1
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Zhang P, Pronovost SM, Marchetti M, Zhang C, Kang X, Kandelouei T, Li C, Edgar BA. Inter-cell type interactions that control JNK signaling in the Drosophila intestine. Nat Commun 2024; 15:5493. [PMID: 38944657 PMCID: PMC11214625 DOI: 10.1038/s41467-024-49786-w] [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: 09/11/2023] [Accepted: 06/14/2024] [Indexed: 07/01/2024] Open
Abstract
JNK signaling is a critical regulator of inflammation and regeneration, but how it is controlled in specific tissue contexts remains unclear. Here we show that, in the Drosophila intestine, the TNF-type ligand, Eiger (Egr), is expressed exclusively by intestinal stem cells (ISCs) and enteroblasts (EBs), where it is induced by stress and during aging. Egr preferentially activates JNK signaling in a paracrine fashion in differentiated enterocytes (ECs) via its receptor, Grindelwald (Grnd). N-glycosylation genes (Alg3, Alg9) restrain this activation, and stress-induced downregulation of Alg3 and Alg9 correlates with JNK activation, suggesting a regulatory switch. JNK activity in ECs induces expression of the intermembrane protease Rhomboid (Rho), driving secretion of EGFR ligands Keren (Krn) and Spitz (Spi), which in turn activate EGFR signaling in progenitor cells (ISCs and EBs) to stimulate their growth and division, as well as to produce more Egr. This study uncovers an N-glycosylation-controlled, paracrine JNK-EGFR-JNK feedforward loop that sustains ISC proliferation during stress-induced gut regeneration.
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Affiliation(s)
- Peng Zhang
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Stephen M Pronovost
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Marco Marchetti
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Chenge Zhang
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Xiaoyu Kang
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Tahmineh Kandelouei
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Christopher Li
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
- Harvard University, Cambridge, MA, 02138, USA
| | - Bruce A Edgar
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA.
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2
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Mallik B, Bhat S, Kumar V. Role of Bin‐Amphiphysin‐Rvs (BAR) domain proteins in mediating neuronal signaling and disease. Synapse 2022; 76:e22248. [DOI: 10.1002/syn.22248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/13/2022] [Accepted: 07/18/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Bhagaban Mallik
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Bhopal Indore Bypass Road Bhopal Madhya Pradesh 462 066 India
| | - Sajad Bhat
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Bhopal Indore Bypass Road Bhopal Madhya Pradesh 462 066 India
| | - Vimlesh Kumar
- Department of Biological Sciences Indian Institute of Science Education and Research (IISER) Bhopal Indore Bypass Road Bhopal Madhya Pradesh 462 066 India
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3
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Blanchette CR, Scalera AL, Harris KP, Zhao Z, Dresselhaus EC, Koles K, Yeh A, Apiki JK, Stewart BA, Rodal AA. Local regulation of extracellular vesicle traffic by the synaptic endocytic machinery. J Cell Biol 2022; 221:e202112094. [PMID: 35320349 PMCID: PMC8952828 DOI: 10.1083/jcb.202112094] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 02/01/2023] Open
Abstract
Neuronal extracellular vesicles (EVs) are locally released from presynaptic terminals, carrying cargoes critical for intercellular signaling and disease. EVs are derived from endosomes, but it is unknown how these cargoes are directed to the EV pathway rather than for conventional endolysosomal degradation. Here, we find that endocytic machinery plays an unexpected role in maintaining a release-competent pool of EV cargoes at synapses. Endocytic mutants, including nervous wreck (nwk), shibire/dynamin, and AP-2, unexpectedly exhibit local presynaptic depletion specifically of EV cargoes. Accordingly, nwk mutants phenocopy synaptic plasticity defects associated with loss of the EV cargo synaptotagmin-4 (Syt4) and suppress lethality upon overexpression of the EV cargo amyloid precursor protein (APP). These EV defects are genetically separable from canonical endocytic functions in synaptic vesicle recycling and synaptic growth. Endocytic machinery opposes the endosomal retromer complex to regulate EV cargo levels and acts upstream of synaptic cargo removal by retrograde axonal transport. Our data suggest a novel molecular mechanism that locally promotes cargo loading into synaptic EVs.
