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Park S, Patel SA, Torr EE, Dureke AGN, McIntyre AM, Skop AR. A protocol for isolating and imaging large extracellular vesicles or midbody remnants from mammalian cell culture. STAR Protoc 2023; 4:102562. [PMID: 37690025 PMCID: PMC10500451 DOI: 10.1016/j.xpro.2023.102562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/14/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023] Open
Abstract
Traditionally, midbody remnants (MBRs) are isolated from cell culture medium using ultracentrifugation, which is expensive and time consuming. Here, we present a protocol for isolating MBRs or large extracellular vesicles (EVs) from mammalian cell culture using either 1.5% polyethylene glycol 6000 (PEG6000) or PEG5000-coated gold nanoparticles. We describe steps for growing cells, collecting media, and precipitating MBRs and EVs from cell culture medium. We then detail characterization of MBRs through immunofluorescent antibody staining and immunofluorescent imaging.
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Affiliation(s)
- Sungjin Park
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Smit A Patel
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Elizabeth E Torr
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | | | - Alina M McIntyre
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Ahna R Skop
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA.
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2
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Jung GI, Londoño-Vásquez D, Park S, Skop AR, Balboula AZ, Schindler K. An oocyte meiotic midbody cap is required for developmental competence in mice. Nat Commun 2023; 14:7419. [PMID: 37973997 PMCID: PMC10654508 DOI: 10.1038/s41467-023-43288-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
Embryo development depends upon maternally derived materials. Mammalian oocytes undergo extreme asymmetric cytokinesis events, producing one large egg and two small polar bodies. During cytokinesis in somatic cells, the midbody and subsequent assembly of the midbody remnant, a signaling organelle containing RNAs, transcription factors and translation machinery, is thought to influence cellular function or fate. The role of the midbody and midbody remnant in gametes, in particular, oocytes, remains unclear. Here, we examined the formation and function of meiotic midbodies (mMB) and mMB remnants using mouse oocytes and demonstrate that mMBs have a specialized cap structure that is orientated toward polar bodies. We show that that mMBs are translationally active, and that mMB caps are required to retain nascent proteins in eggs. We propose that this specialized mMB cap maintains genetic factors in eggs allowing for full developmental competency.
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Affiliation(s)
- Gyu Ik Jung
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Human Genetics Institute of New Jersey, Piscataway, NJ, USA
| | | | - Sungjin Park
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahna R Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahmed Z Balboula
- Animal Sciences Research Center, University of Missouri, Columbia, MO, USA
| | - Karen Schindler
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
- Human Genetics Institute of New Jersey, Piscataway, NJ, USA.
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3
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Park S, Dahn R, Kurt E, Presle A, VanDenHeuvel K, Moravec C, Jambhekar A, Olukoga O, Shepherd J, Echard A, Blower M, Skop AR. The mammalian midbody and midbody remnant are assembly sites for RNA and localized translation. Dev Cell 2023; 58:1917-1932.e6. [PMID: 37552987 PMCID: PMC10592306 DOI: 10.1016/j.devcel.2023.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 06/20/2023] [Accepted: 07/17/2023] [Indexed: 08/10/2023]
Abstract
Long ignored as a vestigial remnant of cytokinesis, the mammalian midbody (MB) is released post-abscission inside large extracellular vesicles called MB remnants (MBRs). Recent evidence suggests that MBRs can modulate cell proliferation and cell fate decisions. Here, we demonstrate that the MB matrix is the site of ribonucleoprotein assembly and is enriched in mRNAs that encode proteins involved in cell fate, oncogenesis, and pluripotency, which we are calling the MB granule. Both MBs and post-abscission MBRs are sites of spatiotemporally regulated translation, which is initiated when nascent daughter cells re-enter G1 and continues after extracellular release. MKLP1 and ARC are necessary for the localization and translation of RNA in the MB dark zone, whereas ESCRT-III is necessary to maintain translation levels in the MB. Our work reveals a unique translation event that occurs during abscission and within a large extracellular vesicle.
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Affiliation(s)
- Sungjin Park
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Randall Dahn
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Elif Kurt
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Adrien Presle
- Institut Pasteur, Université de Paris, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, 75015 Paris, France; Sorbonne Université, Collège doctoral, 75005 Paris, France
| | - Kathryn VanDenHeuvel
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Cara Moravec
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Olushola Olukoga
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Jason Shepherd
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Arnaud Echard
- Institut Pasteur, Université de Paris, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, 75015 Paris, France
| | - Michael Blower
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Ahna R Skop
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI, USA.
