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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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Li Z, Qian W, Song W, Zhao T, Yang Y, Wang W, Wei L, Zhao D, Li Y, Perrimon N, Xia Q, Cheng D. A salivary gland-secreted peptide regulates insect systemic growth. Cell Rep 2022; 38:110397. [PMID: 35196492 DOI: 10.1016/j.celrep.2022.110397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/10/2021] [Accepted: 01/26/2022] [Indexed: 11/03/2022] Open
Abstract
Insect salivary glands have been previously shown to function in pupal attachment and food lubrication by secreting factors into the lumen via an exocrine way. Here, we find in Drosophila that a salivary gland-derived secreted factor (Sgsf) peptide regulates systemic growth via an endocrine way. Sgsf is specifically expressed in salivary glands and secreted into the hemolymph. Sgsf knockout or salivary gland-specific Sgsf knockdown decrease the size of both the body and organs, phenocopying the effects of genetic ablation of salivary glands, while salivary gland-specific Sgsf overexpression increases their size. Sgsf promotes systemic growth by modulating the secretion of the insulin-like peptide Dilp2 from the brain insulin-producing cells (IPCs) and affecting mechanistic target of rapamycin (mTOR) signaling in the fat body. Altogether, our study demonstrates that Sgsf mediates the roles of salivary glands in Drosophila systemic growth, establishing an endocrine function of salivary glands.
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Affiliation(s)
- Zheng Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Wenliang Qian
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Wei Song
- Medical Research Institute, Wuhan University, Wuhan 430071, China; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Tujing Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Yan Yang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Weina Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Ling Wei
- School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Dongchao Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Yaoyao Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China.
| | - Daojun Cheng
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China.
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Duan J, Zhao Y, Li H, Habernig L, Gordon MD, Miao X, Engström Y, Büttner S. Bab2 Functions as an Ecdysone-Responsive Transcriptional Repressor during Drosophila Development. Cell Rep 2020; 32:107972. [PMID: 32726635 DOI: 10.1016/j.celrep.2020.107972] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/30/2020] [Accepted: 07/08/2020] [Indexed: 12/01/2022] Open
Abstract
Drosophila development is governed by distinct ecdysone steroid pulses that initiate spatially and temporally defined gene expression programs. The translation of these signals into tissue-specific responses is crucial for metamorphosis, but the mechanisms that confer specificity to systemic ecdysone pulses are far from understood. Here, we identify Bric-à-brac 2 (Bab2) as an ecdysone-responsive transcriptional repressor that controls temporal gene expression during larval to pupal transition. Bab2 is necessary to terminate Salivary gland secretion (Sgs) gene expression, while premature Bab2 expression blocks Sgs genes and causes precocious salivary gland histolysis. The timely expression of bab2 is controlled by the ecdysone-responsive transcription factor Broad, and manipulation of EcR/USP/Broad signaling induces inappropriate Bab2 expression and termination of Sgs gene expression. Bab2 directly binds to Sgs loci in vitro and represses all Sgs genes in vivo. Our work characterizes Bab2 as a temporal regulator of somatic gene expression in response to systemic ecdysone signaling.
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Affiliation(s)
- Jianli Duan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yunpo Zhao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China; Department of Zoology, Life Science Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
| | - Haichao Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Michael D Gordon
- Department of Zoology, Life Science Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Xuexia Miao
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
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4
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A putative UDP-glycosyltransferase from Heterorhabditis bacteriophora suppresses antimicrobial peptide gene expression and factors related to ecdysone signaling. Sci Rep 2020; 10:12312. [PMID: 32704134 PMCID: PMC7378173 DOI: 10.1038/s41598-020-69306-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/12/2020] [Indexed: 12/20/2022] Open
Abstract
Insect pathogens have adopted an array of mechanisms to subvert the immune pathways of their respective hosts. Suppression may occur directly at the level of host-pathogen interactions, for instance phagocytic capacity or phenoloxidase activation, or at the upstream signaling pathways that regulate these immune effectors. Insect pathogens of the family Baculoviridae, for example, are known to produce a UDP-glycosyltransferase (UGT) that negatively regulates ecdysone signaling. Normally, ecdysone positively regulates both molting and antimicrobial peptide production, so the inactivation of ecdysone by glycosylation results in a failure of host larvae to molt, and probably a reduced antimicrobial response. Here, we examine a putative ecdysteroid glycosyltransferase, Hba_07292 (Hb-ugt-1), which was previously identified in the hemolymph-activated transcriptome of the entomopathogenic nematode Heterorhabditis bacteriophora. Injection of recombinant Hb-ugt-1 (rHb-ugt-1) into Drosophila melanogaster flies resulted in diminished upregulation of antimicrobial peptides associated with both the Toll and Immune deficiency pathways. Ecdysone was implicated in this suppression by a reduction in Broad Complex expression and reduced pupation rates in r Hb-ugt-1-injected larvae. In addition to the finding that H. bacteriophora excreted-secreted products contain glycosyltransferase activity, these results demonstrate that Hb-ugt-1 is an immunosuppressive factor and that its activity likely involves the inactivation of ecdysone.