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Affiliation(s)
| | | | - Kathryn P. Harris
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Zechuan Zhao
- Department of Biology, Brandeis University, Waltham, MA
| | | | - Kate Koles
- Department of Biology, Brandeis University, Waltham, MA
| | - Anna Yeh
- Department of Biology, Brandeis University, Waltham, MA
| | | | - Bryan A. Stewart
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
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4
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Del Signore SJ, Kelley CF, Messelaar EM, Lemos T, Marchan MF, Ermanoska B, Mund M, Fai TG, Kaksonen M, Rodal AA. An autoinhibitory clamp of actin assembly constrains and directs synaptic endocytosis. eLife 2021; 10:69597. [PMID: 34324418 PMCID: PMC8321554 DOI: 10.7554/elife.69597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/21/2021] [Indexed: 01/05/2023] Open
Abstract
Synaptic membrane-remodeling events such as endocytosis require force-generating actin assembly. The endocytic machinery that regulates these actin and membrane dynamics localizes at high concentrations to large areas of the presynaptic membrane, but actin assembly and productive endocytosis are far more restricted in space and time. Here we describe a mechanism whereby autoinhibition clamps the presynaptic endocytic machinery to limit actin assembly to discrete functional events. We found that collective interactions between the Drosophila endocytic proteins Nwk/FCHSD2, Dap160/intersectin, and WASp relieve Nwk autoinhibition and promote robust membrane-coupled actin assembly in vitro. Using automated particle tracking to quantify synaptic actin dynamics in vivo, we discovered that Nwk-Dap160 interactions constrain spurious assembly of WASp-dependent actin structures. These interactions also promote synaptic endocytosis, suggesting that autoinhibition both clamps and primes the synaptic endocytic machinery, thereby constraining actin assembly to drive productive membrane remodeling in response to physiological cues. Neurons constantly talk to each other by sending chemical signals across the tiny gap, or ‘synapse’, that separates two cells. While inside the emitting cell, these molecules are safely packaged into small, membrane-bound vessels. Upon the right signal, the vesicles fuse with the external membrane of the neuron and spill their contents outside, for the receiving cell to take up and decode. The emitting cell must then replenish its vesicle supply at the synapse through a recycling mechanism known as endocytosis. To do so, it uses dynamically assembling rod-like ‘actin’ filaments, which work in concert with many other proteins to pull in patches of membrane as new vesicles. The proteins that control endocytosis and actin assembly abound at neuronal synapses, and, when mutated, are linked to many neurological diseases. Unlike other cell types, neurons appear to ‘pre-deploy’ these actin-assembly proteins to synaptic membranes, but to keep them inactive under normal conditions. How neurons control the way this machinery is recruited and activated remains unknown. To investigate this question, Del Signore et al. conducted two sets of studies. First, they exposed actin to several different purified proteins in initial ‘test tube’ experiments. This revealed that, depending on the conditions, a group of endocytosis proteins could prevent or promote actin assembly: assembly occurred only if the proteins were associated with membranes. Next, Del Signore et al. mutated these proteins in fruit fly larvae, and performed live cell microscopy to determine their impact on actin assembly and endocytosis. Consistent with the test tube findings, endocytosis mutants had more actin assembly overall, implying that the proteins were required to prevent random actin assembly. However, the same mutants had reduced levels of endocytosis, suggesting that the proteins were also necessary for productive actin assembly. Together, these experiments suggest that, much like a mousetrap holds itself poised ready to spring, some endocytic proteins play a dual role to restrain actin assembly when and where it is not needed, and to promote it at sites of endocytosis. These results shed new light on how neurons might build and maintain effective, working synapses. Del Signore et al. hope that this knowledge may help to better understand and combat neurological diseases, such as Alzheimer’s, which are linked to impaired membrane traffic and cell signalling.