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4
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del Castillo U, Gnazzo MM, Turpin CGS, Nguyen KCQ, Semaya E, Lam Y, de Cruz MA, Bembenek JN, Hall DH, Riggs B, Gelfand VI, Skop AR. Conserved role for Ataxin-2 in mediating endoplasmic reticulum dynamics. Traffic 2019; 20:436-447. [PMID: 30989774 PMCID: PMC6553494 DOI: 10.1111/tra.12647] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 12/17/2022]
Abstract
Ataxin-2, a conserved RNA-binding protein, is implicated in the late-onset neurodegenerative disease Spinocerebellar ataxia type-2 (SCA2). SCA2 is characterized by shrunken dendritic arbors and torpedo-like axons within the Purkinje neurons of the cerebellum. Torpedo-like axons have been described to contain displaced endoplasmic reticulum (ER) in the periphery of the cell; however, the role of Ataxin-2 in mediating ER function in SCA2 is unclear. We utilized the Caenorhabditis elegans and Drosophila homologs of Ataxin-2 (ATX-2 and DAtx2, respectively) to determine the role of Ataxin-2 in ER function and dynamics in embryos and neurons. Loss of ATX-2 and DAtx2 resulted in collapse of the ER in dividing embryonic cells and germline, and ultrastructure analysis revealed unique spherical stacks of ER in mature oocytes and fragmented and truncated ER tubules in the embryo. ATX-2 and DAtx2 reside in puncta adjacent to the ER in both C. elegans and Drosophila embryos. Lastly, depletion of DAtx2 in cultured Drosophila neurons recapitulated the shrunken dendritic arbor phenotype of SCA2. ER morphology and dynamics were severely disrupted in these neurons. Taken together, we provide evidence that Ataxin-2 plays an evolutionary conserved role in ER dynamics and morphology in C. elegans and Drosophila embryos during development and in fly neurons, suggesting a possible SCA2 disease mechanism.
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Affiliation(s)
- Urko del Castillo
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611
| | - Megan M. Gnazzo
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Christopher G. Sorensen Turpin
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996
| | - Ken C. Q. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Emily Semaya
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Yuwan Lam
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Matthew A. de Cruz
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Joshua N. Bembenek
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx New York, NY 10461
| | - Blake Riggs
- Department of Biology, San Francisco State University, San Francisco, CA 94132
| | - Vladimir I. Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611
| | - Ahna R. Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
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Skop AR. The entrance: how life experience shaped my passion for diversity and inclusion. Mol Biol Cell 2018; 29:2608-2610. [PMID: 30376436 PMCID: PMC6249843 DOI: 10.1091/mbc.e18-07-0431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
I am deeply honored to receive the American Society for Cell Biology (ASCB) Prize for Excellence in Inclusivity made possible through a grant from the Howard Hughes Medical Institute. This generous award of $5000 will go toward travel and registration support for underrepresented students from the University of Wisconsin–Madison to attend the ASCB and SACNAS (Society for Advancement of Chicanos/Hispanics and Native Americans in Science) conferences. In this essay, I have woven together a few stories on how my life experiences have shaped my passion for diversity and inclusion in STEM.
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Affiliation(s)
- Ahna R Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
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6
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Bonner MK, Han BH, Skop AR. Correction: Profiling of the Mammalian Mitotic Spindle Proteome Reveals an ER Protein, OSTD-1, as Being Necessary for Cell Division and ER Morphology. PLoS One 2017; 12:e0171399. [PMID: 28135330 PMCID: PMC5279803 DOI: 10.1371/journal.pone.0171399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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7
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Gnazzo MM, Uhlemann EME, Villarreal AR, Shirayama M, Dominguez EG, Skop AR. The RNA-binding protein ATX-2 regulates cytokinesis through PAR-5 and ZEN-4. Mol Biol Cell 2016; 27:3052-3064. [PMID: 27559134 PMCID: PMC5063614 DOI: 10.1091/mbc.e16-04-0219] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/17/2016] [Indexed: 12/15/2022] Open
Abstract
The mechanisms that mediate the temporal and spatial recruitment of cell division factors to the spindle midzone and midbody remain unclear. Cell division is regulated by the conserved RNA-binding protein, ATX-2/Ataxin-2, which facilitates the targeting of ZEN-4 to the spindle midzone by mediating PAR-5. The spindle midzone harbors both microtubules and proteins necessary for furrow formation and the completion of cytokinesis. However, the mechanisms that mediate the temporal and spatial recruitment of cell division factors to the spindle midzone and midbody remain unclear. Here we describe a mechanism governed by the conserved RNA-binding protein ATX-2/Ataxin-2, which targets and maintains ZEN-4 at the spindle midzone. ATX-2 does this by regulating the amount of PAR-5 at mitotic structures, particularly the spindle, centrosomes, and midbody. Preventing ATX-2 function leads to elevated levels of PAR-5, enhanced chromatin and centrosome localization of PAR-5–GFP, and ultimately a reduction of ZEN-4–GFP at the spindle midzone. Codepletion of ATX-2 and PAR-5 rescued the localization of ZEN-4 at the spindle midzone, indicating that ATX-2 mediates the localization of ZEN-4 upstream of PAR-5. We provide the first direct evidence that ATX-2 is necessary for cytokinesis and suggest a model in which ATX-2 facilitates the targeting of ZEN-4 to the spindle midzone by mediating the posttranscriptional regulation of PAR-5.
