51
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Borah S, Thaller DJ, Hakhverdyan Z, Rodriguez EC, Isenhour AW, Rout MP, King MC, Lusk CP. Heh2/Man1 may be an evolutionarily conserved sensor of NPC assembly state. Mol Biol Cell 2021; 32:1359-1373. [PMID: 34010011 PMCID: PMC8694041 DOI: 10.1091/mbc.e20-09-0584] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Integral membrane proteins of the Lap2-emerin-MAN1 (LEM) family have emerged as important components of the inner nuclear membrane (INM) required for the functional and physical integrity of the nuclear envelope. However, like many INM proteins, there is limited understanding of the biochemical interaction networks that enable LEM protein function. Here, we show that Heh2/Man1 can interact with major scaffold components of the nuclear pore complex (NPC), specifically the inner ring complex (IRC), in evolutionarily distant yeasts. Although an N-terminal domain is required for Heh2 targeting to the INM, we demonstrate that more stable interactions with the NPC are mediated by a C-terminal winged helix (WH) domain, thus decoupling INM targeting and NPC binding. Inhibiting Heh2's interactions with the NPC by deletion of the Heh2 WH domain leads to NPC clustering. Interestingly, Heh2's association with NPCs can also be disrupted by knocking out several outer ring nucleoporins. Thus, Heh2's interaction with NPCs depends on the structural integrity of both major NPC scaffold complexes. We propose a model in which Heh2 acts as a sensor of NPC assembly state, which may be important for NPC quality control mechanisms and the segregation of NPCs during cell division.
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Affiliation(s)
- Sapan Borah
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - David J Thaller
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | | - Elisa C Rodriguez
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Anthony W Isenhour
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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52
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Hamed M, Caspar B, Port SA, Kehlenbach RH. A nuclear export sequence promotes CRM1-dependent targeting of the nucleoporin Nup214 to the nuclear pore complex. J Cell Sci 2021; 134:jcs.258095. [PMID: 33589493 DOI: 10.1242/jcs.258095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/02/2021] [Indexed: 11/20/2022] Open
Abstract
Nup214 is a major nucleoporin on the cytoplasmic side of the nuclear pore complex with roles in late steps of nuclear protein and mRNA export. It interacts with the nuclear export receptor CRM1 (also known as XPO1) via characteristic phenylalanine-glycine (FG) repeats in its C-terminal region. Here, we identify a classic nuclear export sequence (NES) in Nup214 that mediates Ran-dependent binding to CRM1. Nup214 versions with mutations in the NES, as well as wild-type Nup214 in the presence of the selective CRM1 inhibitor leptomycin B, accumulate in the nucleus of Nup214-overexpressing cells. Furthermore, physiological binding partners of Nup214, such as Nup62 and Nup88, are recruited to the nucleus together with Nup214. Nuclear export of mutant Nup214 can be rescued by artificial nuclear export sequences at the C-terminal end of Nup214, leading also to a correct localization of Nup88. Our results suggest a function of the Nup214 NES in the biogenesis of the nuclear pore complex and/or in terminal steps of CRM1-dependent protein export.
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Affiliation(s)
- Mohamed Hamed
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Birgit Caspar
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Sarah A Port
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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53
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Li J, Levin DS, Kim AJ, Pappas SS, Dauer WT. TorsinA restoration in a mouse model identifies a critical therapeutic window for DYT1 dystonia. J Clin Invest 2021; 131:139606. [PMID: 33529159 DOI: 10.1172/jci139606] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/27/2021] [Indexed: 12/18/2022] Open
Abstract
In inherited neurodevelopmental diseases, pathogenic processes unique to critical periods during early brain development may preclude the effectiveness of gene modification therapies applied later in life. We explored this question in a mouse model of DYT1 dystonia, a neurodevelopmental disease caused by a loss-of-function mutation in the TOR1A gene encoding torsinA. To define the temporal requirements for torsinA in normal motor function and gene replacement therapy, we developed a mouse line enabling spatiotemporal control of the endogenous torsinA allele. Suppressing torsinA during embryogenesis caused dystonia-mimicking behavioral and neuropathological phenotypes. Suppressing torsinA during adulthood, however, elicited no discernible abnormalities, establishing an essential requirement for torsinA during a developmental critical period. The developing CNS exhibited a parallel "therapeutic critical period" for torsinA repletion. Although restoring torsinA in juvenile DYT1 mice rescued motor phenotypes, there was no benefit from adult torsinA repletion. These data establish a unique requirement for torsinA in the developing nervous system and demonstrate that the critical period genetic insult provokes permanent pathophysiology mechanistically delinked from torsinA function. These findings imply that to be effective, torsinA-based therapeutic strategies must be employed early in the course of DYT1 dystonia.
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Affiliation(s)
- Jay Li
- Medical Scientist Training Program.,Cellular and Molecular Biology Graduate Program
| | - Daniel S Levin
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Samuel S Pappas
- Peter O'Donnell Jr. Brain Institute.,Department of Neurology
| | - William T Dauer
- Peter O'Donnell Jr. Brain Institute.,Department of Neurology.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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54
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Ding B, Tang Y, Ma S, Akter M, Liu ML, Zang T, Zhang CL. Disease Modeling with Human Neurons Reveals LMNB1 Dysregulation Underlying DYT1 Dystonia. J Neurosci 2021; 41:2024-2038. [PMID: 33468570 PMCID: PMC7939088 DOI: 10.1523/jneurosci.2507-20.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 02/08/2023] Open
Abstract
DYT1 dystonia is a hereditary neurologic movement disorder characterized by uncontrollable muscle contractions. It is caused by a heterozygous mutation in Torsin A (TOR1A), a gene encoding a membrane-embedded ATPase. While animal models provide insights into disease mechanisms, significant species-dependent differences exist since animals with the identical heterozygous mutation fail to show pathology. Here, we model DYT1 by using human patient-specific cholinergic motor neurons (MNs) that are generated through either direct conversion of patients' skin fibroblasts or differentiation of induced pluripotent stem cells (iPSCs). These human MNs with the heterozygous TOR1A mutation show reduced neurite length and branches, markedly thickened nuclear lamina, disrupted nuclear morphology, and impaired nucleocytoplasmic transport (NCT) of mRNAs and proteins, whereas they lack the perinuclear "blebs" that are often observed in animal models. Furthermore, we uncover that the nuclear lamina protein LMNB1 is upregulated in DYT1 cells and exhibits abnormal subcellular distribution in a cholinergic MNs-specific manner. Such dysregulation of LMNB1 can be recapitulated by either ectopic expression of the mutant TOR1A gene or shRNA-mediated downregulation of endogenous TOR1A in healthy control MNs. Interestingly, downregulation of LMNB1 can largely ameliorate all the cellular defects in DYT1 MNs. These results reveal the value of disease modeling with human patient-specific neurons and indicate that dysregulation of LMNB1, a crucial component of the nuclear lamina, may constitute a major molecular mechanism underlying DYT1 pathology.SIGNIFICANCE STATEMENT Inaccessibility to patient neurons greatly impedes our understanding of the pathologic mechanisms for dystonia. In this study, we employ reprogrammed human patient-specific motor neurons (MNs) to model DYT1, the most severe hereditary form of dystonia. Our results reveal disease-dependent deficits in nuclear morphology and nucleocytoplasmic transport (NCT). Most importantly, we further identify LMNB1 dysregulation as a major contributor to these deficits, uncovering a new pathologic mechanism for DYT1 dystonia.
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Affiliation(s)
- Baojin Ding
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana 70503
| | - Yu Tang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- National Clinical Research Center for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan Province 410008, China
| | - Shuaipeng Ma
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Masuma Akter
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana 70503
| | - Meng-Lu Liu
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Tong Zang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Chun-Li Zhang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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55
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A matter of wrapper: Defects in the nuclear envelope of lagging and bridging chromatin threatens genome integrity. Semin Cell Dev Biol 2021; 123:124-130. [DOI: 10.1016/j.semcdb.2021.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 03/08/2021] [Indexed: 01/07/2023]
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56
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Köhler A. Nuclear envelope lipids request border surveillance. J Cell Biol 2021; 220:e202101164. [PMID: 33599714 PMCID: PMC7883742 DOI: 10.1083/jcb.202101164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In this issue, Thaller et al. (2021. J. Cell Biol.https://doi.org/10.1083/jcb.202004222) explore how the ESCRT protein Chm7 is recruited to sites of defective nuclear pore assembly. They show that a lipid, phosphatidic acid, is enriched at pathological nuclear envelope herniations, where it promotes Chm7 recruitment for membrane surveillance and repair.
