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R P, Rakshit S, Shanmugam G, George M, Sarkar K. Wiskott Aldrich syndrome protein (WASp)-deficient Th1 cells promote R-loop-driven transcriptional insufficiency and transcription-coupled nucleotide excision repair factor (TC-NER)-driven genome-instability in the pathogenesis of T cell acute lymphoblastic leukemia. Clin Immunol 2024; 263:110204. [PMID: 38582251 DOI: 10.1016/j.clim.2024.110204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/21/2024] [Accepted: 04/01/2024] [Indexed: 04/08/2024]
Abstract
BACKGROUND T-ALL is an aggressive hematological tumor that develops as the result of a multi-step oncogenic process which causes expansion of hematopoietic progenitors that are primed for T cell development to undergo malignant transformation and growth. Even though first-line therapy has a significant response rate, 40% of adult patients and 20% of pediatric patients will relapse. Therefore, there is an unmet need for treatment for relapsed/refractory T-ALL to develop potential targeted therapies. METHODS Pediatric T-ALL patient derived T cells were grown under either nonskewingTh0 or Th1-skewing conditions to further process for ChIP-qPCR, RDIP-qPCR and other RT-PCR assays. Endogenous WASp was knocked out using CRISPR-Cas9 and was confirmed using flow cytometry and western blotting. LC-MS/MS was performed to find out proteomic dataset of WASp-interactors generated from Th1-skewed, human primary Th-cells. DNA-damage was assessed by immunofluorescence confocal-imaging and single-cell gel electrophoresis (comet assay). Overexpression of RNaseH1 was also done to restore normal Th1-transcription in WASp-deficient Th1-skewed cells. RESULTS We discovered that nuclear-WASp is required for suppressing R-loop production (RNA/DNA-hybrids) at Th1-network genes by ribonucleaseH2 (RNH2) and topoisomerase1. Nuclear-WASp is associated with the factors involved in preventing and dissolving R-loops in Th1 cells. In nuclear- WASp-reduced malignant Th1-cells, R-loops accumulate in vivo and are processed into DNA-breaks by transcription-coupled-nucleotide-excision repair (TC-NER). Several epigenetic modifications were also found to be involved at Th1 gene locus which are responsible for active/repressive marks of particular genes. By demonstrating WASp as a physiologic regulator of programmed versus unprogrammed R-loops, we suggest that the transcriptional role of WASp in vivo extends also to prevent transcription-linked DNA damage during malignancy and through modification of epigenetic dysregulations. CONCLUSION Our findings present a provocative possibility of resetting R-loops as a therapeutic intervention to correct both immune deficiency and malignancy in T-cell acute lymphoblastic leukemia patients and a novel role of WASp in the epigenetic regulation of T helper cell differentiation in T-ALL patients, anticipating WASp's requirement for the suppression of T-ALL progression.
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Affiliation(s)
- Pradeep R
- Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu 603203, India
| | - Sudeshna Rakshit
- Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu 603203, India
| | - Geetha Shanmugam
- Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu 603203, India
| | - Melvin George
- Department of Clinical Pharmacology, SRM Medical College Hospital and Research Centre, Kattankulathur, Tamil Nadu 603203, India
| | - Koustav Sarkar
- Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu 603203, India.
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2
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Davidson KA, Nakamura M, Verboon JM, Parkhurst SM. Centralspindlin proteins Pavarotti and Tumbleweed along with WASH regulate nuclear envelope budding. J Cell Biol 2023; 222:e202211074. [PMID: 37163553 PMCID: PMC10174194 DOI: 10.1083/jcb.202211074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/14/2023] [Accepted: 04/26/2023] [Indexed: 05/12/2023] Open
Abstract
Nuclear envelope (NE) budding is a nuclear pore-independent nuclear export pathway, analogous to the egress of herpesviruses, and required for protein quality control, synapse development, and mitochondrial integrity. The physical formation of NE buds is dependent on the Wiskott-Aldrich Syndrome protein, Wash, its regulatory complex (SHRC), and Arp2/3, and requires Wash's actin nucleation activity. However, the machinery governing cargo recruitment and organization within the NE bud remains unknown. Here, we identify Pavarotti (Pav) and Tumbleweed (Tum) as new molecular components of NE budding. Pav and Tum interact directly with Wash and define a second nuclear Wash-containing complex required for NE budding. Interestingly, we find that the actin-bundling activity of Pav is required, suggesting a structural role in the physical and/or organizational aspects of NE buds. Thus, Pav and Tum are providing exciting new entry points into the physical machineries of this alternative nuclear export pathway for large cargos during cell differentiation and development.
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Affiliation(s)
- Kerri A. Davidson
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | | | - Jeffrey M. Verboon
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Susan M. Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
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3
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Nakamura M, Hui J, Stjepić V, Parkhurst SM. Scar/WAVE has Rac GTPase-independent functions during cell wound repair. Sci Rep 2023; 13:4763. [PMID: 36959278 PMCID: PMC10036328 DOI: 10.1038/s41598-023-31973-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/20/2023] [Indexed: 03/25/2023] Open
Abstract
Rho family GTPases regulate both linear and branched actin dynamics by activating downstream effectors to facilitate the assembly and function of complex cellular structures such as lamellipodia and contractile actomyosin rings. Wiskott-Aldrich Syndrome (WAS) family proteins are downstream effectors of Rho family GTPases that usually function in a one-to-one correspondence to regulate branched actin nucleation. In particular, the WAS protein Scar/WAVE has been shown to exhibit one-to-one correspondence with Rac GTPase. Here we show that Rac and SCAR are recruited to cell wounds in the Drosophila repair model and are required for the proper formation and maintenance of the dynamic actomyosin ring formed at the wound periphery. Interestingly, we find that SCAR is recruited to wounds earlier than Rac and is still recruited to the wound periphery in the presence of a potent Rac inhibitor. We also show that while Rac is important for actin recruitment to the actomyosin ring, SCAR serves to organize the actomyosin ring and facilitate its anchoring to the overlying plasma membrane. These differing spatiotemporal recruitment patterns and wound repair phenotypes highlight the Rac-independent functions of SCAR and provide an exciting new context in which to investigate these newly uncovered SCAR functions.
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Affiliation(s)
- Mitsutoshi Nakamura
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - Justin Hui
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - Viktor Stjepić
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - Susan M Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA.