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Affiliation(s)
| | | | | | - Tania Lemos
- Department of Biology, Brandeis University, Walltham, United States
| | | | | | - Markus Mund
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Thomas G Fai
- Department of Mathematics, Brandeis University, Waltham, United States
| | - Marko Kaksonen
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
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5
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Titlow J, Robertson F, Järvelin A, Ish-Horowicz D, Smith C, Gratton E, Davis I. Syncrip/hnRNP Q is required for activity-induced Msp300/Nesprin-1 expression and new synapse formation. J Cell Biol 2020; 219:133707. [PMID: 32040548 PMCID: PMC7055005 DOI: 10.1083/jcb.201903135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 01/09/2023] Open
Abstract
Memory and learning involve activity-driven expression of proteins and cytoskeletal reorganization at new synapses, requiring posttranscriptional regulation of localized mRNA a long distance from corresponding nuclei. A key factor expressed early in synapse formation is Msp300/Nesprin-1, which organizes actin filaments around the new synapse. How Msp300 expression is regulated during synaptic plasticity is poorly understood. Here, we show that activity-dependent accumulation of Msp300 in the postsynaptic compartment of the Drosophila larval neuromuscular junction is regulated by the conserved RNA binding protein Syncrip/hnRNP Q. Syncrip (Syp) binds to msp300 transcripts and is essential for plasticity. Single-molecule imaging shows that msp300 is associated with Syp in vivo and forms ribosome-rich granules that contain the translation factor eIF4E. Elevated neural activity alters the dynamics of Syp and the number of msp300:Syp:eIF4E RNP granules at the synapse, suggesting that these particles facilitate translation. These results introduce Syp as an important early acting activity-dependent regulator of a plasticity gene that is strongly associated with human ataxias.
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Affiliation(s)
- Joshua Titlow
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Aino Järvelin
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford, UK.,Medical Research Council Lab for Molecular Cell Biology, University College London, London, UK
| | - Carlas Smith
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California Irvine, Irvine, CA
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, UK
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6
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Fan D, Yang S, Han Y, Zhang R, Yang L. Isoflurane-induced expression of miR-140-5p aggravates neurotoxicity in diabetic rats by targeting SNX12. J Toxicol Sci 2020; 45:69-76. [PMID: 32062618 DOI: 10.2131/jts.45.69] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
MicroRNAs (miRNAs) are widely known as critical regulators in isoflurane-induced neurotoxicity during the development of brain. Moreover, isoflurane could aggravate cognitive impairment in diabetic rats. The present study was designed to investigate the role and mechanism of miR-140-5p on isoflurane-induced neurotoxicity in diabetic rats. Firstly, a diabetic rat model was established by injection of streptozotocin (STZ) and identified by Morris water maze test. The result indicated that isoflurane treatment exacerbated STZ-induced cognitive impairment, as demonstrated by increase of the latency to the platform and decrease of the proportion of time spent in the target quadrant. Secondly, miR-140-5p was up-regulated in diabetic rats treated with isoflurane. Functional assays revealed that knockdown of miR-140-5p attenuated neurotoxicity in diabetic rats, which was shown by a decrease of the latency to the platform and an increase of the proportion of time spent in the target quadrant. Mechanistically, we demonstrated that miR-140-5p directly bonded to SNX12 (sorting nexin 12). At last, the neuroprotective effect of miR-140-5p knockdown against isoflurane-aggravated neurotoxicity in diabetic rats was dependent on up-regulation of SNX12 and inhibition of cell apoptosis. In summary, these meaningful results demonstrated the mitigation of miR-140-5p knockdown against isoflurane-aggravated neurotoxicity in diabetic rats via SNX12, suggesting a novel target for neuroprotection in diabetes under isoflurane treatment.
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Affiliation(s)
- Dongyi Fan
- Department of Anesthesiology, the Fifth Affiliated Hospital of Sun Yat-Sen University, China
| | - Simin Yang
- Department of Anesthesiology, the Fifth Affiliated Hospital of Sun Yat-Sen University, China
| | - Yuxiang Han
- Department of Anesthesiology, the Fifth Affiliated Hospital of Sun Yat-Sen University, China
| | - Ru Zhang
- Department of Anesthesiology, the Fifth Affiliated Hospital of Sun Yat-Sen University, China
| | - Lukun Yang
- Department of Anesthesiology, the Fifth Affiliated Hospital of Sun Yat-Sen University, China
