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Perales IE, Jones SD, Piaszynski KM, Geyer PK. Developmental changes in nuclear lamina components during germ cell differentiation. Nucleus 2024; 15:2339214. [PMID: 38597409 PMCID: PMC11008544 DOI: 10.1080/19491034.2024.2339214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
The nuclear lamina (NL) changes composition for regulation of nuclear events. We investigated changes that occur in Drosophila oogenesis, revealing switches in NL composition during germ cell differentiation. Germline stem cells (GSCs) express only LamB and predominantly emerin, whereas differentiating nurse cells predominantly express LamC and emerin2. A change in LamC-specific localization also occurs, wherein phosphorylated LamC redistributes to the nuclear interior only in the oocyte, prior to transcriptional reactivation of the meiotic genome. These changes support existing concepts that LamC promotes differentiation, a premise that was tested. Remarkably ectopic LamC production in GSCs did not promote premature differentiation. Increased LamC levels in differentiating germ cells altered internal nuclear structure, increased RNA production, and reduced female fertility due to defects in eggshell formation. These studies suggest differences between Drosophila lamins are regulatory, not functional, and reveal an unexpected robustness to level changes of a major scaffolding component of the NL.
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Affiliation(s)
- Isabella E. Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Samuel D. Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | | | - Pamela K. Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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Kono Y, Shimi T. Crosstalk between mitotic reassembly and repair of the nuclear envelope. Nucleus 2024; 15:2352203. [PMID: 38780365 PMCID: PMC11123513 DOI: 10.1080/19491034.2024.2352203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
In eukaryotic cells, the nuclear envelope (NE) is a membrane partition between the nucleus and the cytoplasm to compartmentalize nuclear contents. It plays an important role in facilitating nuclear functions including transcription, DNA replication and repair. In mammalian cells, the NE breaks down and then reforms during cell division, and in interphase it is restored shortly after the NE rupture induced by mechanical force. In this way, the partitioning effect is regulated through dynamic processes throughout the cell cycle. A failure in rebuilding the NE structure triggers the mixing of nuclear and cytoplasmic contents, leading to catastrophic consequences for the nuclear functions. Whereas the precise details of molecular mechanisms for NE reformation during cell division and NE restoration in interphase are still being investigated, here, we mostly focus on mammalian cells to describe key aspects that have been identified and to discuss the crosstalk between them.
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Affiliation(s)
- Yohei Kono
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Takeshi Shimi
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
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Perales IE, Jones SD, Duan T, Geyer PK. Maintenance of germline stem cell homeostasis despite severe nuclear distortion. Dev Biol 2024; 515:139-150. [PMID: 39038593 PMCID: PMC11317214 DOI: 10.1016/j.ydbio.2024.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 07/24/2024]
Abstract
Stem cell loss in aging and disease is associated with nuclear deformation. Yet, how nuclear shape influences stem cell homeostasis is poorly understood. We investigated this connection using Drosophila germline stem cells, as survival of these stem cells is compromised by dysfunction of the nuclear lamina, the extensive protein network that lines the inner nuclear membrane and gives shape to the nucleus. To induce nuclear distortion in germline stem cells, we used the GAL4-UAS system to increase expression of the permanently farnesylated nuclear lamina protein, Kugelkern, a rate limiting factor for nuclear growth. We show that elevated Kugelkern levels cause severe nuclear distortion in germline stem cells, including extensive thickening and lobulation of the nuclear envelope and nuclear lamina, as well as alteration of internal nuclear compartments. Despite these changes, germline stem cell number, proliferation, and female fertility are preserved, even as females age. Collectively, these data demonstrate that disruption of nuclear architecture does not cause a failure of germline stem cell survival or homeostasis, revealing that nuclear deformation does not invariably promote stem cell loss.
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Affiliation(s)
- Isabella E Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Samuel D Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Tingting Duan
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA.
