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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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Dominado N, La Marca JE, Siddall NA, Heaney J, Tran M, Cai Y, Yu F, Wang H, Somers WG, Quinn LM, Hime GR. Rbf Regulates Drosophila Spermatogenesis via Control of Somatic Stem and Progenitor Cell Fate in the Larval Testis. Stem Cell Reports 2017; 7:1152-1163. [PMID: 27974223 PMCID: PMC5161748 DOI: 10.1016/j.stemcr.2016.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 12/02/2022] Open
Abstract
The Drosophila testis has been fundamental to understanding how stem cells interact with their endogenous microenvironment, or niche, to control organ growth in vivo. Here, we report the identification of two independent alleles for the highly conserved tumor suppressor gene, Retinoblastoma-family protein (Rbf), in a screen for testis phenotypes in X chromosome third-instar lethal alleles. Rbf mutant alleles exhibit overproliferation of spermatogonial cells, which is phenocopied by the molecularly characterized Rbf11 null allele. We demonstrate that Rbf promotes cell-cycle exit and differentiation of the somatic and germline stem cells of the testes. Intriguingly, depletion of Rbf specifically in the germline does not disrupt stem cell differentiation, rather Rbf loss of function in the somatic lineage drives overproliferation and differentiation defects in both lineages. Together our observations suggest that Rbf in the somatic lineage controls germline stem cell renewal and differentiation non-autonomously via essential roles in the microenvironment of the germline lineage. Rbf null testes exhibit failure of germline stem cells to differentiate Rbf expression in somatic cells of L3 testes rescues the GSC differentiation defect Somatic Rbf RNAi disrupts cyst stem cell and germline stem cell differentiation Somatic depletion of E2f1 rescues Rbf germline proliferation and differentiation
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Affiliation(s)
- Nicole Dominado
- Centre for Stem Cell Systems, Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - John E La Marca
- Department of Genetics, La Trobe University, Melbourne, VIC 3086, Australia
| | - Nicole A Siddall
- Centre for Stem Cell Systems, Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - James Heaney
- Centre for Stem Cell Systems, Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Mai Tran
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Yu Cai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117543, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117543, Singapore
| | - Hongyan Wang
- Neuroscience & Behavioral Disorder Program, Duke-National University of Singapore, Singapore 169857, Singapore; Department of Physiology, National University of Singapore, Singapore 117597, Singapore
| | - W Gregory Somers
- Department of Genetics, La Trobe University, Melbourne, VIC 3086, Australia
| | - Leonie M Quinn
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia; The John Curtin School of Medical Research, The Australian National University, Acton, ACT 2601, Australia.
| | - Gary R Hime
- Centre for Stem Cell Systems, Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC 3010, Australia.
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Liu Y, Ge Q, Chan B, Liu H, Singh SR, Manley J, Lee J, Weideman AM, Hou G, Hou SX. Whole-animal genome-wide RNAi screen identifies networks regulating male germline stem cells in Drosophila. Nat Commun 2016; 7:12149. [PMID: 27484291 PMCID: PMC4976209 DOI: 10.1038/ncomms12149] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 06/03/2016] [Indexed: 12/21/2022] Open
Abstract
Stem cells are regulated both intrinsically and externally, including by signals from the local environment and distant organs. To identify genes and pathways that regulate stem-cell fates in the whole organism, we perform a genome-wide transgenic RNAi screen through ubiquitous gene knockdowns, focusing on regulators of adult Drosophila testis germline stem cells (GSCs). Here we identify 530 genes that regulate GSC maintenance and differentiation. Of these, we further knock down 113 selected genes using cell-type-specific Gal4s and find that more than half were external regulators, that is, from the local microenvironment or more distal sources. Some genes, for example, versatile (vers), encoding a heterochromatin protein, regulates GSC fates differentially in different cell types and through multiple pathways. We also find that mitosis/cytokinesis proteins are especially important for male GSC maintenance. Our findings provide valuable insights and resources for studying stem cell regulation at the organismal level.
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Affiliation(s)
- Ying Liu
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Qinglan Ge
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Brian Chan
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Hanhan Liu
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Shree Ram Singh
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Jacob Manley
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Jae Lee
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Ann Marie Weideman
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Gerald Hou
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
| | - Steven X Hou
- Basic Research Laboratory, National Cancer Institute at Frederick, National Institutes of Health, 1050 Boyles Street, Building 560, Room 12-70, Frederick, Maryland 21702, USA
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Papagiannouli F, Lohmann I. Shaping the niche: lessons from the Drosophila testis and other model systems. Biotechnol J 2012; 7:723-36. [PMID: 22488937 DOI: 10.1002/biot.201100352] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 01/31/2012] [Accepted: 02/27/2012] [Indexed: 11/12/2022]
Abstract
Stem cells are fascinating, as they supply the cells that construct our adult bodies and replenish, as we age, worn out, damaged, and diseased tissues. Stem cell regulation relies on intrinsic signals but also on inputs emanating from the neighbouring niche. The Drosophila testis provides an excellent system for studying such processes. Although recent advances have uncovered several signalling, cytoskeletal and other factors affecting niche homeostasis and testis differentiation, many aspects of niche regulation and maintenance remain unsolved. In this review, we discuss aspects of niche establishment and integrity not yet fully understood and we compare it to the current knowledge in other model systems such as vertebrates and plants. We also address specific questions on stem cell maintenance and niche regulation in the Drosophila testis under the control of Hox genes. Finally, we provide insights on the striking functional conservation of homologous genes in plants and animals and their respective stem cell niches. Elucidating conserved mechanisms of stem cell control in both lineages could reveal the importance underlying this conservation and justify the evolutionary pressure to adapt homologous molecules for performing the same task.
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Affiliation(s)
- Fani Papagiannouli
- Centre for Organismal Studies (COS) Heidelberg and CellNetworks - Cluster of Excellence, Heidelberg, Germany.
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