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Affiliation(s)
- Alwin Köhler
- Max Perutz Labs, University of Vienna and Medical University of Vienna, Vienna Biocenter Campus, Vienna, Austria
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57
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Thaller DJ, Tong D, Marklew CJ, Ader NR, Mannino PJ, Borah S, King MC, Ciani B, Lusk CP. Direct binding of ESCRT protein Chm7 to phosphatidic acid-rich membranes at nuclear envelope herniations. J Cell Biol 2021; 220:e202004222. [PMID: 33464310 PMCID: PMC7816628 DOI: 10.1083/jcb.202004222] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 11/04/2020] [Accepted: 12/11/2020] [Indexed: 12/03/2022] Open
Abstract
Mechanisms that control nuclear membrane remodeling are essential to maintain the integrity of the nucleus but remain to be fully defined. Here, we identify a phosphatidic acid (PA)-binding capacity in the nuclear envelope (NE)-specific ESCRT, Chm7, in budding yeast. Chm7's interaction with PA-rich membranes is mediated through a conserved hydrophobic stretch of amino acids, which confers recruitment to the NE in a manner that is independent of but required for Chm7's interaction with the LAP2-emerin-MAN1 (LEM) domain protein Heh1 (LEM2). Consistent with the functional importance of PA binding, mutation of this region abrogates recruitment of Chm7 to membranes and abolishes Chm7 function in the context of NE herniations that form during defective nuclear pore complex (NPC) biogenesis. In fact, we show that a PA sensor specifically accumulates within these NE herniations. We suggest that local control of PA metabolism is important for ensuring productive NE remodeling and that its dysregulation may contribute to pathologies associated with defective NPC assembly.
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Affiliation(s)
- David J. Thaller
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Danqing Tong
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Christopher J. Marklew
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield, UK
| | - Nicholas R. Ader
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | | | - Sapan Borah
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Megan C. King
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Barbara Ciani
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield, Brook Hill, Sheffield, UK
| | - C. Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
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58
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Li J, Kim S, Pappas SS, Dauer WT. CNS critical periods: implications for dystonia and other neurodevelopmental disorders. JCI Insight 2021; 6:142483. [PMID: 33616084 PMCID: PMC7934928 DOI: 10.1172/jci.insight.142483] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Critical periods are discrete developmental stages when the nervous system is especially sensitive to stimuli that facilitate circuit maturation. The distinctive landscapes assumed by the developing CNS create analogous periods of susceptibility to pathogenic insults and responsiveness to therapy. Here, we review critical periods in nervous system development and disease, with an emphasis on the neurodevelopmental disorder DYT1 dystonia. We highlight clinical and laboratory observations supporting the existence of a critical period during which the DYT1 mutation is uniquely harmful, and the implications for future therapeutic development.
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Affiliation(s)
- Jay Li
- Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Sumin Kim
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | | | - William T. Dauer
- Peter O’Donnell Jr. Brain Institute
- Department of Neurology, and
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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59
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Röhrl JM, Arnold R, Djabali K. Nuclear Pore Complexes Cluster in Dysmorphic Nuclei of Normal and Progeria Cells during Replicative Senescence. Cells 2021; 10:cells10010153. [PMID: 33466669 PMCID: PMC7828780 DOI: 10.3390/cells10010153] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 01/10/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disease caused by a mutation in LMNA. A G608G mutation in exon 11 of LMNA is responsible for most HGPS cases, generating a truncated protein called “progerin”. Progerin is permanently farnesylated and accumulates in HGPS cells, causing multiple cellular defects such as nuclear dysmorphism, a thickened lamina, loss of heterochromatin, premature senescence, and clustering of Nuclear Pore Complexes (NPC). To identify the mechanism of NPC clustering in HGPS cells, we evaluated post-mitotic NPC assembly in control and HGPS cells and found no defects. Next, we examined the occurrence of NPC clustering in control and HGPS cells during replicative senescence. We reported that NPC clustering occurs solely in the dysmorphic nuclei of control and HGPS cells. Hence, NPC clustering occurred at a higher frequency in HGPS cells compared to control cells at early passages; however, in late cultures with similar senescence index, NPCs clustering occurred at a similar rate in both control and HGPS. Our results show that progerin does not disrupt post-mitotic reassembly of NPCs. However, NPCs frequently cluster in dysmorphic nuclei with a high progerin content. Additionally, nuclear envelope defects that arise during replicative senescence cause NPC clustering in senescent cells with dysmorphic nuclei.
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60
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Maturation Kinetics of a Multiprotein Complex Revealed by Metabolic Labeling. Cell 2020; 183:1785-1800.e26. [DOI: 10.1016/j.cell.2020.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 09/21/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022]
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61
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Liu S, Pellman D. The coordination of nuclear envelope assembly and chromosome segregation in metazoans. Nucleus 2020; 11:35-52. [PMID: 32208955 PMCID: PMC7289584 DOI: 10.1080/19491034.2020.1742064] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/08/2020] [Accepted: 03/10/2020] [Indexed: 01/25/2023] Open
Abstract
The nuclear envelope (NE) is composed of two lipid bilayer membranes that enclose the eukaryotic genome. In interphase, the NE is perforated by thousands of nuclear pore complexes (NPCs), which allow transport in and out of the nucleus. During mitosis in metazoans, the NE is broken down and then reassembled in a manner that enables proper chromosome segregation and the formation of a single nucleus in each daughter cell. Defects in coordinating NE reformation and chromosome segregation can cause aberrant nuclear architecture. This includes the formation of micronuclei, which can trigger a catastrophic mutational process commonly observed in cancers called chromothripsis. Here, we discuss the current understanding of the coordination of NE reformation with chromosome segregation during mitotic exit in metazoans. We review differing models in the field and highlight recent work suggesting that normal NE reformation and chromosome segregation are physically linked through the timing of mitotic spindle disassembly.
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Affiliation(s)
- Shiwei Liu
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - David Pellman
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
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62
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Nordeen SA, Turman DL, Schwartz TU. Yeast Nup84-Nup133 complex structure details flexibility and reveals conservation of the membrane anchoring ALPS motif. Nat Commun 2020; 11:6060. [PMID: 33247142 PMCID: PMC7695694 DOI: 10.1038/s41467-020-19885-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/29/2020] [Indexed: 01/07/2023] Open
Abstract
The hallmark of the eukaryotic cell is the complex endomembrane system that compartmentalizes cellular functions. Transport into and out of the nucleus occurs through the nuclear pore complex (NPC). The heptameric Nup84 or Y complex is an essential scaffolding component of the NPC. Here we report two nanobody-bound structures: the full-length Nup84-Nup133 C-terminal domain complex and the Nup133 N-terminal domain, both from S. cerevisiae. Together with previously published structures, this work enables the structural description of the entire 575 kDa Y complex from one species. The structure of Nup84-Nup133CTD details the high flexibility of this dimeric unit of the Y complex. Further, the Nup133NTD contains a structurally conserved amphipathic lipid packing sensor motif, confirmed by liposome interaction studies. The presented structures reveal important details about the function of the Y complex that affect our understanding of NPC structure and assembly.
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Affiliation(s)
- Sarah A. Nordeen
- grid.116068.80000 0001 2341 2786Department of Biology, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Daniel L. Turman
- grid.116068.80000 0001 2341 2786Department of Biology, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Thomas U. Schwartz
- grid.116068.80000 0001 2341 2786Department of Biology, Massachusetts Institute of Technology, Cambridge, MA USA
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63
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Kwon M, Leibowitz ML, Lee JH. Small but mighty: the causes and consequences of micronucleus rupture. Exp Mol Med 2020; 52:1777-1786. [PMID: 33230251 PMCID: PMC8080619 DOI: 10.1038/s12276-020-00529-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
Micronuclei are small DNA-containing nuclear structures that are spatially isolated from the main nucleus. They are frequently found in pathologies, including cancer. It was recently shown that these nuclear structures are not only biomarkers of disease but also play an active role in tumor biology. Many consequences of micronucleus formation on tumor biology are dependent on the frequent and irreversible rupture of their nuclear envelopes, which results in the exposure of their DNA contents to the cytoplasm. In this review, we discuss models of defective nuclear envelope deposition on missegregated chromosomes that lead to nuclear envelope rupture. Furthermore, we expound upon the various downstream consequences of micronucleus nuclear envelope rupture on cells. These consequences include a massive DNA rearrangement phenomenon called chromothripsis and activation of the cGAS-STING innate immune signaling pathway, which can be a double-edged sword with tumorigenesis and tumor prevention functions. Although micronuclei are small structures, the impact they have on cells and their microenvironment is quite large. Micronuclei, which contain faulty chromosomes or chromosome fragments and occur outside the main cellular nucleus, are prone to rupturing, which leads to DNA changes that can drive tumor development. A team led by Mijung Kwon from Ewha Womans University in Seoul and Jae-Ho Lee of Ajou University School of Medicine in Suwon, both in South Korea, review how these micronuclei tend to burst, spilling their contents into the cell with devastating consequences. The chromosomes they contain break into tiny fragments and this broken DNA finds its way into the main nucleus, leading to chromosomal rearrangements that can permanently alter genomic function. The rupture of micronuclei also activates a part of the innate immune system that can promote cancer cell invasion and spread. Drugs targeting these processes could aid in the treatment of cancer.
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Affiliation(s)
- Mijung Kwon
- Department of Life Science and the Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, 03760, Korea.
| | - Mitchell L Leibowitz
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Jae-Ho Lee
- Department of Biochemistry and Molecular Biology, Suwon, 16499, South Korea. .,Institute of Medical Science, Ajou University School of Medicine, Suwon, 16499, South Korea.
