151
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Olmos Y, Carlton JG. The ESCRT machinery: new roles at new holes. Curr Opin Cell Biol 2016; 38:1-11. [PMID: 26775243 PMCID: PMC5023845 DOI: 10.1016/j.ceb.2015.12.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/14/2015] [Accepted: 12/21/2015] [Indexed: 01/04/2023]
Abstract
The ESCRT machinery drives a diverse collection of membrane remodeling events, including multivesicular body biogenesis, release of enveloped retroviruses and both reformation of the nuclear envelope and cytokinetic abscission during mitotic exit. These events share the requirement for a topologically equivalent membrane remodeling for their completion and the cells deployment of the ESCRT machinery in these different contexts highlights its functionality as a transposable membrane-fission machinery. Here, we will examine recent data describing ESCRT-III dependent membrane remodeling and explore new roles for the ESCRT-III complex at the nuclear envelope.
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Affiliation(s)
- Y Olmos
- Division of Cancer Studies, Section of Cell Biology and Imaging, King's College London, London SE1 1UL, United Kingdom
| | - J G Carlton
- Division of Cancer Studies, Section of Cell Biology and Imaging, King's College London, London SE1 1UL, United Kingdom.
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152
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D'Avino PP, Capalbo L. Regulation of midbody formation and function by mitotic kinases. Semin Cell Dev Biol 2016; 53:57-63. [PMID: 26802517 DOI: 10.1016/j.semcdb.2016.01.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/14/2016] [Indexed: 12/22/2022]
Abstract
Cytokinesis is the final phase of cell division and safeguards the correct distribution of genomic and cytoplasmic materials between the two nascent daughter cells. The final separation, or abscission, of the daughter cells depends on the proper assembly of an organelle at the intercellular bridge, the midbody, which acts as a platform for the recruitment and organisation of various proteins involved in both the control and execution of the abscission process. Recent studies have led to the identification of the mechanisms, signalling pathways and molecules that control the two tightly linked processes of midbody formation and abscission. Here we review our current knowledge of the role that mitotic kinases play in these processes and offer our perspectives on the potential future challenges that await researchers in the field.
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Affiliation(s)
- Pier Paolo D'Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Luisa Capalbo
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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153
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Negative membrane curvature catalyzes nucleation of endosomal sorting complex required for transport (ESCRT)-III assembly. Proc Natl Acad Sci U S A 2015; 112:15892-7. [PMID: 26668364 DOI: 10.1073/pnas.1518765113] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) machinery functions in HIV-1 budding, cytokinesis, multivesicular body biogenesis, and other pathways, in the course of which it interacts with concave membrane necks and bud rims. To test the role of membrane shape in regulating ESCRT assembly, we nanofabricated templates for invaginated supported lipid bilayers. The assembly of the core ESCRT-III subunit CHMP4B/Snf7 is preferentially nucleated in the resulting 100-nm-deep membrane concavities. ESCRT-II and CHMP6 accelerate CHMP4B assembly by increasing the concentration of nucleation seeds. Superresolution imaging was used to visualize CHMP4B/Snf7 concentration in a negatively curved annulus at the rim of the invagination. Although Snf7 assemblies nucleate slowly on flat membranes, outward growth onto the flat membrane is efficiently nucleated at invaginations. The nucleation behavior provides a biophysical explanation for the timing of ESCRT-III recruitment and membrane scission in HIV-1 budding.
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154
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Sydor AM, Czymmek KJ, Puchner EM, Mennella V. Super-Resolution Microscopy: From Single Molecules to Supramolecular Assemblies. Trends Cell Biol 2015; 25:730-748. [DOI: 10.1016/j.tcb.2015.10.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/03/2015] [Accepted: 10/05/2015] [Indexed: 11/25/2022]
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155
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Monroe N, Hill CP. Meiotic Clade AAA ATPases: Protein Polymer Disassembly Machines. J Mol Biol 2015; 428:1897-911. [PMID: 26555750 DOI: 10.1016/j.jmb.2015.11.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 12/20/2022]
Abstract
Meiotic clade AAA ATPases (ATPases associated with diverse cellular activities), which were initially grouped on the basis of phylogenetic classification of their AAA ATPase cassette, include four relatively well characterized family members, Vps4, spastin, katanin and fidgetin. These enzymes all function to disassemble specific polymeric protein structures, with Vps4 disassembling the ESCRT-III polymers that are central to the many membrane-remodeling activities of the ESCRT (endosomal sorting complexes required for transport) pathway and spastin, katanin p60 and fidgetin affecting multiple aspects of cellular dynamics by severing microtubules. They share a common domain architecture that features an N-terminal MIT (microtubule interacting and trafficking) domain followed by a single AAA ATPase cassette. Meiotic clade AAA ATPases function as hexamers that can cycle between the active assembly and inactive monomers/dimers in a regulated process, and they appear to disassemble their polymeric substrates by translocating subunits through the central pore of their hexameric ring. Recent studies with Vps4 have shown that nucleotide-induced asymmetry is a requirement for substrate binding to the pore loops and that recruitment to the protein lattice via MIT domains also relieves autoinhibition and primes the AAA ATPase cassettes for substrate binding. The most striking, unifying feature of meiotic clade AAA ATPases may be their MIT domain, which is a module that is found in a wide variety of proteins that localize to ESCRT-III polymers. Spastin also displays an adjacent microtubule binding sequence, and the presence of both ESCRT-III and microtubule binding elements may underlie the recent findings that the ESCRT-III disassembly function of Vps4 and the microtubule-severing function of spastin, as well as potentially katanin and fidgetin, are highly coordinated.
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Affiliation(s)
- Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA.
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156
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Chiaruttini N, Redondo-Morata L, Colom A, Humbert F, Lenz M, Scheuring S, Roux A. Relaxation of Loaded ESCRT-III Spiral Springs Drives Membrane Deformation. Cell 2015; 163:866-79. [PMID: 26522593 PMCID: PMC4644223 DOI: 10.1016/j.cell.2015.10.017] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 05/26/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
Abstract
ESCRT-III is required for lipid membrane remodeling in many cellular processes, from abscission to viral budding and multi-vesicular body biogenesis. However, how ESCRT-III polymerization generates membrane curvature remains debated. Here, we show that Snf7, the main component of ESCRT-III, polymerizes into spirals at the surface of lipid bilayers. When covering the entire membrane surface, these spirals stopped growing when densely packed: they had a polygonal shape, suggesting that lateral compression could deform them. We reasoned that Snf7 spirals could function as spiral springs. By measuring the polymerization energy and the rigidity of Snf7 filaments, we showed that they were deformed while growing in a confined area. Furthermore, we observed that the elastic expansion of compressed Snf7 spirals generated an area difference between the two sides of the membrane and thus curvature. This spring-like activity underlies the driving force by which ESCRT-III could mediate membrane deformation and fission. Snf7 forms highly flexible filaments that spontaneously curl Snf7 filaments forms spirals at the surface of lipid membranes Snf7 spirals are springs as they can deform under lateral compression Relaxation of compressed Snf7 spirals leads to membrane deformation
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Affiliation(s)
- Nicolas Chiaruttini
- University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
| | - Lorena Redondo-Morata
- U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France
| | - Adai Colom
- University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland; U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France
| | - Frédéric Humbert
- University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
| | - Martin Lenz
- LPTMS,CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Simon Scheuring
- U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France.
| | - Aurélien Roux
- University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland.
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157
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D'Avino PP, Capalbo L. New Auroras on the Roles of the Chromosomal Passenger Complex in Cytokinesis: Implications for Cancer Therapies. Front Oncol 2015; 5:221. [PMID: 26528433 PMCID: PMC4604319 DOI: 10.3389/fonc.2015.00221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/28/2015] [Indexed: 11/24/2022] Open
Abstract
The chromosomal passenger complex (CPC), composed of a kinase component, Aurora B, the scaffolding subunit inner centromeric protein, Borealin, and Survivin, is a key regulator of cell division. It controls multiple events, from chromosome condensation in prophase to the final separation or abscission of the two daughter cells. The essential functions of the CPC during metaphase, however, have always hindered an accurate study of its role during cytokinesis. The recent development of small molecule inhibitors against Aurora B and the use of elegant technologies such as chemical genetics have offered new approaches to study the functions of the CPC at the end of cell division. Here, we review the recent findings about the roles of the CPC in controlling the assembly of the cleavage furrow, central spindle, and midbody. We will also discuss the crucial function of this complex in controlling abscission timing in order to prevent abscission when lagging chromatin is present at the cleavage site, thereby avoiding the formation of genetically abnormal daughter cells. Finally, we offer our perspective on how to exploit the potential therapeutic applications of inhibiting CPC activity during cytokinesis in cancer cells.
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Affiliation(s)
| | - Luisa Capalbo
- Department of Pathology, University of Cambridge , Cambridge , UK
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158
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Kharitidi D, Apaja PM, Manteghi S, Suzuki K, Malitskaya E, Roldan A, Gingras MC, Takagi J, Lukacs GL, Pause A. Interplay of Endosomal pH and Ligand Occupancy in Integrin α5β1 Ubiquitination, Endocytic Sorting, and Cell Migration. Cell Rep 2015; 13:599-609. [PMID: 26456826 DOI: 10.1016/j.celrep.2015.09.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/30/2015] [Accepted: 09/04/2015] [Indexed: 01/18/2023] Open
Abstract
Membrane trafficking of integrins plays a pivotal role in cell proliferation and migration. How endocytosed integrins are targeted either for recycling or lysosomal delivery is not fully understood. Here, we show that fibronectin (FN) binding to α5β1 integrin triggers ubiquitination and internalization of the receptor complex. Acidification facilitates FN dissociation from integrin α5β1 in vitro and in early endosomes, promoting receptor complex deubiquitination by the USP9x and recycling to the cell surface. Depending on residual ligand occupancy of receptors, some α5β1 integrins remain ubiquitinated and are captured by ESCRT-0/I, containing histidine domain-containing protein tyrosine phosphatase (HD-PTP) and ubiquitin-associated protein 1 (UBAP1), and are directed for lysosomal proteolysis, limiting receptor downstream signaling and cell migration. Thus, HD-PTP or UBAP1 depletion confers a pro-invasive phenotype. Thus, pH-dependent FN-integrin dissociation and deubiquitination of the activated integrin α5β1 are required for receptor resensitization and cell migration, representing potential targets to modulate tumor invasiveness.