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Pan X, Neufeld TP, O'Connor MB. A Tissue- and Temporal-Specific Autophagic Switch Controls Drosophila Pre-metamorphic Nutritional Checkpoints. Curr Biol 2019; 29:2840-2851.e4. [PMID: 31422886 DOI: 10.1016/j.cub.2019.07.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/24/2019] [Accepted: 07/10/2019] [Indexed: 01/28/2023]
Abstract
Properly timed production of steroid hormones by endocrine tissues regulates juvenile-to-adult transitions in both mammals (puberty) and holometabolous insects (metamorphosis). Nutritional conditions influence the temporal control of the transition, but the mechanisms responsible are ill defined. Here we demonstrate that autophagy acts as an endocrine organ-specific, nutritionally regulated gating mechanism to help ensure productive metamorphosis in Drosophila. Autophagy in the endocrine organ is specifically stimulated by nutrient restriction at the early, but not the late, third-instar larva stage. The timing of autophagy induction correlates with the nutritional checkpoints, which inhibit precocious metamorphosis during nutrient restriction in undersized larvae. Suppression of autophagy causes dysregulated pupariation of starved larvae, which leads to pupal lethality, whereas forced autophagy induction results in developmental delay/arrest in well-fed animals. Induction of autophagy disrupts production of the steroid hormone ecdysone at the time of pupariation not by destruction of hormone biosynthetic capacity but rather by limiting the availability of the steroid hormone precursor cholesterol in the endocrine cells via a lipophagy mechanism. Interestingly, autophagy in the endocrine organ functions by interacting with the endolysosome system, yet shows multiple features not fully consistent with a canonical autophagy process. Taken together, our findings demonstrate an autophagy mechanism in endocrine cells that helps shape the nutritional checkpoints and guarantee a successful juvenile-to-adult transition in animals confronting nutritional stress.
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Affiliation(s)
- Xueyang Pan
- Department of Genetics, Cell Biology and Development and the Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology and Development and the Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael B O'Connor
- Department of Genetics, Cell Biology and Development and the Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA.
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Moulos P, Alexandratos A, Nellas I, Dedos SG. Refining a steroidogenic model: an analysis of RNA-seq datasets from insect prothoracic glands. BMC Genomics 2018; 19:537. [PMID: 30005604 PMCID: PMC6045881 DOI: 10.1186/s12864-018-4896-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/25/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The prothoracic gland (PG), the principal steroidogenic organ of insects, has been proposed as a model for steroid hormone biosynthesis and regulation. RESULTS To validate the robustness of the model, we present an analysis of accumulated transcriptomic data from PGs of two model species, Drosophila melanogaster and Bombyx mori. We identify that the common core components of the model in both species are encoded by nine genes. Five of these are Halloween genes whose expression differs substantially between the PGs of these species. CONCLUSIONS We conclude that the PGs can be a model for steroid hormone synthesis and regulation within the context of mitochondrial cholesterol transport and steroid biosynthesis but beyond these core mechanisms, gene expression in insect PGs is too diverse to fit in a context-specific model and should be analysed within a species-specific framework.
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Affiliation(s)
- Panagiotis Moulos
- HybridStat Predictive Analytics, Aiolou 19, 10551 Athens, Greece
- Biomedical Sciences Research Center ‘Alexander Fleming’, Fleming 34, 16672 Vari, Greece
| | | | - Ioannis Nellas
- Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Skarlatos G. Dedos
- Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
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