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64
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Lord CL, Wente SR. Nuclear envelope-vacuole contacts mitigate nuclear pore complex assembly stress. J Cell Biol 2020; 219:211463. [PMID: 33053148 PMCID: PMC7563749 DOI: 10.1083/jcb.202001165] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/10/2020] [Accepted: 09/23/2020] [Indexed: 01/04/2023] Open
Abstract
The intricacy of nuclear pore complex (NPC) biogenesis imposes risks of failure that can cause defects in nuclear transport and nuclear envelope (NE) morphology; however, cellular mechanisms used to alleviate NPC assembly stress are not well defined. In the budding yeast Saccharomyces cerevisiae, we demonstrate that NVJ1- and MDM1-enriched NE-vacuole contacts increase when NPC assembly is compromised in several nup mutants, including nup116ΔGLFG cells. These interorganelle nucleus-vacuole junctions (NVJs) cooperate with lipid droplets to maintain viability and enhance NPC formation in assembly mutants. Additionally, NVJs function with ATG1 to remodel the NE and promote vacuole-dependent degradation of specific nucleoporins in nup116ΔGLFG cells. Importantly, NVJs significantly improve the physiology of NPC assembly mutants, despite having only negligible effects when NPC biogenesis is unperturbed. These results therefore define how NE-vacuole interorganelle contacts coordinate responses to mitigate deleterious cellular effects caused by disrupted NPC assembly.
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65
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Pike JA, Khan AO, Pallini C, Thomas SG, Mund M, Ries J, Poulter NS, Styles IB. Topological data analysis quantifies biological nano-structure from single molecule localization microscopy. Bioinformatics 2020; 36:1614-1621. [PMID: 31626286 PMCID: PMC7162425 DOI: 10.1093/bioinformatics/btz788] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 09/03/2019] [Accepted: 10/17/2019] [Indexed: 01/23/2023] Open
Abstract
Motivation Localization microscopy data is represented by a set of spatial coordinates, each corresponding to a single detection, that form a point cloud. This can be analyzed either by rendering an image from these coordinates, or by analyzing the point cloud directly. Analysis of this type has focused on clustering detections into distinct groups which produces measurements such as cluster area, but has limited capacity to quantify complex molecular organization and nano-structure. Results We present a segmentation protocol which, through the application of persistence-based clustering, is capable of probing densely packed structures which vary in scale. An increase in segmentation performance over state-of-the-art methods is demonstrated. Moreover we employ persistent homology to move beyond clustering, and quantify the topological structure within data. This provides new information about the preserved shapes formed by molecular architecture. Our methods are flexible and we demonstrate this by applying them to receptor clustering in platelets, nuclear pore components, endocytic proteins and microtubule networks. Both 2D and 3D implementations are provided within RSMLM, an R package for pointillist-based analysis and batch processing of localization microscopy data. Availability and implementation RSMLM has been released under the GNU General Public License v3.0 and is available at https://github.com/JeremyPike/RSMLM. Tutorials for this library implemented as Binder ready Jupyter notebooks are available at https://github.com/JeremyPike/RSMLM-tutorials. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jeremy A Pike
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Abdullah O Khan
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Chiara Pallini
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Steven G Thomas
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Markus Mund
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany.,Department of Biochemistry, University of Geneva, 1211 Geneva 4, Switzerland
| | - Jonas Ries
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg 69117, Germany
| | - Natalie S Poulter
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Iain B Styles
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK.,School of Computer Science, University of Birmingham, Birmingham B15 2TT, UK
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66
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Allegretti M, Zimmerli CE, Rantos V, Wilfling F, Ronchi P, Fung HKH, Lee CW, Hagen W, Turoňová B, Karius K, Börmel M, Zhang X, Müller CW, Schwab Y, Mahamid J, Pfander B, Kosinski J, Beck M. In-cell architecture of the nuclear pore and snapshots of its turnover. Nature 2020; 586:796-800. [PMID: 32879490 DOI: 10.1038/s41586-020-2670-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 06/01/2020] [Indexed: 12/25/2022]
Abstract
Nuclear pore complexes (NPCs) fuse the inner and outer membranes of the nuclear envelope. They comprise hundreds of nucleoporins (Nups) that assemble into multiple subcomplexes and form large central channels for nucleocytoplasmic exchange1,2. How this architecture facilitates messenger RNA export, NPC biogenesis and turnover remains poorly understood. Here we combine in situ structural biology and integrative modelling with correlative light and electron microscopy and molecular perturbation to structurally analyse NPCs in intact Saccharomyces cerevisiae cells within the context of nuclear envelope remodelling. We find an in situ conformation and configuration of the Nup subcomplexes that was unexpected from the results of previous in vitro analyses. The configuration of the Nup159 complex appears critical to spatially accommodate its function as an mRNA export platform, and as a mediator of NPC turnover. The omega-shaped nuclear envelope herniae that accumulate in nup116Δ cells3 conceal partially assembled NPCs lacking multiple subcomplexes, including the Nup159 complex. Under conditions of starvation, herniae of a second type are formed that cytoplasmically expose NPCs. These results point to a model of NPC turnover in which NPC-containing vesicles bud off from the nuclear envelope before degradation by the autophagy machinery. Our study emphasizes the importance of investigating the structure-function relationship of macromolecular complexes in their cellular context.
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Affiliation(s)
- Matteo Allegretti
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christian E Zimmerli
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Vasileios Rantos
- Centre for Structural Systems Biology (CSSB), DESY and European Molecular Biology Laboratory, Hamburg, Germany
| | | | - Paolo Ronchi
- Electron Microscopy Core Facility (EMCF), European Molecular Biology Laboratory, Heidelberg, Germany
| | - Herman K H Fung
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Chia-Wei Lee
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wim Hagen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Beata Turoňová
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Kai Karius
- Centre for Structural Systems Biology (CSSB), DESY and European Molecular Biology Laboratory, Hamburg, Germany
| | - Mandy Börmel
- Electron Microscopy Core Facility (EMCF), European Molecular Biology Laboratory, Heidelberg, Germany
| | - Xiaojie Zhang
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Yannick Schwab
- Electron Microscopy Core Facility (EMCF), European Molecular Biology Laboratory, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Boris Pfander
- Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Jan Kosinski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany. .,Centre for Structural Systems Biology (CSSB), DESY and European Molecular Biology Laboratory, Hamburg, Germany.
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany. .,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany. .,Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany.
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67
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Abstract
During closed mitosis in fission yeast, growing microtubules push onto the nuclear envelope to deform it, which results in fission into two daughter nuclei. The resistance of the envelope to bending, quantified by the flexural stiffness, helps determine the microtubule-dependent nuclear shape transformations. Computational models of envelope mechanics have assumed values of the flexural stiffness of the envelope based on simple scaling arguments. The validity of these estimates is in doubt, however, owing to the complex structure of the nuclear envelope. Here, we performed computational analysis of the bending of the nuclear envelope under applied force using a model that accounts for envelope geometry. Our calculations show that the effective bending modulus of the nuclear envelope is an order of magnitude larger than a single membrane and approximately five times greater than the nuclear lamina. This large bending modulus is in part due to the 45 nm separation between the two membranes, which supports larger bending moments in the structure. Further, the effective bending modulus is highly sensitive to the geometry of the nuclear envelope, ranging from twofold to an order magnitude larger than the corresponding single membrane. These results suggest that spatial variations in geometry and mechanical environment of the envelope may cause a spatial distribution of flexural stiffness in the same nucleus. Overall, our calculations support the possibility that the nuclear envelope may balance significant mechanical stresses in yeast and in cells from higher organisms.
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Affiliation(s)
- Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204
| | - Tanmay P Lele
- Department of Biomedical Engineering and Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
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68
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Ganeva I, Kukulski W. Membrane Architecture in the Spotlight of Correlative Microscopy. Trends Cell Biol 2020; 30:577-587. [DOI: 10.1016/j.tcb.2020.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022]
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69
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Bahmanyar S, Schlieker C. Lipid and protein dynamics that shape nuclear envelope identity. Mol Biol Cell 2020; 31:1315-1323. [PMID: 32530796 PMCID: PMC7353140 DOI: 10.1091/mbc.e18-10-0636] [Citation(s) in RCA: 34] [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: 02/18/2020] [Revised: 04/13/2020] [Accepted: 04/17/2020] [Indexed: 12/17/2022] Open
Abstract
The nuclear envelope (NE) is continuous with the endoplasmic reticulum (ER), yet the NE carries out many functions distinct from those of bulk ER. This functional specialization depends on a unique protein composition that defines NE identity and must be both established and actively maintained. The NE undergoes extensive remodeling in interphase and mitosis, so mechanisms that seal NE holes and protect its unique composition are critical for maintaining its functions. New evidence shows that closure of NE holes relies on regulated de novo lipid synthesis, providing a link between lipid metabolism and generating and maintaining NE identity. Here, we review regulation of the lipid bilayers of the NE and suggest ways to generate lipid asymmetry across the NE despite its direct continuity with the ER. We also discuss the elusive mechanism of membrane fusion during nuclear pore complex (NPC) biogenesis. We propose a model in which NPC biogenesis is carefully controlled to ensure that a permeability barrier has been established before membrane fusion, thereby avoiding a major threat to compartmentalization.
