1
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Rollins KR, Blankenship JT. Dysregulation of the endoplasmic reticulum blocks recruitment of centrosome-associated proteins resulting in mitotic failure. Development 2023; 150:dev201917. [PMID: 37971218 PMCID: PMC10690056 DOI: 10.1242/dev.201917] [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: 04/24/2023] [Accepted: 10/17/2023] [Indexed: 11/19/2023]
Abstract
The endoplasmic reticulum (ER) undergoes a remarkable transition in morphology during cell division to aid in the proper portioning of the ER. However, whether changes in ER behaviors modulate mitotic events is less clear. Like many animal embryos, the early Drosophila embryo undergoes rapid cleavage cycles in a lipid-rich environment. Here, we show that mitotic spindle formation, centrosomal maturation, and ER condensation occur with similar time frames in the early syncytium. In a screen for Rab family GTPases that display dynamic function at these stages, we identified Rab1. Rab1 disruption led to an enhanced buildup of ER at the spindle poles and produced an intriguing 'mini-spindle' phenotype. ER accumulation around the mitotic space negatively correlates with spindle length/intensity. Importantly, centrosomal maturation is defective in these embryos, as mitotic recruitment of key centrosomal proteins is weakened after Rab1 disruption. Finally, division failures and ER overaccumulation is rescued by Dynein inhibition, demonstrating that Dynein is essential for ER spindle recruitment. These results reveal that ER levels must be carefully tuned during mitotic processes to ensure proper assembly of the division machinery.
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Affiliation(s)
| | - J. Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
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2
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Xu C, Xu J, Tang HW, Ericsson M, Weng JH, DiRusso J, Hu Y, Ma W, Asara JM, Perrimon N. A phosphate-sensing organelle regulates phosphate and tissue homeostasis. Nature 2023; 617:798-806. [PMID: 37138087 PMCID: PMC10443203 DOI: 10.1038/s41586-023-06039-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 03/31/2023] [Indexed: 05/05/2023]
Abstract
Inorganic phosphate (Pi) is one of the essential molecules for life. However, little is known about intracellular Pi metabolism and signalling in animal tissues1. Following the observation that chronic Pi starvation causes hyperproliferation in the digestive epithelium of Drosophila melanogaster, we determined that Pi starvation triggers the downregulation of the Pi transporter PXo. In line with Pi starvation, PXo deficiency caused midgut hyperproliferation. Interestingly, immunostaining and ultrastructural analyses showed that PXo specifically marks non-canonical multilamellar organelles (PXo bodies). Further, by Pi imaging with a Förster resonance energy transfer (FRET)-based Pi sensor2, we found that PXo restricts cytosolic Pi levels. PXo bodies require PXo for biogenesis and undergo degradation following Pi starvation. Proteomic and lipidomic characterization of PXo bodies unveiled their distinct feature as an intracellular Pi reserve. Therefore, Pi starvation triggers PXo downregulation and PXo body degradation as a compensatory mechanism to increase cytosolic Pi. Finally, we identified connector of kinase to AP-1 (Cka), a component of the STRIPAK complex and JNK signalling3, as the mediator of PXo knockdown- or Pi starvation-induced hyperproliferation. Altogether, our study uncovers PXo bodies as a critical regulator of cytosolic Pi levels and identifies a Pi-dependent PXo-Cka-JNK signalling cascade controlling tissue homeostasis.
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Affiliation(s)
- Chiwei Xu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Robin Chemers Neustein Laboratory of Mammalian Development and Cell Biology, The Rockefeller University, New York, NY, USA.
| | - Jun Xu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hong-Wen Tang
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Maria Ericsson
- Department of Cell Biology, Electron Microscopy Facility, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Jui-Hsia Weng
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jonathan DiRusso
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Wenzhe Ma
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - John M Asara
- Department of Medicine, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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3
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Sokac AM, Biel N, De Renzis S. Membrane-actin interactions in morphogenesis: Lessons learned from Drosophila cellularization. Semin Cell Dev Biol 2023; 133:107-122. [PMID: 35396167 PMCID: PMC9532467 DOI: 10.1016/j.semcdb.2022.03.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 01/12/2023]
Abstract
During morphogenesis, changes in the shapes of individual cells are harnessed to mold an entire tissue. These changes in cell shapes require the coupled remodeling of the plasma membrane and underlying actin cytoskeleton. In this review, we highlight cellularization of the Drosophila embryo as a model system to uncover principles of how membrane and actin dynamics are co-regulated in space and time to drive morphogenesis.