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4
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Hui J, Nakamura M, Dubrulle J, Parkhurst SM. Coordinated efforts of different actin filament populations are needed for optimal cell wound repair. Mol Biol Cell 2023; 34:ar15. [PMID: 36598808 PMCID: PMC10011732 DOI: 10.1091/mbc.e22-05-0155] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cells are subjected to a barrage of daily insults that often lead to their cortices being ripped open and requiring immediate repair. An important component of the cell's repair response is the formation of an actomyosin ring at the wound periphery to mediate its closure. Here we show that inhibition of myosin or the linear actin nucleation factors Diaphanous and/or dishevelled associated activator of morphogenesis results in a disrupted contractile apparatus and delayed wound closure. We also show that the branched actin nucleators WASp and SCAR function nonredundantly as scaffolds to assemble and maintain this contractile actomyosin cable. Removing branched actin leads to the formation of smaller circular actin-myosin structures at the cell cortex and to slow wound closure. Removing linear and branched actin simultaneously results in failed wound closure. Surprisingly, removal of branched actin and myosin results in the formation of parallel linear F-actin filaments that undergo a chiral swirling movement to close the wound, uncovering a new mechanism of cell wound closure. Taken together, we demonstrate the roles of different actin substructures that are required for optimal actomyosin ring formation and the extraordinary resilience of the cell to undergo wound repair when it is unable to form different subsets of these substructures.
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Affiliation(s)
- Justin Hui
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109
| | | | - Julien Dubrulle
- Cellular Imaging Shared Resource, Fred Hutchinson Cancer Center, Seattle, WA 98109
| | - Susan M Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109
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5
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Molina-Pelayo C, Olguin P, Mlodzik M, Glavic A. The conserved Pelado/ZSWIM8 protein regulates actin dynamics by promoting linear actin filament polymerization. Life Sci Alliance 2022; 5:5/12/e202201484. [PMID: 35940847 PMCID: PMC9375228 DOI: 10.26508/lsa.202201484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/24/2022] Open
Abstract
Actin filament polymerization can be branched or linear, which depends on the associated regulatory proteins. Competition for actin monomers occurs between proteins that induce branched or linear actin polymerization. Cell specialization requires the regulation of actin filaments to allow the formation of cell type-specific structures, like cuticular hairs in Drosophila, formed by linear actin filaments. Here, we report the functional analysis of CG34401/pelado, a gene encoding a SWIM domain-containing protein, conserved throughout the animal kingdom, called ZSWIM8 in mammals. Mutant pelado epithelial cells display actin hair elongation defects. This phenotype is reversed by increasing actin monomer levels or by either pushing linear actin polymerization or reducing branched actin polymerization. Similarly, in hemocytes, Pelado is essential to induce filopodia, a linear actin-based structure. We further show that this function of Pelado/ZSWIM8 is conserved in human cells, where Pelado inhibits branched actin polymerization in a cell migration context. In summary, our data indicate that the function of Pelado/ZSWIM8 in regulating actin cytoskeletal dynamics is conserved, favoring linear actin polymerization at the expense of branched filaments.
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Affiliation(s)
- Claudia Molina-Pelayo
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departamento de Biología, Centro FONDAP de Regulación del Genoma, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Patricio Olguin
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA .,Departamento de Neurociencia, Programa de Genética Humana, Instituto de Ciencias Biomédicas, Instituto de Neurociencia Biomédica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marek Mlodzik
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alvaro Glavic
- Departamento de Biología, Centro FONDAP de Regulación del Genoma, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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6
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Hunt EL, Rai H, Harris TJC. SCAR/WAVE complex recruitment to a supracellular actomyosin cable by myosin activators and a junctional Arf-GEF during Drosophila dorsal closure. Mol Biol Cell 2022; 33. [DOI: 10.1091/mbc.e22-03-0107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Expansive Arp2/3 actin networks and contractile actomyosin networks can be spatially and temporally segregated within the cell, but the networks also interact closely at various sites, including adherens junctions. However, molecular mechanisms coordinating these interactions remain unclear. We found that the SCAR/WAVE complex, an Arp2/3 activator, is enriched at adherens junctions of the leading edge actomyosin cable during Drosophila dorsal closure. Myosin activators were both necessary and sufficient for SCAR/WAVE accumulation at leading edge junctions. The same myosin activators were previously shown to recruit the cytohesin Arf-GEF Steppke to these sites, and mammalian studies have linked Arf small G protein signaling to SCAR/WAVE activation. During dorsal closure, we find that Steppke is required for SCAR/WAVE enrichment at the actomyosin-linked junctions. Arp2/3 also localizes to adherens junctions of the leading edge cable. We propose that junctional actomyosin activity acts through Steppke to recruit SCAR/WAVE and Arp2/3 for regulation of the leading edge supracellular actomyosin cable during dorsal closure.
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Affiliation(s)
- Erin L. Hunt
- Department of Cell & Systems Biology, University of Toronto
| | - Hrishika Rai
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata
- International Visiting Graduate Students Study Abroad Program, University of Toronto
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7
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Goswami R, Bello AI, Bean J, Costanzo KM, Omer B, Cornelio-Parra D, Odah R, Ahluwalia A, Allan SK, Nguyen N, Shores T, Aziz NA, Mohan RD. The Molecular Basis of Spinocerebellar Ataxia Type 7. Front Neurosci 2022; 16:818757. [PMID: 35401096 PMCID: PMC8987156 DOI: 10.3389/fnins.2022.818757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/07/2022] [Indexed: 11/19/2022] Open
Abstract
Spinocerebellar ataxia (SCA) type 7 (SCA7) is caused by a CAG trinucleotide repeat expansion in the ataxin 7 (ATXN7) gene, which results in polyglutamine expansion at the amino terminus of the ATXN7 protein. Although ATXN7 is expressed widely, the best characterized symptoms of SCA7 are remarkably tissue specific, including blindness and degeneration of the brain and spinal cord. While it is well established that ATXN7 functions as a subunit of the Spt Ada Gcn5 acetyltransferase (SAGA) chromatin modifying complex, the mechanisms underlying SCA7 remain elusive. Here, we review the symptoms of SCA7 and examine functions of ATXN7 that may provide further insights into its pathogenesis. We also examine phenotypes associated with polyglutamine expanded ATXN7 that are not considered symptoms of SCA7.
