1
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Liu X, Gao Y, Li Y, El Wakil A, Moussian B, Zhang J. Syntaxin5 is essential for survival by ensuring midgut epithelial homeostsis and regulating feeding in Locusta migratoria. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 202:105934. [PMID: 38879326 DOI: 10.1016/j.pestbp.2024.105934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/13/2024] [Accepted: 04/26/2024] [Indexed: 06/19/2024]
Abstract
Syntaxin5 (Syx5) belongs to SNAREs family, which play important roles in fusion of vesicles to target membranes. Most of what we know about functions of Syx5 originates from studies in fungal or vertebrate cells, how Syx5 operates during the development of insects is poorly understood. In this study, we investigated the role of LmSyx5 in the gut development of the hemimetabolous insect Locusta migratoria. LmSyx5 was expressed in many tissues, with higher levels in the gut. Knockdown of LmSyx5 by RNA interference (RNAi) considerably suppressed feeding in both nymphs and adults. The dsLmSyx5-injected locusts lost body weight and finally died at a mortality of 100%. Furthermore, hematoxylin-eosin staining indicated that the midgut is deformed in dsLmSyx5-treated nymphs and the brush border in midgut epithelial cells is severely damaged, suggesting that LmSyx5 is involved in morphogenesis of the midgut. TEM further showed that the endoplasmic reticulum of midgut cells have a bloated appearance. Taken together, these results suggest that LmSyx5 is essential for midgut epithelial homeostsis that affects growth and development of L. migratoria. Thus, Syx5 is a promising RNAi target for controlling L. migratoria, and even other pests.
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Affiliation(s)
- Xiaojian Liu
- Shanxi Key Laboratory of Nucleic Acid Biopesticides; Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Ya Gao
- Shanxi Key Laboratory of Nucleic Acid Biopesticides; Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yao Li
- Shanxi Key Laboratory of Nucleic Acid Biopesticides; Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Abeer El Wakil
- Faculty of Education, Department of Biological and Geological Sciences, Alexandria University, Alexandria, Egypt
| | - Bernard Moussian
- INRAE, CNRS, Université Côte d'Azur, Institut Sophia Agrobiotech, Sophia Antipolis, France
| | - Jianzhen Zhang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides; Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China.
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2
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Szenci G, Glatz G, Takáts S, Juhász G. The Ykt6-Snap29-Syx13 SNARE complex promotes crinophagy via secretory granule fusion with Lamp1 carrier vesicles. Sci Rep 2024; 14:3200. [PMID: 38331993 PMCID: PMC10853563 DOI: 10.1038/s41598-024-53607-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/02/2024] [Indexed: 02/10/2024] Open
Abstract
In the Drosophila larval salivary gland, developmentally programmed fusions between lysosomes and secretory granules (SGs) and their subsequent acidification promote the maturation of SGs that are secreted shortly before puparium formation. Subsequently, ongoing fusions between non-secreted SGs and lysosomes give rise to degradative crinosomes, where the superfluous secretory material is degraded. Lysosomal fusions control both the quality and quantity of SGs, however, its molecular mechanism is incompletely characterized. Here we identify the R-SNARE Ykt6 as a novel regulator of crinosome formation, but not the acidification of maturing SGs. We show that Ykt6 localizes to Lamp1+ carrier vesicles, and forms a SNARE complex with Syntaxin 13 and Snap29 to mediate fusion with SGs. These Lamp1 carriers represent a distinct vesicle population that are functionally different from canonical Arl8+, Cathepsin L+ lysosomes, which also fuse with maturing SGs but are controlled by another SNARE complex composed of Syntaxin 13, Snap29 and Vamp7. Ykt6- and Vamp7-mediated vesicle fusions also determine the fate of SGs, as loss of either of these SNAREs prevents crinosomes from acquiring endosomal PI3P. Our results highlight that fusion events between SGs and different lysosome-related vesicle populations are critical for fine regulation of the maturation and crinophagic degradation of SGs.
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Affiliation(s)
- Győző Szenci
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, 1117, Hungary
- Doctoral School of Biology, Institute of Biology, Eötvös Loránd University, Budapest, 1117, Hungary
| | - Gábor Glatz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, 1117, Hungary
| | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, 1117, Hungary.
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, 1117, Hungary.