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Affiliation(s)
- Anna Marie Sokac
- Department of Cell and Developmental Biology, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA; Graduate Program in Integrative and Molecular Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Natalie Biel
- Department of Cell and Developmental Biology, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA; Graduate Program in Integrative and Molecular Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stefano De Renzis
- European Molecular Biology Laboratory Heidelberg, 69117 Heidelberg, Germany
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4
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Blaise AM, Corcoran EE, Wattenberg ES, Zhang YL, Cottrell JR, Koleske AJ. In vitro fluorescence assay to measure GDP/GTP exchange of guanine nucleotide exchange factors of Rho family GTPases. Biol Methods Protoc 2021; 7:bpab024. [PMID: 35087952 PMCID: PMC8789339 DOI: 10.1093/biomethods/bpab024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/14/2021] [Indexed: 11/14/2022] Open
Abstract
Guanine nucleotide exchange factors (GEFs) are enzymes that promote the activation of GTPases through GTP loading. Whole exome sequencing has identified rare variants in GEFs that are associated with disease, demonstrating that GEFs play critical roles in human development. However, the consequences of these rare variants can only be understood through measuring their effects on cellular activity. Here, we provide a detailed, user-friendly protocol for purification and fluorescence-based analysis of the two GEF domains within the protein, Trio. This analysis offers a straight-forward, quantitative tool to test the activity of GEF domains on their respective GTPases, as well as utilize high-throughput screening to identify regulators and inhibitors. This protocol can be adapted for characterization of other Rho family GEFs. Such analyses are crucial for the complete understanding of the roles of GEF genetic variants in human development and disease.
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Affiliation(s)
- Alyssa M Blaise
- Departments of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
- Neuroscience, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
| | - Ellen E Corcoran
- Departments of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
- Neuroscience, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
| | - Eve S Wattenberg
- Departments of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
- Neuroscience, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
| | - Yan-Ling Zhang
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Anthony J Koleske
- Departments of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
- Neuroscience, Yale School of Medicine, Yale University, New Haven, CT 06520-8024, USA
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5
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Lauri A, Fasano G, Venditti M, Dallapiccola B, Tartaglia M. In vivo Functional Genomics for Undiagnosed Patients: The Impact of Small GTPases Signaling Dysregulation at Pan-Embryo Developmental Scale. Front Cell Dev Biol 2021; 9:642235. [PMID: 34124035 PMCID: PMC8194860 DOI: 10.3389/fcell.2021.642235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/12/2021] [Indexed: 12/24/2022] Open
Abstract
While individually rare, disorders affecting development collectively represent a substantial clinical, psychological, and socioeconomic burden to patients, families, and society. Insights into the molecular mechanisms underlying these disorders are required to speed up diagnosis, improve counseling, and optimize management toward targeted therapies. Genome sequencing is now unveiling previously unexplored genetic variations in undiagnosed patients, which require functional validation and mechanistic understanding, particularly when dealing with novel nosologic entities. Functional perturbations of key regulators acting on signals' intersections of evolutionarily conserved pathways in these pathological conditions hinder the fine balance between various developmental inputs governing morphogenesis and homeostasis. However, the distinct mechanisms by which these hubs orchestrate pathways to ensure the developmental coordinates are poorly understood. Integrative functional genomics implementing quantitative in vivo models of embryogenesis with subcellular precision in whole organisms contribute to answering these questions. Here, we review the current knowledge on genes and mechanisms critically involved in developmental syndromes and pediatric cancers, revealed by genomic sequencing and in vivo models such as insects, worms and fish. We focus on the monomeric GTPases of the RAS superfamily and their influence on crucial developmental signals and processes. We next discuss the effectiveness of exponentially growing functional assays employing tractable models to identify regulatory crossroads. Unprecedented sophistications are now possible in zebrafish, i.e., genome editing with single-nucleotide precision, nanoimaging, highly resolved recording of multiple small molecules activity, and simultaneous monitoring of brain circuits and complex behavioral response. These assets permit accurate real-time reporting of dynamic small GTPases-controlled processes in entire organisms, owning the potential to tackle rare disease mechanisms.