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Affiliation(s)
- Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Christian Schlieker
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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70
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Rampello AJ, Laudermilch E, Vishnoi N, Prophet SM, Shao L, Zhao C, Lusk CP, Schlieker C. Torsin ATPase deficiency leads to defects in nuclear pore biogenesis and sequestration of MLF2. J Cell Biol 2020; 219:151708. [PMID: 32342107 PMCID: PMC7265317 DOI: 10.1083/jcb.201910185] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/11/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
Nuclear envelope herniations (blebs) containing FG-nucleoporins and ubiquitin are the phenotypic hallmark of Torsin ATPase manipulation. Both the dynamics of blebbing and the connection to nuclear pore biogenesis remain poorly understood. We employ a proteomics-based approach to identify myeloid leukemia factor 2 (MLF2) as a luminal component of the bleb. Using an MLF2-based live-cell imaging platform, we demonstrate that nuclear envelope blebbing occurs rapidly and synchronously immediately after nuclear envelope reformation during mitosis. Bleb formation is independent of ubiquitin conjugation within the bleb, but strictly dependent on POM121, a transmembrane nucleoporin essential for interphase nuclear pore biogenesis. Nup358, a late marker for interphase nuclear pore complex (NPC) biogenesis, is underrepresented relative to FG-nucleoporins in nuclear envelopes of Torsin-deficient cells. The kinetics of bleb formation, its dependence on POM121, and a reduction of mature NPCs in Torsin-deficient cells lead us to conclude that the hallmark phenotype of Torsin manipulation represents aberrant NPC intermediates.
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Affiliation(s)
- Anthony J Rampello
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Ethan Laudermilch
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Nidhi Vishnoi
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Sarah M Prophet
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Lin Shao
- Department of Neuroscience, Yale School of Medicine, New Haven, CT
| | - Chenguang Zhao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - Christian Schlieker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT.,Department of Cell Biology, Yale School of Medicine, New Haven, CT
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71
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Cheng LC, Baboo S, Lindsay C, Brusman L, Martinez-Bartolomé S, Tapia O, Zhang X, Yates JR, Gerace L. Identification of new transmembrane proteins concentrated at the nuclear envelope using organellar proteomics of mesenchymal cells. Nucleus 2020; 10:126-143. [PMID: 31142202 PMCID: PMC6550788 DOI: 10.1080/19491034.2019.1618175] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The double membrane nuclear envelope (NE), which is contiguous with the ER, contains nuclear pore complexes (NPCs) – the channels for nucleocytoplasmic transport, and the nuclear lamina (NL) – a scaffold for NE and chromatin organization. Since numerous human diseases linked to NE proteins occur in mesenchyme-derived cells, we used proteomics to characterize NE and other subcellular fractions isolated from mesenchymal stem cells and from adipocytes and myocytes. Based on spectral abundance, we calculated enrichment scores for proteins in the NE fractions. We demonstrated by quantitative immunofluorescence microscopy that five little-characterized proteins with high enrichment scores are substantially concentrated at the NE, with Itprip exposed at the outer nuclear membrane, Smpd4 enriched at the NPC, and Mfsd10, Tmx4, and Arl6ip6 likely residing in the inner nuclear membrane. These proteins provide new focal points for studying the functions of the NE. Moreover, our datasets provide a resource for evaluating additional potential NE proteins.
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Affiliation(s)
- Li-Chun Cheng
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Sabyasachi Baboo
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Cory Lindsay
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Liza Brusman
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | | | - Olga Tapia
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Xi Zhang
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - John R Yates
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Larry Gerace
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
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72
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The Role of Torsin AAA+ Proteins in Preserving Nuclear Envelope Integrity and Safeguarding Against Disease. Biomolecules 2020; 10:biom10030468. [PMID: 32204310 PMCID: PMC7175109 DOI: 10.3390/biom10030468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/17/2022] Open
Abstract
Torsin ATPases are members of the AAA+ (ATPases associated with various cellular activities) superfamily of proteins, which participate in essential cellular processes. While AAA+ proteins are ubiquitously expressed and demonstrate distinct subcellular localizations, Torsins are the only AAA+ to reside within the nuclear envelope (NE) and endoplasmic reticulum (ER) network. Moreover, due to the absence of integral catalytic features, Torsins require the NE- and ER-specific regulatory cofactors, lamina-associated polypeptide 1 (LAP1) and luminal domain like LAP1 (LULL1), to efficiently trigger their atypical mode of ATP hydrolysis. Despite their implication in an ever-growing list of diverse processes, the specific contributions of Torsin/cofactor assemblies in maintaining normal cellular physiology remain largely enigmatic. Resolving gaps in the functional and mechanistic principles of Torsins and their cofactors are of considerable medical importance, as aberrant Torsin behavior is the principal cause of the movement disorder DYT1 early-onset dystonia. In this review, we examine recent findings regarding the phenotypic consequences of compromised Torsin and cofactor activities. In particular, we focus on the molecular features underlying NE defects and the contributions of Torsins to nuclear pore complex biogenesis, as well as the growing implications of Torsins in cellular lipid metabolism. Additionally, we discuss how understanding Torsins may facilitate the study of essential but poorly understood processes at the NE and ER, and aid in the development of therapeutic strategies for dystonia.
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73
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Mobbs GW, Hoelz A. Nucleoporin Condensates Drive Nuclear Pore Complex Assembly in Oocytes. Trends Biochem Sci 2020; 45:278-280. [PMID: 32169173 DOI: 10.1016/j.tibs.2020.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/28/2020] [Accepted: 01/29/2020] [Indexed: 02/06/2023]
Abstract
Oocytes stockpile nuclear pore complexes (NPCs) in cytoplasmic membrane sheets called annulate lamellae (AL) in preparation for rapid cell cycles during embryogenesis. Recently, Hampoelz et al. reported that AL-NPC assembly depends on the coordinated formation, transport, and interaction of biomolecular condensates containing distinct sets of nucleoporins.
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Affiliation(s)
- George W Mobbs
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - André Hoelz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
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74
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Carlton JG, Jones H, Eggert US. Membrane and organelle dynamics during cell division. Nat Rev Mol Cell Biol 2020; 21:151-166. [DOI: 10.1038/s41580-019-0208-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2019] [Indexed: 12/31/2022]
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75
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Lee CW, Wilfling F, Ronchi P, Allegretti M, Mosalaganti S, Jentsch S, Beck M, Pfander B. Selective autophagy degrades nuclear pore complexes. Nat Cell Biol 2020; 22:159-166. [DOI: 10.1038/s41556-019-0459-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 12/17/2019] [Indexed: 01/02/2023]
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76
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Rempel IL, Steen A, Veenhoff LM. Poor old pores-The challenge of making and maintaining nuclear pore complexes in aging. FEBS J 2020; 287:1058-1075. [PMID: 31912972 PMCID: PMC7154712 DOI: 10.1111/febs.15205] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/20/2019] [Accepted: 01/06/2020] [Indexed: 12/11/2022]
Abstract
The nuclear pore complex (NPC) is the sole gateway to the nuclear interior, and its function is essential to all eukaryotic life. Controlling the functionality of NPCs is a tremendous challenge for cells. Firstly, NPCs are large structures, and their complex assembly does occasionally go awry. Secondly, once assembled, some components of the NPC persist for an extremely long time and, as a result, are susceptible to accumulate damage. Lastly, a significant proportion of the NPC is composed of intrinsically disordered proteins that are prone to aggregation. In this review, we summarize how the quality of NPCs is guarded in young cells and discuss the current knowledge on the fate of NPCs during normal aging in different tissues and organisms. We discuss the extent to which current data supports a hypothesis that NPCs are poorly maintained during aging of nondividing cells, while in dividing cells the main challenge is related to the assembly of new NPCs. Our survey of current knowledge points toward NPC quality control as an important node in aging of both dividing and nondividing cells. Here, the loss of protein homeostasis during aging is central and the NPC appears to both be impacted by, and to drive, this process.
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Affiliation(s)
- Irina L Rempel
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, The Netherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, The Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, The Netherlands
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77
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King GA, Ünal E. The dynamic nuclear periphery as a facilitator of gamete health and rejuvenation. Curr Genet 2020; 66:487-493. [PMID: 31915924 DOI: 10.1007/s00294-019-01050-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 12/26/2022]
Abstract
The nuclear periphery is a hotspot for the accumulation of age-induced damage in eukaryotic cells. The types of damage that occur at the periphery and their phenotypic consequences have begun to be characterized; however, the mechanisms by which cells repair or eliminate nuclear damage remain poorly understood. Using budding yeast meiosis as a natural system to study cellular rejuvenation, we recently discovered a novel nuclear quality control event, in which age-induced damage is sequestered away from dividing chromosomes to a discarded nuclear compartment that we term the GUNC (for "Gametogenesis Uninherited Nuclear Compartment"). Interestingly, extensive nuclear remodeling occurs even in young cells, including a surprising modularity of the nuclear pore complex, suggesting a general contribution to gamete fitness. In this review, we discuss these findings in the context of recent evidence that the nuclear periphery is a highly dynamic region critical for cellular health.
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Affiliation(s)
- Grant A King
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, 94720, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, 94720, USA.