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Affiliation(s)
- Rituparna Goswami
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Abudu I. Bello
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Joe Bean
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Kara M. Costanzo
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Bwaar Omer
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Dayanne Cornelio-Parra
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Revan Odah
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Amit Ahluwalia
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Shefaa K. Allan
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Nghi Nguyen
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Taylor Shores
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
| | - N. Ahmad Aziz
- Population Health Sciences, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Ryan D. Mohan
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Kansas City, MO, United States
- *Correspondence: Ryan D. Mohan,
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8
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Stark K, Crowe O, Lewellyn L. Precise levels of the Drosophila adaptor protein Dreadlocks maintain the size and stability of germline ring canals. J Cell Sci 2021; 134:238107. [PMID: 33912915 PMCID: PMC8106954 DOI: 10.1242/jcs.254730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/15/2021] [Indexed: 01/24/2023] Open
Abstract
Intercellular bridges are essential for fertility in many organisms. The developing fruit fly egg has become the premier model system to study intercellular bridges. During oogenesis, the oocyte is connected to supporting nurse cells by relatively large intercellular bridges, or ring canals. Once formed, the ring canals undergo a 20-fold increase in diameter to support the movement of materials from the nurse cells to the oocyte. Here, we demonstrate a novel role for the conserved SH2/SH3 adaptor protein Dreadlocks (Dock) in regulating ring canal size and structural stability in the germline. Dock localizes at germline ring canals throughout oogenesis. Loss of Dock leads to a significant reduction in ring canal diameter, and overexpression of Dock causes dramatic defects in ring canal structure and nurse cell multinucleation. The SH2 domain of Dock is required for ring canal localization downstream of Src64 (also known as Src64B), and the function of one or more of the SH3 domains is necessary for the strong overexpression phenotype. Genetic interaction and localization studies suggest that Dock promotes WASp-mediated Arp2/3 activation in order to determine ring canal size and regulate growth. This article has an associated First Person interview with the first author of the paper. Summary:Drosophila Dock likely functions downstream of WASp and the Arp2/3 complex to regulate the size and stability of the germline ring canals in the developing egg chamber.
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Affiliation(s)
- Kara Stark
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208, USA
| | - Olivia Crowe
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208, USA
| | - Lindsay Lewellyn
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208, USA
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9
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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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10
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Verboon JM, Nakamura M, Davidson KA, Decker JR, Nandakumar V, Parkhurst SM. Drosophila Wash and the Wash regulatory complex function in nuclear envelope budding. J Cell Sci 2020; 133:jcs243576. [PMID: 32503943 PMCID: PMC7358131 DOI: 10.1242/jcs.243576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
Nuclear envelope (NE) budding is a recently described phenomenon wherein large macromolecular complexes are packaged inside the nucleus and extruded through the nuclear membranes. Although a general outline of the cellular events occurring during NE budding is now in place, little is yet known about the molecular machinery and mechanisms underlying the physical aspects of NE bud formation. Using a multidisciplinary approach, we identify Wash, its regulatory complex (SHRC), capping protein and Arp2/3 as new molecular components involved in the physical aspects of NE bud formation in a Drosophila model system. Interestingly, Wash affects NE budding in two ways: indirectly through general nuclear lamina disruption via an SHRC-independent interaction with Lamin B leading to inefficient NE bud formation, and directly by blocking NE bud formation along with its SHRC, capping protein and Arp2/3. In addition to NE budding emerging as an important cellular process, it shares many similarities with herpesvirus nuclear egress mechanisms, suggesting new avenues for exploration in both normal and disease biology.
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Affiliation(s)
- Jeffrey M Verboon
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Mitsutoshi Nakamura
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Kerri A Davidson
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jacob R Decker
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Vivek Nandakumar
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Susan M Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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11
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Cloud V, Thapa A, Morales-Sosa P, Miller TM, Miller SA, Holsapple D, Gerhart PM, Momtahan E, Jack JL, Leiva E, Rapp SR, Shelton LG, Pierce RA, Martin-Brown S, Florens L, Washburn MP, Mohan RD. Ataxin-7 and Non-stop coordinate SCAR protein levels, subcellular localization, and actin cytoskeleton organization. eLife 2019; 8:e49677. [PMID: 31348003 PMCID: PMC6693919 DOI: 10.7554/elife.49677] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 07/22/2019] [Indexed: 12/18/2022] Open
Abstract
Atxn7, a subunit of SAGA chromatin remodeling complex, is subject to polyglutamine expansion at the amino terminus, causing spinocerebellar ataxia type 7 (SCA7), a progressive retinal and neurodegenerative disease. Within SAGA, the Atxn7 amino terminus anchors Non-stop, a deubiquitinase, to the complex. To understand the scope of Atxn7-dependent regulation of Non-stop, substrates of the deubiquitinase were sought. This revealed Non-stop, dissociated from Atxn7, interacts with Arp2/3 and WAVE regulatory complexes (WRC), which control actin cytoskeleton assembly. There, Non-stop countered polyubiquitination and proteasomal degradation of WRC subunit SCAR. Dependent on conserved WRC interacting receptor sequences (WIRS), Non-stop augmentation increased protein levels, and directed subcellular localization, of SCAR, decreasing cell area and number of protrusions. In vivo, heterozygous mutation of SCAR did not significantly rescue knockdown of Atxn7, but heterozygous mutation of Atxn7 rescued haploinsufficiency of SCAR.