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Affiliation(s)
- Antonella Lauri
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | | | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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6
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Saito M, Nakayama M, Fujita K, Uchida A, Yano H, Goto S, Okazawa H, Sone M. Role of the Drosophila YATA protein in the proper subcellular localization of COPI revealed by in vivo analysis. Genes Genet Syst 2021; 95:303-314. [PMID: 33583916 DOI: 10.1266/ggs.20-00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
yata mutants of Drosophila melanogaster exhibit phenotypes including progressive brain shrinkage, developmental abnormalities and shortened lifespan, whereas in mammals, null mutations of the yata ortholog Scyl1 result in motor neuron degeneration. yata mutation also causes defects in the anterograde intracellular trafficking of a subset of proteins including APPL, which is the Drosophila ortholog of mammalian APP, a causative molecule in Alzheimer's disease. SCYL1 binds and regulates the function of coat protein complex I (COPI) in secretory vesicles. Here, we reveal a role for the Drosophila YATA protein in the proper localization of COPI. Immunohistochemical analyses performed using confocal microscopy and structured illumination microscopy showed that YATA colocalizes with COPI and GM130, a cis-Golgi marker. Analyses using transgenically expressed YATA with a modified N-terminal sequence revealed that the N-terminal portion of YATA is required for the proper subcellular localization of YATA. Analysis using transgenically expressed YATA proteins in which the C-terminal sequence was modified revealed a function for the C-terminal portion of YATA in the subcellular localization of COPI. Notably, when YATA was mislocalized, it also caused the mislocalization of COPI, indicating that YATA plays a role in directing COPI to the proper subcellular site. Moreover, when both YATA and COPI were mislocalized, the staining pattern of GM130 revealed Golgi with abnormal elongated shapes. Thus, our in vivo data indicate that YATA plays a role in the proper subcellular localization of COPI.
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Affiliation(s)
- Maiko Saito
- Department of Biomolecular Science, Faculty of Science, Toho University
| | - Minoru Nakayama
- Department of Biomolecular Science, Faculty of Science, Toho University
| | - Kyota Fujita
- Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University
| | - Atsuko Uchida
- Department of Neuroscience, The Ohio State University
| | | | - Satoshi Goto
- Department of Life Science, College of Science, Rikkyo University
| | - Hitoshi Okazawa
- Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University
| | - Masaki Sone
- Department of Biomolecular Science, Faculty of Science, Toho University
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7
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The Arf-GEF Steppke promotes F-actin accumulation, cell protrusions and tissue sealing during Drosophila dorsal closure. PLoS One 2020; 15:e0239357. [PMID: 33186390 PMCID: PMC7665897 DOI: 10.1371/journal.pone.0239357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/02/2020] [Indexed: 01/05/2023] Open
Abstract
Cytohesin Arf-GEFs promote actin polymerization and protrusions of cultured cells, whereas the Drosophila cytohesin, Steppke, antagonizes actomyosin networks in several developmental contexts. To reconcile these findings, we analyzed epidermal leading edge actin networks during Drosophila embryo dorsal closure. Here, Steppke is required for F-actin of the actomyosin cable and for actin-based protrusions. steppke mutant defects in the leading edge actin networks are associated with improper sealing of the dorsal midline, but are distinguishable from effects of myosin mis-regulation. Steppke localizes to leading edge cell-cell junctions with accumulations of the F-actin regulator Enabled emanating from either side. Enabled requires Steppke for full leading edge recruitment, and genetic interaction shows the proteins cooperate for dorsal closure. Inversely, Steppke over-expression induces ectopic, actin-rich, lamellar cell protrusions, an effect dependent on the Arf-GEF activity and PH domain of Steppke, but independent of Steppke recruitment to myosin-rich AJs via its coiled-coil domain. Thus, Steppke promotes actin polymerization and cell protrusions, effects that occur in conjunction with Steppke's previously reported regulation of myosin contractility during dorsal closure.
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8
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Greig J, Bulgakova NA. Arf6 determines tissue architecture by stabilizing intercellular adhesion. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190682. [PMID: 32829688 DOI: 10.1098/rstb.2019.0682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Correct cell shape is indispensable for tissue architecture, with cell shape being determined by cortical actin and surface adhesion. The role of adhesion in remodelling tissue is to counteract the deformation of cells by force, resulting from actomyosin contractility, and to maintain tissue integrity. The dynamics of this adhesion are critical to the processes of cell shape formation and maintenance. Here, we show that the trafficking molecule Arf6 has a direct impact on cell elongation, by acting to stabilize E-cadherin-based adhesion complexes at the cell surface, in addition to its canonical role in endocytosis. We demonstrate that these functions of Arf6 are dependent on the molecule Flotillin1, which recruits Arf6 to the plasma membrane. Our data suggest that Arf6 and Flotillin1 operate in a pathway distinct from clathrin-mediated endocytosis. Altogether, we demonstrate that Arf6- and Flotillin1-dependent regulation of the dynamics of cell adhesion contribute to moulding tissue in vivo. This article is part of the discussion meeting issue 'Contemporary morphogenesis'.
