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Shimizu H, Hosseini-Alghaderi S, Woodcock SA, Baron M. Alternative mechanisms of Notch activation by partitioning into distinct endosomal domains. J Cell Biol 2024; 223:e202211041. [PMID: 38358349 PMCID: PMC10868400 DOI: 10.1083/jcb.202211041] [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] [Received: 11/11/2022] [Revised: 11/17/2023] [Accepted: 01/30/2024] [Indexed: 02/16/2024] Open
Abstract
Different membrane microdomain compositions provide unique environments that can regulate signaling receptor function. We identify microdomains on the endosome membrane of Drosophila endosomes, enriched in lipid-raft or clathrin/ESCRT-0, which are associated with Notch activation by distinct, ligand-independent mechanisms. Transfer of Notch between microdomains is regulated by Deltex and Suppressor of deltex ubiquitin ligases and is limited by a gate-keeper role for ESCRT complexes. Ubiquitination of Notch by Deltex recruits it to the clathrin/ESCRT-0 microdomain and enhances Notch activation by an ADAM10-independent/TRPML-dependent mechanism. This requirement for Deltex is bypassed by the downregulation of ESCRT-III. In contrast, while ESCRT-I depletion also activates Notch, it does so by an ADAM10-dependent/TRPML-independent mechanism and Notch is retained in the lipid raft-like microdomain. In the absence of such endosomal perturbation, different activating Notch mutations also localize to different microdomains and are activated by different mechanisms. Our findings demonstrate the interplay between Notch regulators, endosomal trafficking components, and Notch genetics, which defines membrane locations and activation mechanisms.
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Affiliation(s)
- Hideyuki Shimizu
- School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Samira Hosseini-Alghaderi
- School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Simon A. Woodcock
- School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Martin Baron
- School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
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2
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Xie Y, Tan Y, Wen X, Deng W, Yu J, Li M, Meng F, Wang X, Zhu D. The Expression and Function of Notch Involved in Ovarian Development and Fecundity in Basilepta melanopus. INSECTS 2024; 15:292. [PMID: 38667422 PMCID: PMC11050577 DOI: 10.3390/insects15040292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/10/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024]
Abstract
Basilepta melanopus is a pest that severely affects oil tea plants, and the Notch signaling pathway plays a significant role in the early development of insect ovaries. In this study, we explored the function of the notch gene within the Notch signaling pathway in the reproductive system of B. melanopus. The functional domains and expression patterns of Bmnotch were analyzed. Bmnotch contains 45 epidermal growth factor-like (EGF-like) domains, one negative regulatory region, one NODP domain and one repeat-containing domain superfamily. The qPCR reveals heightened expression in early developmental stages and specific tissues like the head and ovaries. The RNA interference (RNAi)-based suppression of notch decreased its expression by 52.1%, exhibiting heightened sensitivity to dsNotch at lower concentrations. Phenotypic and mating experiments have demonstrated that dsNotch significantly impairs ovarian development, leading to reduced mating frequencies and egg production. This decline underscores the Notch pathway's crucial role in fecundity. The findings advocate for RNAi-based, Notch-targeted pest control as an effective and sustainable strategy for managing B. melanopus populations, signifying a significant advancement in forest pest control endeavors.
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Affiliation(s)
- Yifei Xie
- Laboratory of Insect Behavior and Evolutionary Ecology, College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha 410004, China; (Y.X.); (Y.T.); (F.M.)
- Institute of Forestry and Grassland Protection, Hunan Academy of Forestry, Changsha 410018, China; (W.D.); (J.Y.); (M.L.)
| | - Yifan Tan
- Laboratory of Insect Behavior and Evolutionary Ecology, College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha 410004, China; (Y.X.); (Y.T.); (F.M.)
| | - Xuanye Wen
- Center for Biological Disaster Prevention and Control, National Forestry and Grassland Administration, Shenyang 110031, China;
| | - Wan Deng
- Institute of Forestry and Grassland Protection, Hunan Academy of Forestry, Changsha 410018, China; (W.D.); (J.Y.); (M.L.)
| | - Jinxiu Yu
- Institute of Forestry and Grassland Protection, Hunan Academy of Forestry, Changsha 410018, China; (W.D.); (J.Y.); (M.L.)
| | - Mi Li
- Institute of Forestry and Grassland Protection, Hunan Academy of Forestry, Changsha 410018, China; (W.D.); (J.Y.); (M.L.)
| | - Fanhui Meng
- Laboratory of Insect Behavior and Evolutionary Ecology, College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha 410004, China; (Y.X.); (Y.T.); (F.M.)
| | - Xiudan Wang
- Laboratory of Insect Behavior and Evolutionary Ecology, College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha 410004, China; (Y.X.); (Y.T.); (F.M.)
| | - Daohong Zhu
- Laboratory of Insect Behavior and Evolutionary Ecology, College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha 410004, China; (Y.X.); (Y.T.); (F.M.)