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78
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Hampoelz B, Schwarz A, Ronchi P, Bragulat-Teixidor H, Tischer C, Gaspar I, Ephrussi A, Schwab Y, Beck M. Nuclear Pores Assemble from Nucleoporin Condensates During Oogenesis. Cell 2019; 179:671-686.e17. [PMID: 31626769 PMCID: PMC6838685 DOI: 10.1016/j.cell.2019.09.022] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 08/09/2019] [Accepted: 09/20/2019] [Indexed: 02/02/2023]
Abstract
The molecular events that direct nuclear pore complex (NPC) assembly toward nuclear envelopes have been conceptualized in two pathways that occur during mitosis or interphase, respectively. In gametes and embryonic cells, NPCs also occur within stacked cytoplasmic membrane sheets, termed annulate lamellae (AL), which serve as NPC storage for early development. The mechanism of NPC biogenesis at cytoplasmic membranes remains unknown. Here, we show that during Drosophila oogenesis, Nucleoporins condense into different precursor granules that interact and progress into NPCs. Nup358 is a key player that condenses into NPC assembly platforms while its mRNA localizes to their surface in a translation-dependent manner. In concert, Microtubule-dependent transport, the small GTPase Ran and nuclear transport receptors regulate NPC biogenesis in oocytes. We delineate a non-canonical NPC assembly mechanism that relies on Nucleoporin condensates and occurs away from the nucleus under conditions of cell cycle arrest.
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Affiliation(s)
- Bernhard Hampoelz
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| | - Andre Schwarz
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Paolo Ronchi
- European Molecular Biology Laboratory, Electron Microscopy Core Facility, Heidelberg, Germany
| | | | - Christian Tischer
- Center for Bioimage Analysis, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Imre Gaspar
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Anne Ephrussi
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Yannick Schwab
- European Molecular Biology Laboratory, Electron Microscopy Core Facility, Heidelberg, Germany; European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Martin Beck
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Max Planck Institute of Biophysics, Frankfurt am Main, Germany; European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany.
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79
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Thevathasan JV, Kahnwald M, Cieśliński K, Hoess P, Peneti SK, Reitberger M, Heid D, Kasuba KC, Hoerner SJ, Li Y, Wu YL, Mund M, Matti U, Pereira PM, Henriques R, Nijmeijer B, Kueblbeck M, Sabinina VJ, Ellenberg J, Ries J. Nuclear pores as versatile reference standards for quantitative superresolution microscopy. Nat Methods 2019; 16:1045-1053. [PMID: 31562488 PMCID: PMC6768092 DOI: 10.1038/s41592-019-0574-9] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/14/2019] [Indexed: 12/18/2022]
Abstract
Quantitative fluorescence and superresolution microscopy are often limited by insufficient data quality or artifacts. In this context, it is essential to have biologically relevant control samples to benchmark and optimize the quality of microscopes, labels and imaging conditions. Here, we exploit the stereotypic arrangement of proteins in the nuclear pore complex as in situ reference structures to characterize the performance of a variety of microscopy modalities. We created four genome edited cell lines in which we endogenously labeled the nucleoporin Nup96 with mEGFP, SNAP-tag, HaloTag or the photoconvertible fluorescent protein mMaple. We demonstrate their use (1) as three-dimensional resolution standards for calibration and quality control, (2) to quantify absolute labeling efficiencies and (3) as precise reference standards for molecular counting. These cell lines will enable the broader community to assess the quality of their microscopes and labels, and to perform quantitative, absolute measurements.
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Affiliation(s)
- Jervis Vermal Thevathasan
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | | | | | - Philipp Hoess
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Sudheer Kumar Peneti
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Manuel Reitberger
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Division of Stem Cells and Cancer, German Cancer Research Center, Heidelberg, Germany
| | - Daniel Heid
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Department for Applied Tumor Biology, Heidelberg University Hospital, Heidelberg, Germany
| | - Krishna Chaitanya Kasuba
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Eidgenössische Technische Hochschule Zurich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Sarah Janice Hoerner
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences and Interdisciplinary Center for Neuroscience, Heidelberg University, Heidelberg, Germany
| | - Yiming Li
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
| | - Yu-Le Wu
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Markus Mund
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
- Department of Biochemistry, University of Geneva, Science 2, Genève, Switzerland
| | - Ulf Matti
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
| | - Pedro Matos Pereira
- MRC-Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Ricardo Henriques
- MRC-Laboratory for Molecular Cell Biology, University College London, London, UK
| | | | | | | | - Jan Ellenberg
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany
| | - Jonas Ries
- EMBL, Cell Biology and Biophysics, Heidelberg, Germany.
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80
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Abstract
Cellular nuclei are bound by two uniformly separated lipid membranes that are fused with each other at numerous donut-shaped pores. These membranes are structurally supported by an array of distinct proteins with distinct mechanical functions. As a result, the nuclear envelope possesses unique mechanical properties, which enables it to resist cytoskeletal forces. Here, we review studies that are beginning to provide quantitative insights into nuclear membrane mechanics. We discuss how the mechanical properties of the fused nuclear membranes mediate their response to mechanical forces exerted on the nucleus and how structural reinforcement by different nuclear proteins protects the nuclear membranes against rupture. We also highlight some open questions in nuclear envelope mechanics, and discuss their relevance in the context of health and disease.
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Affiliation(s)
- Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
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81
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Fišerová J, Maninová M, Sieger T, Uhlířová J, Šebestová L, Efenberková M, Čapek M, Fišer K, Hozák P. Nuclear pore protein TPR associates with lamin B1 and affects nuclear lamina organization and nuclear pore distribution. Cell Mol Life Sci 2019; 76:2199-2216. [PMID: 30762072 PMCID: PMC11105453 DOI: 10.1007/s00018-019-03037-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 01/22/2019] [Accepted: 02/01/2019] [Indexed: 10/27/2022]
Abstract
The organization of the nuclear periphery is crucial for many nuclear functions. Nuclear lamins form dense network at the nuclear periphery and play a substantial role in chromatin organization, transcription regulation and in organization of nuclear pore complexes (NPCs). Here, we show that TPR, the protein located preferentially within the nuclear baskets of NPCs, associates with lamin B1. The depletion of TPR affects the organization of lamin B1 but not lamin A/C within the nuclear lamina as shown by stimulated emission depletion microscopy. Finally, reduction of TPR affects the distribution of NPCs within the nuclear envelope and the effect can be reversed by simultaneous knock-down of lamin A/C or the overexpression of lamin B1. Our work suggests a novel role for the TPR at the nuclear periphery: the TPR contributes to the organization of the nuclear lamina and in cooperation with lamins guards the interphase assembly of nuclear pore complexes.
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Affiliation(s)
- Jindřiška Fišerová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic.
| | - Miloslava Maninová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Tomáš Sieger
- Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic
| | - Jana Uhlířová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Lenka Šebestová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Michaela Efenberková
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Martin Čapek
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
| | - Karel Fišer
- CLIP Laboratories, Department of Paediatric Haematology and Oncology, Second Faculty of Medicine, Charles University and University Hospital Motol Prague, V Úvalu 84, 150 06, Prague, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
- Microscopy Centre-LM and EM, Institute of Molecular Genetics CAS, v.v.i., Vídeňská 1083, 142 00, Prague, Czech Republic
- Division BIOCEV, Institute of Molecular Genetics CAS, v.v.i., Průmyslová 595, Vestec, 252 50, Prague, Czech Republic
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82
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Li Y, Wu YL, Hoess P, Mund M, Ries J. Depth-dependent PSF calibration and aberration correction for 3D single-molecule localization. BIOMEDICAL OPTICS EXPRESS 2019; 10:2708-2718. [PMID: 31259045 PMCID: PMC6583355 DOI: 10.1364/boe.10.002708] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/02/2019] [Accepted: 04/09/2019] [Indexed: 05/22/2023]
Abstract
Three-dimensional single molecule localization microscopy relies on the fitting of the individual molecules with a point spread function (PSF) model. The reconstructed images often show local squeezing or expansion in z. A common cause is depth-induced aberrations in conjunction with an imperfect PSF model calibrated from beads on a coverslip, resulting in a mismatch between measured PSF and real PSF. Here, we developed a strategy for accurate z-localization in which we use the imperfect PSF model for fitting, determine the fitting errors and correct for them in a post-processing step. We present an open-source software tool and a simple experimental calibration procedure that allow retrieving accurate z-positions in any PSF engineering approach or fitting modality, even at large imaging depths.
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Affiliation(s)
- Yiming Li
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Yu-Le Wu
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Philipp Hoess
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Markus Mund
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
- Current affiliation: Department of Biochemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland
| | - Jonas Ries
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics unit, Meyerhofstr. 1, 69117 Heidelberg, Germany
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83
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Alvarado-Kristensson M, Rosselló CA. The Biology of the Nuclear Envelope and Its Implications in Cancer Biology. Int J Mol Sci 2019; 20:E2586. [PMID: 31137762 PMCID: PMC6566445 DOI: 10.3390/ijms20102586] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/07/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022] Open
Abstract
The formation of the nuclear envelope and the subsequent compartmentalization of the genome is a defining feature of eukaryotes. Traditionally, the nuclear envelope was purely viewed as a physical barrier to preserve genetic material in eukaryotic cells. However, in the last few decades, it has been revealed to be a critical cellular component in controlling gene expression and has been implicated in several human diseases. In cancer, the relevance of the cell nucleus was first reported in the mid-1800s when an altered nuclear morphology was observed in tumor cells. This review aims to give a current and comprehensive view of the role of the nuclear envelope on cancer first by recapitulating the changes of the nuclear envelope during cell division, second, by reviewing the role of the nuclear envelope in cell cycle regulation, signaling, and the regulation of the genome, and finally, by addressing the nuclear envelope link to cell migration and metastasis and its use in cancer prognosis.