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7
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IPIP27 Coordinates PtdIns(4,5)P 2 Homeostasis for Successful Cytokinesis. Curr Biol 2019; 29:775-789.e7. [PMID: 30799246 PMCID: PMC6408333 DOI: 10.1016/j.cub.2019.01.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/03/2018] [Accepted: 01/15/2019] [Indexed: 12/12/2022]
Abstract
During cytokinesis, an actomyosin contractile ring drives the separation of the two daughter cells. A key molecule in this process is the inositol lipid PtdIns(4,5)P2, which recruits numerous factors to the equatorial region for contractile ring assembly. Despite the importance of PtdIns(4,5)P2 in cytokinesis, the regulation of this lipid in cell division remains poorly understood. Here, we identify a role for IPIP27 in mediating cellular PtdIns(4,5)P2 homeostasis. IPIP27 scaffolds the inositol phosphatase oculocerebrorenal syndrome of Lowe (OCRL) by coupling it to endocytic BAR domain proteins. Loss of IPIP27 causes accumulation of PtdIns(4,5)P2 on aberrant endomembrane vacuoles, mislocalization of the cytokinetic machinery, and extensive cortical membrane blebbing. This phenotype is observed in Drosophila and human cells and can result in cytokinesis failure. We have therefore identified IPIP27 as a key modulator of cellular PtdIns(4,5)P2 homeostasis required for normal cytokinesis. The results indicate that scaffolding of inositol phosphatase activity is critical for maintaining PtdIns(4,5)P2 homeostasis and highlight a critical role for this process in cell division. IPIP27 scaffolds the inositol phosphatase OCRL via coupling to BAR domain proteins IPIP27 scaffolding of OCRL is critical for cellular PtdIns(4,5)P2 homeostasis IPIP27 is required for cortical actin and membrane stability during cytokinesis IPIP27 function is conserved from flies to humans
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8
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Wasserman SS, Shteiman-Kotler A, Harris K, Iliadi KG, Persaud A, Zhong Y, Zhang Y, Fang X, Boulianne GL, Stewart B, Rotin D. Regulation of SH3PX1 by dNedd4-long at the Drosophila neuromuscular junction. J Biol Chem 2018; 294:1739-1752. [PMID: 30518551 DOI: 10.1074/jbc.ra118.005161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/12/2018] [Indexed: 11/06/2022] Open
Abstract
Drosophila Nedd4 (dNedd4) is a HECT E3 ubiquitin ligase present in two major isoforms: short (dNedd4S) and long (dNedd4Lo), with the latter containing two unique regions (N terminus and Middle). Although dNedd4S promotes neuromuscular synaptogenesis (NMS), dNedd4Lo inhibits it and impairs larval locomotion. To explain how dNedd4Lo inhibits NMS, MS analysis was performed to find its binding partners and identified SH3PX1, which binds dNedd4Lo unique Middle region. SH3PX1 contains SH3, PX, and BAR domains and is present at neuromuscular junctions, where it regulates active zone ultrastructure and presynaptic neurotransmitter release. Here, we demonstrate direct binding of SH3PX1 to the dNedd4Lo Middle region (which contains a Pro-rich sequence) in vitro and in cells, via the SH3PX1-SH3 domain. In Drosophila S2 cells, dNedd4Lo overexpression reduces SH3PX1 levels at the cell periphery. In vivo overexpression of dNedd4Lo post-synaptically, but not pre-synaptically, reduces SH3PX1 levels at the subsynaptic reticulum and impairs neurotransmitter release. Unexpectedly, larvae that overexpress dNedd4Lo post-synaptically and are heterozygous for a null mutation in SH3PX1 display increased neurotransmission compared with dNedd4Lo or SH3PX1 mutant larvae alone, suggesting a compensatory effect from the remaining SH3PX1 allele. These results suggest a post-synaptic-specific regulation of SH3PX1 by dNedd4Lo.
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Affiliation(s)
- Samantha S Wasserman
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Ontario M5G 0A4, Canada
| | - Alina Shteiman-Kotler
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Ontario M5G 0A4, Canada
| | - Kathryn Harris
- Department of Cell and System Biology, University of Toronto, Ontario M5G 0A4, Canada
| | - Konstantin G Iliadi
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada
| | - Avinash Persaud
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada
| | - Yvonne Zhong
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Ontario M5G 0A4, Canada
| | - Yi Zhang
- Department of Gastrointestinal Surgery, Jilin University, Changchun 130033, China
| | - Xuedong Fang
- Department of Gastrointestinal Surgery, Jilin University, Changchun 130033, China
| | - Gabrielle L Boulianne
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Ontario M5G 0A4, Canada
| | - Bryan Stewart
- Department of Cell and System Biology, University of Toronto, Ontario M5G 0A4, Canada
| | - Daniela Rotin
- Hospital for Sick Children, Cell Biology and Developmental and Stem Cell Biology programs, University of Toronto, Ontario M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Ontario M5G 0A4, Canada.