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Affiliation(s)
- Megan M Gnazzo
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Eva-Maria E Uhlemann
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Alex R Villarreal
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Masaki Shirayama
- Program in Molecular Medicine, RNA Therapeutics Institute, and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605
| | - Eddie G Dominguez
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705
| | - Ahna R Skop
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706
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8
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Gnazzo MM, Skop AR. Spindlegate: the biological consequences of disrupting traffic. Dev Cell 2014; 28:480-2. [PMID: 24636255 DOI: 10.1016/j.devcel.2014.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The function of membrane trafficking during mitosis has become the focus of increasing interest. In this issue of Developmental Cell, Hehnly and Doxsey (2014) provide new insight into the role that endosomes play during spindle assembly.
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Affiliation(s)
- Megan M Gnazzo
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ahna R Skop
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA.
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9
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Pittman KJ, Skop AR. Anterior PAR proteins function during cytokinesis and maintain DYN-1 at the cleavage furrow in Caenorhabditis elegans. Cytoskeleton (Hoboken) 2012; 69:826-39. [PMID: 22887994 DOI: 10.1002/cm.21053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 12/25/2022]
Abstract
PAR proteins are key regulators of cellular polarity and have links to the endocytic machinery and the actin cytoskeleton. Our data suggest a unique role for PAR proteins in cytokinesis. We have found that at the onset of cytokinesis, anterior PAR-6 and posterior PAR-2 proteins are redistributed to the furrow membrane in a temporal and spatial manner. PAR-6 and PAR-2 localize to the furrow membrane during ingression but PAR-2-GFP is distinct in that it is excluded from the extreme tip of the furrow. Once the midbody has formed, PAR-2-GFP becomes restricted to the midbody region (the midbody plus the membrane flanking it). Depletion of both anterior PAR proteins, PAR-3 and PAR-6, led to an increase in multinucleate embryos, suggesting that the anterior PAR proteins are necessary during cytokinesis and that PAR-3 and PAR-6 function in cytokinesis may be partially redundant. Lastly, anterior PAR proteins play a role in the maintenance of DYN-1 in the cleavage furrow. Our data indicate that the PAR proteins are involved in the events that occur during cytokinesis and may play a role in promoting the membrane trafficking and remodeling events that occur during this time.
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Affiliation(s)
- Kelly J Pittman
- Laboratory of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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10
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Shivas JM, Skop AR. Arp2/3 mediates early endosome dynamics necessary for the maintenance of PAR asymmetry in Caenorhabditis elegans. Mol Biol Cell 2012; 23:1917-27. [PMID: 22456506 PMCID: PMC3350555 DOI: 10.1091/mbc.e12-01-0006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/23/2012] [Accepted: 03/23/2012] [Indexed: 01/06/2023] Open
Abstract
The widely conserved Arp2/3 complex regulates branched actin dynamics that are necessary for a variety of cellular processes. In Caenorhabditis elegans, the actin cytoskeleton has been extensively characterized in its role in establishing PAR asymmetry; however, the contributions of actin to the maintenance of polarity before the onset of mitosis are less clear. Endocytic recycling has emerged as a key mechanism in the dynamic stabilization of cellular polarity, and the large GTPase dynamin participates in the stabilization of cortical polarity during maintenance phase via endocytosis in C. elegans. Here we show that disruption of Arp2/3 function affects the formation and localization of short cortical actin filaments and foci, endocytic regulators, and polarity proteins during maintenance phase. We detect actin associated with events similar to early endosomal fission, movement of endosomes into the cytoplasm, and endosomal movement from the cytoplasm to the plasma membrane, suggesting the involvement of actin in regulating processes at the early endosome. We also observe aberrant accumulations of PAR-6 cytoplasmic puncta near the centrosome along with early endosomes. We propose a model in which Arp2/3 affects the efficiency of rapid endocytic recycling of polarity cues that ultimately contributes to their stable maintenance.