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Wada E, Susumu N, Kaya M, Hayashi YK. Characteristics of nuclear architectural abnormalities of myotubes differentiated from Lmna H222P/H222P skeletal muscle cells. In Vitro Cell Dev Biol Anim 2024; 60:781-792. [PMID: 38724872 DOI: 10.1007/s11626-024-00915-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/22/2024] [Indexed: 08/03/2024]
Abstract
The presence of nuclear architectural abnormalities is a hallmark of the nuclear envelopathies, which are a group of diseases caused by mutations in genes encoding nuclear envelope proteins. Mutations in the lamin A/C gene cause several diseases, named laminopathies, including muscular dystrophies, progeria syndromes, and lipodystrophy. A mouse model carrying with the LmnaH222P/H222P mutation (H222P) was shown to develop severe cardiomyopathy but only mild skeletal myopathy, although abnormal nuclei were observed in their striated muscle. In this report, we analyzed the abnormal-shaped nuclei in myoblasts and myotubes isolated from skeletal muscle of H222P mice, and evaluated the expression of nuclear envelope proteins in these abnormal myonuclei. Primary skeletal muscle cells from H222P mice proliferated and efficiently differentiated into myotubes in vitro, similarly to those from wild-type mice. During cell proliferation, few abnormal-shaped nuclei were detected; however, numerous markedly abnormal myonuclei were observed in myotubes from H222P mice on days 5 and 7 of differentiation. Time-lapse observation demonstrated that myonuclei with a normal shape maintained their normal shape, whereas abnormal-shaped myonuclei remained abnormal for at least 48 h during differentiation. Among the abnormal-shaped myonuclei, 65% had a bleb with a string structure, and 35% were severely deformed. The area and nuclear contents of the nuclear blebs were relatively stable, whereas the myocytes with nuclear blebs were actively fused within primary myotubes. Although myonuclei were markedly deformed, the deposition of DNA damage marker (γH2AX) or apoptotic marker staining was rarely observed. Localizations of lamin A/C and emerin were maintained within the blebs, strings, and severely deformed regions of myonuclei; however, lamin B1, nesprin-1, and a nuclear pore complex protein were absent in these abnormal regions. These results demonstrate that nuclear membranes from H222P skeletal muscle cells do not rupture and are resistant to DNA damage, despite these marked morphological changes.
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Affiliation(s)
- Eiji Wada
- Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan
| | - Nao Susumu
- Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan
| | - Motoshi Kaya
- Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yukiko K Hayashi
- Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan.
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Keuper K, Bartek J, Maya-Mendoza A. The nexus of nuclear envelope dynamics, circular economy and cancer cell pathophysiology. Eur J Cell Biol 2024; 103:151394. [PMID: 38340500 DOI: 10.1016/j.ejcb.2024.151394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024] Open
Abstract
The nuclear envelope (NE) is a critical component in maintaining the function and structure of the eukaryotic nucleus. The NE and lamina are disassembled during each cell cycle to enable an open mitosis. Nuclear architecture construction and deconstruction is a prime example of a circular economy, as it fulfills a highly efficient recycling program bound to continuous assessment of the quality and functionality of the building blocks. Alterations in the nuclear dynamics and lamina structure have emerged as important contributors to both oncogenic transformation and cancer progression. However, the knowledge of the NE breakdown and reassembly is still limited to a fraction of participating proteins and complexes. As cancer cells contain highly diverse nuclei in terms of DNA content, but also in terms of nuclear number, size, and shape, it is of great interest to understand the intricate relationship between these nuclear features in cancer cell pathophysiology. In this review, we provide insights into how those NE dynamics are regulated, and how lamina destabilization processes may alter the NE circular economy. Moreover, we expand the knowledge of the lamina-associated domain region by using strategic algorithms, including Artificial Intelligence, to infer protein associations, assess their function and location, and predict cancer-type specificity with implications for the future of cancer diagnosis, prognosis and treatment. Using this approach we identified NUP98 and MECP2 as potential proteins that exhibit upregulation in Acute Myeloid Leukemia (LAML) patients with implications for early diagnosis.