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9
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Abstract
Prokaryotic type II adaptive immune systems have been developed into the versatile CRISPR technology, which has been widely applied in site-specific genome editing and has revolutionized biomedical research due to its superior efficiency and flexibility. Recent studies have greatly diversified CRISPR technologies by coupling it with various DNA repair mechanisms and targeting strategies. These new advances have significantly expanded the generation of genetically modified animal models, either by including species in which targeted genetic modification could not be achieved previously, or through introducing complex genetic modifications that take multiple steps and cost years to achieve using traditional methods. Herein, we review the recent developments and applications of CRISPR-based technology in generating various animal models, and discuss the everlasting impact of this new progress on biomedical research.
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Affiliation(s)
- Xun Ma
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Avery Sum-Yu Wong
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Hei-Yin Tam
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Samuel Yung-Kin Tsui
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Dittman Lai-Shun Chung
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Bo Feng
- Key Laboratory for Regenerative Medicine in Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China. .,Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Guangdong 510530, China.,SBS Core Laboratory, CUHK Shenzhen Research Institute, Shenzhen Guangdong 518057, China
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10
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Liu C, Zhai X, Du H, Cao Y, Cao H, Wang Y, Yu X, Gao J, Xu Z. Sorting nexin 9 (SNX9) is not essential for development and auditory function in mice. Oncotarget 2018; 7:68921-68932. [PMID: 27655699 PMCID: PMC5356600 DOI: 10.18632/oncotarget.12040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 09/02/2016] [Indexed: 12/20/2022] Open
Abstract
Sorting nexins are a large family of evolutionarily conserved proteins that play fundamental roles in endocytosis, endosomal sorting and signaling. As an important member of sorting nexin family, sorting nexin 9 (SNX9) has been shown to participate in coordinating actin polymerization with membrane tubulation and vesicle formation. We previously showed that SNX9 is expressed in mouse auditory hair cells and might regulate actin polymerization in those cells. To further examine the physiological role of SNX9, we generated Snx9 knockout mice using homologous recombination method. Unexpectedly, Snx9 knockout mice have normal viability and fertility, and are morphologically and behaviorally indistinguishable from control mice. Further investigation revealed that the morphology and function of auditory hair cells are not affected by Snx9 inactivation, and Snx9 knockout mice have normal hearing threshold. In conclusion, our data revealed that Snx9-deficient mice do not show defects in development as well as auditory function, suggesting that SNX9 is not essential for mice development and hearing.
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Affiliation(s)
- Chengcheng Liu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Xiaoyan Zhai
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Yujie Cao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Huiren Cao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Xiao Yu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, P. R. China
| | - Jiangang Gao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, P. R. China
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11
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Mallik B, Kumar V. Regulation of actin-Spectrin cytoskeleton by ICA69 at the Drosophila neuromuscular junction. Commun Integr Biol 2017. [PMCID: PMC5824968 DOI: 10.1080/19420889.2017.1381806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bin-Amphiphysin-Rvs (BAR) domain containing proteins with their membrane deforming properties have emerged as key players in shaping up neuronal morphology and regulating cytoskeletal dynamics. However, the in vivo contexts in which BAR-domain proteins integrate membrane dynamics with cytoskeletal rearrangements remain poorly understood. Recently, we identified islet cell autoantigen 69 kDa as one of the N-BAR-domain containing proteins which regulate synaptic development and organization at the Drosophila neuromuscular junction. ICA69 genetically functions downstream of Rab2 to regulate synapse morphology. We found that ICA69 alters Spectrin level at the Drosophila NMJ, and redistributes actin regulatory proteins in cultured cells suggesting that ICA69 may regulate NMJ organization by regulating actin-Spectrin cytoskeleton. We propose a model in which ICA69 genetically interact with components of actin regulatory proteins for cytoskeleton dynamics to regulate NMJ development and synapse organization.