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Affiliation(s)
- Dmitri Kharitidi
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6
| | - Pirjo M Apaja
- Department of Physiology and Research Group Focused on Protein Structure, McGill University, Montreal, Canada, H3G 1Y6
| | - Sanaz Manteghi
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6
| | - Kei Suzuki
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Elena Malitskaya
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6
| | - Ariel Roldan
- Department of Physiology and Research Group Focused on Protein Structure, McGill University, Montreal, Canada, H3G 1Y6
| | - Marie-Claude Gingras
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Gergely L Lukacs
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6; Department of Physiology and Research Group Focused on Protein Structure, McGill University, Montreal, Canada, H3G 1Y6.
| | - Arnim Pause
- Department of Biochemistry, Goodman Cancer Research Centre, McGill University, Montreal, Canada, H3G 1Y6.
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159
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Kettle E, Page SL, Morgan GP, Malladi CS, Wong CL, Boadle RA, Marsh BJ, Robinson PJ, Chircop M. A Cholesterol-Dependent Endocytic Mechanism Generates Midbody Tubules During Cytokinesis. Traffic 2015; 16:1174-92. [DOI: 10.1111/tra.12328] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/24/2015] [Accepted: 08/24/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Emma Kettle
- Children's Medical Research Institute; The University of Sydney; 214 Hawkesbury Road Westmead NSW 2145 Australia
| | - Scott L. Page
- Children's Medical Research Institute; The University of Sydney; 214 Hawkesbury Road Westmead NSW 2145 Australia
| | - Garry P. Morgan
- Institute for Molecular Biosciences, Queensland Bioscience Precinct; The University of Queensland; Brisbane Queensland 4072 Australia
| | - Chandra S. Malladi
- Department of Molecular Physiology, School of Medicine; University of Western Sydney; Penrith NSW 2751 Australia
| | - Chin L. Wong
- Children's Medical Research Institute; The University of Sydney; 214 Hawkesbury Road Westmead NSW 2145 Australia
| | - Ross A. Boadle
- Westmead Millennium Institute for Medical Research; 176 Hawkesbury Road Westmead NSW 2145 Australia
| | - Brad J. Marsh
- Institute for Molecular Biosciences, Queensland Bioscience Precinct; The University of Queensland; Brisbane Queensland 4072 Australia
| | - Phillip J. Robinson
- Children's Medical Research Institute; The University of Sydney; 214 Hawkesbury Road Westmead NSW 2145 Australia
| | - Megan Chircop
- Children's Medical Research Institute; The University of Sydney; 214 Hawkesbury Road Westmead NSW 2145 Australia
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160
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Nakayama K. Regulation of cytokinesis by membrane trafficking involving small GTPases and the ESCRT machinery. Crit Rev Biochem Mol Biol 2015; 51:1-6. [PMID: 26362026 DOI: 10.3109/10409238.2015.1085827] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
During cell division, cells undergo membrane remodeling to achieve changes in their size and shape. In addition, cell division entails local delivery and retrieval of membranes and specific proteins as well as remodeling of cytoskeletons, in particular, upon cytokinetic abscission. Accumulating lines of evidence highlight that endocytic membrane removal from and subsequent membrane delivery to the plasma membrane are crucial for the changes in cell size and shape, and that trafficking of vesicles carrying specific proteins to the abscission site participate in local remodeling of membranes and cytoskeletons. Furthermore, the endosomal sorting complex required for transport (ESCRT) machinery has been shown to play crucial roles in cytokinetic abscission. Here, the author briefly overviews membrane-trafficking events early in cell division, and subsequently focus on regulation and functional significance of membrane trafficking involving Rab11 and Arf6 small GTPases in late cytokinesis phases and assembly of the ESCRT machinery in cytokinetic abscission.
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Affiliation(s)
- Kazuhisa Nakayama
- a Graduate School of Pharmaceutical Sciences, Kyoto University , Kyoto , Japan
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161
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Abstract
New work identifies components of the abscission checkpoint that prevent premature severing of the bridge connecting cells at the end of cell division. Kinase activities allow the membrane remodeling machinery to take their mark, but prevent them from leaving the starting block.
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Affiliation(s)
- Carolyn Ott
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Jennifer Lippincott-Schwartz
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
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162
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Abstract
The endosomal sorting complexes required for transport (ESCRTs) collectively comprise a machinery that was first known for its function in the degradation of transmembrane proteins in the endocytic pathway of eukaryotic cells. Since their discovery, however, ESCRTs have been recognized as playing important roles at the plasma membrane, which appears to be the original site of function for the ESCRT machinery. This article reviews some of the major research findings that have shaped our current understanding of how the ESCRT machinery controls membrane dynamics and considers new roles for the ESCRT machinery that might be driven by these mechanisms.
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Affiliation(s)
- Greg Odorizzi
- Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
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163
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Abstract
Recycling endosomes recently have emerged as major regulators of cytokinesis and abscission steps of cell division. Rab11-endosomes in particular were shown to transport proteins to the mitotic ingression furrow and play a key role in establishing the abscission site. Rab11 GTPase functions by binding and activating various effector proteins, such as Rab11 family interacting proteins (FIPs). FIPs appear to be at the core of many Rab11 functions, with FIP3 playing a role in targeting of the Rab11-endosomes during mitosis. Here we summarize the newest finding regarding the roles and regulation of FIP3 and Rab11 complex, as well as describe the methods developed to analyze membrane and cytoskeleton dynamics during abscission step of cytokinesis.
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Affiliation(s)
- Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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164
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Siriwardana NS, Meyer RD, Panchenko MV. The novel function of JADE1S in cytokinesis of epithelial cells. Cell Cycle 2015; 14:2821-34. [PMID: 26151225 DOI: 10.1080/15384101.2015.1068476] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
JADE1 belongs to a small family of PHD zinc finger proteins that interacts with histone acetyl transferase (HAT) HBO1 and is associated with chromatin. We recently reported JADE1 chromatin shuttling and phosphorylation during G2/M to G1 transition, which was sensitive to Aurora A inhibition. In the current study we examined mechanisms of the cell cycle regulation by the small isoform of JADE1 protein, JADE1S, and report data showing that JADE1S has a novel function in the regulation of cytokinesis. Using FACS assays, we show that, JADE1S depletion facilitated rates of G1-cells accumulation in synchronously dividing HeLa cell cultures. Depletion of JADE1S protein in asynchronously dividing cells decreased the proportion of cytokinetic cells, and increased the proportion of multi-nuclear cells, indicative of premature and failed cytokinesis. In contrast, moderate overexpression of JADE1S increased the number of cytokinetic cells in time- and dose- dependent manner, indicating cytokinetic delay. Pharmacological inhibition of Aurora B kinase resulted in the release of JADE1S-mediated cytokinetic delay and allowed progression of abscission in cells over-expressing JADE1S. Finally, we show that JADE1S protein localized to centrosomes in interphase and mitotic cells, while during cytokinesis JADE1S localized to the midbody. Neither JADE1L nor partner of JADE1, HAT HBO1 was localized to the centrosomes or midbodies. Our study identifies the novel role for JADE1S in regulation of cytokinesis and suggests function in Aurora B kinase-mediated cytokinesis checkpoint.
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165
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Olmos Y, Hodgson L, Mantell J, Verkade P, Carlton JG. ESCRT-III controls nuclear envelope reformation. Nature 2015; 522:236-9. [PMID: 26040713 PMCID: PMC4471131 DOI: 10.1038/nature14503] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 04/27/2015] [Indexed: 12/12/2022]
Abstract
During telophase, the nuclear envelope (NE) reforms around daughter nuclei to ensure proper segregation of nuclear and cytoplasmic contents. NE reformation requires the coating of chromatin by membrane derived from the endoplasmic reticulum, and a subsequent annular fusion step to ensure that the formed envelope is sealed. How annular fusion is accomplished is unknown, but it is thought to involve the p97 AAA-ATPase complex and bears a topological equivalence to the membrane fusion event that occurs during the abscission phase of cytokinesis. Here we show that the endosomal sorting complex required for transport-III (ESCRT-III) machinery localizes to sites of annular fusion in the forming NE in human cells, and is necessary for proper post-mitotic nucleo-cytoplasmic compartmentalization. The ESCRT-III component charged multivesicular body protein 2A (CHMP2A) is directed to the forming NE through binding to CHMP4B, and provides an activity essential for NE reformation. Localization also requires the p97 complex member ubiquitin fusion and degradation 1 (UFD1). Our results describe a novel role for the ESCRT machinery in cell division and demonstrate a conservation of the machineries involved in topologically equivalent mitotic membrane remodelling events.