- Institute of Genetics, HUN-REN Biological Research Centre Szeged, Szeged, 6726, Hungary.
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3
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Abstract
Intercellular communication by Wnt proteins governs many essential processes during development, tissue homeostasis and disease in all metazoans. Many context-dependent effects are initiated in the Wnt-producing cells and depend on the export of lipidated Wnt proteins. Although much focus has been on understanding intracellular Wnt signal transduction, the cellular machinery responsible for Wnt secretion became better understood only recently. After lipid modification by the acyl-transferase Porcupine, Wnt proteins bind their dedicated cargo protein Evi/Wntless for transport and secretion. Evi/Wntless and Porcupine are conserved transmembrane proteins, and their 3D structures were recently determined. In this Review, we summarise studies and structural data highlighting how Wnts are transported from the ER to the plasma membrane, and the role of SNX3-retromer during the recycling of its cargo receptor Evi/Wntless. We also describe the regulation of Wnt export through a post-translational mechanism and review the importance of Wnt secretion for organ development and cancer, and as a future biomarker.
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Affiliation(s)
- Lucie Wolf
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant and Department of Cell and Molecular Biology, 69120 Heidelberg, Germany
| | - Michael Boutros
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant and Department of Cell and Molecular Biology, 69120 Heidelberg, Germany
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4
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Sánchez-Martín P, Kriegenburg F, Alves L, Adam J, Elsaesser J, Babic R, Mancilla H, Licheva M, Tascher G, Münch C, Eimer S, Kraft C. ULK1-mediated phosphorylation regulates the conserved role of YKT6 in autophagy. J Cell Sci 2023; 136:jcs260546. [PMID: 36644903 PMCID: PMC10022743 DOI: 10.1242/jcs.260546] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/06/2023] [Indexed: 01/17/2023] Open
Abstract
Autophagy is a catabolic process during which cytosolic material is enwrapped in a newly formed double-membrane structure called the autophagosome, and subsequently targeted for degradation in the lytic compartment of the cell. The fusion of autophagosomes with the lytic compartment is a tightly regulated step and involves membrane-bound SNARE proteins. These play a crucial role as they promote lipid mixing and fusion of the opposing membranes. Among the SNARE proteins implicated in autophagy, the essential SNARE protein YKT6 is the only SNARE protein that is evolutionarily conserved from yeast to humans. Here, we show that alterations in YKT6 function, in both mammalian cells and nematodes, produce early and late autophagy defects that result in reduced survival. Moreover, mammalian autophagosomal YKT6 is phospho-regulated by the ULK1 kinase, preventing premature bundling with the lysosomal SNARE proteins and thereby inhibiting autophagosome-lysosome fusion. Together, our findings reveal that timely regulation of the YKT6 phosphorylation status is crucial throughout autophagy progression and cell survival.
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Affiliation(s)
- Pablo Sánchez-Martín
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Franziska Kriegenburg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Ludovico Alves
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Julius Adam
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Jana Elsaesser
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Riccardo Babic
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Hector Mancilla
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Georg Tascher
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Christian Münch
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Stefan Eimer
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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5
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Alvarez-Rodrigo I, Willnow D, Vincent JP. The logistics of Wnt production and delivery. Curr Top Dev Biol 2023; 153:1-60. [PMID: 36967191 DOI: 10.1016/bs.ctdb.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Wnts are secreted proteins that control stem cell maintenance, cell fate decisions, and growth during development and adult homeostasis. Wnts carry a post-translational modification not seen in any other secreted protein: during biosynthesis, they are appended with a palmitoleoyl moiety that is required for signaling but also impairs solubility and hence diffusion in the extracellular space. In some contexts, Wnts act only in a juxtacrine manner but there are also instances of long range action. Several proteins and processes ensure that active Wnts reach the appropriate target cells. Some, like Porcupine, Wntless, and Notum are dedicated to Wnt function; we describe their activities in molecular detail. We also outline how the cell infrastructure (secretory, endocytic, and retromer pathways) contribute to the progression of Wnts from production to delivery. We then address how Wnts spread in the extracellular space and form a signaling gradient despite carrying a hydrophobic moiety. We highlight particularly the role of lipid-binding Wnt interactors and heparan sulfate proteoglycans. Finally, we briefly discuss how evolution might have led to the emergence of this unusual signaling pathway.