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Affiliation(s)
- Jessica M. Shivas
- Department of Genetics and Medical Genetics, University of Wisconsin–Madison, Madison, WI 53706
| | - Ahna R. Skop
- Department of Genetics and Medical Genetics, University of Wisconsin–Madison, Madison, WI 53706
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11
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Abstract
Mitosis is a fundamental process in the development of all organisms. The mitotic spindle guides the cell through mitosis as it mediates the segregation of chromosomes, the orientation of the cleavage furrow, and the progression of cell division. Birth defects and tissue-specific cancers often result from abnormalities in mitotic events. Here, we report a proteomic study of the mitotic spindle from Chinese Hamster Ovary (CHO) cells. Four different isolations of metaphase spindles were subjected to Multi-dimensional Protein Identification Technology (MudPIT) analysis and tandem mass spectrometry. We identified 1155 proteins and used Gene Ontology (GO) analysis to categorize proteins into cellular component groups. We then compared our data to the previously published CHO midbody proteome and identified proteins that are unique to the CHO spindle. Our data represent the first mitotic spindle proteome in CHO cells, which augments the list of mitotic spindle components from mammalian cells.
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Affiliation(s)
- Mary Kate Bonner
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Daniel S. Poole
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Tao Xu
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ali Sarkeshik
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
| | - John R. Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ahna R. Skop
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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12
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Ai E, Poole DS, Skop AR. Long astral microtubules and RACK-1 stabilize polarity domains during maintenance phase in Caenorhabditis elegans embryos. PLoS One 2011; 6:e19020. [PMID: 21533050 PMCID: PMC3080402 DOI: 10.1371/journal.pone.0019020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/14/2011] [Indexed: 11/18/2022] Open
Abstract
Cell polarity is a very well conserved process important for cell differentiation, cell migration, and embryonic development. After the establishment of distinct cortical domains, polarity cues have to be stabilized and maintained within a fluid and dynamic membrane to achieve proper cell asymmetry. Microtubules have long been thought to deliver the signals required to polarize a cell. While previous studies suggest that microtubules play a key role in the establishment of polarity, the requirement of microtubules during maintenance phase remains unclear. In this study, we show that depletion of Caenorhabditis elegans RACK-1, which leads to short astral microtubules during prometaphase, specifically affects maintenance of cortical PAR domains and Dynamin localization. We then investigated the consequence of knocking down other factors that also abolish astral microtubule elongation during polarity maintenance phase. We found a correlation between short astral microtubules and the instability of PAR-6 and PAR-2 domains during maintenance phase. Our data support a necessary role for astral microtubules in the maintenance phase of cell polarity.
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Affiliation(s)
- Erkang Ai
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Daniel S. Poole
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ahna R. Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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Skop AR. Anterior embryonic polarity is maintained by dynamin. Dev Biol 2010. [DOI: 10.1016/j.ydbio.2010.05.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Abstract
Successful cytokinesis is critical for cell proliferation and development. In animal cells, cytokinesis relies on temporally and spatially regulated membrane addition to the cleavage site. An important source for the new membrane is recycling endosomes. Yet how these endocytic vesicles are transported and regulated remains unclear. Several potential factors have been recently identified that regulate the trafficking of recycling endosomes during cytokinesis. Dynein and dynactin are required for the retrograde transport of recycling endosomes, while Kinesin-1 is responsible for endosome delivery to the furrow and midbody. Other regulators of recycling endosome trafficking have been identified, including RACK1, JIP3/4 and ECT2, which target recycling endosomes during the cell cycle. Here, we provide insights into the mechanisms controlling endosomal trafficking during cytokinesis.