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Affiliation(s)
- Yolanda Olmos
- Division of Cancer Studies, Section of Cell Biology and Imaging King’s College London London SE1 1UL
| | - Lorna Hodgson
- School of Biochemistry University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
| | - Judith Mantell
- School of Biochemistry University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
- Wolfson Bioimaging Facility University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
| | - Paul Verkade
- School of Biochemistry University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
- Wolfson Bioimaging Facility University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
- School of Physiology & Pharmacology University of Bristol Medical Sciences Building University Walk Bristol BS8 1TD
| | - Jeremy G Carlton
- Division of Cancer Studies, Section of Cell Biology and Imaging King’s College London London SE1 1UL
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166
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Caballe A, Wenzel DM, Agromayor M, Alam SL, Skalicky JJ, Kloc M, Carlton JG, Labrador L, Sundquist WI, Martin-Serrano J. ULK3 regulates cytokinetic abscission by phosphorylating ESCRT-III proteins. eLife 2015; 4:e06547. [PMID: 26011858 PMCID: PMC4475061 DOI: 10.7554/elife.06547] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/23/2015] [Indexed: 11/13/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) machinery mediates the physical separation between daughter cells during cytokinetic abscission. This process is regulated by the abscission checkpoint, a genome protection mechanism that relies on Aurora B and the ESCRT-III subunit CHMP4C to delay abscission in response to chromosome missegregation. In this study, we show that Unc-51-like kinase 3 (ULK3) phosphorylates and binds ESCRT-III subunits via tandem MIT domains, and thereby, delays abscission in response to lagging chromosomes, nuclear pore defects, and tension forces at the midbody. Our structural and biochemical studies reveal an unusually tight interaction between ULK3 and IST1, an ESCRT-III subunit required for abscission. We also demonstrate that IST1 phosphorylation by ULK3 is an essential signal required to sustain the abscission checkpoint and that ULK3 and CHMP4C are functionally linked components of the timer that controls abscission in multiple physiological situations. DOI:http://dx.doi.org/10.7554/eLife.06547.001 Our cells multiply by dividing into two. Many proteins are involved in this process, including a group called the ESCRT-III complex. This group is required to complete the final stage of cell division when the single membrane that surrounds the two new daughter cells separates. Before the cell divides, its DNA—which is packaged in structures called chromosomes—is copied, and the two sets of chromosomes are pulled to opposite ends of the cell. This ensures that each daughter cell will have a complete set of DNA. If the cell divides before the chromosomes have finished moving to opposite ends of the cell, the daughter cells may end up with the wrong number of chromosomes. This can lead to cancer or other diseases. To prevent this, cells have evolved a quality control system called the ‘abscission checkpoint’, which delays cell division until the chromosomes have properly separated. Previous studies have shown that when the checkpoint is active, an ESCRT-III complex protein called CHMP4C is inactivated by an enzyme, which prevents the cell from dividing. Other signals that indicate that the new daughter cells are not yet ready to separate can also delay cell division, but it is not clear how those defects are detected by the checkpoint. Here, Caballe, Wenzel et al. found that a protein called ULK3 can bind to several proteins in the ESCRT-III complex, including one called IST1. In doing so, ULK3 is able to delay cell division if the chromosomes have not finished separating, if there are defects in the nucleus of the cell, or if the cell is experiencing high levels of mechanical tension at the site where the membrane will separate. The experiments also show that ULK3 needs to bind to and regulate the activity of IST1 to sustain the abscission checkpoint, and that CHMP4C is required for this process. Caballe, Wenzel et al.'s findings reveal that ULK3 plays an essential role in controlling when a cell divides and imply that there may be additional proteins involved that release cells from the checkpoint delay imposed by ULK3. The next challenges will be to identify these proteins and to understand how all checkpoint proteins work together to regulate cell division. DOI:http://dx.doi.org/10.7554/eLife.06547.002
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Affiliation(s)
- Anna Caballe
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
| | - Dawn M Wenzel
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Monica Agromayor
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
| | - Steven L Alam
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Magdalena Kloc
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
| | - Jeremy G Carlton
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
| | - Leticia Labrador
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Juan Martin-Serrano
- Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom
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167
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Dionne LK, Wang XJ, Prekeris R. Midbody: from cellular junk to regulator of cell polarity and cell fate. Curr Opin Cell Biol 2015; 35:51-8. [PMID: 25950842 DOI: 10.1016/j.ceb.2015.04.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 01/02/2023]
Abstract
At late mitosis, the mother cell divides by the formation of a cleavage furrow, leaving two daughter cells connected by a thin intercellular bridge. During ingression of the cleavage furrow, the central spindle microtubules are compacted to form the structure known as the midbody (MB). The MB is situated within the intercellular bridge, with the abscission site sometimes occurring on one side of the MB. As a result of this one-sided (asymmetric) abscission, only one daughter cell can inherit the post-mitotic MB. Interestingly, recent studies have identified post-mitotic MBs as novel signaling platforms regulating stem cell fate and proliferation. Additionally, MBs were proposed to serve a role of polarity cues during the neurite outgrowth and apical lumen formation. Thus, abscission and MB inheritance is clearly a highly regulated cellular event that can affect development and various other cellular functions. In this review we discuss the latest findings regarding post-mitotic MB functions, as well as the machinery regulating MB inheritance and accumulation.
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Affiliation(s)
- Lai Kuan Dionne
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Xiao-Jing Wang
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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168
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Lian ATY, Hains PG, Sarcevic B, Robinson PJ, Chircop M. IQGAP1 is associated with nuclear envelope reformation and completion of abscission. Cell Cycle 2015; 14:2058-74. [PMID: 25928398 DOI: 10.1080/15384101.2015.1044168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The final stage of mitosis is cytokinesis, which results in 2 independent daughter cells. Cytokinesis has 2 phases: membrane ingression followed by membrane abscission. IQGAP1 is a scaffold protein that interacts with proteins implicated in mitosis, including F-actin, myosin and CaM. IQGAP1 in yeast recruits actin and myosin II filaments to the contractile ring for membrane ingression. In contrast, we show that mammalian IQGAP1 is not required for ingression, but coordinates nuclear pore complex (NPC) reassembly and completion of abscission. Depletion of IQGAP1 disrupts Nup98 and mAb414 nuclear envelope localization and delays abscission timing. IQGAP1 phosphorylation increases 15-fold upon mitotic entry at S86, S330 and T1434, with the latter site being targeted by CDK2/Cyclin A and CDK1/Cyclin A/B in vitro. Expressing the phospho-deficient mutant IQGAP1-S330A impairs NPC reassembly in cells undergoing abscission. Thus, mammalian IQGAP1 functions later in mitosis than its yeast counterpart to regulate nuclear pore assembly in a S330 phosphorylation-dependent manner during the abscission phase of cytokinesis.
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Affiliation(s)
- Audrey T Y Lian
- a Children's Medical Research Institute; The University of Sydney ; Westmead , New South Wales , Australia
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169
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Han H, Monroe N, Votteler J, Shakya B, Sundquist WI, Hill CP. Binding of Substrates to the Central Pore of the Vps4 ATPase Is Autoinhibited by the Microtubule Interacting and Trafficking (MIT) Domain and Activated by MIT Interacting Motifs (MIMs). J Biol Chem 2015; 290:13490-9. [PMID: 25833946 DOI: 10.1074/jbc.m115.642355] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 12/21/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) pathway drives reverse topology membrane fission events within multiple cellular pathways, including cytokinesis, multivesicular body biogenesis, repair of the plasma membrane, nuclear membrane vesicle formation, and HIV budding. The AAA ATPase Vps4 is recruited to membrane necks shortly before fission, where it catalyzes disassembly of the ESCRT-III lattice. The N-terminal Vps4 microtubule-interacting and trafficking (MIT) domains initially bind the C-terminal MIT-interacting motifs (MIMs) of ESCRT-III subunits, but it is unclear how the enzyme then remodels these substrates in response to ATP hydrolysis. Here, we report quantitative binding studies that demonstrate that residues from helix 5 of the Vps2p subunit of ESCRT-III bind to the central pore of an asymmetric Vps4p hexamer in a manner that is dependent upon the presence of flexible nucleotide analogs that can mimic multiple states in the ATP hydrolysis cycle. We also find that substrate engagement is autoinhibited by the Vps4p MIT domain and that this inhibition is relieved by binding of either Type 1 or Type 2 MIM elements, which bind the Vps4p MIT domain through different interfaces. These observations support the model that Vps4 substrates are initially recruited by an MIM-MIT interaction that activates the Vps4 central pore to engage substrates and generate force, thereby triggering ESCRT-III disassembly.
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Affiliation(s)
- Han Han
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
| | - Nicole Monroe
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
| | - Jörg Votteler
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
| | - Binita Shakya
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
| | - Wesley I Sundquist
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
| | - Christopher P Hill
- From the Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650
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170
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St-Denis N, Gupta GD, Lin ZY, Gonzalez-Badillo B, Pelletier L, Gingras AC. Myotubularin-related proteins 3 and 4 interact with polo-like kinase 1 and centrosomal protein of 55 kDa to ensure proper abscission. Mol Cell Proteomics 2015; 14:946-60. [PMID: 25659891 PMCID: PMC4390272 DOI: 10.1074/mcp.m114.046086] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/22/2015] [Indexed: 11/06/2022] Open
Abstract
The myotubularins are a family of phosphatases that dephosphorylate the phosphatidylinositols phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-phosphate. Several family members are mutated in disease, yet the biological functions of the majority of myotubularins remain unknown. To gain insight into the roles of the individual enzymes, we have used affinity purification coupled to mass spectrometry to identify protein-protein interactions for the myotubularins. The myotubularin interactome comprises 66 high confidence (false discovery rate ≤1%) interactions, including 18 pairwise interactions between individual myotubularins. The results reveal a number of potential signaling contexts for this family of enzymes, including an intriguing, novel role for myotubularin-related protein 3 and myotubularin-related protein 4 in the regulation of abscission, the final step of mitosis in which the membrane bridge remaining between two daughter cells is cleaved. Both depletion and overexpression of either myotubularin-related protein 3 or myotubularin-related protein 4 result in abnormal midbody morphology and cytokinesis failure. Interestingly, myotubularin-related protein 3 and myotubularin-related protein 4 do not exert their effects through lipid regulation at the midbody, but regulate abscission during early mitosis, by interacting with the mitotic kinase polo-like kinase 1, and with centrosomal protein of 55 kDa (CEP55), an important regulator of abscission. Structure-function analysis reveals that, consistent with known intramyotubularin interactions, myotubularin-related protein 3 and myotubularin-related protein 4 interact through their respective coiled coil domains. The interaction between myotubularin-related protein 3 and polo-like kinase 1 relies on the divergent, nonlipid binding Fab1, YOTB, Vac1, and EEA1 domain of myotubularin-related protein 3, and myotubularin-related protein 4 interacts with CEP55 through a short GPPXXXY motif, analogous to endosomal sorting complex required for transport-I components. Disruption of any of these interactions results in abscission failure, by disrupting the proper recruitment of CEP55, and subsequently, of endosomal sorting complex required for transport-I, to the midbody. Our data suggest that myotubularin-related protein 3 and myotubularin-related protein 4 may act as a bridge between CEP55 and polo-like kinase 1, ensuring proper CEP55 phosphorylation and regulating CEP55 recruitment to the midbody. This work provides a novel role for myotubularin-related protein 3/4 heterodimers, and highlights the temporal and spatial complexity of the regulation of cytokinesis.