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Affiliation(s)
- Veronica Cloud
- University of Missouri - Kansas CityKansas CityUnited States
| | - Ada Thapa
- University of Missouri - Kansas CityKansas CityUnited States
| | | | - Tayla M Miller
- University of Missouri - Kansas CityKansas CityUnited States
| | - Sara A Miller
- University of Missouri - Kansas CityKansas CityUnited States
| | | | - Paige M Gerhart
- University of Missouri - Kansas CityKansas CityUnited States
| | - Elaheh Momtahan
- University of Missouri - Kansas CityKansas CityUnited States
| | - Jarrid L Jack
- University of Missouri - Kansas CityKansas CityUnited States
| | - Edgardo Leiva
- University of Missouri - Kansas CityKansas CityUnited States
| | - Sarah R Rapp
- University of Missouri - Kansas CityKansas CityUnited States
| | | | | | | | | | - Michael P Washburn
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Pathology and Laboratory MedicineUniversity of Kansas Medical CenterKansas CityUnited States
| | - Ryan D Mohan
- University of Missouri - Kansas CityKansas CityUnited States
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12
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Activation of Arp2/3 by WASp Is Essential for the Endocytosis of Delta Only during Cytokinesis in Drosophila. Cell Rep 2019; 28:1-10.e3. [DOI: 10.1016/j.celrep.2019.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/26/2019] [Accepted: 06/04/2019] [Indexed: 12/11/2022] Open
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13
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Caridi CP, D'Agostino C, Ryu T, Zapotoczny G, Delabaere L, Li X, Khodaverdian VY, Amaral N, Lin E, Rau AR, Chiolo I. Nuclear F-actin and myosins drive relocalization of heterochromatic breaks. Nature 2018; 559:54-60. [PMID: 29925946 PMCID: PMC6051730 DOI: 10.1038/s41586-018-0242-8] [Citation(s) in RCA: 232] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 05/18/2018] [Indexed: 12/13/2022]
Abstract
Heterochromatin mainly comprises repeated DNA sequences that are prone to ectopic recombination. In Drosophila cells, 'safe' repair of heterochromatic double-strand breaks by homologous recombination relies on the relocalization of repair sites to the nuclear periphery before strand invasion. The mechanisms responsible for this movement were unknown. Here we show that relocalization occurs by directed motion along nuclear actin filaments assembled at repair sites by the Arp2/3 complex. Relocalization requires nuclear myosins associated with the heterochromatin repair complex Smc5/6 and the myosin activator Unc45, which is recruited to repair sites by Smc5/6. ARP2/3, actin nucleation and myosins also relocalize heterochromatic double-strand breaks in mouse cells. Defects in this pathway result in impaired heterochromatin repair and chromosome rearrangements. These findings identify de novo nuclear actin filaments and myosins as effectors of chromatin dynamics for heterochromatin repair and stability in multicellular eukaryotes.
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Affiliation(s)
- Christopher P Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Carla D'Agostino
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Taehyun Ryu
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Xiao Li
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Varandt Y Khodaverdian
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Nuno Amaral
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
- Karolinska Institute, Stockholm, Sweden
| | - Emily Lin
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Alesandra R Rau
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, USA.
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14
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Verboon JM, Decker JR, Nakamura M, Parkhurst SM. Wash exhibits context-dependent phenotypes and, along with the WASH regulatory complex, regulates Drosophila oogenesis. J Cell Sci 2018; 131:jcs.211573. [PMID: 29549166 DOI: 10.1242/jcs.211573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 03/12/2018] [Indexed: 12/12/2022] Open
Abstract
WASH, a Wiskott-Aldrich syndrome (WAS) family protein, has many cell and developmental roles related to its function as a branched actin nucleation factor. Similar to mammalian WASHC1, which is embryonic lethal, Drosophila Wash was found to be essential for oogenesis and larval development. Recently, however, Drosophila wash was reported to be homozygous viable. Here, we verify that the original wash null allele harbors an unrelated lethal background mutation; however, this unrelated lethal mutation does not contribute to any Wash oogenesis phenotypes. Significantly, we find that: (1) the homozygous wash null allele retains partial lethality, leading to non-Mendelian inheritance; (2) the allele's functions are subject to its specific genetic background; and (3) the homozygous stock rapidly accumulates modifications that allow it to become robust. Together, these results suggest that Wash plays an important role in oogenesis via the WASH regulatory complex. Finally, we show that another WAS family protein, SCAR/WAVE, plays a similar role in oogenesis and that it is upregulated as one of the modifications that allows the wash allele to survive in the homozygous state.
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Affiliation(s)
- Jeffrey M Verboon
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA 98109
| | - Jacob R Decker
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA 98109
| | - Mitsutoshi Nakamura
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA 98109
| | - Susan M Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA 98109
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15
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Sarkar K, Han SS, Wen KK, Ochs HD, Dupré L, Seidman MM, Vyas YM. R-loops cause genomic instability in T helper lymphocytes from patients with Wiskott-Aldrich syndrome. J Allergy Clin Immunol 2017; 142:219-234. [PMID: 29248492 DOI: 10.1016/j.jaci.2017.11.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 11/07/2017] [Accepted: 11/10/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Wiskott-Aldrich syndrome (WAS), X-linked thrombocytopenia (XLT), and X-linked neutropenia, which are caused by WAS mutations affecting Wiskott-Aldrich syndrome protein (WASp) expression or activity, manifest in immunodeficiency, autoimmunity, genomic instability, and lymphoid and other cancers. WASp supports filamentous actin formation in the cytoplasm and gene transcription in the nucleus. Although the genetic basis for XLT/WAS has been clarified, the relationships between mutant forms of WASp and the diverse features of these disorders remain ill-defined. OBJECTIVE We sought to define how dysfunctional gene transcription is causally linked to the degree of TH cell deficiency and genomic instability in the XLT/WAS clinical spectrum. METHODS In human TH1- or TH2-skewing cell culture systems, cotranscriptional R-loops (RNA/DNA duplex and displaced single-stranded DNA) and DNA double-strand breaks (DSBs) were monitored in multiple samples from patients with XLT and WAS and in normal T cells depleted of WASp. RESULTS WASp deficiency provokes increased R-loops and R-loop-mediated DSBs in TH1 cells relative to TH2 cells. Mechanistically, chromatin occupancy of serine 2-unphosphorylated RNA polymerase II is increased, and that of topoisomerase 1, an R-loop preventing factor, is decreased at R-loop-enriched regions of IFNG and TBX21 (TH1 genes) in TH1 cells. These aberrations accompany increased unspliced (intron-retained) and decreased spliced mRNA of IFNG and TBX21 but not IL13 (TH2 gene). Significantly, increased cellular load of R-loops and DSBs, which are normalized on RNaseH1-mediated suppression of ectopic R-loops, inversely correlates with disease severity scores. CONCLUSION Transcriptional R-loop imbalance is a novel molecular defect causative in TH1 immunodeficiency and genomic instability in patients with WAS. The study proposes that cellular R-loop load could be used as a potential biomarker for monitoring symptom severity and prognostic outcome in the XLT-WAS clinical spectrum and could be targeted therapeutically.
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Affiliation(s)
- Koustav Sarkar
- Division of Pediatric Hematology-Oncology, Carver College of Medicine and the University of Iowa Stead Family Children's Hospital, Iowa City, Md
| | - Seong-Su Han
- Division of Pediatric Hematology-Oncology, Carver College of Medicine and the University of Iowa Stead Family Children's Hospital, Iowa City, Md
| | - Kuo-Kuang Wen
- Division of Pediatric Hematology-Oncology, Carver College of Medicine and the University of Iowa Stead Family Children's Hospital, Iowa City, Md
| | - Hans D Ochs
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, University of Washington, Seattle, Md
| | - Loïc Dupré
- INSERM, UMR1043, Centre de Physiopathologie de Toulouse Purpan, Toulouse, Md; Université Toulouse III Paul-Sabatier, Toulouse, Md; CNRS, UMR5282, Toulouse, Md; Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Md; CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Md
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health (NIH), NIH Biomedical Research Center, Baltimore, Md
| | - Yatin M Vyas
- Division of Pediatric Hematology-Oncology, Carver College of Medicine and the University of Iowa Stead Family Children's Hospital, Iowa City, Md.