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Affiliation(s)
- Maria Alvarado-Kristensson
- Molecular Pathology, Department of Translational Medicine, Lund University, Skåne University Hospital, 20502 Malmö, Sweden.
| | - Catalina Ana Rosselló
- Laboratory of Molecular Cell Biomedicine, University of the Balearic Islands, 07121 Palma de Mallorca, Spain.
- Lipopharma Therapeutics, Isaac Newton, 07121 Palma de Mallorca, Spain.
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84
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Jevtić P, Schibler AC, Wesley CC, Pegoraro G, Misteli T, Levy DL. The nucleoporin ELYS regulates nuclear size by controlling NPC number and nuclear import capacity. EMBO Rep 2019; 20:embr.201847283. [PMID: 31085625 DOI: 10.15252/embr.201847283] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/13/2022] Open
Abstract
How intracellular organelles acquire their characteristic sizes is a fundamental question in cell biology. Given stereotypical changes in nuclear size in cancer, it is important to understand the mechanisms that control nuclear size in human cells. Using a high-throughput imaging RNAi screen, we identify and mechanistically characterize ELYS, a nucleoporin required for post-mitotic nuclear pore complex (NPC) assembly, as a determinant of nuclear size in mammalian cells. ELYS knockdown results in small nuclei, reduced nuclear lamin B2 localization, lower NPC density, and decreased nuclear import. Increasing nuclear import by importin α overexpression rescues nuclear size and lamin B2 import, while inhibiting importin α/β-mediated nuclear import decreases nuclear size. Conversely, ELYS overexpression increases nuclear size, enriches nuclear lamin B2 at the nuclear periphery, and elevates NPC density and nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases nuclear size. Thus, we identify ELYS as a novel positive effector of mammalian nuclear size and propose that nuclear size is sensitive to NPC density and nuclear import capacity.
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Affiliation(s)
- Predrag Jevtić
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | | | - Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Gianluca Pegoraro
- High Throughput Imaging Facility (HiTIF), National Cancer Institute, NIH, Bethesda, MD, USA
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
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85
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Roberts B, Hendershott MC, Arakaki J, Gerbin KA, Malik H, Nelson A, Gehring J, Hookway C, Ludmann SA, Yang R, Haupt A, Grancharova T, Valencia V, Fuqua MA, Tucker A, Rafelski SM, Gunawardane RN. Fluorescent Gene Tagging of Transcriptionally Silent Genes in hiPSCs. Stem Cell Reports 2019; 12:1145-1158. [PMID: 30956114 PMCID: PMC6522946 DOI: 10.1016/j.stemcr.2019.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 12/27/2022] Open
Abstract
We describe a multistep method for endogenous tagging of transcriptionally silent genes in human induced pluripotent stem cells (hiPSCs). A monomeric EGFP (mEGFP) fusion tag and a constitutively expressed mCherry fluorescence selection cassette were delivered in tandem via homology-directed repair to five genes not expressed in hiPSCs but important for cardiomyocyte sarcomere function: TTN, MYL7, MYL2, TNNI1, and ACTN2. CRISPR/Cas9 was used to deliver the selection cassette and subsequently mediate its excision via microhomology-mediated end-joining and non-homologous end-joining. Most excised clones were effectively tagged, and all properly tagged clones expressed the mEGFP fusion protein upon differentiation into cardiomyocytes, allowing live visualization of these cardiac proteins at the sarcomere. This methodology provides a broadly applicable strategy for endogenously tagging transcriptionally silent genes in hiPSCs, potentially enabling their systematic and dynamic study during differentiation and morphogenesis.
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Affiliation(s)
- Brock Roberts
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | | | - Joy Arakaki
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | | | - Haseeb Malik
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | | | - Jamie Gehring
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | | | | | - Ruian Yang
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | - Amanda Haupt
- Allen Institute for Cell Science, Seattle, WA 98109, USA
| | | | | | | | - Andrew Tucker
- Allen Institute for Cell Science, Seattle, WA 98109, USA
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86
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Abstract
Nuclear pore complexes (NPCs) mediate nucleocytoplasmic exchange. They are exceptionally large protein complexes that fuse the inner and outer nuclear membranes to form channels across the nuclear envelope. About 30 different protein components, termed nucleoporins, assemble in multiple copies into an intricate cylindrical architecture. Here, we review our current knowledge of the structure of nucleoporins and how those come together in situ. We delineate architectural principles on several hierarchical organization levels, including isoforms, posttranslational modifications, nucleoporins, and higher-order oligomerization of nucleoporin subcomplexes. We discuss how cells exploit this modularity to faithfully assemble NPCs.
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Affiliation(s)
- Bernhard Hampoelz
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , ,
| | - Amparo Andres-Pons
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Current affiliation: Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland;
| | - Panagiotis Kastritis
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Current affiliation: ZIK HALOmem, Martin Luther University of Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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87
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Thaller DJ, Allegretti M, Borah S, Ronchi P, Beck M, Lusk CP. An ESCRT-LEM protein surveillance system is poised to directly monitor the nuclear envelope and nuclear transport system. eLife 2019; 8:e45284. [PMID: 30942170 PMCID: PMC6461442 DOI: 10.7554/elife.45284] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022] Open
Abstract
The integrity of the nuclear membranes coupled to the selective barrier of nuclear pore complexes (NPCs) are essential for the segregation of nucleoplasm and cytoplasm. Mechanical membrane disruption or perturbation to NPC assembly triggers an ESCRT-dependent surveillance system that seals nuclear pores: how these pores are sensed and sealed is ill defined. Using a budding yeast model, we show that the ESCRT Chm7 and the integral inner nuclear membrane (INM) protein Heh1 are spatially segregated by nuclear transport, with Chm7 being actively exported by Xpo1/Crm1. Thus, the exposure of the INM triggers surveillance with Heh1 locally activating Chm7. Sites of Chm7 hyperactivation show fenestrated sheets at the INM and potential membrane delivery at sites of nuclear envelope herniation. Our data suggest that perturbation to the nuclear envelope barrier would lead to local nuclear membrane remodeling to promote membrane sealing. Our findings have implications for disease mechanisms linked to NPC assembly and nuclear envelope integrity.
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Affiliation(s)
- David J Thaller
- Department of Cell BiologyYale School of MedicineNew HavenUnited States
| | - Matteo Allegretti
- Structural and Computational Biology UnitEuropean Molecular Biology LaboratoryMeyerhofstrasseGermany
| | - Sapan Borah
- Department of Cell BiologyYale School of MedicineNew HavenUnited States
| | - Paolo Ronchi
- Electron Microscopy Core FacilityEuropean Molecular Biology LaboratoryMeyerhofstrasseGermany
| | - Martin Beck
- Structural and Computational Biology UnitEuropean Molecular Biology LaboratoryMeyerhofstrasseGermany
| | - C Patrick Lusk
- Department of Cell BiologyYale School of MedicineNew HavenUnited States
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88
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Bilir Ş, Kojidani T, Mori C, Osakada H, Kobayashi S, Koujin T, Hiraoka Y, Haraguchi T. Roles of Nup133, Nup153 and membrane fenestrations in assembly of the nuclear pore complex at the end of mitosis. Genes Cells 2019; 24:338-353. [PMID: 30821042 DOI: 10.1111/gtc.12677] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 02/15/2019] [Accepted: 02/24/2019] [Indexed: 12/25/2022]
Abstract
Reassembly of the nuclear pore complex (NPC) at the end of mitosis is an important event for eukaryotic nuclear function. In this study, we examined the dynamic behaviors of the endoplasmic reticulum (ER) by "Live CLEM" imaging. In metaphase, numerous fenestrations on the ER membrane were observed around chromosomes. In telophase, these fenestrations became filled at the region attached to chromosomes, whereas they remained open at the region unattached to chromosomes, suggesting that NPC assembly takes place at fenestrations on the membrane. To determine the roles of nucleoporins in postmitotic NPC formation, we used artificial beads conjugated with anti-GFP antibody, which captures GFP-fused proteins on the beads when incorporated into cells. Live CLEM imaging of telophase cells containing Nup133-coated beads or Nup153-coated beads showed that Nup133 and Nup153, as the sole effector molecules, assembled the NPC-like structure on the membrane fenestrations. Indirect immunofluorescence staining of the Nup133-coated beads showed that Nup133 effectively assembled Nup107 and ELYS, whereas minimal assembly of Nup98 and Nup62 was observed; the Nup153-coated bead effectively assembled Nup98, Nup62 and Pom121, but assembled neither Nup107 nor ELYS. Our results suggest that Nup133 and Nup153 play different roles in assembling the NPC on membrane fenestrations.