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Affiliation(s)
- Nicole St-Denis
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Gagan D Gupta
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Zhen Yuan Lin
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Beatriz Gonzalez-Badillo
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Laurence Pelletier
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; §Department of Molecular Genetics, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Anne-Claude Gingras
- From the ‡Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; §Department of Molecular Genetics, University of Toronto, Toronto ON M5S 1A8, Canada
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171
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Fontana F, Siva K, Denti MA. A network of RNA and protein interactions in Fronto Temporal Dementia. Front Mol Neurosci 2015; 8:9. [PMID: 25852467 PMCID: PMC4365750 DOI: 10.3389/fnmol.2015.00009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 02/25/2015] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal dementia (FTD) is a neurodegenerative disorder characterized by degeneration of the fronto temporal lobes and abnormal protein inclusions. It exhibits a broad clinicopathological spectrum and has been linked to mutations in seven different genes. We will provide a picture, which connects the products of these genes, albeit diverse in nature and function, in a network. Despite the paucity of information available for some of these genes, we believe that RNA processing and post-transcriptional regulation of gene expression might constitute a common theme in the network. Recent studies have unraveled the role of mutations affecting the functions of RNA binding proteins and regulation of microRNAs. This review will combine all the recent findings on genes involved in the pathogenesis of FTD, highlighting the importance of a common network of interactions in order to study and decipher the heterogeneous clinical manifestations associated with FTD. This approach could be helpful for the research of potential therapeutic strategies.
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Affiliation(s)
- Francesca Fontana
- Laboratory of RNA Biology and Biotechnology, Centre for Integrative Biology, University of TrentoTrento, Italy
| | - Kavitha Siva
- Laboratory of RNA Biology and Biotechnology, Centre for Integrative Biology, University of TrentoTrento, Italy
| | - Michela A. Denti
- Laboratory of RNA Biology and Biotechnology, Centre for Integrative Biology, University of TrentoTrento, Italy
- CNR, Institute of NeurosciencePadua, Italy
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172
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Kitagawa M, Lee SH. The chromosomal passenger complex (CPC) as a key orchestrator of orderly mitotic exit and cytokinesis. Front Cell Dev Biol 2015; 3:14. [PMID: 25798441 PMCID: PMC4350427 DOI: 10.3389/fcell.2015.00014] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/19/2015] [Indexed: 02/01/2023] Open
Abstract
Understanding the molecular network of orderly mitotic exit to re-establish a functional interphase nucleus is critical because disordered mitotic exit inevitably leads to genomic instability. In contrast to the mechanisms of the entrance to mitosis, however, little is known about what controls the orderly exit from mitosis, particularly in mammalian cells. The chromosomal passenger complex (CPC), which is composed of Aurora B, INCENP, Borealin and Survivin, is one of the most widely studied and highly conserved hetero-tetrameric complexes. The CPC orchestrates proper chromosome segregation with cytokinesis by targeting to specific locations at different stages of mitosis. Recent studies reveal that controlling CPC localization and Aurora B kinase activity also serves as a key surveillance mechanism for the orderly mitotic exit. This ensures the reformation of a functional interphase nucleus from condensed mitotic chromosomes by delaying mitotic exit and cytokinetic processes in response to defects in chromosome segregation. In this review, we will summarize the latest insight into the molecular mechanisms that regulate CPC localization during mitotic exit and discuss how targeting Aurora B activity to different locations at different times impacts executing multiple mitotic exit events in order and recently proposed surveillance mechanisms. Finally, we briefly discuss the potential implication of deregulated Aurora B in inducing genomic damage and tumorigenesis with current efforts in targeting Aurora B activity for anti-cancer therapy.
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Affiliation(s)
- Mayumi Kitagawa
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School Singapore Singapore
| | - Sang Hyun Lee
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School Singapore Singapore
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173
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Jiang D, Hu B, Wei L, Xiong Y, Wang G, Ni T, Zong C, Ni R, Lu C. High expression of vacuolar protein sorting 4B (VPS4B) is associated with accelerated cell proliferation and poor prognosis in human hepatocellular carcinoma. Pathol Res Pract 2015; 211:240-7. [DOI: 10.1016/j.prp.2014.11.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 10/26/2014] [Accepted: 11/21/2014] [Indexed: 12/19/2022]
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174
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Abstract
Cytokinesis mediates the physical separation of dividing cells after chromosome segregation. In animal cell cytokinesis, a contractile ring, mainly composed of actin and myosin filaments, ingresses a cleavage furrow midway between the two spindle poles. A distinct machinery, involving the endosomal sorting complex required for transport III (ESCRT-III), subsequently splits the plasma membrane of nascent daughter cells in a process termed abscission. Here, we provide a brief overview of early cytokinesis events in animal cells and then cover in depth recently emerging models for the assembly and function of the abscission machinery and its temporal coordination with chromosome segregation.
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Affiliation(s)
- Beata Mierzwa
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria.
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175
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Super-resolution imaging of ESCRT-proteins at HIV-1 assembly sites. PLoS Pathog 2015; 11:e1004677. [PMID: 25710462 PMCID: PMC4339578 DOI: 10.1371/journal.ppat.1004677] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 01/12/2015] [Indexed: 11/19/2022] Open
Abstract
The cellular endosomal sorting complex required for transport (ESCRT) machinery is involved in membrane budding processes, such as multivesicular biogenesis and cytokinesis. In HIV-infected cells, HIV-1 hijacks the ESCRT machinery to drive HIV release. Early in the HIV-1 assembly process, the ESCRT-I protein Tsg101 and the ESCRT-related protein ALIX are recruited to the assembly site. Further downstream, components such as the ESCRT-III proteins CHMP4 and CHMP2 form transient membrane associated lattices, which are involved in virus-host membrane fission. Although various geometries of ESCRT-III assemblies could be observed, the actual membrane constriction and fission mechanism is not fully understood. Fission might be driven from inside the HIV-1 budding neck by narrowing the membranes from the outside by larger lattices surrounding the neck, or from within the bud. Here, we use super-resolution fluorescence microscopy to elucidate the size and structure of the ESCRT components Tsg101, ALIX, CHMP4B and CHMP2A during HIV-1 budding below the diffraction limit. To avoid the deleterious effects of using fusion proteins attached to ESCRT components, we performed measurements on the endogenous protein or, in the case of CHMP4B, constructs modified with the small HA tag. Due to the transient nature of the ESCRT interactions, the fraction of HIV-1 assembly sites with colocalizing ESCRT complexes was low (1.5%-3.4%). All colocalizing ESCRT clusters exhibited closed, circular structures with an average size (full-width at half-maximum) between 45 and 60 nm or a diameter (determined using a Ripley's L-function analysis) of roughly 60 to 100 nm. The size distributions for colocalizing clusters were narrower than for non-colocalizing clusters, and significantly smaller than the HIV-1 bud. Hence, our results support a membrane scission process driven by ESCRT protein assemblies inside a confined structure, such as the bud neck, rather than by large lattices around the neck or in the bud lumen. In the case of ALIX, a cloud of individual molecules surrounding the central clusters was often observed, which we attribute to ALIX molecules incorporated into the nascent HIV-1 Gag shell. Experiments performed using YFP-tagged Tsg101 led to an over 10-fold increase in ESCRT structures colocalizing with HIV-1 budding sites indicating an influence of the fusion protein tag on the function of the ESCRT protein.
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176
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Menon MB, Gaestel M. Sep(t)arate or not – how some cells take septin-independent routes through cytokinesis. J Cell Sci 2015; 128:1877-86. [PMID: 25690008 DOI: 10.1242/jcs.164830] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cytokinesis is the final step of cell division, and is a process that requires a precisely coordinated molecular machinery to fully separate the cytoplasm of the parent cell and to establish the intact outer cell barrier of the daughter cells. Among various cytoskeletal proteins involved, septins are known to be essential mediators of cytokinesis. In this Commentary, we present recent observations that specific cell divisions can proceed in the absence of the core mammalian septin SEPT7 and its Drosophila homolog Peanut (Pnut) and that thus challenge the view that septins have an essential role in cytokinesis. In the pnut mutant neuroepithelium, orthogonal cell divisions are successfully completed. Similarly, in the mouse, Sept7-null mutant early embryonic cells and, more importantly, planktonically growing adult hematopoietic cells undergo productive proliferation. Hence, as discussed here, mechanisms must exist that compensate for the lack of SEPT7 and the other core septins in a cell-type-specific manner. Despite there being crucial non-canonical immune-relevant functions of septins, septin depletion is well tolerated by the hematopoietic system. Thus differential targeting of cytokinesis could form the basis for more specific anti-proliferative therapies to combat malignancies arising from cell types that require septins for cytokinesis, such as carcinomas and sarcomas, without impairing hematopoiesis that is less dependent on septin.