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Affiliation(s)
- Kristina Keuper
- DNA Replication and Cancer Group, Danish Cancer Institute, Copenhagen, Denmark; Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark
| | - Jiri Bartek
- Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SciLifeLab, Stockholm, Sweden
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Rose M, Burgess JT, Cheong CM, Adams MN, Shahrouzi P, O’Byrne KJ, Richard DJ, Bolderson E. The expression and role of the Lem-D proteins Ankle2, Emerin, Lemd2, and TMPO in triple-negative breast cancer cell growth. Front Oncol 2024; 14:1222698. [PMID: 38720803 PMCID: PMC11076778 DOI: 10.3389/fonc.2024.1222698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 02/28/2024] [Indexed: 05/12/2024] Open
Abstract
Background Triple-negative breast cancer (TNBC) is a sub-classification of breast carcinomas, which leads to poor survival outcomes for patients. TNBCs do not possess the hormone receptors that are frequently targeted as a therapeutic in other cancer subtypes and, therefore, chemotherapy remains the standard treatment for TNBC. Nuclear envelope proteins are frequently dysregulated in cancer cells, supporting their potential as novel cancer therapy targets. The Lem-domain (Lem-D) (LAP2, Emerin, MAN1 domain, and Lem-D) proteins are a family of inner nuclear membrane proteins, which share a ~45-residue Lem-D. The Lem-D proteins, including Ankle2, Lemd2, TMPO, and Emerin, have been shown to be associated with many of the hallmarks of cancer. This study aimed to define the association between the Lem-D proteins and TNBC and determine whether these proteins could be promising therapeutic targets. Methods GENT2, TCGA, and KM plotter were utilized to investigate the expression and prognostic implications of several Lem-D proteins: Ankle2, TMPO, Emerin, and Lemd2 in publicly available breast cancer patient data. Immunoblotting and immunofluorescent analysis of immortalized non-cancerous breast cells and a panel of TNBC cells were utilized to establish whether protein expression of the Lem-D proteins was significantly altered in TNBC. SiRNA was used to decrease individual Lem-D protein expression, and functional assays, including proliferation assays and apoptosis assays, were conducted. Results The Lem-D proteins were generally overexpressed in TNBC patient samples at the mRNA level and showed variable expression at the protein level in TNBC cell lysates. Similarly, protein levels were generally negatively correlated with patient survival outcomes. siRNA-mediated depletion of the individual Lem-D proteins in TNBC cells induced aberrant nuclear morphology, decreased proliferation, and induced cell death. However, minimal effects on nuclear morphology or cell viability were observed following Lem-D depletion in non-cancerous MCF10A cells. Conclusion There is evidence to suggest that Ankle2, TMPO, Emerin, and Lemd2 expressions are correlated with breast cancer patient outcomes, but larger patient sample numbers are required to confirm this. siRNA-mediated depletion of these proteins was shown to specifically impair TNBC cell growth, suggesting that the Lem-D proteins may be a specific anti-cancer target.
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Affiliation(s)
- Maddison Rose
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Joshua T. Burgess
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Chee Man Cheong
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Mark N. Adams
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Parastoo Shahrouzi
- Department of Medical Genetics, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Kenneth J. O’Byrne
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Cancer Services, Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Derek J. Richard
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Emma Bolderson
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
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Fishburn AT, Florio CJ, Lopez NJ, Link NL, Shah PS. Molecular functions of ANKLE2 and its implications in human disease. Dis Model Mech 2024; 17:dmm050554. [PMID: 38691001 PMCID: PMC11103583 DOI: 10.1242/dmm.050554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024] Open
Abstract
Ankyrin repeat and LEM domain-containing 2 (ANKLE2) is a scaffolding protein with established roles in cell division and development, the dysfunction of which is increasingly implicated in human disease. ANKLE2 regulates nuclear envelope disassembly at the onset of mitosis and its reassembly after chromosome segregation. ANKLE2 dysfunction is associated with abnormal nuclear morphology and cell division. It regulates the nuclear envelope by mediating protein-protein interactions with barrier to autointegration factor (BANF1; also known as BAF) and with the kinase and phosphatase that modulate the phosphorylation state of BAF. In brain development, ANKLE2 is crucial for proper asymmetric division of neural progenitor cells. In humans, pathogenic loss-of-function mutations in ANKLE2 are associated with primary congenital microcephaly, a condition in which the brain is not properly developed at birth. ANKLE2 is also linked to other disease pathologies, including congenital Zika syndrome, cancer and tauopathy. Here, we review the molecular roles of ANKLE2 and the recent literature on human diseases caused by its dysfunction.