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6
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Linnemannstöns K, Karuna M P, Witte L, Choezom D, Honemann‐Capito M, Lagurin AS, Schmidt CV, Shrikhande S, Steinmetz L, Wiebke M, Lenz C, Gross JC. Microscopic and biochemical monitoring of endosomal trafficking and extracellular vesicle secretion in an endogenous in vivo model. J Extracell Vesicles 2022; 11:e12263. [PMID: 36103151 PMCID: PMC9473323 DOI: 10.1002/jev2.12263] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/17/2022] [Accepted: 05/22/2022] [Indexed: 11/10/2022] Open
Abstract
Extracellular vesicle (EV) secretion enables cell-cell communication in multicellular organisms. During development, EV secretion and the specific loading of signalling factors in EVs contributes to organ development and tissue differentiation. Here, we present an in vivo model to study EV secretion using the fat body and the haemolymph of the fruit fly, Drosophila melanogaster. The system makes use of tissue-specific EV labelling and is amenable to genetic modification by RNAi. This allows the unique combination of microscopic visualisation of EVs in different organs and quantitative biochemical purification to study how EVs are generated within the cells and which factors regulate their secretion in vivo. Characterisation of the system revealed that secretion of EVs from the fat body is mainly regulated by Rab11 and Rab35, highlighting the importance of recycling Rab GTPase family members for EV secretion. We furthermore discovered a so far unknown function of Rab14 along with the kinesin Klp98A in EV biogenesis and secretion.
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Affiliation(s)
- Karen Linnemannstöns
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
- Hematology and OncologyUniversity Medical Center GoettingenGoettingenGermany
- Molecular OncologyUniversity Medical Center GoettingenGoettingenGermany
| | - Pradhipa Karuna M
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
| | - Leonie Witte
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
| | - Dolma Choezom
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
| | | | - Alex Simon Lagurin
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
| | | | - Shreya Shrikhande
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
| | | | - Möbius Wiebke
- Electron Microscopy Core Unit, Department of NeurogeneticsMax Planck Institute of Experimental MedicineGöttingenGermany
| | - Christof Lenz
- Institute of Clinical ChemistryUniversity Medical Center GöttingenGöttingenGermany
- Bioanalytical Mass Spectrometry GroupMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Julia Christina Gross
- Developmental BiochemistryUniversity Medical Center GoettingenGoettingenGermany
- Hematology and OncologyUniversity Medical Center GoettingenGoettingenGermany
- Department of MedicineHealth and Medical UniversityPotsdamGermany
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7
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Waghmare I, Page-McCaw A. Regulation of Wnt distribution and function by Drosophila glypicans. J Cell Sci 2022; 135:274233. [PMID: 35112708 PMCID: PMC8918805 DOI: 10.1242/jcs.259405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The extracellular distribution of secreted Wnt proteins is crucial for their ability to induce a response in target cells at short and long ranges to ensure proper development. Wnt proteins are evolutionarily conserved ligands that are lipid-modified, and their hydrophobic nature interferes with their solubility in the hydrophilic extracellular environment. This raises the question of how Wnt proteins spread extracellularly despite their lipid modifications, which are essential for both their secretion and function. Seminal studies on Drosophila Wingless (Wg), a prototypical Wnt, have discovered multiple mechanisms by which Wnt proteins spread. A central theme emerges from these studies: the Wnt lipid moiety is shielded from the aqueous environment, allowing the ligands to spread and remain viable for signaling. Wnt distribution in vivo is primarily facilitated by glypicans, which are cell-surface heparan sulfate proteoglycans, and recent studies have further provided mechanistic insight into how glypicans facilitate Wnt distribution. In this Review, we discuss the many diverse mechanisms of Wnt distribution, with a particular focus on glypican-mediated mechanisms.
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8
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Gross JC. Extracellular WNTs: Trafficking, Exosomes, and Ligand-Receptor Interaction. Handb Exp Pharmacol 2021; 269:29-43. [PMID: 34505202 DOI: 10.1007/164_2021_531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
WNT signaling is a key developmental pathway in tissue organization. A recent focus of research is the secretion of WNT proteins from source cells. Research over the past decade on how WNTs are produced and released into the extracellular space has unravelled very specific control mechanisms in the early secretory pathway, specialized trafficking routes, and redundant forms of packaging for delivery to target cells. In this review I discuss the findings that WNT proteins have been found on extracellular vesicles (EVs) such as exosomes and possible functional implications. There is an ongoing debate in the WNT signaling field whether EV are relevant in vivo and can fulfill specific functions, also fueled by the general preconception of EV secretion as cellular garbage disposal. As part of the EV research community, I want to give an overview of what we know and don't know about WNT secretion on EVs and offer a more unifying model that can explain current discrepancies in observations regarding WNT secretion.