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16
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Abstract
Real-time imaging of regulated exocytosis in secreting organs can provide unprecedented temporal and spatial detail. Here, we highlight recent advances in 3D time-lapse imaging in Drosophila salivary glands at single-granule resolution. Using fluorescently labeled proteins expressed in the fly, it is now possible to image the dynamics of vesicle biogenesis and the cytoskeletal factors involved in secretion. 3D imaging over time allows one to visualize and define the temporal sequence of events, including clearance of cortical actin, fusion pore formation, mixing of the vesicular and plasma membranes and recruitment of components of the cytoskeleton. We will also discuss the genetic tools available in the fly that allow one to interrogate the essential factors involved in secretory vesicle formation, cargo secretion and the ultimate integration of the vesicular and plasma membranes. We argue that the combination of high-resolution real-time imaging and powerful genetics provides a platform to investigate the role of any factor in regulated secretion.
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Affiliation(s)
- Duy T Tran
- Section on Biological Chemistry, NIDCR, National Institutes of Health, 30 Convent Drive, Bethesda, MD 20892, USA
| | - Kelly G Ten Hagen
- Developmental Glycobiology Section, NIDCR, National Institutes of Health, 30 Convent Drive, Bethesda, MD 20892, USA
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17
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Nagel BM, Bechtold M, Rodriguez LG, Bogdan S. Drosophila WASH is required for integrin-mediated cell adhesion, cell motility and lysosomal neutralization. J Cell Sci 2016; 130:344-359. [PMID: 27884932 DOI: 10.1242/jcs.193086] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein and SCAR homolog (WASH; also known as Washout in flies) is a conserved actin-nucleation-promoting factor controlling Arp2/3 complex activity in endosomal sorting and recycling. Previous studies have identified WASH as an essential regulator in Drosophila development. Here, we show that homozygous wash mutant flies are viable and fertile. We demonstrate that Drosophila WASH has conserved functions in integrin receptor recycling and lysosome neutralization. WASH generates actin patches on endosomes and lysosomes, thereby mediating both aforementioned functions. Consistently, loss of WASH function results in cell spreading and cell migration defects of macrophages, and an increased lysosomal acidification that affects efficient phagocytic and autophagic clearance. WASH physically interacts with the vacuolar (V)-ATPase subunit Vha55 that is crucial to establish and maintain lysosome acidification. As a consequence, starved flies that lack WASH function show a dramatic increase in acidic autolysosomes, causing a reduced lifespan. Thus, our data highlight a conserved role for WASH in the endocytic sorting and recycling of membrane proteins, such as integrins and the V-ATPase, that increase the likelihood of survival under nutrient deprivation.
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Affiliation(s)
- Benedikt M Nagel
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany.,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
| | - Meike Bechtold
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | | | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany .,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
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18
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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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19
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Localized, Reactive F-Actin Dynamics Prevents Abnormal Somatic Cell Penetration by Mature Spermatids. Dev Cell 2016; 38:507-21. [DOI: 10.1016/j.devcel.2016.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 04/15/2016] [Accepted: 07/01/2016] [Indexed: 12/15/2022]
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20
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Verboon JM, Sugumar B, Parkhurst SM. Wiskott-Aldrich syndrome proteins in the nucleus: aWASH with possibilities. Nucleus 2016; 6:349-59. [PMID: 26305109 PMCID: PMC4915506 DOI: 10.1080/19491034.2015.1086051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actin and proteins that regulate its dynamics or interactions have well-established roles in the cytoplasm where they function as key components of the cytoskeleton to control diverse processes, including cellular infrastructure, cellular motility, cell signaling, and vesicle transport. Recent work has also uncovered roles for actin and its regulatory proteins in the nucleus, primarily in mechanisms governing gene expression. The Wiskott Aldrich Syndrome (WAS) family of proteins, comprising the WASP/N-WASP, SCAR/WAVE, WHAMM/JMY/WHAMY, and WASH subfamilies, function in the cytoplasm where they activate the Arp2/3 complex to form branched actin filaments. WAS proteins are present in the nucleus and have been implicated as transcriptional regulators. We found that Drosophila Wash, in addition to transcriptional effects, is involved in global nuclear architecture. Here we summarize the regulation and function of nuclear WAS proteins, and highlight how our work with Wash expands the possibilities for the functions of these proteins in the nucleus.
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Affiliation(s)
- Jeffrey M Verboon
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Bina Sugumar
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
| | - Susan M Parkhurst
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
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21
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Arp2/3-mediated F-actin formation controls regulated exocytosis in vivo. Nat Commun 2015; 6:10098. [PMID: 26639106 PMCID: PMC4686765 DOI: 10.1038/ncomms10098] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/02/2015] [Indexed: 02/07/2023] Open
Abstract
The actin cytoskeleton plays crucial roles in many cellular processes, including regulated secretion. However, the mechanisms controlling F-actin dynamics in this process are largely unknown. Through 3D time-lapse imaging in a secreting organ, we show that F-actin is actively disassembled along the apical plasma membrane at the site of secretory vesicle fusion and re-assembled directionally on vesicle membranes. Moreover, we show that fusion pore formation and PIP2 redistribution precedes actin and myosin recruitment to secretory vesicle membranes. Finally, we show essential roles for the branched actin nucleators Arp2/3- and WASp in the process of secretory cargo expulsion and integration of vesicular membranes with the apical plasma membrane. Our results highlight previously unknown roles for branched actin in exocytosis and provide a genetically tractable system to image the temporal and spatial dynamics of polarized secretion in vivo. The cytoskeleton plays a crucial role in secretion. Here Tran et al. demonstrate that cortical actin is rearranged at the site of vesicle fusion and recruited to fused secretory granules in Drosophila salivary glands, and show that branched actin nucleators are required for cargo expulsion.