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Affiliation(s)
- Joshua Greig
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Natalia A Bulgakova
- Department of Biomedical Science and Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
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9
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Wilson KA, Beck JN, Nelson CS, Hilsabeck TA, Promislow D, Brem RB, Kapahi P. GWAS for Lifespan and Decline in Climbing Ability in Flies upon Dietary Restriction Reveal decima as a Mediator of Insulin-like Peptide Production. Curr Biol 2020; 30:2749-2760.e3. [PMID: 32502405 DOI: 10.1016/j.cub.2020.05.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 03/17/2020] [Accepted: 05/06/2020] [Indexed: 12/16/2022]
Abstract
Dietary restriction (DR) is the most robust means to extend lifespan and delay age-related diseases across species. An underlying assumption in the aging field is that DR enhances both lifespan and physical activity through similar mechanisms, but this has not been rigorously tested in different genetic backgrounds. Furthermore, nutrient response genes responsible for lifespan extension or age-related decline in functionality remain underexplored in natural populations. To address this, we measured nutrient-dependent changes in lifespan and age-related decline in climbing ability in the Drosophila Genetic Reference Panel fly strains. On average, DR extended lifespan and delayed decline in climbing ability, but there was a lack of correlation between these traits across individual strains, suggesting that distinct genetic factors modulate these traits independently and that genotype determines response to diet. Only 50% of strains showed positive response to DR for both lifespan and climbing ability, 14% showed a negative response for one trait but not both, and 35% showed no change in one or both traits. Through GWAS, we uncovered a number of genes previously not known to be diet responsive nor to influence lifespan or climbing ability. We validated decima as a gene that alters lifespan and daedalus as one that influences age-related decline in climbing ability. We found that decima influences insulin-like peptide transcription in the GABA receptor neurons downstream of short neuropeptide F precursor (sNPF) signaling. Modulating these genes produced independent effects on lifespan and physical activity decline, which suggests that these age-related traits can be regulated through distinct mechanisms.
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Affiliation(s)
- Kenneth A Wilson
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA; Davis School of Gerontology, University of Southern California, University Park, Los Angeles, CA 90007, USA
| | - Jennifer N Beck
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA; Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Room A-632, San Francisco, CA 94143, USA
| | | | - Tyler A Hilsabeck
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA; Davis School of Gerontology, University of Southern California, University Park, Los Angeles, CA 90007, USA
| | - Daniel Promislow
- Department of Pathology, University of Washington, Seattle, WA 98195, USA; Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Rachel B Brem
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA; Davis School of Gerontology, University of Southern California, University Park, Los Angeles, CA 90007, USA; Department of Plant and Microbial Biology, University of California, Berkeley, 111 Koshland Hall, Berkeley, CA 94720, USA.
| | - Pankaj Kapahi
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA; Davis School of Gerontology, University of Southern California, University Park, Los Angeles, CA 90007, USA; Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Room A-632, San Francisco, CA 94143, USA.
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10
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Zheng S, West JJ, Yu CG, Harris TJC. Arf-GEF localization and function at myosin-rich adherens junctions via coiled-coil heterodimerization with an adaptor protein. Mol Biol Cell 2019; 30:3090-3103. [PMID: 31693432 PMCID: PMC6938242 DOI: 10.1091/mbc.e19-10-0566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Tissue dynamics require regulated interactions between adherens junctions and cytoskeletal networks. For example, myosin-rich adherens junctions recruit the cytohesin Arf-GEF Steppke, which down-regulates junctional tension and facilitates tissue stretching. We dissected this recruitment mechanism with structure–function and other analyses of Steppke and Stepping stone, an implicated adaptor protein. During Drosophila dorsal closure, Steppke’s coiled-coil domain was necessary and sufficient for junctional recruitment. Purified coiled-coil domains of Steppke and Stepping stone heterodimerized through a hydrophobic surface of the Steppke domain. This mapped surface was required for Steppke’s junctional localization and tissue regulation. Stepping stone colocalized with Steppke at junctions, and was required for junctional Steppke localization and proper tissue stretching. A second conserved region of Stepping stone was necessary and largely sufficient for junctional localization. Remarkably, this region could substitute for the Steppke coiled-coil domain for junction localization and regulation, suggesting the main role of the Steppke coiled-coil domain is linkage to the junctional targeting region of Stepping stone. Thus, coiled-coil heterodimerization with Stepping stone normally recruits Step to junctions. Intriguingly, Stepping stone’s junctional localization also seems partly dependent on Steppke.