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Affiliation(s)
- Manoj B Menon
- Institute of Physiological Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Matthias Gaestel
- Institute of Physiological Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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177
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Abstract
Cell division ends with the physical separation of the two daughter cells, a process known as cytokinesis. This final event ensures that nuclear and cytoplasmic contents are accurately partitioned between the two nascent cells. Cytokinesis is one of the most dramatic changes in cell shape and requires an extensive reorganization of the cell's cytoskeleton. Here, we describe the cytoskeletal structures, factors, and signaling pathways that orchestrate this robust and yet highly dynamic process in animal cells. Finally, we discuss possible future directions in this growing area of cell division research and its implications in human diseases, including cancer.
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Affiliation(s)
- Pier Paolo D'Avino
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari c/o Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, 00185 Roma, Italy
| | - Mark Petronczki
- Cell Division and Aneuploidy Laboratory, Cancer Research UK-London Research Institute, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, United Kingdom
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178
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Hu B, Jiang D, Chen Y, Wei L, Zhang S, Zhao F, Ni R, Lu C, Wan C. High CHMP4B expression is associated with accelerated cell proliferation and resistance to doxorubicin in hepatocellular carcinoma. Tumour Biol 2015; 36:2569-81. [PMID: 25874485 DOI: 10.1007/s13277-014-2873-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 11/18/2014] [Indexed: 01/17/2023] Open
Abstract
Charged multivesicular body protein 4B (CHMP4B), a subunit of the endosomal sorting complex required for transport (ESCRT)-III complex, plays an important part in cytokinetic membrane abscission and the late stage of mitotic cell division. In this study, we explored the prognostic significance of CHMP4B in human hepatocellular carcinoma (HCC) and its impact on the physiology of HCC cells. Western blot and immunohistochemistrical analyses showed that CHMP4B was significantly upregulated in HCC tissues, compared with adjacent non-tumorous tissues. Meanwhile, clinicopathological analysis revealed that high CHMP4B expression was correlated with multiple clinicopathological variables, including AFP, cirrhosis, AJCC stage, Ki-67 expression, and poor prognosis. More importantly, univariate and multivariate survival analyses demonstrated that CHMP4B served as an independent prognostic factor for survival of HCC patients. Using HCC cell cultures, we found that the expression of CHMP4B was progressively upregulated after the release from serum starvation. To verify whether CHMP4B could regulate the proliferation of HCC cells, CHMP4B was knocked down through the transfection of CHMP4B-siRNA oligos. Flow cytometry and CCK-8 assays indicated that interference of CHMP4B led to cell cycle arrest and proliferative impairment of HCC cells. Additionally, depletion of CHMP4B expression could increase the sensitivity to doxorubicin in HepG2 and Huh7 cells. Taken together, our results implied that CHMP4B could be a promising prognostic biomarker as well as a potential therapeutic target of HCC.
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Affiliation(s)
- Baoying Hu
- Basic Medical Research Centre, Medical College, Nantong University, Nantong, 226001, China
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179
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Bailey JK, Fields AT, Cheng K, Lee A, Wagenaar E, Lagrois R, Schmidt B, Xia B, Ma D. WD repeat-containing protein 5 (WDR5) localizes to the midbody and regulates abscission. J Biol Chem 2015; 290:8987-9001. [PMID: 25666610 DOI: 10.1074/jbc.m114.623611] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Indexed: 12/25/2022] Open
Abstract
Cytokinesis partitions the cytoplasm of a parent cell into two daughter cells and is essential for the completion of cell division. The final step of cytokinesis in animal cells is abscission, which is a process leading to the physical separation of two daughter cells. Abscission requires membrane traffic and microtubule disassembly at a specific midbody region called the secondary ingression. Here, we report that WD repeat-containing protein 5 (WDR5), a core subunit of COMPASS/MLL family histone H3 lysine 4 methyltransferase (H3K4MT) complexes, resides at the midbody and associates with a subset of midbody regulatory proteins, including PRC1 and CYK4/MKLP1. Knockdown of WDR5 impairs abscission and increases the incidence of multinucleated cells. Further investigation revealed that the abscission delay is primarily due to slower formation of secondary ingressions in WDR5 knockdown cells. Consistent with these defects, midbody microtubules in WDR5 knockdown cells also display enhanced resistance to depolymerization by nocodazole. Recruitment of WDR5 to the midbody dark zone appears to require integrity of the WDR5 central arginine-binding cavity, as mutations that disrupt histone H3 and MLL1 binding to this pocket also abolish the midbody localization of WDR5. Taken together, these data suggest that WDR5 is specifically targeted to the midbody in the absence of chromatin and that it promotes abscission, perhaps by facilitating midbody microtubule disassembly.
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Affiliation(s)
- Jeffrey K Bailey
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Alexander T Fields
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Kaijian Cheng
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Albert Lee
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Eric Wagenaar
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Remy Lagrois
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Bailey Schmidt
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Bin Xia
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Dzwokai Ma
- From the Neuroscience Research Institute, Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
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180
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Matias NR, Mathieu J, Huynh JR. Abscission is regulated by the ESCRT-III protein shrub in Drosophila germline stem cells. PLoS Genet 2015; 11:e1004653. [PMID: 25647097 PMCID: PMC4372032 DOI: 10.1371/journal.pgen.1004653] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 07/31/2014] [Indexed: 11/18/2022] Open
Abstract
Abscission is the final event of cytokinesis that leads to the physical separation of the two daughter cells. Recent technical advances have allowed a better understanding of the cellular and molecular events leading to abscission in isolated yeast or mammalian cells. However, how abscission is regulated in different cell types or in a developing organism remains poorly understood. Here, we characterized the function of the ESCRT-III protein Shrub during cytokinesis in germ cells undergoing a series of complete and incomplete divisions. We found that Shrub is required for complete abscission, and that levels of Shrub are critical for proper timing of abscission. Loss or gain of Shrub delays abscission in germline stem cells (GSCs), and leads to the formation of stem-cysts, where daughter cells share the same cytoplasm as the mother stem cell and cannot differentiate. In addition, our results indicate a negative regulation of Shrub by the Aurora B kinase during GSC abscission. Finally, we found that Lethal giant discs (lgd), known to be required for Shrub function in the endosomal pathway, also regulates the duration of abscission in GSCs. Abscission is the final step of cytokinesis which allows the physical separation of sister cells through the scission of a thin cytoplasmic bridge that links them at the end of mitosis. The duration of abscission varies depending on cell types, indicating that the event is developmentally regulated. Recently, we have identified two kinases, Aurora B and CycB/Cdk-1, which regulate the timing of abscission in germ cells and in mammalian cells. However, these kinases are upstream regulators and do not perform abscission per se. Here, we show that Shrub, a potential target of Aurora B and one of the most downstream effectors of abscission, is required for complete abscission in germline stem cells. In the absence of Shrub, the mother stem cell remains linked to its daughter cells, which then share the same cytoplasm and cannot differentiate. Loss of Shrub and Aurora B have opposite effects on abscission duration suggesting that Aurora B regulates negatively Shrub. We further show that Shrub acts together with its interactor Lethal giant disc to ensure proper abscission timing.
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Affiliation(s)
- Neuza Reis Matias
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
- CNRS UMR3215, Inserm U934, Paris, France
| | - Juliette Mathieu
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
- CNRS UMR3215, Inserm U934, Paris, France
- * E-mail: (JM); (JRH)
| | - Jean-René Huynh
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
- CNRS UMR3215, Inserm U934, Paris, France
- * E-mail: (JM); (JRH)
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181
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Eikenes ÅH, Malerød L, Christensen AL, Steen CB, Mathieu J, Nezis IP, Liestøl K, Huynh JR, Stenmark H, Haglund K. ALIX and ESCRT-III coordinately control cytokinetic abscission during germline stem cell division in vivo. PLoS Genet 2015; 11:e1004904. [PMID: 25635693 PMCID: PMC4312039 DOI: 10.1371/journal.pgen.1004904] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 11/18/2014] [Indexed: 12/21/2022] Open
Abstract
Abscission is the final step of cytokinesis that involves the cleavage of the intercellular bridge connecting the two daughter cells. Recent studies have given novel insight into the spatiotemporal regulation and molecular mechanisms controlling abscission in cultured yeast and human cells. The mechanisms of abscission in living metazoan tissues are however not well understood. Here we show that ALIX and the ESCRT-III component Shrub are required for completion of abscission during Drosophila female germline stem cell (fGSC) division. Loss of ALIX or Shrub function in fGSCs leads to delayed abscission and the consequent formation of stem cysts in which chains of daughter cells remain interconnected to the fGSC via midbody rings and fusome. We demonstrate that ALIX and Shrub interact and that they co-localize at midbody rings and midbodies during cytokinetic abscission in fGSCs. Mechanistically, we show that the direct interaction between ALIX and Shrub is required to ensure cytokinesis completion with normal kinetics in fGSCs. We conclude that ALIX and ESCRT-III coordinately control abscission in Drosophila fGSCs and that their complex formation is required for accurate abscission timing in GSCs in vivo. Cytokinesis, the final step of cell division, concludes with a process termed abscission, during which the two daughter cells physically separate. In spite of their importance, the molecular machineries controlling abscission are poorly characterized especially in the context of living metazoan tissues. Here we provide molecular insight into the mechanism of abscission using the fruit fly Drosophila melanogaster as a model organism. We show that the scaffold protein ALIX and the ESCRT-III component Shrub are required for completion of abscission in Drosophila female germline stem cells (fGSCs). ESCRT-III has been implicated in topologically similar membrane scission events as abscission, namely intraluminal vesicle formation at endosomes and virus budding. Here we demonstrate that ALIX and Shrub co-localize and interact to promote abscission with correct timing in Drosophila fGSCs. We thus show that ALIX and ESCRT-III coordinately control abscission in Drosophila fGSCs cells and report an evolutionarily conserved function of the ALIX/ESCRT-III pathway during cytokinesis in a multi-cellular organism.