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22
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Abstract
Epithelial repair in the Drosophila embryo is achieved through 2 dynamic cytoskeletal machineries: a contractile actomyosin cable and actin-based cellular protrusions. Rho family small GTPases (Rho, Rac, and Cdc42) are cytoskeletal regulators that control both of these wound repair mechanisms. Cdc42 is necessary for cellular protrusions and, when absent, wounds are slow to repair and never completely close. Rac proteins accumulate at specific regions in the wound leading edge cells and Rac-deficient embryos exhibit slower repair kinetics. Mutants for both Rho1 and its effector Rok impair the ability of wounds to close by disrupting the leading-edge actin cable. Our studies highlight the importance of these proteins in wound repair and identify a downstream effector of Rho1 signaling in this process.
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Affiliation(s)
- Jeffrey M Verboon
- a Division of Basic Sciences; Fred Hutchinson Cancer Research Center ; Seattle , WA USA
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23
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SUMOylation-disrupting WAS mutation converts WASp from a transcriptional activator to a repressor of NF-κB response genes in T cells. Blood 2015; 126:1670-82. [PMID: 26261240 DOI: 10.1182/blood-2015-05-646182] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/08/2015] [Indexed: 11/20/2022] Open
Abstract
In Wiskott-Aldrich syndrome (WAS), immunodeficiency and autoimmunity often comanifest, yet how WAS mutations misregulate chromatin-signaling in Thelper (TH) cells favoring development of auto-inflammation over protective immunity is unclear. Previously, we identified an essential promoter-specific, coactivator role of nuclear-WASp in TH1 gene transcription. Here we identify small ubiquitin-related modifier (SUMO)ylation as a novel posttranslational modification of WASp, impairment of which converts nuclear-WASp from a transcriptional coactivator to a corepressor of nuclear factor (NF)-κB response genes in human (TH)1-differentiating cells. V75M, one of many disease-causing mutations occurring in SUMO*motif (72-ψψψψKDxxxxSY-83) of WASp, compromises WASp-SUMOylation, associates with COMMD1 to attenuate NF-κB signaling, and recruits histone deacetylases-6 (HDAC6) to p300-marked promoters of NF-κB response genes that pattern immunity but not inflammation. Consequently, proteins mediating adaptive immunity (IFNG, STAT1, TLR1) are deficient, whereas those mediating auto-inflammation (GM-CSF, TNFAIP2, IL-1β) are paradoxically increased in TH1 cells expressing SUMOylation-deficient WASp. Moreover, SUMOylation-deficient WASp favors ectopic development of the TH17-like phenotype (↑IL17A, IL21, IL22, IL23R, RORC, and CSF2) under TH1-skewing conditions, suggesting a role for WASp in modulating TH1/TH17 plasticity. Notably, pan-histone deacetylase inhibitors lift promoter-specific repression imposed by SUMOylation-deficient WASp and restore misregulated gene expression. Our findings uncovering a SUMOylation-based mechanism controlling WASp's dichotomous roles in transcription may have implications for personalized therapy for patients carrying mutations that perturb WASp-SUMOylation.
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24
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Spencer AK, Siddiqui BA, Thomas JH. Cell shape change and invagination of the cephalic furrow involves reorganization of F-actin. Dev Biol 2015; 402:192-207. [PMID: 25929228 DOI: 10.1016/j.ydbio.2015.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 11/26/2022]
Abstract
Invagination of epithelial sheets to form furrows is a fundamental morphogenetic movement and is found in a variety of developmental events including gastrulation and vertebrate neural tube formation. The cephalic furrow is a deep epithelial invagination that forms during Drosophila gastrulation. In the first phase of cephalic furrow formation, the initiator cells that will lead invagination undergo apicobasal shortening and apical constriction in the absence of epithelial invagination. In the second phase of cephalic furrow formation, the epithelium starts to invaginate, accompanied by both basal expansion and continued apicobasal shortening of the initiator cells. The cells adjacent to the initiator cells also adopt wedge shapes, but only after invagination is well underway. Myosin II does not appear to drive apical constriction in cephalic furrow formation. However, cortical F-actin is increased in the apices of the initiator cells and in invaginating cells during both phases of cephalic furrow formation. These findings suggest that a novel mechanism for epithelial invagination is involved in cephalic furrow formation.
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Affiliation(s)
- Allison K Spencer
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, STOP 6540, Lubbock, TX 79430, United States
| | - Bilal A Siddiqui
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, STOP 6540, Lubbock, TX 79430, United States
| | - Jeffrey H Thomas
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, STOP 6540, Lubbock, TX 79430, United States.
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25
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Wash interacts with lamin and affects global nuclear organization. Curr Biol 2015; 25:804-810. [PMID: 25754639 DOI: 10.1016/j.cub.2015.01.052] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/29/2014] [Accepted: 01/21/2015] [Indexed: 11/23/2022]
Abstract
The cytoplasmic functions of Wiskott-Aldrich syndrome family (WAS) proteins are well established and include roles in cytoskeleton reorganization and membrane-cytoskeletal interactions important for membrane/vesicle trafficking, morphogenesis, immune response, and signal transduction. Misregulation of these proteins is associated with immune deficiency and metastasis [1-4]. Cytoplasmic WAS proteins act as effectors of Rho family GTPases and polymerize branched actin through the Arp2/3 complex [1, 5]. Previously, we identified Drosophila washout (wash) as a new member of the WAS family with essential cytoplasmic roles in early development [6, 7]. Studies in mammalian cells and Dictyostelium suggest that WASH functions primarily in a multiprotein complex that regulates endosome shape and trafficking in an Arp2/3-dependent manner [8-11]. However, roles for classically cytoplasmic proteins in the nucleus are beginning to emerge, in particular, as participants in the regulation of gene expression [12, 13]. Here, we show that Drosophila Wash is present in the nucleus, where it plays a key role in global nuclear organization. wash mutant and knockdown nuclei disrupt subnuclear structures/organelles and exhibit the abnormal wrinkled morphology reminiscent of those observed in diverse laminopathies [14-16]. We find that nuclear Wash interacts with B-type Lamin (Lamin Dm0), and, like Lamin, Wash associates with constitutive heterochromatin. Wash knockdown increases chromatin accessibility of repressive compartments and results in a global redistribution of repressive histone modifications. Thus, our results reveal a novel role for Wash in modulating nucleus morphology and in the organization of both chromatin and non-chromatin nuclear sub-structures.