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3
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Chen Y, Li H, Yi TC, Shen J, Zhang J. Notch Signaling in Insect Development: A Simple Pathway with Diverse Functions. Int J Mol Sci 2023; 24:14028. [PMID: 37762331 PMCID: PMC10530718 DOI: 10.3390/ijms241814028] [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: 07/31/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Notch signaling is an evolutionarily conserved pathway which functions between adjacent cells to establish their distinct identities. Despite operating in a simple mechanism, Notch signaling plays remarkably diverse roles in development to regulate cell fate determination, organ growth and tissue patterning. While initially discovered and characterized in the model insect Drosophila melanogaster, recent studies across various insect species have revealed the broad involvement of Notch signaling in shaping insect tissues. This review focuses on providing a comprehensive picture regarding the roles of the Notch pathway in insect development. The roles of Notch in the formation and patterning of the insect embryo, wing, leg, ovary and several specific structures, as well as in physiological responses, are summarized. These results are discussed within the developmental context, aiming to deepen our understanding of the diversified functions of the Notch signaling pathway in different insect species.
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Affiliation(s)
- Yao Chen
- Department of Plant Biosecurity and MOA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Y.C.)
| | - Haomiao Li
- Department of Plant Biosecurity and MOA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Y.C.)
| | - Tian-Ci Yi
- Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China
| | - Jie Shen
- Department of Plant Biosecurity and MOA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Y.C.)
| | - Junzheng Zhang
- Department of Plant Biosecurity and MOA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing 100193, China; (Y.C.)
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4
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Endocytosis at the Crossroad of Polarity and Signaling Regulation: Learning from Drosophila melanogaster and Beyond. Int J Mol Sci 2022; 23:ijms23094684. [PMID: 35563080 PMCID: PMC9101507 DOI: 10.3390/ijms23094684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 02/06/2023] Open
Abstract
Cellular trafficking through the endosomal–lysosomal system is essential for the transport of cargo proteins, receptors and lipids from the plasma membrane inside the cells and across membranous organelles. By acting as sorting stations, vesicle compartments direct the fate of their content for degradation, recycling to the membrane or transport to the trans-Golgi network. To effectively communicate with their neighbors, cells need to regulate their compartmentation and guide their signaling machineries to cortical membranes underlying these contact sites. Endosomal trafficking is indispensable for the polarized distribution of fate determinants, adaptors and junctional proteins. Conversely, endocytic machineries cooperate with polarity and scaffolding components to internalize receptors and target them to discrete membrane domains. Depending on the cell and tissue context, receptor endocytosis can terminate signaling responses but can also activate them within endosomes that act as signaling platforms. Therefore, cell homeostasis and responses to environmental cues rely on the dynamic cooperation of endosomal–lysosomal machineries with polarity and signaling cues. This review aims to address advances and emerging concepts on the cooperative regulation of endocytosis, polarity and signaling, primarily in Drosophila melanogaster and discuss some of the open questions across the different cell and tissue types that have not yet been fully explored.
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E3 Ubiquitin Ligase Regulators of Notch Receptor Endocytosis: From Flies to Humans. Biomolecules 2022; 12:biom12020224. [PMID: 35204725 PMCID: PMC8961608 DOI: 10.3390/biom12020224] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 02/04/2023] Open
Abstract
Notch is a developmental receptor, conserved in the evolution of the metazoa, which regulates cell fate proliferation and survival in numerous developmental contexts, and also regulates tissue renewal and repair in adult organisms. Notch is activated by proteolytic removal of its extracellular domain and the subsequent release of its intracellular domain, which then acts in the nucleus as part of a transcription factor complex. Numerous regulatory mechanisms exist to tune the amplitude, duration and spatial patterning of this core signalling mechanism. In Drosophila, Deltex (Dx) and Suppressor of dx (Su(dx)) are E3 ubiquitin ligases which interact with the Notch intracellular domain to regulate its endocytic trafficking, with impacts on both ligand-dependent and ligand-independent signal activation. Homologues of Dx and Su(dx) have been shown to also interact with one or more of the four mammalian Notch proteins and other target substrates. Studies have shown similarities, specialisations and diversifications of the roles of these Notch regulators. This review collates together current research on vertebrate Dx and Su(dx)-related proteins, provides an overview of their various roles, and discusses their contributions to cell fate regulation and disease.