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Affiliation(s)
- Julia Christina Gross
- Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany. .,Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany. .,Health and Medical University Potsdam, Potsdam, Germany.
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9
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Mehta S, Hingole S, Chaudhary V. The Emerging Mechanisms of Wnt Secretion and Signaling in Development. Front Cell Dev Biol 2021; 9:714746. [PMID: 34485301 PMCID: PMC8415634 DOI: 10.3389/fcell.2021.714746] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/20/2021] [Indexed: 12/22/2022] Open
Abstract
Wnts are highly-conserved lipid-modified secreted proteins that activate multiple signaling pathways. These pathways regulate crucial processes during various stages of development and maintain tissue homeostasis in adults. One of the most fascinating aspects of Wnt protein is that despite being hydrophobic, they are known to travel several cell distances in the extracellular space. Research on Wnts in the past four decades has identified several factors and uncovered mechanisms regulating their expression, secretion, and mode of extracellular travel. More recently, analyses on the importance of Wnt protein gradients in the growth and patterning of developing tissues have recognized the complex interplay of signaling mechanisms that help in maintaining tissue homeostasis. This review aims to present an overview of the evidence for the various modes of Wnt protein secretion and signaling and discuss mechanisms providing precision and robustness to the developing tissues.
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Affiliation(s)
| | | | - Varun Chaudhary
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
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10
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Sakata N, Shirakawa R, Goto K, Trinh DA, Horiuchi H. Double prenylation of SNARE protein Ykt6 is required for lysosomal hydrolase trafficking. J Biochem 2021; 169:363-370. [PMID: 33035318 DOI: 10.1093/jb/mvaa111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 09/18/2020] [Indexed: 11/14/2022] Open
Abstract
Ykt6 is an evolutionarily conserved SNARE protein regulating Golgi membrane fusion and other diverse membrane trafficking pathways. Unlike most SNARE proteins, Ykt6 lacks a transmembrane domain but instead has a tandem cysteine motif at the C-terminus. Recently, we have demonstrated that Ykt6 undergoes double prenylation at the C-terminal two cysteines first by farnesyltransferase and then by a newly identified protein prenyltransferase named geranylgeranyltransferase type-III (GGTase-III). GGTase-III consists of a novel α subunit prenyltransferase alpha subunit repeat containing 1 (PTAR1) and the β subunit of Rab geranylgeranyltransferase. PTAR1 knockout (KO) cells, where Ykt6 is singly prenylated with a farnesyl moiety, exhibit structural and functional abnormalities in the Golgi apparatus with delayed intra-Golgi trafficking and impaired protein glycosylation. It remains unclear whether the second prenylation of Ykt6 is required for proper trafficking of lysosomal hydrolases from Golgi to lysosomes. Here, we show that lysosomal hydrolases, cathepsin D and β-hexosaminidase, were missorted at the trans-Golgi network and secreted into the extracellular space in PTAR1 KO cells. Moreover, maturation of these hydrolases was disturbed. LC3B, an autophagy marker, was accumulated in PTAR1 KO cells, suggesting defects in cellular degradation pathways. Thus, doubly prenylated Ykt6, but not singly prenylated Ykt6, is critical for the efficient sorting and trafficking of acid hydrolases to lysosomes.
