that Rab2 is critical for the delivery of autophagic and endocytic cargo to lysosomes and for their degradation, and that it promotes autophagosome–lysosome fusion. The results suggest Rab2 and Rab7 coordinately promote autophagic and endosomal degradation and lysosome function. Rab7 promotes fusion of autophagosomes and late endosomes with lysosomes in yeast and metazoan cells, acting together with its effector, the tethering complex HOPS. Here we show that another small GTPase, Rab2, is also required for autophagosome and endosome maturation and proper lysosome function in Drosophila melanogaster. We demonstrate that Rab2 binds to HOPS, and that its active, GTP-locked form associates with autolysosomes. Importantly, expression of active Rab2 promotes autolysosomal fusions unlike that of GTP-locked Rab7, suggesting that its amount is normally rate limiting. We also demonstrate that RAB2A is required for autophagosome clearance in human breast cancer cells. In conclusion, we identify Rab2 as a key factor for autophagic and endocytic cargo delivery to and degradation in lysosomes.
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Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Sarolta Tóth
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Péter Benkő
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Zsolt Lakatos
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Attila Boda
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Gábor Glatz
- Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged H-6726, Hungary
| | - Martina Zobel
- FIRC (Fondazione Italiana per la Ricerca sul Cancro) Institute of Molecular Oncology (IFOM), Milan 20139, Italy
| | - Sara Bisi
- FIRC (Fondazione Italiana per la Ricerca sul Cancro) Institute of Molecular Oncology (IFOM), Milan 20139, Italy
| | - Krisztina Hegedűs
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Giorgio Scita
- FIRC (Fondazione Italiana per la Ricerca sul Cancro) Institute of Molecular Oncology (IFOM), Milan 20139, Italy.,Department of Oncology and Hemato-Oncology, School of Medicine, University of Milan, Milan 20122, Italy
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary .,Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged H-6726, Hungary
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59
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Liu M, Feng Z, Ke H, Liu Y, Sun T, Dai J, Cui W, Pastor-Pareja JC. Tango1 spatially organizes ER exit sites to control ER export. J Cell Biol 2017; 216:1035-1049. [PMID: 28280122 PMCID: PMC5379956 DOI: 10.1083/jcb.201611088] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 01/03/2023] Open
Abstract
Exit of secretory cargo from the endoplasmic reticulum (ER) takes place at specialized domains called ER exit sites (ERESs). In mammals, loss of TANGO1 and other MIA/cTAGE (melanoma inhibitory activity/cutaneous T cell lymphoma-associated antigen) family proteins prevents ER exit of large cargoes such as collagen. Here, we show that Drosophila melanogaster Tango1, the only MIA/cTAGE family member in fruit flies, is a critical organizer of the ERES-Golgi interface. Tango1 rings hold COPII (coat protein II) carriers and Golgi in close proximity at their center. Loss of Tango1, present at ERESs in all tissues, reduces ERES size and causes ERES-Golgi uncoupling, which impairs secretion of not only collagen, but also all other cargoes we examined. Further supporting an organizing role of Tango1, its overexpression creates more and larger ERESs. Our results suggest that spatial coordination of ERES, carrier, and Golgi elements through Tango1's multiple interactions increases secretory capacity in Drosophila and allows secretion of large cargo.
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Affiliation(s)
- Min Liu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhi Feng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongmei Ke
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ying Liu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tianhui Sun
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianli Dai
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wenhong Cui
- School of Life Sciences, Tsinghua University, Beijing 100084, China
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60
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Caviglia S, Flores-Benitez D, Lattner J, Luschnig S, Brankatschk M. Rabs on the fly: Functions of Rab GTPases during development. Small GTPases 2017; 10:89-98. [PMID: 28118081 PMCID: PMC6380344 DOI: 10.1080/21541248.2017.1279725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The organization of intracellular transport processes is adapted specifically to different cell types, developmental stages, and physiologic requirements. Some protein traffic routes are universal to all cells and constitutively active, while other routes are cell-type specific, transient, and induced under particular conditions only. Small GTPases of the Rab (Ras related in brain) subfamily are conserved across eukaryotes and regulate most intracellular transit pathways. The complete sets of Rab proteins have been identified in model organisms, and molecular principles underlying Rab functions have been uncovered. Rabs provide intracellular landmarks that define intracellular transport sequences. Nevertheless, it remains a challenge to systematically map the subcellular distribution of all Rabs and their functional interrelations. This task requires novel tools to precisely describe and manipulate the Rab machinery in vivo. Here we discuss recent findings about Rab roles during development and we consider novel approaches to investigate Rab functions in vivo.
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Affiliation(s)
- Sara Caviglia
- a Danish Stem Cell Center (DanStem), University of Copenhagen , Copenhagen , Denmark.,c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland
| | - David Flores-Benitez
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Johanna Lattner
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Stefan Luschnig
- c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland.,d Institute of Neurobiology and Cluster of Excellence Cells-in-Motion (EXC 1003 - CiM), University of Münster , Münster , Germany
| | - Marko Brankatschk
- e The Biotechnological Center of the TU Dresden (BIOTEC) , Dresden , Germany
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61
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Fári K, Takács S, Ungár D, Sinka R. The role of acroblast formation during Drosophila spermatogenesis. Biol Open 2016; 5:1102-10. [PMID: 27481842 PMCID: PMC5004609 DOI: 10.1242/bio.018275] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Protein recycling is important for maintaining homeostasis of the Golgi and its cisternae. The Vps54 (Scat) protein, a subunit of the GARP tethering complex, is a central factor in retrograde transport to the trans-Golgi. We found the scat1 mutant to be male sterile in Drosophila with individualization problems occurring during spermatogenesis. Another typically observed phenotype was the abnormal nuclear structure in elongated mutant cysts. When examining the structure and function of the Golgi, a failure in acrosome formation and endosome-Golgi vesicular transport were found in the scat1 mutant. This acrosome formation defect was due to a fault in the trans-Golgi side of the acroblast ribbon. When testing a mutation in a second retrograde transport protein, Fws, a subunit of the conserved oligomeric Golgi (COG) tethering complex, the acroblast structure, was again disrupted. fwsP caused a similar, albeit milder, acrosome and sperm individualization phenotype as the scat1 mutant. In the case of fwsP the cis side of the acroblast ribbon was dispersed, in-line with the intra-Golgi retrograde function of COG. Our results highlight the importance of an intact acroblast for acrosome formation, nuclear elongation and therefore sperm maturation. Moreover, these results suggest the importance of retrograde tethering complexes in the formation of a functional Golgi ribbon. Summary: This study demonstrates that retrograde tethering complexes are necessary to form a functional acroblast, which is essential for normal nuclear elongation and acrosome formation during Drosophila spermatogenesis.
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Affiliation(s)
- Karolina Fári
- Department of Genetics, University of Szeged, Szeged 6726, Hungary
| | - Sándor Takács
- Department of Genetics, University of Szeged, Szeged 6726, Hungary
| | - Dániel Ungár
- Department of Biology, University of York, York YO10 5DD, UK
| | - Rita Sinka
- Department of Genetics, University of Szeged, Szeged 6726, Hungary
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