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Sang Q, Wang G, Morton DB, Wu H, Xie B. The ZO-1 protein Polychaetoid as an upstream regulator of the Hippo pathway in Drosophila. PLoS Genet 2021; 17:e1009894. [PMID: 34748546 PMCID: PMC8610254 DOI: 10.1371/journal.pgen.1009894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 11/23/2021] [Accepted: 10/19/2021] [Indexed: 01/15/2023] Open
Abstract
The generation of a diversity of photoreceptor (PR) subtypes with different spectral sensitivities is essential for color vision in animals. In the Drosophila eye, the Hippo pathway has been implicated in blue- and green-sensitive PR subtype fate specification. Specifically, Hippo pathway activation promotes green-sensitive PR fate at the expense of blue-sensitive PRs. Here, using a sensitized triple heterozygote-based genetic screening approach, we report the identification of the single Drosophila zonula occludens-1 (ZO-1) protein Polychaetoid (Pyd) as a new regulator of the Hippo pathway during the blue- and green-sensitive PR subtype binary fate choice. We demonstrate that Pyd acts upstream of the core components and the upstream regulator Pez in the Hippo pathway. Furthermore, We found that Pyd represses the activity of Su(dx), a E3 ligase that negatively regulates Pez and can physically interact with Pyd, during PR subtype fate specification. Together, our results identify a new mechanism underlying the Hippo signaling pathway in post-mitotic neuronal fate specification. The Hippo signaling pathway was originally discovered for its critical role in tissue growth and organ size control. Its evolutionarily conserved roles in various biological processes, including cell differentiation, stem cell regeneration and homeostasis, innate immune biology, as well as tumorigenesis, have been subsequently found in other species. During the development of the Drosophila eye, the Hippo pathway promotes green- and represses blue-sensitive photoreceptor (PR) subtype fate specification. Taking advantage of this binary PR fate choice, we screened Drosophila chromosomal deficiency lines to seek new regulators of the Hippo signaling pathway. We identified the Drosophila membrane-associated ZO-1 protein Pyd as an upstream regulator of the Hippo pathway to specify PR subtypes. Our results have demonstrated that Pyd represses Su(dx)’s activity in the Hippo pathway to specify PR subtypes. Our results demonstrate a new mechanism underlying the Hippo signaling pathway in post-mitotic neuronal fate specification.
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Affiliation(s)
- Qingliang Sang
- Integrative Biomedical and Diagnostic Sciences Department, School of Dentistry, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Gang Wang
- Integrative Biomedical and Diagnostic Sciences Department, School of Dentistry, Oregon Health and Science University, Portland, Oregon, United States of America
| | - David B. Morton
- Integrative Biomedical and Diagnostic Sciences Department, School of Dentistry, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Hui Wu
- Integrative Biomedical and Diagnostic Sciences Department, School of Dentistry, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Baotong Xie
- Integrative Biomedical and Diagnostic Sciences Department, School of Dentistry, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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7
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Distant activation of Notch signaling induces stem cell niche assembly. PLoS Genet 2021; 17:e1009489. [PMID: 33780456 PMCID: PMC8031783 DOI: 10.1371/journal.pgen.1009489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/08/2021] [Accepted: 03/15/2021] [Indexed: 11/26/2022] Open
Abstract
Here we show that multiple modes of Notch signaling activation specify the complexity of spatial cellular interactions necessary for stem cell niche assembly. In particular, we studied the formation of the germline stem cell niche in Drosophila ovaries, which is a two-step process whereby terminal filaments are formed first. Then, terminal filaments signal to the adjacent cap cell precursors, resulting in Notch signaling activation, which is necessary for the lifelong acquisition of stem cell niche cell fate. The genetic data suggest that in order to initiate the process of stem cell niche assembly, Notch signaling is activated among non-equipotent cells via distant induction, where germline Delta is delivered to somatic cells located several diameters away via cellular projections generated by primordial germ cells. At the same time, to ensure the robustness of niche formation, terminal filament cell fate can also be induced by somatic Delta via cis- or trans-inhibition. This exemplifies a double security mechanism that guarantees that the germline stem cell niche is formed, since it is indispensable for the adjacent germline precursor cells to acquire and maintain stemness necessary for successful reproduction. These findings contribute to our understanding of the formation of stem cell niches in their natural environment, which is important for stem cell biology and regenerative medicine. Adult organs often contain a stem cell niche that maintains stem cells necessary for the replenishment of different types of terminally differentiated cells that are continuously lost. This study reveals that various modes of Notch signaling activation induce the formation of the germline stem cell niche in Drosophila. We show for the first time that even among non-equipotent cells, Notch signaling can be trans-activated via distant induction mode, where the ligand Delta is delivered via cellular protrusions to the somatic stem cell niche precursors located several cell diameters away. Moreover, there is a second security mechanism controlled by the soma that additionally ensures that the stem cell niche is formed. In the stem cell niche precursors, Notch signaling can be locally inhibited by the somatic Delta. While Notch signaling trans-inhibition has been proposed via mathematical modelling, our findings show that a group of cells that have high Delta can be seen in a living organism, confirming that this mode of Notch signaling inhibition by trans-Delta exists in vivo. This work provides significant advances in the understanding of Notch signaling and the stem cell niche formation, which is important for the fields of stem cell biology and regenerative medicine.