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26
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Verboon JM, Rahe TK, Rodriguez-Mesa E, Parkhurst SM. Wash functions downstream of Rho1 GTPase in a subset of Drosophila immune cell developmental migrations. Mol Biol Cell 2015; 26:1665-74. [PMID: 25739458 PMCID: PMC4436778 DOI: 10.1091/mbc.e14-08-1266] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 02/25/2015] [Indexed: 01/12/2023] Open
Abstract
Drosophila immune cells undergo four stereotypical developmental migrations to populate the embryo. Wash is a downstream effector of Rho1 and establishes Rho1>Wash>Arp2/3 as the regulatory pathway controlling the cytoskeleton during one of these developmental hemocyte migrations in a WASH regulatory complex–independent manner. Drosophila immune cells, the hemocytes, undergo four stereotypical developmental migrations to populate the embryo, where they provide immune reconnoitering, as well as a number of non–immune-related functions necessary for proper embryogenesis. Here, we describe a role for Rho1 in one of these developmental migrations in which posteriorly located hemocytes migrate toward the head. This migration requires the interaction of Rho1 with its downstream effector Wash, a Wiskott–Aldrich syndrome family protein. Both Wash knockdown and a Rho1 transgene harboring a mutation that prevents Wash binding exhibit the same developmental migratory defect as Rho1 knockdown. Wash activates the Arp2/3 complex, whose activity is needed for this migration, whereas members of the WASH regulatory complex (SWIP, Strumpellin, and CCDC53) are not. Our results suggest a WASH complex–independent signaling pathway to regulate the cytoskeleton during a subset of hemocyte developmental migrations.
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Affiliation(s)
- Jeffrey M Verboon
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Travis K Rahe
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Evelyn Rodriguez-Mesa
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Susan M Parkhurst
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
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27
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Cetera M, Ramirez-San Juan GR, Oakes PW, Lewellyn L, Fairchild MJ, Tanentzapf G, Gardel ML, Horne-Badovinac S. Epithelial rotation promotes the global alignment of contractile actin bundles during Drosophila egg chamber elongation. Nat Commun 2014; 5:5511. [PMID: 25413675 PMCID: PMC4241503 DOI: 10.1038/ncomms6511] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/08/2014] [Indexed: 01/05/2023] Open
Abstract
Tissues use numerous mechanisms to change shape during development. The Drosophila egg chamber is an organ-like structure that elongates to form an elliptical egg. During elongation the follicular epithelial cells undergo a collective migration that causes the egg chamber to rotate within its surrounding basement membrane. Rotation coincides with the formation of a “molecular corset”, in which actin bundles in the epithelium and fibrils in the basement membrane are all aligned perpendicular to the elongation axis. Here we show that rotation plays a critical role in building the actin-based component of the corset. Rotation begins shortly after egg chamber formation and requires lamellipodial protrusions at each follicle cell’s leading edge. During early stages, rotation is necessary for tissue-level actin bundle alignment, but it becomes dispensable after the basement membrane is polarized. This work highlights how collective cell migration can be used to build a polarized tissue organization for organ morphogenesis.
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Affiliation(s)
- Maureen Cetera
- 1] Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA [2] Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
| | - Guillermina R Ramirez-San Juan
- 1] Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA [2] Institute for Biophysical Dynamics, James Franck Institute and Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Patrick W Oakes
- Institute for Biophysical Dynamics, James Franck Institute and Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Lindsay Lewellyn
- 1] Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA [2] Department of Biological Sciences, Butler University, 4600 Sunset Boulevard, Indianapolis, Indiana 46208, USA
| | - Michael J Fairchild
- Life Sciences Centre, Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Guy Tanentzapf
- Life Sciences Centre, Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, James Franck Institute and Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Sally Horne-Badovinac
- 1] Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA [2] Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
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28
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Sadhukhan S, Sarkar K, Taylor M, Candotti F, Vyas YM. Nuclear role of WASp in gene transcription is uncoupled from its ARP2/3-dependent cytoplasmic role in actin polymerization. THE JOURNAL OF IMMUNOLOGY 2014; 193:150-60. [PMID: 24872192 DOI: 10.4049/jimmunol.1302923] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Defects in Wiskott-Aldrich Syndrome protein (WASp) underlie development of WAS, an X-linked immunodeficiency and autoimmunity disorder of childhood. Nucleation-promoting factors (NPFs) of the WASp family generate F-actin in the cytosol via the VCA (verprolin-homology, cofilin-homology, and acidic) domain and support RNA polymerase II-dependent transcription in the nucleus. Whether nuclear-WASp requires the integration of its actin-related protein (ARP)2/3-dependent cytoplasmic function to reprogram gene transcription, however, remains unresolved. Using the model of human TH cell differentiation, we find that WASp has a functional nuclear localizing and nuclear exit sequences, and accordingly, its effects on transcription are controlled mainly at the level of its nuclear entry and exit via the nuclear pore. Human WASp does not use its VCA-dependent, ARP2/3-driven, cytoplasmic effector mechanisms to support histone H3K4 methyltransferase activity in the nucleus of TH1-skewed cells. Accordingly, an isolated deficiency of nuclear-WASp is sufficient to impair the transcriptional reprogramming of TBX21 and IFNG promoters in TH1-skewed cells, whereas an isolated deficiency of cytosolic-WASp does not impair this process. In contrast, nuclear presence of WASp in TH2-skewed cells is small, and its loss does not impair transcriptional reprogramming of GATA3 and IL4 promoters. Our study unveils an ARP2/3:VCA-independent function of nuclear-WASp in TH1 gene activation that is uncoupled from its cytoplasmic role in actin polymerization.