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Affiliation(s)
- Natsumi Sakata
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan
| | - Ryutaro Shirakawa
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan
| | - Kota Goto
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan
| | - Duc Anh Trinh
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan
| | - Hisanori Horiuchi
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan
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11
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Witte L, Linnemannstöns K, Honemann-Capito M, Gross JC. Visualization and Quantitation of Wg trafficking in the Drosophila Wing Imaginal Epithelium. Bio Protoc 2021; 11:e4040. [PMID: 34250206 DOI: 10.21769/bioprotoc.4040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/17/2021] [Accepted: 03/04/2021] [Indexed: 11/02/2022] Open
Abstract
Secretory Wnt trafficking can be studied in the polarized epithelial monolayer of Drosophila wing imaginal discs (WID). In this tissue, Wg (Drosophila Wnt-I) is presented on the apical surface of its source cells before being internalized into the endosomal pathway. Long-range Wg secretion and spread depend on secondary secretion from endosomal compartments, but the exact post-endocytic fate of Wg is poorly understood. Here, we summarize and present three protocols for the immunofluorescence-based visualization and quantitation of different pools of intracellular and extracellular Wg in WID: (1) steady-state extracellular Wg; (2) dynamic Wg trafficking inside endosomal compartments; and (3) dynamic Wg release to the cell surface. Using a genetic driver system for gene manipulation specifically at the posterior part of the WID (EnGal4) provides a robust internal control that allows for direct comparison of signal intensities of control and manipulated compartments of the same WID. Therefore, it also circumvents the high degree of staining variability usually associated with whole-tissue samples. In combination with the genetic manipulation of Wg pathway components that is easily feasible in Drosophila, these methods provide a tool-set for the dissection of secretory Wg trafficking and can help us to understand how Wnt proteins travel along endosomal compartments for short- and long-range signal secretion. Graphic abstract: Figure 1. Visualization of extracellular and intracellular Wg trafficking in Drosophila wing imaginal discs. While staining of extracellular Wg without permeabilization exclusively visualizes Wg bound to the extracellular surface (left), Wg uptake and endosomal trafficking can be visualized using an antibody uptake assay (middle). Dynamic Wg release can be visualized by performing a non-permeabilizing staining at a permissive temperature that sustains secretory Wg transport (right).
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Affiliation(s)
- Leonie Witte
- Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Karen Linnemannstöns
- Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Mona Honemann-Capito
- Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Julia Christina Gross
- Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany.,HMU Health and Medical University Potsdam, Potsdam, Germany
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12
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Serra ND, Sundaram MV. Transcytosis in the development and morphogenesis of epithelial tissues. EMBO J 2021; 40:e106163. [PMID: 33792936 DOI: 10.15252/embj.2020106163] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 12/21/2020] [Accepted: 01/14/2021] [Indexed: 12/15/2022] Open
Abstract
Transcytosis is a form of specialized transport through which an extracellular cargo is endocytosed, shuttled across the cytoplasm in membrane-bound vesicles, and secreted at a different plasma membrane surface. This important process allows membrane-impermeable macromolecules to pass through a cell and become accessible to adjacent cells and tissue compartments. Transcytosis also promotes redistribution of plasma membrane proteins and lipids to different regions of the cell surface. Here we review transcytosis and highlight in vivo studies showing how developing epithelial cells use it to change shape, to migrate, and to relocalize signaling molecules.
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Affiliation(s)
- Nicholas D Serra
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Meera V Sundaram
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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13
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Wu YC, Chiang YC, Chou SH, Pan CL. Wnt signalling and endocytosis: Mechanisms, controversies and implications for stress responses. Biol Cell 2020; 113:95-106. [PMID: 33253438 DOI: 10.1111/boc.202000099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/15/2020] [Accepted: 11/25/2020] [Indexed: 01/17/2023]
Abstract
Wnt signalling is one of a few conserved pathways that control diverse aspects of development and morphogenesis in all metazoan species. Endocytosis is a key mechanism that regulates the secretion and graded extracellular distribution of Wnt glycoproteins from the source cells, as well as Wnt signal transduction in the receiving cells. However, controversies exist regarding the requirement of clathrin-dependent endocytosis in Wnt signalling. Various lines of evidence from recent studies suggest that Wnt-β-catenin signalling is also involved in the regulation of cellular stress responses in adulthood, a role that is beyond its canonical functions in animal development. In this review, we summarise recent advances in the molecular and cellular mechanisms by which endocytosis modulates Wnt signalling. We also discuss how Wnt signalling could be repurposed to regulate mitochondrial stress response in the nematode Caenorhabditis elegans.