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Affiliation(s)
- Shiyu Zheng
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Junior J West
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Cao Guo Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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11
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An Actomyosin-Arf-GEF Negative Feedback Loop for Tissue Elongation under Stress. Curr Biol 2017; 27:2260-2270.e5. [DOI: 10.1016/j.cub.2017.06.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/15/2017] [Accepted: 06/14/2017] [Indexed: 02/06/2023]
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12
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Rodrigues FF, Harris TJC. Key roles of Arf small G proteins and biosynthetic trafficking for animal development. Small GTPases 2017; 10:403-410. [PMID: 28410007 DOI: 10.1080/21541248.2017.1304854] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Although biosynthetic trafficking can function constitutively, it also functions specifically for certain developmental processes. These processes require either a large increase to biosynthesis or the biosynthesis and targeted trafficking of specific players. We review the conserved molecular mechanisms that direct biosynthetic trafficking, and discuss how their genetic disruption affects animal development. Specifically, we consider Arf small G proteins, such as Arf1 and Sar1, and their coat effectors, COPI and COPII, and how these proteins promote biosynthetic trafficking for cleavage of the Drosophila embryo, the growth of neuronal dendrites and synapses, extracellular matrix secretion for bone development, lumen development in epithelial tubes, notochord and neural tube development, and ciliogenesis. Specific need for the biosynthetic trafficking system is also evident from conserved CrebA/Creb3-like transcription factors increasing the expression of secretory machinery during several of these developmental processes. Moreover, dysfunctional trafficking leads to a range of developmental syndromes.
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Affiliation(s)
- Francisco F Rodrigues
- Department of Cell & Systems Biology, University of Toronto , Toronto , Ontario , Canada
| | - Tony J C Harris
- Department of Cell & Systems Biology, University of Toronto , Toronto , Ontario , Canada
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13
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Rodrigues FF, Shao W, Harris TJC. The Arf GAP Asap promotes Arf1 function at the Golgi for cleavage furrow biosynthesis in Drosophila. Mol Biol Cell 2016; 27:3143-3155. [PMID: 27535433 PMCID: PMC5063621 DOI: 10.1091/mbc.e16-05-0272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/11/2016] [Indexed: 11/11/2022] Open
Abstract
Drosophila embryo cleavage requires the conserved Arf GAP Asap. Asap seems to recycle Arf1 to the Golgi from post-Golgi membranes for optimal Golgi output and cleavage furrow biosynthesis. Biosynthetic traffic from the Golgi drives plasma membrane growth. For Drosophila embryo cleavage, this growth is rapid but regulated for cycles of furrow ingression and regression. The highly conserved small G protein Arf1 organizes Golgi trafficking. Arf1 is activated by guanine nucleotide exchange factors, but essential roles for Arf1 GTPase-activating proteins (GAPs) are less clear. We report that the conserved Arf GAP Asap is required for cleavage furrow ingression in the early embryo. Because Asap can affect multiple subcellular processes, we used genetic approaches to dissect its primary effect. Our data argue against cytoskeletal or endocytic involvement and reveal a common role for Asap and Arf1 in Golgi organization. Although Asap lacked Golgi enrichment, it was necessary and sufficient for Arf1 accumulation at the Golgi, and a conserved Arf1-Asap binding site was required for Golgi organization and output. Of note, Asap relocalized to the nuclear region at metaphase, a shift that coincided with subtle Golgi reorganization preceding cleavage furrow regression. We conclude that Asap is essential for Arf1 to function at the Golgi for cleavage furrow biosynthesis. Asap may recycle Arf1 to the Golgi from post-Golgi membranes, providing optimal Golgi output for specific stages of the cell cycle.
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Affiliation(s)
- Francisco F Rodrigues
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Wei Shao
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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