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Affiliation(s)
- Adam T. Fishburn
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Cole J. Florio
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Nick J. Lopez
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Nichole L. Link
- Department of Neurobiology, University of Utah, 20 South 2030 East, Salt Lake City, UT 84112, USA
| | - Priya S. Shah
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
- Department of Chemical Engineering, University of California, One Shields Avenue, Davis, CA 95616, USA
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Baskar D, Preethish-Kumar V, Polavarapu K, Vengalil S, Nashi S, Menon D, Ganaraja VH, Girija MS, Nandeesh BN, Arunachal G, Nalini A. Clinical and Genetic Heterogeneity of Nuclear Envelopathy Related Muscular Dystrophies in an Indian Cohort. J Neuromuscul Dis 2024; 11:969-979. [PMID: 39058449 PMCID: PMC11380268 DOI: 10.3233/jnd-230172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Introduction Nuclear envelopathies occur due to structural and/or functional defects in various nuclear envelope proteins such as lamin A/C and lamin related proteins. This study is the first report on the phenotype-genotype patterns of nuclear envelopathy-related muscular dystrophies from India. Methods In this retrospective study, we have described patients with genetically confirmed muscular dystrophy associated with nuclear envelopathy. Data on clinical, laboratory findings and muscle MRI were collected. Results Sixteen patients were included with median age at onset of 3 years (range: 1 month - 17 years). Three genes were involved: LMNA (11, 68.75%), EMD (4, 25%) and SYNE1 (1, 6.25%). The 11 patients with LMNA variants were Congenital muscular dystrophy (MDCL)=4, Limb Girdle Muscular Dystrophy (LGMD1B)=4 and Emery-Dreifuss Muscular Dystrophy (EDMD2)=3. On muscle biopsy, one patient from each laminopathy phenotype (n = 3) revealed focal perivascular inflammatory infiltrate. Other notable features were ophthalmoparesis in one and facial weakness in one. None had cardiac involvement. Patients with EDMD1 had both upper (UL) and lower limb (LL) proximo-distal weakness. Cardiac rhythm disturbances such as sick sinus syndrome and atrial arrhythmias were noted in two patients with EDMD1. Only one patient with variant c.654_658dup (EMD) lost ambulation in the 3rd decade, 18 years after disease onset. Two had finger contractures with EMD and SYNE1 variants respectively. All patients with LMNA and SYNE1 variants were ambulant at the time of evaluation. Mean duration of illness (years) was 11.6±13 (MDCL), 3.2±1.0 (EDMD2), 10.4±12.8 (LGMD1B), 11.8±8.4 (EDMD1) and 3 (EDMD4). One patient had a novel SYNE1 mutation (c.22472dupA, exon 123) and presented with UL phenotype and prominent finger and wrist contractures. Conclusion The salient features included ophthalmoparesis and facial weakness in LMNA, prominent finger contractures in EMD and SYNE1 and upper limb phenotype with the novel pathogenic variant in SYNE1.