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Affiliation(s)
- Åsmund H. Eikenes
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Lene Malerød
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anette Lie Christensen
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Chloé B. Steen
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Juliette Mathieu
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
- CNRS UMR3215, Inserm U934 F-75248, Paris, France
| | - Ioannis P. Nezis
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Knut Liestøl
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Jean-René Huynh
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
- CNRS UMR3215, Inserm U934 F-75248, Paris, France
| | - Harald Stenmark
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kaisa Haglund
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- * E-mail:
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182
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Scheffer LL, Sreetama SC, Sharma N, Medikayala S, Brown KJ, Defour A, Jaiswal JK. Mechanism of Ca²⁺-triggered ESCRT assembly and regulation of cell membrane repair. Nat Commun 2014; 5:5646. [PMID: 25534348 PMCID: PMC4333728 DOI: 10.1038/ncomms6646] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 10/22/2014] [Indexed: 12/11/2022] Open
Abstract
In muscle and other mechanically active tissue, cell membranes are constantly injured, and their repair depends on the injury-induced increase in cytosolic calcium. Here, we show that injury-triggered Ca(2+) increase results in assembly of ESCRT III and accessory proteins at the site of repair. This process is initiated by the calcium-binding protein-apoptosis-linked gene (ALG)-2. ALG-2 facilitates accumulation of ALG-2-interacting protein X (ALIX), ESCRT III and Vps4 complex at the injured cell membrane, which in turn results in cleavage and shedding of the damaged part of the cell membrane. Lack of ALG-2, ALIX or Vps4B each prevents shedding, and repair of the injured cell membrane. These results demonstrate Ca(2+)-dependent accumulation of ESCRT III-Vps4 complex following large focal injury to the cell membrane and identify the role of ALG-2 as the initiator of sequential ESCRT III-Vps4 complex assembly that facilitates scission and repair of the injured cell membrane.
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Affiliation(s)
- Luana L Scheffer
- Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA
| | - Sen Chandra Sreetama
- Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA
| | - Nimisha Sharma
- Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA
| | - Sushma Medikayala
- Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA
| | - Kristy J Brown
- 1] Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA [2] Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington DC, USA
| | - Aurelia Defour
- Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA
| | - Jyoti K Jaiswal
- 1] Children's National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue, NW, Washington DC 20010-2970, USA [2] Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington DC, USA
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183
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Fung KYY, Dai L, Trimble WS. Cell and molecular biology of septins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 310:289-339. [PMID: 24725429 DOI: 10.1016/b978-0-12-800180-6.00007-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Septins are a family of GTP-binding proteins that assemble into cytoskeletal filaments. Unlike other cytoskeletal components, septins form ordered arrays of defined stoichiometry that can polymerize into long filaments and bundle laterally. Septins associate directly with membranes and have been implicated in providing membrane stability and serving as diffusion barriers for membrane proteins. In addition, septins bind other proteins and have been shown to function as multimolecular scaffolds by recruiting components of signaling pathways. Remarkably, septins participate in a spectrum of cellular processes including cytokinesis, ciliogenesis, cell migration, polarity, and cell-pathogen interactions. Given their breadth of functions, it is not surprising that septin abnormalities have also been linked to human diseases. In this review, we discuss the current knowledge of septin structure, assembly and function, and discuss these in the context of human disease.
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Affiliation(s)
- Karen Y Y Fung
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Lu Dai
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada
| | - William S Trimble
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada; Department of Biochemistry, University of Toronto, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada.
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184
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Bhutta MS, McInerny CJ, Gould GW. ESCRT function in cytokinesis: location, dynamics and regulation by mitotic kinases. Int J Mol Sci 2014; 15:21723-39. [PMID: 25429432 PMCID: PMC4284674 DOI: 10.3390/ijms151221723] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 01/22/2023] Open
Abstract
Mammalian cytokinesis proceeds by constriction of an actomyosin ring and furrow ingression, resulting in the formation of the midbody bridge connecting two daughter cells. At the centre of the midbody resides the Flemming body, a dense proteinaceous ring surrounding the interlocking ends of anti-parallel microtubule arrays. Abscission, the terminal step of cytokinesis, occurs near the Flemming body. A series of broad processes govern abscission: the initiation and stabilisation of the abscission zone, followed by microtubule severing and membrane scission-The latter mediated by the endosomal sorting complex required for transport (ESCRT) proteins. A key goal of cell and developmental biologists is to develop a clear understanding of the mechanisms that underpin abscission, and how the spatiotemporal coordination of these events with previous stages in cell division is accomplished. This article will focus on the function and dynamics of the ESCRT proteins in abscission and will review recent work, which has begun to explore how these complex protein assemblies are regulated by the cell cycle machinery.
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Affiliation(s)
- Musab S Bhutta
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Christopher J McInerny
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Gwyn W Gould
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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185
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Jongsma MLM, Berlin I, Neefjes J. On the move: organelle dynamics during mitosis. Trends Cell Biol 2014; 25:112-24. [PMID: 25466831 DOI: 10.1016/j.tcb.2014.10.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/23/2014] [Accepted: 10/28/2014] [Indexed: 10/24/2022]
Abstract
A cell constitutes the minimal self-replicating unit of all organisms, programmed to propagate its genome as it proceeds through mitotic cell division. The molecular processes entrusted with ensuring high fidelity of DNA replication and subsequent segregation of chromosomes between daughter cells have therefore been studied extensively. However, to process the information encoded in its genome a cell must also pass on its non-genomic identity to future generations. To achieve productive sharing of intracellular organelles, cells have evolved complex mechanisms of organelle inheritance. Many membranous compartments undergo vast spatiotemporal rearrangements throughout mitosis. These controlled organizational changes are crucial to enabling completion of the division cycle and ensuring successful progeny. Herein we review current understanding of intracellular organelle segregation during mitotic division in mammalian cells, with a focus on compartment organization and integrity throughout the inheritance process.
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Affiliation(s)
- Marlieke L M Jongsma
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Ilana Berlin
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Jacques Neefjes
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
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186
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Reinecke JB, Katafiasz D, Naslavsky N, Caplan S. Novel functions for the endocytic regulatory proteins MICAL-L1 and EHD1 in mitosis. Traffic 2014; 16:48-67. [PMID: 25287187 DOI: 10.1111/tra.12234] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 01/01/2023]
Abstract
During interphase, recycling endosomes mediate the transport of internalized cargo back to the plasma membrane. However, in mitotic cells, recycling endosomes are essential for the completion of cytokinesis, the last phase of mitosis that promotes the physical separation the two daughter cells. Despite recent advances, our understanding of the molecular determinants that regulate recycling endosome dynamics during cytokinesis remains incomplete. We have previously demonstrated that Molecule Interacting with CasL Like-1 (MICAL-L1) and C-terminal Eps15 Homology Domain protein 1 (EHD1) coordinately regulate receptor transport from tubular recycling endosomes during interphase. However, their potential roles in controlling cytokinesis had not been addressed. In this study, we show that MICAL-L1 and EHD1 regulate mitosis. Depletion of either protein resulted in increased numbers of bi-nucleated cells. We provide evidence that bi-nucleation in MICAL-L1- and EHD1-depleted cells is a consequence of impaired recycling endosome transport during late cytokinesis. However, depletion of MICAL-L1, but not EHD1, resulted in aberrant chromosome alignment and lagging chromosomes, suggesting an EHD1-independent function for MICAL-L1 earlier in mitosis. Moreover, we provide evidence that MICAL-L1 and EHD1 differentially influence microtubule dynamics during early and late mitosis. Collectively, our new data suggest several unanticipated roles for MICAL-L1 and EHD1 during the cell cycle.
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Affiliation(s)
- James B Reinecke
- Department of Biochemistry and Molecular Biology and Fred and Pamela Buffet Cancer Research Center, University of Nebraska Medical Center, Omaha, NE, USA
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187
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Phosphoinositides: Lipids with informative heads and mastermind functions in cell division. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:832-43. [PMID: 25449648 DOI: 10.1016/j.bbalip.2014.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 01/22/2023]
Abstract
Phosphoinositides are low abundant but essential phospholipids in eukaryotic cells and refer to phosphatidylinositol and its seven polyphospho-derivatives. In this review, we summarize our current knowledge on phosphoinositides in multiple aspects of cell division in animal cells, including mitotic cell rounding, longitudinal cell elongation, cytokinesis furrow ingression, intercellular bridge abscission and post-cytokinesis events. PtdIns(4,5)P₂production plays critical roles in spindle orientation, mitotic cell shape and bridge stability after furrow ingression by recruiting force generator complexes and numerous cytoskeleton binding proteins. Later, PtdIns(4,5)P₂hydrolysis and PtdIns3P production are essential for normal cytokinesis abscission. Finally, emerging functions of PtdIns3P and likely PtdIns(4,5)P₂have recently been reported for midbody remnant clearance after abscission. We describe how the multiple functions of phosphoinositides in cell division reflect their distinct roles in local recruitment of protein complexes, membrane traffic and cytoskeleton remodeling. This article is part of a Special Issue entitled Phosphoinositides.