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Affiliation(s)
- Yu-Chun Wu
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yueh-Chen Chiang
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shih-Hua Chou
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Liang Pan
- Institute of Molecular Medicine and Center for Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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14
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Karuna M P, Witte L, Linnemannstoens K, Choezom D, Danieli-Mackay A, Honemann-Capito M, Gross JC. Phosphorylation of Ykt6 SNARE Domain Regulates Its Membrane Recruitment and Activity. Biomolecules 2020; 10:biom10111560. [PMID: 33207719 PMCID: PMC7696345 DOI: 10.3390/biom10111560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/17/2022] Open
Abstract
Sensitive factor attachment protein receptors (SNARE) proteins are important mediators of protein trafficking that regulate the membrane fusion of specific vesicle populations and their target organelles. The SNARE protein Ykt6 lacks a transmembrane domain and attaches to different organelle membranes. Mechanistically, Ykt6 activity is thought to be regulated by a conformational change from a closed cytosolic form to an open membrane-bound form, yet the mechanism that regulates this transition is unknown. We identified phosphorylation sites in the SNARE domain of Ykt6 that mediate Ykt6 membrane recruitment and are essential for cellular growth. Using proximity-dependent labeling and membrane fractionation, we found that phosphorylation regulates Ykt6 conversion from a closed to an open conformation. This conformational switch recruits Ykt6 to several organelle membranes, where it functionally regulates the trafficking of Wnt proteins and extracellular vesicle secretion in a concentration-dependent manner. We propose that phosphorylation of its SNARE domain leads to a conformational switch from a cytosolic, auto-inhibited Ykt6 to an active SNARE at different membranes.
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Affiliation(s)
- Pradhipa Karuna M
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Leonie Witte
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Karen Linnemannstoens
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Dolma Choezom
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Adi Danieli-Mackay
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Mona Honemann-Capito
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Julia Christina Gross
- Hematology and Oncology, University Medical Center Goettingen, 37077 Goettingen, Germany; (P.K.M.); (L.W.); (K.L.); (D.C.); (A.D.-M.); (M.H.-C.)
- Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
- HMU Health and Medical University Potsdam, 14471 Potsdam, Germany
- Correspondence:
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Witte L, Linnemannstöns K, Schmidt K, Honemann-Capito M, Grawe F, Wodarz A, Gross JC. The kinesin motor Klp98A mediates apical to basal Wg transport. Development 2020; 147:dev.186833. [PMID: 32665246 PMCID: PMC7438014 DOI: 10.1242/dev.186833] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/02/2020] [Indexed: 12/23/2022]
Abstract
Development and tissue homeostasis rely on the tight regulation of morphogen secretion. In the Drosophila wing imaginal disc epithelium, Wg secretion for long-range signal transduction occurs after apical Wg entry into the endosomal system, followed by secretory endosomal transport. Although Wg release appears to occur from the apical and basal cell sides, its exact post-endocytic fate and the functional relevance of polarized endosomal Wg trafficking are poorly understood. Here, we identify the kinesin-3 family member Klp98A as the master regulator of intracellular Wg transport after apical endocytosis. In the absence of Klp98A, functional mature endosomes accumulate in the apical cytosol, and endosome transport to the basal cytosol is perturbed. Despite the resulting Wg mislocalization, Wg signal transduction occurs normally. We conclude that transcytosis-independent routes for Wg trafficking exist and demonstrate that Wg can be recycled apically via Rab4-recycling endosomes in the absence of Klp98A. Summary: In the polarized wing disc epithelium of Drosophila, Kinesin-like protein 98A mediates transcytosis of multivesicular endosomes.
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Affiliation(s)
- Leonie Witte
- Hematology and Oncology, University Medical Center Goettingen, 37075 Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Karen Linnemannstöns
- Hematology and Oncology, University Medical Center Goettingen, 37075 Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Kevin Schmidt
- Hematology and Oncology, University Medical Center Goettingen, 37075 Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Mona Honemann-Capito
- Hematology and Oncology, University Medical Center Goettingen, 37075 Goettingen, Germany.,Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
| | - Ferdinand Grawe
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, 50931 Cologne, Germany.,Cluster of Excellence-Cellular Stress Response in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Andreas Wodarz
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, 50931 Cologne, Germany.,Cluster of Excellence-Cellular Stress Response in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Julia Christina Gross
- Hematology and Oncology, University Medical Center Goettingen, 37075 Goettingen, Germany .,Developmental Biochemistry, University Medical Center Goettingen, 37077 Goettingen, Germany
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