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Affiliation(s)
- Erkang Ai
- Department of Genetics & Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
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15
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Shivas JM, Morrison HA, Bilder D, Skop AR. Polarity and endocytosis: reciprocal regulation. Trends Cell Biol 2010; 20:445-52. [PMID: 20493706 DOI: 10.1016/j.tcb.2010.04.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 04/09/2010] [Accepted: 04/13/2010] [Indexed: 10/19/2022]
Abstract
The establishment and maintenance of polarized plasma membrane domains is essential for cellular function and proper development of organisms. The molecules and pathways involved in determining cell polarity are remarkably well conserved between animal species. Historically, exocytic mechanisms have received primary emphasis among trafficking routes responsible for cell polarization. Accumulating evidence now reveals that endocytosis plays an equally important role in the proper localization of key polarity proteins. Intriguingly, some polarity proteins can also regulate the endocytic machinery. Here, we review emerging evidence for the reciprocal regulation between polarity proteins and endocytic pathways, and discuss possible models for how these distinct processes could interact to create separate cellular domains.
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Affiliation(s)
- Jessica M Shivas
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
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16
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Nakayama Y, Shivas JM, Poole DS, Squirrell JM, Kulkoski JM, Schleede JB, Skop AR. Dynamin participates in the maintenance of anterior polarity in the Caenorhabditis elegans embryo. Dev Cell 2009; 16:889-900. [PMID: 19531359 DOI: 10.1016/j.devcel.2009.04.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2008] [Revised: 03/24/2009] [Accepted: 04/21/2009] [Indexed: 01/10/2023]
Abstract
Cell polarity is crucial for the generation of cell diversity. Recent evidence suggests that the actin cytoskeleton plays a key role in establishment of embryonic polarity, yet the mechanisms that maintain polarity cues in particular membrane domains during development remain unclear. Dynamin, a large GTPase, functions in both endocytosis and actin dynamics. Here, the Caenorhabditis elegans dynamin ortholog, DYN-1, maintains anterior polarity cues. DYN-1-GFP foci are enriched in the anterior cortex in a manner dependent on the anterior polarity proteins, PAR-6 and PKC-3. Membrane internalization and actin comet formation are enriched in the anterior, and are dependent on DYN-1. PAR-6-labeled puncta are also internalized from cortical accumulations of DYN-1-GFP. Our results demonstrate a mechanism for the spatial and temporal regulation of endocytosis in the anterior of the embryo, contributing to the precise localization and maintenance of polarity factors within a dynamic plasma membrane.
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Affiliation(s)
- Yuji Nakayama
- Department of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
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Abstract
Membrane trafficking pathways are necessary for the addition and removal of membrane during cytokinesis. In animal cells, recycling endosomes act as a major source of the additional membranes during furrow progression and abscission. However, the mechanisms and factors that regulate recycling endosomes during the cell cycle remain poorly understood. Here, we show that the Caenorhabditis elegans Receptor of Activated C Kinase 1 (RACK-1) is required for cytokinesis, germline membrane organization, and the recruitment of RAB-11-labeled recycling endosomes to the pericentrosomal region and spindle. RACK-1 is also required for proper chromosome separation and astral microtubule length. RACK-1 localizes to the centrosomes, kinetochores, the midbody, and nuclear envelopes during the cell cycle. We found that RACK-1 directly binds to DNC-2, the C. elegans p50/dynamitin subunit of the dynactin complex. Last, RACK-1 may facilitate the sequestration of recycling endosomes by targeting DNC-2 to centrosomes and the spindle. Our findings suggest a mechanism by which RACK-1 directs the dynactin-dependent redistribution of recycling endosomes during the cell cycle, thus ensuring proper membrane trafficking events during cytokinesis.
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Affiliation(s)
- Erkang Ai
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
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Zhang H, Skop AR, White JG. Src and Wnt signaling regulate dynactin accumulation to the P2-EMS cell border in C. elegans embryos. J Cell Sci 2008; 121:155-61. [PMID: 18187449 DOI: 10.1242/jcs.015966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2024] Open
Abstract
In many organisms, the dynein-dynactin complex is required for the alignment of the mitotic spindle onto the axis of polarity of a cell undergoing asymmetric cell division. How this complex transduces polarity cues, either intrinsic or extrinsic, and rotationally aligns the spindle accordingly is not well understood. The Caenorhabditis elegans blastomere P2 polarizes the neighboring EMS blastomere, which causes the EMS spindle to rotationally align along the defined axis of polarity via two redundant signaling pathways: Wnt and Src. Here, we describe how components of the dynactin complex became locally enriched at the P2-EMS border prior to and during rotational alignment of their spindles. Wnt and Src signaling were required for both localized dynactin enrichment, and for rotational alignment of the P2 and EMS spindles. Depleting the trimeric G-protein subunit G alpha did not abolish dynactin accumulation to the P2-EMS border, yet both EMS and P2 spindles failed to rotationally align, indicating that G alpha might act to regulate dynein/dynactin motor activity. By RNAi of a weak dnc-1(ts) allele, we showed that dynactin activity was required at least for EMS spindle rotational alignment.