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Affiliation(s)
- Şükriye Bilir
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Tomoko Kojidani
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan.,Japan Women's University, Tokyo, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Hiroko Osakada
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Shouhei Kobayashi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Takako Koujin
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology (NICT), Kobe, Japan
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89
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Suresh S, Osmani SA. Poring over chromosomes: mitotic nuclear pore complex segregation. Curr Opin Cell Biol 2019; 58:42-49. [PMID: 30798206 DOI: 10.1016/j.ceb.2019.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/09/2019] [Accepted: 01/18/2019] [Indexed: 01/23/2023]
Abstract
Eukaryotic cells rely on flux of macromolecules between the nucleus and the cytoplasm for growth and survival. Bidirectional transport is achieved through Nuclear Pore Complexes (NPCs) embedded in the Nuclear Envelope (NE). NPC proteins perform other cellular functions during mitosis, chromatin organization, DNA repair and gene regulation. Dysregulation of NPC number, or defects in their structure and function, are linked to numerous diseases but how NPCs are faithfully inherited during mitosis is poorly understood. In this review, we discuss recent insights to mechanisms of mammalian mitotic NPC segregation and NPC assembly as well as mitotic NPC inheritance via the mitotic chromatin located NPC protein Nup2 in Aspergillus nidulans. We suggest mitotic Nup2 chromatin-based mechanisms could also operate in vertebrate cells.
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Affiliation(s)
- Subbulakshmi Suresh
- Department of Molecular Genetics, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
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90
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Pappas SS, Liang CC, Kim S, Rivera CO, Dauer WT. TorsinA dysfunction causes persistent neuronal nuclear pore defects. Hum Mol Genet 2019; 27:407-420. [PMID: 29186574 DOI: 10.1093/hmg/ddx405] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/15/2017] [Indexed: 01/09/2023] Open
Abstract
A critical challenge to deciphering the pathophysiology of neurodevelopmental disease is identifying which of the myriad abnormalities that emerge during CNS maturation persist to contribute to long-term brain dysfunction. Childhood-onset dystonia caused by a loss-of-function mutation in the AAA+ protein torsinA exemplifies this challenge. Neurons lacking torsinA develop transient nuclear envelope (NE) malformations during CNS maturation, but no NE defects are described in mature torsinA null neurons. We find that during postnatal CNS maturation torsinA null neurons develop mislocalized and dysfunctional nuclear pore complexes (NPC) that lack NUP358, normally added late in NPC biogenesis. SUN1, a torsinA-related molecule implicated in interphase NPC biogenesis, also exhibits localization abnormalities. Whereas SUN1 and associated nuclear membrane abnormalities resolve in juvenile mice, NPC defects persist into adulthood. These findings support a role for torsinA function in NPC biogenesis during neuronal maturation and implicate altered NPC function in dystonia pathophysiology.
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Affiliation(s)
| | | | - Sumin Kim
- Cellular and Molecular Biology Program
| | | | - William T Dauer
- Department of Neurology.,Cellular and Molecular Biology Program.,Department of Cell and Developmental Biology.,VA Ann Arbor Health System, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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91
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Schroeder LK, Barentine AES, Merta H, Schweighofer S, Zhang Y, Baddeley D, Bewersdorf J, Bahmanyar S. Dynamic nanoscale morphology of the ER surveyed by STED microscopy. J Cell Biol 2019; 218:83-96. [PMID: 30442642 PMCID: PMC6314542 DOI: 10.1083/jcb.201809107] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 01/21/2023] Open
Abstract
The endoplasmic reticulum (ER) is composed of interconnected membrane sheets and tubules. Superresolution microscopy recently revealed densely packed, rapidly moving ER tubules mistaken for sheets by conventional light microscopy, highlighting the importance of revisiting classical views of ER structure with high spatiotemporal resolution in living cells. In this study, we use live-cell stimulated emission depletion (STED) microscopy to survey the architecture of the ER at 50-nm resolution. We determine the nanoscale dimensions of ER tubules and sheets for the first time in living cells. We demonstrate that ER sheets contain highly dynamic, subdiffraction-sized holes, which we call nanoholes, that coexist with uniform sheet regions. Reticulon family members localize to curved edges of holes within sheets and are required for their formation. The luminal tether Climp63 and microtubule cytoskeleton modulate their nanoscale dynamics and organization. Thus, by providing the first quantitative analysis of ER membrane structure and dynamics at the nanoscale, our work reveals that the ER in living cells is not limited to uniform sheets and tubules; instead, we suggest the ER contains a continuum of membrane structures that includes dynamic nanoholes in sheets as well as clustered tubules.
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Affiliation(s)
- Lena K Schroeder
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT
| | - Andrew E S Barentine
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT.,Department of Biomedical Engineering, Yale University, New Haven, CT
| | - Holly Merta
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT
| | - Sarah Schweighofer
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT
| | - Yongdeng Zhang
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT
| | - David Baddeley
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT.,Nanobiology Institute, Yale University, West Haven, CT.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Joerg Bewersdorf
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT .,Department of Biomedical Engineering, Yale University, New Haven, CT.,Nanobiology Institute, Yale University, West Haven, CT
| | - Shirin Bahmanyar
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT
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92
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Multivariate Control of Transcript to Protein Variability in Single Mammalian Cells. Cell Syst 2018; 7:398-411.e6. [DOI: 10.1016/j.cels.2018.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 06/28/2018] [Accepted: 09/05/2018] [Indexed: 12/28/2022]
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93
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Liu S, Kwon M, Mannino M, Yang N, Renda F, Khodjakov A, Pellman D. Nuclear envelope assembly defects link mitotic errors to chromothripsis. Nature 2018; 561:551-555. [PMID: 30232450 PMCID: PMC6599625 DOI: 10.1038/s41586-018-0534-z] [Citation(s) in RCA: 210] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/04/2018] [Indexed: 01/09/2023]
Abstract
Defects in the architecture or integrity of the nuclear envelope (NE) are associated with a variety of human diseases1. Micronuclei, one common nuclear aberration, are an origin for chromothripsis2, a catastrophic mutational process commonly observed in cancer3–5. Chromothripsis occurs after micronuclei spontaneously lose NE integrity, which generates chromosome fragmentation6. NE disruption exposes DNA to the cytoplasm and initiates innate immune proinflammatory signaling7. Despite its importance, the basis for the NE fragility of micronuclei has not been determined. Here, we demonstrate that micronuclei undergo defective NE assembly: Only “core” NE proteins8,9 assemble efficiently on lagging chromosomes whereas “non-core” NE proteins8,9, including nuclear pore complexes (NPCs), do not. Consequently, micronuclei fail to properly import key proteins necessary for NE and genome integrity. We show that spindle microtubules block NPC/non-core NE assembly on lagging chromosomes, causing an irreversible NE assembly defect. Accordingly, experimental manipulations that position missegregated chromosomes away from the spindle correct defective NE assembly, prevent spontaneous NE disruption, and suppress DNA damage in micronuclei. Thus, during mitotic exit in metazoan cells, chromosome segregation and NE assembly are only loosely coordinated by the timing of mitotic spindle disassembly. The absence of precise checkpoint controls may explain why errors during mitotic exit are frequent and often trigger catastrophic genome rearrangements4,5.
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Affiliation(s)
- Shiwei Liu
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Mijung Kwon
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Mark Mannino
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Nachen Yang
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Fioranna Renda
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - David Pellman
- Howard Hughes Medical Institute, Chevy Chase, MD, USA. .,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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94
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McCloskey A, Ibarra A, Hetzer MW. Tpr regulates the total number of nuclear pore complexes per cell nucleus. Genes Dev 2018; 32:1321-1331. [PMID: 30228202 PMCID: PMC6169833 DOI: 10.1101/gad.315523.118] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/23/2018] [Indexed: 01/16/2023]
Abstract
In this study, McCloskey et al. investigated the underlying mechanisms that control how many nuclear transport channels are assembled into a given nuclear envelope. Their results show that depletion of the NPC basket protein Tpr, but not Nup153, dramatically increases the total NPC number in various cell types and provide insight into a critical role of the nucleoporin Tpr in coordinating signal transduction pathways during cell proliferation and the dynamic organization of the nucleus. The total number of nuclear pore complexes (NPCs) per nucleus varies greatly between different cell types and is known to change during cell differentiation and cell transformation. However, the underlying mechanisms that control how many nuclear transport channels are assembled into a given nuclear envelope remain unclear. Here, we report that depletion of the NPC basket protein Tpr, but not Nup153, dramatically increases the total NPC number in various cell types. This negative regulation of Tpr occurs via a phosphorylation cascade of extracellular signal-regulated kinase (ERK), the central kinase of the mitogen-activated protein kinase (MAPK) pathway. Tpr serves as a scaffold for ERK to phosphorylate the nucleoporin (Nup) Nup153, which is critical for early stages of NPC biogenesis. Our results reveal a critical role of the Nup Tpr in coordinating signal transduction pathways during cell proliferation and the dynamic organization of the nucleus.
