The ESCRT Machinery regulates Retromer dependent Transcytosis of Septate Junction Components in Drosophila

Loss of ESCRT function in Drosophila imaginal discs is known to cause neoplastic overgrowth fuelled by mis-regulation of signalling pathways. Its impact on junctional integrity, however, remains obscure. To dissect the events leading to neoplasia, we used transmission electron microscopy (TEM) on wing imaginal discs temporally depleted of the ESCRT-III core component Shrub. We find a specific requirement for Shrub in maintaining Septate Junction (SJ) integrity by transporting the Claudin Megatrachea (Mega) to the SJ. In absence of Shrub function, Mega is lost from the SJ and becomes trapped on endosomes coated with the endosomal retrieval machinery Retromer. We show that ESCRT function is required for apical localization and mobility of Retromer positive carrier vesicles, which mediate the biosynthetic delivery of Mega to the SJ. Accordingly, loss of Retromer function impairs the anterograde transport of several SJ core components, revealing a novel physiological role for this ancient endosomal agent.

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Expanding the Junction: New Insights into Non-Occluding Roles for Septate Junction Proteins during Development

Journal of Developmental Biology ◽

10.3390/jdb9010011 ◽

2021 ◽

Vol 9 (1) ◽

pp. 11

Author(s):

Clinton Rice ◽

Oindrila De ◽

Haifa Alhadyian ◽

Sonia Hall ◽

Robert E. Ward

Keyword(s):

Drosophila Melanogaster ◽

Barrier Function ◽

Septate Junction ◽

Accessory Proteins ◽

Organ Function ◽

The Past ◽

Core Components ◽

Developmental Contexts ◽

Mechanistic Understanding ◽

Junction Proteins

The septate junction (SJ) provides an occluding function for epithelial tissues in invertebrate organisms. This ability to seal the paracellular route between cells allows internal tissues to create unique compartments for organ function and endows the epidermis with a barrier function to restrict the passage of pathogens. Over the past twenty-five years, numerous investigators have identified more than 30 proteins that are required for the formation or maintenance of the SJs in Drosophila melanogaster, and have determined many of the steps involved in the biogenesis of the junction. Along the way, it has become clear that SJ proteins are also required for a number of developmental events that occur throughout the life of the organism. Many of these developmental events occur prior to the formation of the occluding junction, suggesting that SJ proteins possess non-occluding functions. In this review, we will describe the composition of SJs, taking note of which proteins are core components of the junction versus resident or accessory proteins, and the steps involved in the biogenesis of the junction. We will then elaborate on the functions that core SJ proteins likely play outside of their role in forming the occluding junction and describe studies that provide some cell biological perspectives that are beginning to provide mechanistic understanding of how these proteins function in developmental contexts.

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Discovery of wing imaginal discs in the penultimate instar of the lacewing Mallada desjardinsi (Insecta: Neuroptera: Chrysopidae) with histological notes on postembryonic imaginal disc development

Journal of Morphology ◽

10.1002/jmor.21338 ◽

2021 ◽

Vol 282 (5) ◽

pp. 679-684

Author(s):

Shuhei Niitsu ◽

Masayuki Hayashi ◽

Taichi Nemoto ◽

Masashi Nomura ◽

Takehiko Kamito

Keyword(s):

Imaginal Disc ◽

Imaginal Discs ◽

Wing Imaginal Discs

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Oligomerization and endocytosis of Hedgehog is necessary for its efficient exovesicular secretion

Molecular Biology of the Cell ◽

10.1091/mbc.e15-09-0671 ◽

2015 ◽

Vol 26 (25) ◽

pp. 4700-4717 ◽

Cited By ~ 22

Author(s):

Anup Parchure ◽

Neha Vyas ◽

Charles Ferguson ◽

Robert G. Parton ◽

Satyajit Mayor

Keyword(s):

Cell Surface ◽

Long Range ◽

Imaginal Discs ◽

Multivesicular Bodies ◽

Selective Effect ◽

Endosomal Sorting ◽

Drosophila Wing ◽

Dependent Process ◽

Wing Imaginal Discs ◽

Hh Signaling

Hedgehog (Hh) is a secreted morphogen involved in both short- and long-range signaling necessary for tissue patterning during development. It is unclear how this dually lipidated protein is transported over a long range in the aqueous milieu of interstitial spaces. We previously showed that the long-range signaling of Hh requires its oligomerization. Here we show that Hh is secreted in the form of exovesicles. These are derived by the endocytic delivery of cell surface Hh to multivesicular bodies (MVBs) via an endosomal sorting complex required for transport (ECSRT)–dependent process. Perturbations of ESCRT proteins have a selective effect on long-range Hh signaling in Drosophila wing imaginal discs. Of importance, oligomerization-defective Hh is inefficiently incorporated into exovesicles due to its poor endocytic delivery to MVBs. These results provide evidence that nanoscale organization of Hh regulates the secretion of Hh on ESCRT-derived exovesicles, which in turn act as a vehicle for long-range signaling.