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188
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Wang SF, Tsao CH, Lin YT, Hsu DK, Chiang ML, Lo CH, Chien FC, Chen P, Arthur Chen YM, Chen HY, Liu FT. Galectin-3 promotes HIV-1 budding via association with Alix and Gag p6. Glycobiology 2014; 24:1022-35. [PMID: 24996823 PMCID: PMC4181451 DOI: 10.1093/glycob/cwu064] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/10/2014] [Accepted: 06/23/2014] [Indexed: 12/23/2022] Open
Abstract
Galectin-3 has been reported to regulate the functions of a number of immune cell types. We previously reported that galectin-3 is translocated to immunological synapses in T cells upon T-cell receptor engagement, where it associates with ALG-2-interacting protein X (Alix). Alix is known to coordinate with the endosomal sorting complex required for transport (ESCRT) to promote human immunodeficiency virus (HIV)-1 virion release. We hypothesized that galectin-3 plays a role in HIV-1 viral budding. Cotransfection of cells of the Jurkat T line with galectin-3 and HIV-1 plasmids resulted in increased HIV-1 budding, and suppression of galectin-3 expression by RNAi in Hut78 and primary CD4+ T cells led to reduced HIV-1 budding. We used immunofluorescence microscopy to observe the partial colocalization of galectin-3, Alix and Gag in HIV-1-infected cells. Results from co-immunoprecipitation experiments indicate that galectin-3 expression promotes Alix-Gag p6 association, whereas the results of Alix knockdown suggest that galectin-3 promotes HIV-1 budding through Alix. HIV-1 particles released from galectin-3-expressing cells acquire the galectin-3 protein in an Alix-dependent manner, with proteins primarily residing inside the virions. We also found that the galectin-3 N-terminal domain interacts with the proline-rich region of Alix. Collectively, these results suggest that endogenous galectin-3 facilitates HIV-1 budding by promoting the Alix-Gag p6 association.
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Affiliation(s)
- Sheng-Fan Wang
- Department of Medical Laboratory Science and Biotechnology Institute of Biomedical Sciences Center for AIDS Prevention and Research
| | | | | | - Daniel K Hsu
- Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA
| | | | | | - Fan-Ching Chien
- Department of Optics and Photonics, National Central University, Chung-Li, Taiwan
| | - Peilin Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Ming Arthur Chen
- Department of Microbiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Center for AIDS Prevention and Research Department of Microbiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Huan-Yuan Chen
- Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA
| | - Fu-Tong Liu
- Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA
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189
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Bhutta MS, Roy B, Gould GW, McInerny CJ. A complex network of interactions between mitotic kinases, phosphatases and ESCRT proteins regulates septation and membrane trafficking in S. pombe. PLoS One 2014; 9:e111789. [PMID: 25356547 PMCID: PMC4214795 DOI: 10.1371/journal.pone.0111789] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 08/27/2014] [Indexed: 11/18/2022] Open
Abstract
Cytokinesis and cell separation are critical events in the cell cycle. We show that Endosomal Sorting Complex Required for Transport (ESCRT) genes are required for cell separation in Schizosaccharomyces pombe. We identify genetic interactions between ESCRT proteins and polo and aurora kinases and Cdc14 phosphatase that manifest as impaired growth and exacerbated defects in septation, suggesting that the encoded proteins function together to control these processes. Furthermore, we observed defective endosomal sorting in mutants of plo1, ark1 and clp1, as has been reported for ESCRT mutants, consistent with a role for these kinases in the control of ESCRT function in membrane traffic. Multiple observations indicate functional interplay between polo and ESCRT components: firstly, two-hybrid in vivo interactions are reported between Plo1p and Sst4p, Vps28p, Vps25p, Vps20p and Vps32p; secondly, co-immunoprecipitation of human homologues of Vps20p, Vps32p, Vps24p and Vps2p by human Plk1; and thirdly, in vitro phosphorylation of budding yeast Vps32p and Vps20p by polo kinase. Two-hybrid analyses also identified interactions between Ark1p and Vps20p and Vps32p, and Clp1p and Vps28p. These experiments indicate a network of interactions between ESCRT proteins, plo1, ark1 and clp1 that coordinate membrane trafficking and cell separation in fission yeast.
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Affiliation(s)
- Musab S. Bhutta
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brinta Roy
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gwyn W. Gould
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher J. McInerny
- Henry Wellcome Laboratory of Cell Biology, Davidson Building, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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190
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Zheng Y, Guo J, Li X, Xie Y, Hou M, Fu X, Dai S, Diao R, Miao Y, Ren J. An integrated overview of spatiotemporal organization and regulation in mitosis in terms of the proteins in the functional supercomplexes. Front Microbiol 2014; 5:573. [PMID: 25400627 PMCID: PMC4212687 DOI: 10.3389/fmicb.2014.00573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/11/2014] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic cells may divide via the critical cellular process of cell division/mitosis, resulting in two daughter cells with the same genetic information. A large number of dedicated proteins are involved in this process and spatiotemporally assembled into three distinct super-complex structures/organelles, including the centrosome/spindle pole body, kinetochore/centromere and cleavage furrow/midbody/bud neck, so as to precisely modulate the cell division/mitosis events of chromosome alignment, chromosome segregation and cytokinesis in an orderly fashion. In recent years, many efforts have been made to identify the protein components and architecture of these subcellular organelles, aiming to uncover the organelle assembly pathways, determine the molecular mechanisms underlying the organelle functions, and thereby provide new therapeutic strategies for a variety of diseases. However, the organelles are highly dynamic structures, making it difficult to identify the entire components. Here, we review the current knowledge of the identified protein components governing the organization and functioning of organelles, especially in human and yeast cells, and discuss the multi-localized protein components mediating the communication between organelles during cell division.
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Affiliation(s)
- Yueyuan Zheng
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Junjie Guo
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Xu Li
- Orthopaedic Department of Anhui Medical University Affiliated Provincial Hospital Hefei, China
| | - Yubin Xie
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Mingming Hou
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Xuyang Fu
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Shengkun Dai
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Rucheng Diao
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Yanyan Miao
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
| | - Jian Ren
- Cancer Center, School of Life Sciences, School of Advanced Computing, Cooperative Innovation Center for High Performance Computing, Sun Yat-sen University Guangzhou, China
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191
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Schiel JA, Prekeris R. ESCRT or Endosomes? Tales of the separation of two daughter Cells. Commun Integr Biol 2014. [DOI: 10.4161/cib.16789] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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192
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Baum DA, Baum B. An inside-out origin for the eukaryotic cell. BMC Biol 2014; 12:76. [PMID: 25350791 PMCID: PMC4210606 DOI: 10.1186/s12915-014-0076-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the origin of the eukaryotic cell has long been recognized as the single most profound change in cellular organization during the evolution of life on earth, this transition remains poorly understood. Models have always assumed that the nucleus and endomembrane system evolved within the cytoplasm of a prokaryotic cell. RESULTS Drawing on diverse aspects of cell biology and phylogenetic data, we invert the traditional interpretation of eukaryotic cell evolution. We propose that an ancestral prokaryotic cell, homologous to the modern-day nucleus, extruded membrane-bound blebs beyond its cell wall. These blebs functioned to facilitate material exchange with ectosymbiotic proto-mitochondria. The cytoplasm was then formed through the expansion of blebs around proto-mitochondria, with continuous spaces between the blebs giving rise to the endoplasmic reticulum, which later evolved into the eukaryotic secretory system. Further bleb-fusion steps yielded a continuous plasma membrane, which served to isolate the endoplasmic reticulum from the environment. CONCLUSIONS The inside-out theory is consistent with diverse kinds of data and provides an alternative framework by which to explore and understand the dynamic organization of modern eukaryotic cells. It also helps to explain a number of previously enigmatic features of cell biology, including the autonomy of nuclei in syncytia and the subcellular localization of protein N-glycosylation, and makes many predictions, including a novel mechanism of interphase nuclear pore insertion.
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193
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Goliand I, Nachmias D, Gershony O, Elia N. Inhibition of ESCRT-II-CHMP6 interactions impedes cytokinetic abscission and leads to cell death. Mol Biol Cell 2014; 25:3740-8. [PMID: 25232011 PMCID: PMC4230781 DOI: 10.1091/mbc.e14-08-1317] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recently the ESCRT-III filamentous complex was designated as the driving force for mammalian cell abscission, that is, fission of the intercellular membrane bridge connecting daughter cells at the end of cytokinesis. However, how ESCRT-III is activated to set on abscission has not been resolved. Here we revisit the role of the upstream canonical ESCRT players ESCRT-II and CHMP6 in abscission. Using high-resolution imaging, we show that these proteins form highly ordered structures at the intercellular bridge during abscission progression. Furthermore, we demonstrate that a truncated version of CHMP6, composed of its first 52 amino acids (CHMP6-N), arrives at the intercellular bridge, blocks abscission, and subsequently leads to cell death. This phenotype is abolished in a mutated version of CHMP6-N designed to prevent CHMP6-N binding to its ESCRT-II partner. Of interest, deleting the first 10 amino acids from CHMP6-N does not interfere with its arrival at the intercellular bridge but almost completely abolishes the abscission failure phenotype. Taken together, these data suggest an active role for ESCRT-II and CHMP6 in ESCRT-mediated abscission. Our work advances the mechanistic understanding of ESCRT-mediated membrane fission in cells and introduces an easily applicable tool for upstream inhibition of the ESCRT pathway in live mammalian cells.
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Affiliation(s)
- Inna Goliand
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Dikla Nachmias
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Ofir Gershony
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Natalie Elia
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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194
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Temporal and spatial organization of ESCRT protein recruitment during HIV-1 budding. Proc Natl Acad Sci U S A 2014; 111:12211-6. [PMID: 25099357 DOI: 10.1073/pnas.1321655111] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
HIV-1 virions assemble at the plasma membrane of mammalian cells and recruit the endosomal sorting complex required for transport (ESCRT) machinery to enable particle release. However, little is known about the temporal and spatial organization of ESCRT protein recruitment. Using multiple-color live-cell total internal reflection fluorescence microscopy, we observed that the ESCRT-I protein Tsg101 is recruited together with Gag to the sites of HIV-1 assembly, whereas later-acting ESCRT proteins (Chmp4b and Vps4A) are recruited sequentially, once Gag assembly is completed. Chmp4b, a protein that is required to mediate particle scission, is recruited to HIV-1 assembly sites ∼10 s before the ATPase Vps4A. Using two-color superresolution imaging, we observed that the ESCRT machinery (Tsg101, Alix, and Chmp4b/c proteins) is positioned at the periphery of the nascent virions, with the Tsg101 assemblages positioned closer to the Gag assemblages than Alix, Chmp4b, or Chmp4c. These results are consistent with the notion that the ESCRT machinery is recruited transiently to the neck of the assembling particle and is thus present at the appropriate time and place to mediate fission between the nascent virus and the plasma membrane.