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Affiliation(s)
- Bhagaban Mallik
- Laboratory of Neurogenetics, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Madhya Pradesh, India
| | - Vimlesh Kumar
- Laboratory of Neurogenetics, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Madhya Pradesh, India
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12
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Mallik B, Dwivedi MK, Mushtaq Z, Kumari M, Verma PK, Kumar V. Regulation of neuromuscular junction organization by Rab2 and its effector ICA69 in Drosophila. Development 2017; 144:2032-2044. [PMID: 28455372 DOI: 10.1242/dev.145920] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 04/19/2017] [Indexed: 12/31/2022]
Abstract
The mechanisms underlying synaptic differentiation, which involves neuronal membrane and cytoskeletal remodeling, are not completely understood. We performed a targeted RNAi-mediated screen of Drosophila BAR-domain proteins and identified islet cell autoantigen 69 kDa (ICA69) as one of the key regulators of morphological differentiation of the larval neuromuscular junction (NMJ). We show that Drosophila ICA69 colocalizes with α-Spectrin at the NMJ. The conserved N-BAR domain of ICA69 deforms liposomes in vitro Full-length ICA69 and the ICAC but not the N-BAR domain of ICA69 induce filopodia in cultured cells. Consistent with its cytoskeleton regulatory role, ICA69 mutants show reduced α-Spectrin immunoreactivity at the larval NMJ. Manipulating levels of ICA69 or its interactor PICK1 alters the synaptic level of ionotropic glutamate receptors (iGluRs). Moreover, reducing PICK1 or Rab2 levels phenocopies ICA69 mutation. Interestingly, Rab2 regulates not only synaptic iGluR but also ICA69 levels. Thus, our data suggest that: (1) ICA69 regulates NMJ organization through a pathway that involves PICK1 and Rab2, and (2) Rab2 functions genetically upstream of ICA69 and regulates NMJ organization and targeting/retention of iGluRs by regulating ICA69 levels.
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Affiliation(s)
- Bhagaban Mallik
- Department of Biological Sciences, AB-3, Indian Institute of Science Education and Research, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Manish Kumar Dwivedi
- Department of Biological Sciences, AB-3, Indian Institute of Science Education and Research, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Zeeshan Mushtaq
- Department of Biological Sciences, AB-3, Indian Institute of Science Education and Research, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Manisha Kumari
- National Institute of Plant Genome Research (NIPGR), New Delhi 110067, India
| | - Praveen Kumar Verma
- National Institute of Plant Genome Research (NIPGR), New Delhi 110067, India
| | - Vimlesh Kumar
- Department of Biological Sciences, AB-3, Indian Institute of Science Education and Research, Bhauri, Bhopal, Madhya Pradesh 462066, India
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Bendris N, Schmid SL. Endocytosis, Metastasis and Beyond: Multiple Facets of SNX9. Trends Cell Biol 2016; 27:189-200. [PMID: 27989654 DOI: 10.1016/j.tcb.2016.11.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 11/26/2022]
Abstract
Sorting nexin (SNX)9 was first discovered as an endocytic accessory protein involved in clathrin-mediated endocytosis. However, recent data suggest that SNX9 is a multifunctional scaffold that coordinates membrane trafficking and remodeling with changes in actin dynamics to affect diverse cellular processes. Here, we review the accumulated knowledge on SNX9 with an emphasis on its recently identified roles in clathrin-independent endocytic pathways, cell invasion, and cell division, which have implications for SNX9 function in human disease, including cancer.
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Affiliation(s)
- Nawal Bendris
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Sandra L Schmid
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Coordinated autoinhibition of F-BAR domain membrane binding and WASp activation by Nervous Wreck. Proc Natl Acad Sci U S A 2016; 113:E5552-61. [PMID: 27601635 DOI: 10.1073/pnas.1524412113] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane remodeling by Fes/Cip4 homology-Bin/Amphiphysin/Rvs167 (F-BAR) proteins is regulated by autoinhibitory interactions between their SRC homology 3 (SH3) and F-BAR domains. The structural basis of autoregulation, and whether it affects interactions of SH3 domains with other cellular ligands, remain unclear. Here we used single-particle electron microscopy to determine the structure of the F-BAR protein Nervous Wreck (Nwk) in both soluble and membrane-bound states. On membrane binding, Nwk SH3 domains do not completely dissociate from the F-BAR dimer, but instead shift from its concave surface to positions on either side of the dimer. Unexpectedly, along with controlling membrane binding, these autoregulatory interactions inhibit the ability of Nwk-SH3a to activate Wiskott-Aldrich syndrome protein (WASp)/actin related protein (Arp) 2/3-dependent actin filament assembly. In Drosophila neurons, Nwk autoregulation restricts SH3a domain-dependent synaptopod formation, synaptic growth, and actin organization. Our results define structural rearrangements in Nwk that control F-BAR-membrane interactions as well as SH3 domain activities, and suggest that these two functions are tightly coordinated in vitro and in vivo.
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