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8
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Zhao S, Wu C, Gao Z, Li X, Guo Z, Wang Z. Notch signaling governs the expression of glypican Dally to define the stem cell niche. Biol Open 2020; 9:bio.047696. [PMID: 31826854 PMCID: PMC6994927 DOI: 10.1242/bio.047696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extracellular glypicans play pivotal roles in organogenesis, stem cell maintenance and cancer development. However, the growth phenotypes associated with different levels of glypican are not consistent in development or tumorigenesis. This requires clarification on how the spatial patterns of glypican relate to the distribution of signaling molecules in different cellular contexts, and how glypican expression is regulated. We have previously reported that Dally, one of the glypican members in Drosophila, is required in the niche for the maintenance of germline stem cells (GSCs) via short-range BMP signaling in ovary. However, the regulatory mechanism of glypican pattern in the ovarian stem cell niche remains elusive. Our current data demonstrate that the Notch pathway is genetically upstream of Dally and its function to maintain GSCs relies on Dally expression. Combining yeast and fruit fly genetics, we illustrate that Dally is under the transcriptional control of Notch signaling via the transcription factor Su(H). Further, we assayed human glypicans and disease-associated variants in Drosophila ovary, which can serve as an effective system to evaluate the structure–function relationship of human homologs. Summary: Spatial regulation of a cell surface glycoprotein defines the territory of germline stem cells.
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Affiliation(s)
- Songhua Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100049, China.,The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chan Wu
- The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyang Gao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Guo
- The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaohui Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100049, China .,The University of Chinese Academy of Sciences, Beijing 100049, China
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Lobo-Pecellín M, Marín-Menguiano M, González-Reyes A. mastermind regulates niche ageing independently of the Notch pathway in the Drosophila ovary. Open Biol 2019; 9:190127. [PMID: 31744422 PMCID: PMC6893403 DOI: 10.1098/rsob.190127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Proper stem cell activity in tissues ensures the correct balance between proliferation and differentiation, thus allowing tissue homeostasis and repair. The Drosophila ovary develops well-defined niches that contain on average 2–4 germline stem cells (GSCs), whose maintenance depends on systemic signals and local factors. A known player in the decline of tissue homeostasis is ageing, which correlates with the waning of resident stem cell populations. In Drosophila, ovaries from old females contain fewer GSCs than those from young flies. We isolated niche cells of aged ovaries, performed a transcriptomic analysis and identified mastermind (mam) as a factor for Drosophila ovarian niche functionality during ageing. We show that mam is upregulated in aged niche cells and that we can induce premature GSC loss by overexpressing mam in otherwise young niche cells. High mam levels in niche cells induce reduced Hedgehog amounts, a decrease in cadherin levels and a likely increase in reactive oxygen species, three scenarios known to provoke GSC loss. Mam is a canonical co-activator of the Notch pathway in many Drosophila tissues. However, we present evidence to support a Notch-independent role for mam in the ovarian germline niche.