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Affiliation(s)
- Dipti Baskar
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | | | - Kiran Polavarapu
- Department of Medicine, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa and Division of Neurology, The Ottawa Hospital, Ottawa, Canada
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Saraswati Nashi
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Deepak Menon
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | | | - Manu Santhappan Girija
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | | | - Gautham Arunachal
- Department of Human Genetics, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
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Bihani A, Avvaru AK, Mishra RK. Biochemical Deconstruction and Reconstruction of Nuclear Matrix Reveals the Layers of Nuclear Organization. Mol Cell Proteomics 2023; 22:100671. [PMID: 37863319 PMCID: PMC10687341 DOI: 10.1016/j.mcpro.2023.100671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/11/2023] [Accepted: 10/15/2023] [Indexed: 10/22/2023] Open
Abstract
Nuclear matrix (NuMat) is the fraction of the eukaryotic nucleus insoluble to detergents and high-salt extractions that manifests as a pan-nuclear fiber-granule network. NuMat consists of ribonucleoprotein complexes, members of crucial nuclear functional modules, and DNA fragments. Although NuMat captures the organization of nonchromatin nuclear space, very little is known about components organization within NuMat. To understand the organization of NuMat components, we subfractionated it with increasing concentrations of the chaotrope guanidinium hydrochloride (GdnHCl) and analyzed the proteomic makeup of the fractions. We observe that the solubilization of proteins at different concentrations of GdnHCl is finite and independent of the broad biophysical properties of the protein sequences. Looking at the extraction pattern of the nuclear envelope and nuclear pore complex, we surmise that this fractionation represents easily solubilized/loosely bound and difficultly solubilized/tightly bound components of NuMat. Microscopic analyses of the localization of key NuMat proteins across sequential GdnHCl extractions of in situ NuMat further elaborate on the divergent extraction patterns. Furthermore, we solubilized NuMat in 8M GdnHCl and upon removal of GdnHCl through dialysis, en masse renaturation leads to RNA-dependent self-assembly of fibrous structures. The major proteome component of the self-assembled fibers comes from the difficultly solubilized, tightly bound component. This fractionation of the NuMat reveals different organizational levels within it which may reflect the structural and functional organization of nuclear architecture.
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Affiliation(s)
- Ashish Bihani
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India.
| | - Akshay K Avvaru
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India; Tata Institute for Genetics and Society (TIGS), Bengaluru, India.
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Barger SR, Penfield L, Bahmanyar S. Nuclear envelope assembly relies on CHMP-7 in the absence of BAF-LEM-mediated hole closure. J Cell Sci 2023; 136:jcs261385. [PMID: 37795681 PMCID: PMC10668030 DOI: 10.1242/jcs.261385] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
Barrier-to-autointegration factor (BAF) protein is a DNA-binding protein that crosslinks chromatin to allow mitotic nuclear envelope (NE) assembly. The LAP2-emerin-MAN1 (LEM)-domain protein LEMD2 and ESCRT-II/III hybrid protein CHMP7 close NE holes surrounding spindle microtubules (MTs). BAF binds LEM-domain family proteins to repair NE ruptures in interphase, but whether BAF-LEM binding participates in NE hole closure around spindle MTs is not known. Here, we took advantage of the stereotypical event of NE formation in fertilized Caenorhabditis elegans oocytes to show that BAF-LEM binding and LEM-2-CHMP-7 have distinct roles in NE closure around spindle MTs. LEM-2 and EMR-1 (homologs of LEMD2 and emerin) function redundantly with BAF-1 (the C. elegans BAF protein) in NE closure. Compromising BAF-LEM binding revealed an additional role for EMR-1 in the maintenance of the NE permeability barrier. In the absence of BAF-LEM binding, LEM-2-CHMP-7 was required for NE assembly and embryo survival. The winged helix domain of LEM-2 recruits CHMP-7 to the NE in C. elegans and a LEM-2-independent nucleoplasmic pool of CHMP-7 also contributes to NE stability. Thus, NE hole closure surrounding spindle MTs requires redundant mechanisms that safeguard against failure in NE assembly to support embryogenesis.
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Affiliation(s)
- Sarah R. Barger
- Yale University, Department of Molecular, Cellular, Developmental Biology, 266 Whitney Ave., New Haven, CT 06511, USA
| | - Lauren Penfield
- Yale University, Department of Molecular, Cellular, Developmental Biology, 266 Whitney Ave., New Haven, CT 06511, USA
| | - Shirin Bahmanyar
- Yale University, Department of Molecular, Cellular, Developmental Biology, 266 Whitney Ave., New Haven, CT 06511, USA
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11
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Shevelyov YY. Interactions of Chromatin with the Nuclear Lamina and Nuclear Pore Complexes. Int J Mol Sci 2023; 24:15771. [PMID: 37958755 PMCID: PMC10649103 DOI: 10.3390/ijms242115771] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
Heterochromatin and euchromatin form different spatial compartments in the interphase nucleus, with heterochromatin being localized mainly at the nuclear periphery. The mechanisms responsible for peripheral localization of heterochromatin are still not fully understood. The nuclear lamina and nuclear pore complexes were obvious candidates for the role of heterochromatin binders. This review is focused on recent studies showing that heterochromatin interactions with the nuclear lamina and nuclear pore complexes maintain its peripheral localization. Differences in chromatin interactions with the nuclear envelope in cell populations and in individual cells are also discussed.