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Affiliation(s)
- Sanjoy Sadhukhan
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213
| | - Koustav Sarkar
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213; Division of Pediatric Hematology-Oncology, University of Iowa Children's Hospital, Iowa City, IA 52242; and
| | - Matthew Taylor
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213
| | - Fabio Candotti
- Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892
| | - Yatin M Vyas
- Division of Pediatric Hematology-Oncology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15213; Division of Pediatric Hematology-Oncology, University of Iowa Children's Hospital, Iowa City, IA 52242; and
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Koch N, Kobler O, Thomas U, Qualmann B, Kessels MM. Terminal axonal arborization and synaptic bouton formation critically rely on abp1 and the arp2/3 complex. PLoS One 2014; 9:e97692. [PMID: 24841972 PMCID: PMC4026379 DOI: 10.1371/journal.pone.0097692] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/23/2014] [Indexed: 01/12/2023] Open
Abstract
Neuronal network formation depends on properly timed and localized generation of presynaptic as well as postsynaptic structures. Although of utmost importance for understanding development and plasticity of the nervous system and neurodegenerative diseases, the molecular mechanisms that ensure the fine-control needed for coordinated establishment of pre- and postsynapses are still largely unknown. We show that the F-actin-binding protein Abp1 is prominently expressed in the Drosophila nervous system and reveal that Abp1 is an important regulator in shaping glutamatergic neuromuscular junctions (NMJs) of flies. STED microscopy shows that Abp1 accumulations can be found in close proximity of synaptic vesicles and at the cell cortex in nerve terminals. Abp1 knock-out larvae have locomotion defects and underdeveloped NMJs that are characterized by a reduced number of both type Ib synaptic boutons and branches of motornerve terminals. Abp1 is able to indirectly trigger Arp2/3 complex-mediated actin nucleation and interacts with both WASP and Scar. Consistently, Arp2 and Arp3 loss-of-function also resulted in impairments of bouton formation and arborization at NMJs, i.e. fully phenocopied abp1 knock-out. Interestingly, neuron- and muscle-specific rescue experiments revealed that synaptic bouton formation critically depends on presynaptic Abp1, whereas the NMJ branching defects can be compensated for by restoring Abp1 functions at either side. In line with this presynaptic importance of Abp1, also presynaptic Arp2 and Arp3 are crucial for the formation of type Ib synaptic boutons. Interestingly, presynaptic Abp1 functions in NMJ formation were fully dependent on the Arp2/3 complex, as revealed by suppression of Abp1-induced synaptic bouton formation and branching of axon terminals upon presynaptic Arp2 RNAi. These data reveal that Abp1 and Arp2/3 complex-mediated actin cytoskeletal dynamics drive both synaptic bouton formation and NMJ branching. Our data furthermore shed light on an intense bidirectional functional crosstalk between pre- and postsynapses during the development of synaptic contacts.
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Affiliation(s)
- Nicole Koch
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
- Research Group Membrane Trafficking and Cytoskeleton, Department of Neurochemistry & Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Oliver Kobler
- Research Group Functional Genetics of the Synapse, Department of Neurochemistry & Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Ulrich Thomas
- Research Group Functional Genetics of the Synapse, Department of Neurochemistry & Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
- * E-mail: (UT); (BQ); (MMK)
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
- * E-mail: (UT); (BQ); (MMK)
| | - Michael M. Kessels
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
- Research Group Membrane Trafficking and Cytoskeleton, Department of Neurochemistry & Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
- * E-mail: (UT); (BQ); (MMK)
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30
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Wang S, Tan KL, Agosto MA, Xiong B, Yamamoto S, Sandoval H, Jaiswal M, Bayat V, Zhang K, Charng WL, David G, Duraine L, Venkatachalam K, Wensel TG, Bellen HJ. The retromer complex is required for rhodopsin recycling and its loss leads to photoreceptor degeneration. PLoS Biol 2014; 12:e1001847. [PMID: 24781186 PMCID: PMC4004542 DOI: 10.1371/journal.pbio.1001847] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/21/2014] [Indexed: 12/22/2022] Open
Abstract
Rhodopsin recycling via the retromer, rather than degradation through lysosomes, can alleviate light-induced photoreceptor degeneration in Drosophila. Rhodopsin mistrafficking can cause photoreceptor (PR) degeneration. Upon light exposure, activated rhodopsin 1 (Rh1) in Drosophila PRs is internalized via endocytosis and degraded in lysosomes. Whether internalized Rh1 can be recycled is unknown. Here, we show that the retromer complex is expressed in PRs where it is required for recycling endocytosed Rh1 upon light stimulation. In the absence of subunits of the retromer, Rh1 is processed in the endolysosomal pathway, leading to a dramatic increase in late endosomes, lysosomes, and light-dependent PR degeneration. Reducing Rh1 endocytosis or Rh1 levels in retromer mutants alleviates PR degeneration. In addition, increasing retromer abundance suppresses degenerative phenotypes of mutations that affect the endolysosomal system. Finally, expressing human Vps26 suppresses PR degeneration in Vps26 mutant PRs. We propose that the retromer plays a conserved role in recycling rhodopsins to maintain PR function and integrity. Upon light exposure, rhodopsins—light-sensing proteins in the eye—trigger visual transduction signaling to activate fly photoreceptor cells. After activation, rhodopsins can be internalized from the cell surface into endosomes and then degraded in lysosomes. This mechanism prevents constant activation of the visual transduction pathway, thereby maintaining the function and integrity of photoreceptor cells. It is not known, however, whether these internalized rhodopsins can be recycled. Here, we show that the retromer, an evolutionarily conserved protein complex, is required for the recycling of rhodopsins. We find that loss of key retromer subunits (Vps35 or Vps26) causes rhodopsin mislocalization in the photoreceptors and severe light-induced photoreceptor degeneration. Conversely, gain of retromer subunits can alleviate photoreceptor degeneration in some contexts. Human retromer components can stand in for depleted fruit fly retromer, suggesting that this complex plays a role in recycling light sensors in both vertebrate and invertebrate photoreceptors.
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Affiliation(s)
- Shiuan Wang
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Melina A. Agosto
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lita Duraine
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Theodore G. Wensel
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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31
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WASH knockout T cells demonstrate defective receptor trafficking, proliferation, and effector function. Mol Cell Biol 2012; 33:958-73. [PMID: 23275443 DOI: 10.1128/mcb.01288-12] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
WASH is an Arp2/3 activator of the Wiskott-Aldrich syndrome protein superfamily that functions during endosomal trafficking processes in collaboration with the retromer and sorting nexins, but its in vivo function has not been examined. To elucidate the physiological role of WASH in T cells, we generated a WASH conditional knockout (WASHout) mouse model. Using CD4(Cre) deletion, we found that thymocyte development and naive T cell activation are unaltered in the absence of WASH. Surprisingly, despite normal T cell receptor (TCR) signaling and interleukin-2 production, WASHout T cells demonstrate significantly reduced proliferative potential and fail to effectively induce experimental autoimmune encephalomyelitis. Interestingly, after activation, WASHout T cells fail to maintain surface levels of TCR, CD28, and LFA-1. Moreover, the levels of the glucose transporter, GLUT1, are also reduced compared to wild-type T cells. We further demonstrate that the loss of surface expression of these receptors in WASHout cells results from aberrant accumulation within the collapsed endosomal compartment, ultimately leading to degradation within the lysosome. Subsequently, activated WASHout T cells experience reduced glucose uptake and metabolic output. Thus, we found that WASH is a newly recognized regulator of TCR, CD28, LFA-1, and GLUT1 endosome-to-membrane recycling. Aberrant trafficking of these key T cell proteins may potentially lead to attenuated proliferation and effector function.
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