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The Serrate locus of Drosophila and its role in morphogenesis of the wing imaginal discs: control of cell proliferation

Development ◽

10.1242/dev.120.3.535 ◽

1994 ◽

Vol 120 (3) ◽

pp. 535-544 ◽

Cited By ~ 38

Author(s):

S.A. Speicher ◽

U. Thomas ◽

U. Hinz ◽

E. Knust

Keyword(s):

Cell Proliferation ◽

Transmembrane Protein ◽

Ectopic Expression ◽

Imaginal Discs ◽

Specific Cell ◽

Loss Of Function ◽

Severe Reduction ◽

Homozygous Mutant ◽

Wing Imaginal Discs ◽

Larval Lethality

The Drosophila gene Serrate encodes a transmembrane protein with 14 EGF-like repeats in its extracellular domain. Here we show that loss-of-function mutations in this gene lead to larval lethality. Homozygous mutant larvae fail to differentiate the anterior spiracles, exhibit poorly developed mouth-hooks and show a severe reduction in the size of the wing and haltere primordia, which is not due to cell death. The few homozygous mutant escapers that pupariate develop into pharate adults that almost completely lack wings and halteres. Clonal analysis in the adult epidermis demonstrates a requirement for Serrate during wing and haltere development. Targeted ectopic expression of Serrate in the imaginal discs using the yeast transcriptional activator Gal4 results in regionally restricted induction of cell proliferation, e.g. the ventral tissues in the case of the wings and halteres. The results suggest that the wild-type function of Serrate is required for the control of position-specific cell proliferation during development of meso- and metathoracic dorsal discs, which in turn exerts a direct effect on morphogenesis.

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Role of D-GADD45 in JNK-Dependent Apoptosis and Regeneration in Drosophila

Genes ◽

10.3390/genes10050378 ◽

2019 ◽

Vol 10 (5) ◽

pp. 378 ◽

Cited By ~ 2

Author(s):

Carlos Camilleri-Robles ◽

Florenci Serras ◽

Montserrat Corominas

Keyword(s):

Cell Cycle ◽

Cell Death ◽

Cell Cycle Control ◽

Imaginal Discs ◽

Cellular Functions ◽

Correct Function ◽

Response To Stress ◽

Wing Imaginal Discs ◽

Harmful Effects

The GADD45 proteins are induced in response to stress and have been implicated in the regulation of several cellular functions, including DNA repair, cell cycle control, senescence, and apoptosis. In this study, we investigate the role of D-GADD45 during Drosophila development and regeneration of the wing imaginal discs. We find that higher expression of D-GADD45 results in JNK-dependent apoptosis, while its temporary expression does not have harmful effects. Moreover, D-GADD45 is required for proper regeneration of wing imaginal discs. Our findings demonstrate that a tight regulation of D-GADD45 levels is required for its correct function both, in development and during the stress response after cell death.

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Chitin synthesis inSpodoptera frugiperda wing imaginal discs. III: Role of the peripodial membrane

Archives of Insect Biochemistry and Physiology ◽

10.1002/arch.940280207 ◽

1995 ◽

Vol 28 (2) ◽

pp. 173-187 ◽

Cited By ~ 5

Author(s):

Piotr Miko?ajczyk ◽

Grazyna Zimowska ◽

Herbert Oberlander ◽

Donald L. Silhacek

Keyword(s):

Imaginal Discs ◽

Chitin Synthesis ◽

Wing Imaginal Discs

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Finger-Like Carbon-Based Nanostructures Produced by Combustion of Flour-Based Sticks (Spaghetti)

C – Journal of Carbon Research ◽

10.3390/c5020021 ◽

2019 ◽

Vol 5 (2) ◽

pp. 21 ◽

Cited By ~ 1

Author(s):

Frederik Ossler ◽

Crispin J. D. Hetherington

Keyword(s):

Electron Microscopy ◽

Carbon Film ◽

Tube Formation ◽

X Ray ◽

The Core ◽

Carbon Structures ◽

Transmission Electron ◽

Core Components ◽

Biomass Materials ◽

Graphene Structures

Biomass is becoming particularly important as a starting material for advanced carbon structures. In this study, we found interesting nanostructures on the surface of burnt spaghetti using scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) for analysis. The structures were elongated and finger-like, with evidence that the tubes have shell and core components. The shell was carbon that included amorphous and layered graphene structures. EDX showed enriched potassium and phosphorous in the core and at the tip of the tubes. The results indicate that tube formation depends on phase separation of polar/ionic and nonpolar moieties when water is produced in the biomass from the pyrolysis/combustion. The tube growth is most probably due to the raising pressure of vapor that cannot escape through the carbon film that is formed at the surface of the stick from flame heat. This process resembles glass blowing or volcanic activity, where the carbon acts as the glass or earth’s crust, respectively. These observations suggest that new interesting tubular nanostructures with different properties on the inside and outside can be produced in a relatively simple way, utilizing processes of combustion of starch-rich biomass materials.

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