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Affiliation(s)
- Haining Zhang
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
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Abstract
Animal and plant cytokineses appear morphologically distinct. Recent studies, however, have revealed that these cellular processes have many things in common, including the requirement of co-ordinated membrane trafficking and cytoskeletal dynamics. At the intersection of these two processes are the members of the dynamin family of ubiquitous eukaryotic GTPases. In this review, we highlight the conserved contribution of classical dynamin and dynamin-related proteins during cytokinesis in both animal and plant systems.
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Affiliation(s)
- Catherine A. Konopka
- Department of Biochemistry and Program in Cellular and Molecular Biology, University of Wisconsin – Madison, Madison, WI 53706, USA
| | - Justin B. Schleede
- Department of Genetics and Medical Genetics, University of Wisconsin – Madison, Madison, WI 53706, USA
| | - Ahna R. Skop
- Department of Genetics and Medical Genetics, University of Wisconsin – Madison, Madison, WI 53706, USA
- Corresponding author: Ahna R. Skop, ; Sebastian Y. Bednarek,
| | - Sebastian Y. Bednarek
- Department of Biochemistry and Program in Cellular and Molecular Biology, University of Wisconsin – Madison, Madison, WI 53706, USA
- Corresponding author: Ahna R. Skop, ; Sebastian Y. Bednarek,
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Otegui MS, Verbrugghe KJ, Skop AR. Midbodies and phragmoplasts: analogous structures involved in cytokinesis. Trends Cell Biol 2005; 15:404-13. [PMID: 16009554 PMCID: PMC3677513 DOI: 10.1016/j.tcb.2005.06.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 06/09/2005] [Accepted: 06/24/2005] [Indexed: 12/21/2022]
Abstract
Cytokinesis is an event common to all organisms that involves the precise coordination of independent pathways involved in cell-cycle regulation and microtubule, membrane, actin and organelle dynamics. In animal cells, the spindle midzone/midbody with associated endo-membrane system are required for late cytokinesis events, including furrow ingression and scission. In plants, cytokinesis is mediated by the phragmoplast, an array of microtubules, actin filaments and associated molecules that act as a framework for the future cell wall. In this article (which is part of the Cytokinesis series), we discuss recent studies that highlight the increasing number of similarities in the components and function of the spindle midzone/midbody in animals and the phragmoplast in plants, suggesting that they might be analogous structures.
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Affiliation(s)
- Marisa S Otegui
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA
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Abstract
Cytokinesis is the essential process that partitions cellular contents into daughter cells. To identify and characterize cytokinesis proteins rapidly, we used a functional proteomic and comparative genomic strategy. Midbodies were isolated from mammalian cells, proteins were identified by multidimensional protein identification technology (MudPIT), and protein function was assessed in Caenorhabditis elegans. Of 172 homologs disrupted by RNA interference, 58% displayed defects in cleavage furrow formation or completion, or germline cytokinesis. Functional dissection of the midbody demonstrated the importance of lipid rafts and vesicle trafficking pathways in cytokinesis, and the utilization of common membrane cytoskeletal components in diverse morphogenetic events in the cleavage furrow, the germline, and neurons.
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Affiliation(s)
- Ahna R Skop
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.
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Abstract
Cytokinesis involves the concerted efforts of the microtubule and actin cytoskeletons as well as vesicle trafficking and membrane remodeling to form the cleavage furrow and complete daughter cell separation. The exact mechanisms that support membrane remodeling during cytokinesis remain largely undefined. In this study, we report that the large GTPase dynamin, a protein involved in membrane tubulation and vesiculation, is essential for successful cytokinesis. Using biochemical and morphological methods, we demonstrate that dynamin localizes to the spindle midzone and the subsequent intercellular bridge in mammalian cells and is also enriched in spindle midbody extracts. In Caenorhabditis elegans, dynamin localized to newly formed cleavage furrow membranes and accumulated at the midbody of dividing embryos in a manner similar to dynamin localization in mammalian cells. Further, dynamin function appears necessary for cytokinesis, as C. elegans embryos from a dyn-1 ts strain, as well as dynamin RNAi-treated embryos, showed a marked defect in the late stages of cytokinesis. These findings indicate that, during mitosis, conventional dynamin is recruited to the spindle midzone and the subsequent intercellular bridge, where it plays an essential role in the final separation of dividing cells.