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Affiliation(s)
- María Lobo-Pecellín
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
| | - Miriam Marín-Menguiano
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
| | - Acaimo González-Reyes
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
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10
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Hsu HJ, Bahader M, Lai CM. Molecular control of the female germline stem cell niche size in Drosophila. Cell Mol Life Sci 2019; 76:4309-4317. [PMID: 31300869 PMCID: PMC11105562 DOI: 10.1007/s00018-019-03223-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/17/2019] [Accepted: 07/05/2019] [Indexed: 11/26/2022]
Abstract
Adult stem cells have a unique capacity to renew themselves and generate differentiated cells that are needed in the body. These cells are recruited and maintained by the surrounding microenvironment, known as the stem cell niche, during organ development. Thus, the stem cell niche is required for proper tissue homeostasis, and its dysregulation is associated with tumorigenesis and tissue degeneration. The identification of niche components and the mechanisms that regulate niche establishment and maintenance, however, are just beginning to be uncovered. Germline stem cells (GSCs) of the Drosophila ovary provide an excellent model for studying the stem cell niche in vivo because of their well-characterized cell biology and the availability of genetic tools. In this review, we introduce the ovarian GSC niche, and the key signaling pathways for niche precursor segregation, niche specification, and niche extracellular environment establishment and niche maintenance that are involved in regulating niche size during development and adulthood.
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Affiliation(s)
- Hwei-Jan Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan.
| | - Majid Bahader
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Ming Lai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, New York, NY, 10065, USA
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Baron M. Combining genetic and biophysical approaches to probe the structure and function relationships of the notch receptor. Mol Membr Biol 2018; 34:33-49. [PMID: 30246579 DOI: 10.1080/09687688.2018.1503742] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Notch is a conserved cell signalling receptor regulating many aspects of development and tissue homeostasis. Notch is activated by ligand-induced proteolytic cleavages that release the Notch intracellular domain, which relocates to the nucleus to regulate gene transcription. Proteolytic activation first requires mechanical force to be applied to the Notch extracellular domain through an endocytic pulling mechanism transmitted through the ligand/receptor interface. This exposes the proteolytic cleavage site allowing the signal to be initiated following removal of the Notch extracellular domain. Ligands can also act, when expressed in the same cell, through non-productive cis-interactions to inhibit Notch activity. Furthermore, ligand selectivity and Notch activation are regulated by numerous post-translational modifications of the extracellular domain. Additional non-canonical trans and cis interactions with other regulatory proteins may modulate alternative mechanisms of Notch activation that depend on endocytic trafficking of the full-length receptor and proteolytic release of the intracellular domain from endo-lysosomal surface. Mutations of Notch, located in different regions of the protein, are associated with a spectrum of different loss and gain of function phenotypes and offer the possibility to dissect distinct regulatory interactions and mechanisms, particularly when combined with detailed structural analysis of Notch in complex with various regulatory partners.
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Affiliation(s)
- Martin Baron
- a School of Biological Sciences , University of Manchester , Manchester , UK
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12
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Yatsenko AS, Shcherbata HR. Stereotypical architecture of the stem cell niche is spatiotemporally established by miR-125-dependent coordination of Notch and steroid signaling. Development 2018; 145:dev.159178. [PMID: 29361571 PMCID: PMC5818007 DOI: 10.1242/dev.159178] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 01/15/2018] [Indexed: 12/15/2022]
Abstract
Stem cell niches act as signaling platforms that regulate stem cell self-renewal and sustain stem cells throughout life; however, the specific developmental events controlling their assembly are not well understood. Here, we show that during Drosophila ovarian germline stem cell niche formation, the status of Notch signaling in the cell can be reprogrammed. This is controlled via steroid-induced miR-125, which targets a negative regulator of Notch signaling, Tom. Thus, miR-125 acts as a spatiotemporal coordinator between paracrine Notch and endocrine steroid signaling. Moreover, a dual security mechanism for Notch signaling activation exists to ensure the robustness of niche assembly. Particularly, stem cell niche cells can be specified either via lateral inhibition, in which a niche cell precursor acquires Notch signal-sending status randomly, or via peripheral induction, whereby Delta is produced by a specific cell. When one mechanism is perturbed due to mutations, developmental defects or environmental stress, the remaining mechanism ensures that the niche is formed, perhaps abnormally, but still functional. This guarantees that the germline stem cells will have their residence, thereby securing progressive oogenesis and, thus, organism reproduction. Highlighted Article: In Drosophila, the robustness of stem cell niche assembly is safeguarded via a dual mechanism of Notch activation. Cellular Notch status can be reprogrammed by miR-125, which spatiotemporally coordinates paracrine and endocrine signaling.
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Affiliation(s)
- Andriy S Yatsenko
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Halyna R Shcherbata
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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