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195
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Crowell EF, Gaffuri AL, Gayraud-Morel B, Tajbakhsh S, Echard A. Engulfment of the midbody remnant after cytokinesis in mammalian cells. J Cell Sci 2014; 127:3840-51. [PMID: 25002399 DOI: 10.1242/jcs.154732] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The midbody remnant (MBR) that is generated after cytokinetic abscission has recently attracted a lot of attention, because it might have crucial consequences for cell differentiation and tumorigenesis in mammalian cells. In these cells, it has been reported that the MBR is either released into the extracellular medium or retracted into one of the two daughter cells where it can be degraded by autophagy. Here, we describe a major alternative pathway in a variety of human and mouse immortalized cells, cancer cells and primary stem cells. Using correlative light and scanning electron microscopy and quantitative assays, we found that sequential abscissions on both sides of the midbody generate free MBRs, which are tightly associated with the cell surface through a Ca(2+)/Mg(2+)-dependent receptor. Surprisingly, MBRs move over the cell surface for several hours, before being eventually engulfed by an actin-dependent phagocytosis-like mechanism. Mathematical modeling combined with experimentation further demonstrates that lysosomal activities fully account for the clearance of MBRs after engulfment. This study changes our understanding of how MBRs are inherited and degraded in mammalian cells and suggests a mechanism by which MBRs might signal over long distances between cells.
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Affiliation(s)
- Elizabeth Faris Crowell
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
| | - Anne-Lise Gaffuri
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
| | - Barbara Gayraud-Morel
- Institut Pasteur, Stem Cells and Development, Department of Developmental & Stem Cell Biology, CNRS URA 2578, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Stem Cells and Development, Department of Developmental & Stem Cell Biology, CNRS URA 2578, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Arnaud Echard
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
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196
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Chircop M. Rho GTPases as regulators of mitosis and cytokinesis in mammalian cells. Small GTPases 2014; 5:29770. [PMID: 24988197 DOI: 10.4161/sgtp.29770] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases regulate a diverse range of cellular functions primarily through their ability to modulate microtubule dynamics and the actin-myosin cytoskeleton. Both of these cytoskeletal structures are crucial for a mitotic cell division. Specifically, their assembly and disassembly is tightly regulated in a temporal manner to ensure that each mitotic stage occurs in the correct sequential order and not prematurely until the previous stage is completed. Thus, it is not surprising that the Rho GTPases, RhoA, and Cdc42, have reported roles in several stages of mitosis: cell cortex stiffening during cell rounding, mitotic spindle formation, and bi-orient attachment of the spindle microtubules to the kinetochore and during cytokinesis play multiple roles in establishing the division plane, assembly, and activation of the contractile ring, membrane ingression, and abscission. Here, I review the molecular mechanisms regulating the spatial and temporal activation of RhoA and Cdc42 during mitosis, and how this is critical for mitotic progression and completion.
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Affiliation(s)
- Megan Chircop
- Children's Medical Research Institute; The University of Sydney; Westmead, Australia
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197
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Staszak AM, Pawłowski TA. Proteomic analysis of embryogenesis and the acquisition of seed dormancy in Norway maple (Acer platanoides L.). Int J Mol Sci 2014; 15:10868-91. [PMID: 24941250 PMCID: PMC4100186 DOI: 10.3390/ijms150610868] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/16/2014] [Accepted: 05/30/2014] [Indexed: 12/16/2022] Open
Abstract
The proteome of zygotic embryos of Acer platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association.
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198
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Cashikar AG, Shim S, Roth R, Maldazys MR, Heuser JE, Hanson PI. Structure of cellular ESCRT-III spirals and their relationship to HIV budding. eLife 2014; 3. [PMID: 24878737 PMCID: PMC4073282 DOI: 10.7554/elife.02184] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 05/27/2014] [Indexed: 12/23/2022] Open
Abstract
The ESCRT machinery along with the AAA+ ATPase Vps4 drive membrane scission for trafficking into multivesicular bodies in the endocytic pathway and for the topologically related processes of viral budding and cytokinesis, but how they accomplish this remains unclear. Using deep-etch electron microscopy, we find that endogenous ESCRT-III filaments stabilized by depleting cells of Vps4 create uniform membrane-deforming conical spirals which are assemblies of specific ESCRT-III heteropolymers. To explore functional roles for ESCRT-III filaments, we examine HIV-1 Gag-mediated budding of virus-like particles and find that depleting Vps4 traps ESCRT-III filaments around nascent Gag assemblies. Interpolating between the observed structures suggests a new role for Vps4 in separating ESCRT-III from Gag or other cargo to allow centripetal growth of a neck constricting ESCRT-III spiral. DOI:http://dx.doi.org/10.7554/eLife.02184.001 Cells contain compartments called organelles that are enclosed within membranes similar to the plasma membrane that surrounds the cell itself. Cells police the proteins on their membranes and move old or damaged proteins into a type of organelle called an endosome. This involves the membrane folding in on itself to form a multivesicular body. The multivesicular bodies deliver their contents to organelles called lysosomes where the old proteins are destroyed. Although it is known that over 30 proteins are involved in the formation of multivesicular bodies, many aspects of how they operate are not well understood. Moreover, disruptions to this process contribute to a large number of diseases including forms of cancer and neurodegeneration. Importantly, the same proteins are hijacked by viruses such as HIV to help them escape from the cells they have infected. Most of the proteins involved in forming multivesicular bodies are part of the ESCRT (Endosomal Sorting Complex Required for Transport) system of proteins. A special set of these proteins—ESCRT-III—is thought to cut the membrane to release vesicles and viruses, as well as helping the membrane to deform. Previously, researchers have been unsure how the ESCRT-III complex works because it has a short lifespan and is too small to see on cellular membranes using standard techniques. Now Cashikar, Shim et al. have used a technique called deep-etch electron microscopy in combination with gene knockdown strategies to reveal the structure of the ESCRT-III complex inside cells. A protein called Vps4 is known to recycle ESCRT-III complexes, so Cashikar, Shim et al. studied cells in which the levels of Vps4 had been depleted in order to increase the lifespan of ESCRT-III complexes. In these cells filaments made of ESCRT-III complexes tended to form conical spirals that matched the size and shape of the vesicles and viruses ESCRT-III is thought to produce. ESCRT-III filaments also accumulated as rings around the molecules destined for incorporation into a vesicle or virus. This indicated a new role for Vps4: it separates ESCRT-III from the contents of the vesicle, leaving it free to form a spiral that drives release of the vesicle or virus from the cell. The next challenge will be to test the predictions of this model using techniques that can capture individual vesicle formation events in real time. Understanding the function of ESCRT-III in greater detail may suggest ways to manipulate this pathway to limit the replication of viruses or the degradation of membrane proteins. DOI:http://dx.doi.org/10.7554/eLife.02184.002
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Affiliation(s)
- Anil G Cashikar
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
| | - Soomin Shim
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
| | - Michael R Maldazys
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
| | - John E Heuser
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
| | - Phyllis I Hanson
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
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199
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ANCHR mediates Aurora-B-dependent abscission checkpoint control through retention of VPS4. Nat Cell Biol 2014; 16:550-60. [PMID: 24814515 DOI: 10.1038/ncb2959] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 04/02/2014] [Indexed: 02/07/2023]
Abstract
During the final stage of cell division, cytokinesis, the Aurora-B-dependent abscission checkpoint (NoCut) delays membrane abscission to avoid DNA damage and aneuploidy in cells with chromosome segregation defects. This arrest depends on Aurora-B-mediated phosphorylation of CHMP4C, a component of the endosomal sorting complex required for transport (ESCRT) machinery that mediates abscission, but the mechanism remains unknown. Here we describe ANCHR (Abscission/NoCut Checkpoint Regulator; ZFYVE19) as a key regulator of the abscission checkpoint, functioning through the most downstream component of the ESCRT machinery, the ATPase VPS4. In concert with CHMP4C, ANCHR associates with VPS4 at the midbody ring following DNA segregation defects to control abscission timing and prevent multinucleation in an Aurora-B-dependent manner. This association prevents VPS4 relocalization to the abscission zone and is relieved following inactivation of Aurora B to allow abscission. We propose that the abscission checkpoint is mediated by ANCHR and CHMP4C through retention of VPS4 at the midbody ring.
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200
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Burnette DT, Shao L, Ott C, Pasapera AM, Fischer RS, Baird MA, Der Loughian C, Delanoe-Ayari H, Paszek MJ, Davidson MW, Betzig E, Lippincott-Schwartz J. A contractile and counterbalancing adhesion system controls the 3D shape of crawling cells. ACTA ACUST UNITED AC 2014; 205:83-96. [PMID: 24711500 PMCID: PMC3987145 DOI: 10.1083/jcb.201311104] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
How adherent and contractile systems coordinate to promote cell shape changes is unclear. Here, we define a counterbalanced adhesion/contraction model for cell shape control. Live-cell microscopy data showed a crucial role for a contractile meshwork at the top of the cell, which is composed of actin arcs and myosin IIA filaments. The contractile actin meshwork is organized like muscle sarcomeres, with repeating myosin II filaments separated by the actin bundling protein α-actinin, and is mechanically coupled to noncontractile dorsal actin fibers that run from top to bottom in the cell. When the meshwork contracts, it pulls the dorsal fibers away from the substrate. This pulling force is counterbalanced by the dorsal fibers' attachment to focal adhesions, causing the fibers to bend downward and flattening the cell. This model is likely to be relevant for understanding how cells configure themselves to complex surfaces, protrude into tight spaces, and generate three-dimensional forces on the growth substrate under both healthy and diseased conditions.
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Affiliation(s)
- Dylan T Burnette
- National Institute of Child Health and Human Development and 2 National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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