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Affiliation(s)
- Heather M. Thompson
- GI Basic Research and Department of Biochemistry and Molecular Biology, Mayo Clinic and Mayo Graduate School Rochester, Minnesota 55905
| | - Ahna R. Skop
- Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, California 94720
- Howard, Hughes Medical Institute, University of California, Berkeley Berkeley, California 94720
| | | | - Barbara J. Meyer
- Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, California 94720
- Howard, Hughes Medical Institute, University of California, Berkeley Berkeley, California 94720
| | - Mark A. McNiven
- GI Basic Research and Department of Biochemistry and Molecular Biology, Mayo Clinic and Mayo Graduate School Rochester, Minnesota 55905
- Correspondence:
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Skop AR, Bergmann D, Mohler WA, White JG. Completion of cytokinesis in C. elegans requires a brefeldin A-sensitive membrane accumulation at the cleavage furrow apex. Curr Biol 2001; 11:735-46. [PMID: 11378383 PMCID: PMC3733387 DOI: 10.1016/s0960-9822(01)00231-7] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The terminal phase of cytokinesis in eukaryotic cells involves breakage of the intercellular canal containing the spindle midzone and resealing of the daughter cells. Recent observations suggest that the spindle midzone is required for this process. In this study, we investigated the possibility that targeted secretion in the vicinity of the spindle midzone is required for the execution of the terminal phase of cytokinesis. RESULTS We inhibited secretion in early C. elegans embryos by treatment with brefeldin A (BFA). Using 4D recordings of dividing cells, we showed that BFA induced stereotyped failures in the terminal phase of cytokinesis; although the furrow ingressed normally, after a few minutes the furrow completely regressed, even though spindle midzone and midbody microtubules appeared normal. In addition, using an FM1-43 membrane probe, we found that membrane accumulated locally at the apices of the late cleavage furrows that form the persisting intercellular canals between daughter cells. However, in BFA-treated embryos this membrane accumulation did not occur, which possibly accounts for the observed cleavage failures. CONCLUSIONS We have shown that BFA disrupts the terminal phase of cytokinesis in the embryonic blastomeres of C. elegans. We observed that membrane accumulates at the apices of the late cleavage furrow by means of a BFA-sensitive mechanism. We suggest that this local membrane accumulation is necessary for the completion of cytokinesis and speculate that the spindle midzone region of animal cells is functionally equivalent to the phragmoplast of plants and acts to target secretion to the equatorial plane of a cleaving cell.
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Affiliation(s)
- Ahna R. Skop
- Laboratory of Molecular Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Dominique Bergmann
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - William A. Mohler
- Laboratory of Molecular Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - John G. White
- Laboratory of Molecular Biology, University of Colorado, Boulder, Colorado 80309, USA
- Department of Anatomy, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Abstract
BACKGROUND During metazoan development, cell diversity arises primarily from asymmetric cell divisions which are executed in two phases: segregation of cytoplasmic factors and positioning of the mitotic spindle - and hence the cleavage plane -relative to the axis of segregation. When polarized cells divide, spindle alignment probably occurs through the capture and subsequent shortening of astral microtubules by a site in the cortex. RESULTS Here, we report that dynactin, the dynein-activator complex, is localized at cortical microtubule attachment sites and is necessary for mitotic spindle alignment in early Caenorhabditis elegans embryos. Using RNA interference techniques, we eliminated expression in early embryos of dnc-1 (the ortholog of the vertebrate gene for p150(Glued)) and dnc-2 (the ortholog of the vertebrate gene for p50/Dynamitin). In both cases, misalignment of mitotic spindles occurred, demonstrating that two components of the dynactin complex, DNC-1 and DNC-2, are necessary to align the spindle. CONCLUSIONS Dynactin complexes may serve as a tether for dynein at the cortex and allow dynein to produce forces on the astral microtubules required for mitotic spindle alignment.
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Affiliation(s)
- Ahna R. Skop
- Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - John G. White
- Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Anatomy, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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