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Affiliation(s)
- Asako McCloskey
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92130, USA
| | - Arkaitz Ibarra
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92130, USA
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92130, USA
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95
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Cai Y, Hossain MJ, Hériché JK, Politi AZ, Walther N, Koch B, Wachsmuth M, Nijmeijer B, Kueblbeck M, Martinic-Kavur M, Ladurner R, Alexander S, Peters JM, Ellenberg J. Experimental and computational framework for a dynamic protein atlas of human cell division. Nature 2018; 561:411-415. [PMID: 30202089 DOI: 10.1038/s41586-018-0518-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/25/2018] [Indexed: 11/09/2022]
Abstract
Essential biological functions, such as mitosis, require tight coordination of hundreds of proteins in space and time. Localization, the timing of interactions and changes in cellular structure are all crucial to ensure the correct assembly, function and regulation of protein complexes1-4. Imaging of live cells can reveal protein distributions and dynamics but experimental and theoretical challenges have prevented the collection of quantitative data, which are necessary for the formulation of a model of mitosis that comprehensively integrates information and enables the analysis of the dynamic interactions between the molecular parts of the mitotic machinery within changing cellular boundaries. Here we generate a canonical model of the morphological changes during the mitotic progression of human cells on the basis of four-dimensional image data. We use this model to integrate dynamic three-dimensional concentration data of many fluorescently knocked-in mitotic proteins, imaged by fluorescence correlation spectroscopy-calibrated microscopy5. The approach taken here to generate a dynamic protein atlas of human cell division is generic; it can be applied to systematically map and mine dynamic protein localization networks that drive cell division in different cell types, and can be conceptually transferred to other cellular functions.
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Affiliation(s)
- Yin Cai
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Roche Diagnostics, Waiblingen, Germany
| | - M Julius Hossain
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Antonio Z Politi
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Nike Walther
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Birgit Koch
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Malte Wachsmuth
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.,Luxendo GmbH, Heidelberg, Germany
| | - Bianca Nijmeijer
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Moritz Kueblbeck
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Marina Martinic-Kavur
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.,Genos, Glycoscience Research Laboratory, Zagreb, Croatia
| | - Rene Ladurner
- Research Institute of Molecular Pathology (IMP), Vienna, Austria.,Stanford School of Medicine, Stanford, CA, USA
| | | | | | - Jan Ellenberg
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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96
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Strauss S, Nickels PC, Strauss MT, Jimenez Sabinina V, Ellenberg J, Carter JD, Gupta S, Janjic N, Jungmann R. Modified aptamers enable quantitative sub-10-nm cellular DNA-PAINT imaging. Nat Methods 2018; 15:685-688. [PMID: 30127504 PMCID: PMC6345375 DOI: 10.1038/s41592-018-0105-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 07/12/2018] [Indexed: 01/12/2023]
Abstract
Although current implementations of super-resolution microscopy are technically approaching true molecular-scale resolution, this has not translated to imaging of biological specimens, because of the large size of conventional affinity reagents. Here we introduce slow off-rate modified aptamers (SOMAmers) as small and specific labeling reagents for use with DNA points accumulation in nanoscale topography (DNA-PAINT). To demonstrate the achievable resolution, specificity, and multiplexing capability of SOMAmers, we labeled and imaged both transmembrane and intracellular targets in fixed and live cells.
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Affiliation(s)
- Sebastian Strauss
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University, Munich, Germany
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Philipp C Nickels
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University, Munich, Germany
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Maximilian T Strauss
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University, Munich, Germany
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Vilma Jimenez Sabinina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | | | | | - Ralf Jungmann
- Department of Physics and Center for Nanoscience, Ludwig Maximilian University, Munich, Germany.
- Max Planck Institute of Biochemistry, Martinsried, Germany.
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97
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From the resolution revolution to evolution: structural insights into the evolutionary relationships between vesicle coats and the nuclear pore. Curr Opin Struct Biol 2018; 52:32-40. [PMID: 30103204 DOI: 10.1016/j.sbi.2018.07.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 11/22/2022]
Abstract
Nuclear pores and coated vesicles are elaborate multi-component protein complexes that oligomerize on membranes, and stabilize or induce membrane curvature. Their components, nucleoporins and coat proteins, respectively, share similar structural folds and some principles of how they interact with membranes. The protocoatomer hypothesis postulates that this is due to divergent evolution from a common ancestor. It therefore has been suggested that nucleoporins and coat proteins have similar higher order architectures. Here, we review recent work that relied on technical advances in cryo-electron microscopy and integrative structural biology to take a fresh look on how these proteins form membrane coats in situ. We discuss the relationship between the architectures of nuclear pores and coated vesicles, and their evolutionary origins.
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98
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Fantastic nuclear envelope herniations and where to find them. Biochem Soc Trans 2018; 46:877-889. [PMID: 30026368 DOI: 10.1042/bst20170442] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/02/2018] [Accepted: 05/04/2018] [Indexed: 12/19/2022]
Abstract
Morphological abnormalities of the bounding membranes of the nucleus have long been associated with human diseases from cancer to premature aging to neurodegeneration. Studies over the past few decades support that there are both cell intrinsic and extrinsic factors (e.g. mechanical force) that can lead to nuclear envelope 'herniations', a broad catch-all term that reveals little about the underlying molecular mechanisms that contribute to these morphological defects. While there are many genetic perturbations that could ultimately change nuclear shape, here, we focus on a subset of nuclear envelope herniations that likely arise as a consequence of disrupting physiological nuclear membrane remodeling pathways required to maintain nuclear envelope homeostasis. For example, stalling of the interphase nuclear pore complex (NPC) biogenesis pathway and/or triggering of NPC quality control mechanisms can lead to herniations in budding yeast, which are remarkably similar to those observed in human disease models of early-onset dystonia. By also examining the provenance of nuclear envelope herniations associated with emerging nuclear autophagy and nuclear egress pathways, we will provide a framework to help understand the molecular pathways that contribute to nuclear deformation.
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99
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Walther N, Hossain MJ, Politi AZ, Koch B, Kueblbeck M, Ødegård-Fougner Ø, Lampe M, Ellenberg J. A quantitative map of human Condensins provides new insights into mitotic chromosome architecture. J Cell Biol 2018; 217:2309-2328. [PMID: 29632028 PMCID: PMC6028534 DOI: 10.1083/jcb.201801048] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 12/29/2022] Open
Abstract
The two Condensin complexes in human cells are essential for mitotic chromosome structure. We used homozygous genome editing to fluorescently tag Condensin I and II subunits and mapped their absolute abundance, spacing, and dynamic localization during mitosis by fluorescence correlation spectroscopy (FSC)-calibrated live-cell imaging and superresolution microscopy. Although ∼35,000 Condensin II complexes are stably bound to chromosomes throughout mitosis, ∼195,000 Condensin I complexes dynamically bind in two steps: prometaphase and early anaphase. The two Condensins rarely colocalize at the chromatid axis, where Condensin II is centrally confined, but Condensin I reaches ∼50% of the chromatid diameter from its center. Based on our comprehensive quantitative data, we propose a three-step hierarchical loop model of mitotic chromosome compaction: Condensin II initially fixes loops of a maximum size of ∼450 kb at the chromatid axis, whose size is then reduced by Condensin I binding to ∼90 kb in prometaphase and ∼70 kb in anaphase, achieving maximum chromosome compaction upon sister chromatid segregation.
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Affiliation(s)
- Nike Walther
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - M Julius Hossain
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Z Politi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Birgit Koch
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Moritz Kueblbeck
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Øyvind Ødegård-Fougner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Marko Lampe
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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100
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Politi AZ, Cai Y, Walther N, Hossain MJ, Koch B, Wachsmuth M, Ellenberg J. Quantitative mapping of fluorescently tagged cellular proteins using FCS-calibrated four-dimensional imaging. Nat Protoc 2018; 13:1445-1464. [PMID: 29844523 PMCID: PMC6609853 DOI: 10.1038/nprot.2018.040] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to tag a protein at its endogenous locus with a fluorescent protein (FP) enables quantitative understanding of protein dynamics at the physiological level. Genome-editing technology has now made this powerful approach routinely applicable to mammalian cells and many other model systems, thereby opening up the possibility to systematically and quantitatively map the cellular proteome in four dimensions. 3D time-lapse confocal microscopy (4D imaging) is an essential tool for investigating spatial and temporal protein dynamics; however, it lacks the required quantitative power to make the kind of absolute and comparable measurements required for systems analysis. In contrast, fluorescence correlation spectroscopy (FCS) provides quantitative proteomic and biophysical parameters such as protein concentration, hydrodynamic radius, and oligomerization but lacks the capability for high-throughput application in 4D spatial and temporal imaging. Here we present an automated experimental and computational workflow that integrates both methods and delivers quantitative 4D imaging data in high throughput. These data are processed to yield a calibration curve relating the fluorescence intensities (FIs) of image voxels to the absolute protein abundance. The calibration curve allows the conversion of the arbitrary FIs to protein amounts for all voxels of 4D imaging stacks. Using our workflow, users can acquire and analyze hundreds of FCS-calibrated image series to map their proteins of interest in four dimensions. Compared with other protocols, the current protocol does not require additional calibration standards and provides an automated acquisition pipeline for FCS and imaging data. The protocol can be completed in 1 d.
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Affiliation(s)
| | - Yin Cai
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Roche Diagnostics, Waiblingen, Germany
| | - Nike Walther
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | | | - Birgit Koch
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Malte Wachsmuth
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Current address: Luxendo GmbH, Heidelberg, Germany
| | - Jan Ellenberg
- EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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