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Affiliation(s)
- Yuri Y Shevelyov
- Laboratory of Analysis of Gene Regulation, National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
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12
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Lee GE, Byun J, Lee CJ, Cho YY. Molecular Mechanisms for the Regulation of Nuclear Membrane Integrity. Int J Mol Sci 2023; 24:15497. [PMID: 37895175 PMCID: PMC10607757 DOI: 10.3390/ijms242015497] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/19/2023] [Accepted: 10/22/2023] [Indexed: 10/29/2023] Open
Abstract
The nuclear membrane serves a critical role in protecting the contents of the nucleus and facilitating material and signal exchange between the nucleus and cytoplasm. While extensive research has been dedicated to topics such as nuclear membrane assembly and disassembly during cell division, as well as interactions between nuclear transmembrane proteins and both nucleoskeletal and cytoskeletal components, there has been comparatively less emphasis on exploring the regulation of nuclear morphology through nuclear membrane integrity. In particular, the role of type II integral proteins, which also function as transcription factors, within the nuclear membrane remains an area of research that is yet to be fully explored. The integrity of the nuclear membrane is pivotal not only during cell division but also in the regulation of gene expression and the communication between the nucleus and cytoplasm. Importantly, it plays a significant role in the development of various diseases. This review paper seeks to illuminate the biomolecules responsible for maintaining the integrity of the nuclear membrane. It will delve into the mechanisms that influence nuclear membrane integrity and provide insights into the role of type II membrane protein transcription factors in this context. Understanding these aspects is of utmost importance, as it can offer valuable insights into the intricate processes governing nuclear membrane integrity. Such insights have broad-reaching implications for cellular function and our understanding of disease pathogenesis.
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Affiliation(s)
- Ga-Eun Lee
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
| | - Jiin Byun
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
| | - Cheol-Jung Lee
- Research Center for Materials Analysis, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon 34133, Chungcheongnam-do, Republic of Korea
| | - Yong-Yeon Cho
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
- RCD Control and Material Research Institute, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea
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Barger SR, Penfield L, Bahmanyar S. Nuclear envelope assembly relies on CHMP-7 in the absence of BAF-LEM-mediated hole closure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.547980. [PMID: 37461528 PMCID: PMC10350047 DOI: 10.1101/2023.07.06.547980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Barrier-to-autointegration factor (BAF) is a DNA binding protein that crosslinks chromatin to assemble the nuclear envelope (NE) after mitosis. BAF also binds the Lap2b-Emerin-Man1 (LEM) domain family of NE proteins to repair interphase ruptures. The NE adaptors to ESCRTs, LEMD2-CHMP7, seal NE holes surrounding mitotic spindle microtubules (MTs), but whether NE hole closure in mitosis involves BAF-LEM binding is not known. Here, we analyze NE sealing after meiosis II in C. elegans oocytes to show that BAF-LEM binding and LEM-2 LEMD2 -CHMP-7 have distinct roles in hole closure around spindle MTs. LEM-2/EMR-1 emerin function redundantly with BAF-1 to seal the NE. Compromising BAF-LEM binding revealed an additional role for EMR-1 in maintenance of the NE permeability barrier and an essential role for LEM-2-CHMP-7 in preventing NE assembly failure. The WH domain of LEM-2 recruits the majority of CHMP-7 to the NE in C. elegans and a LEM-2 -independent pool of CHMP-7, which is mostly enriched in the nucleoplasm, also contributes to NE stability. Thus, NE hole closure surrounding spindle MTs requires redundant mechanisms that safeguard against failure in NE assembly to support embryogenesis.
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Affiliation(s)
- Sarah R. Barger
- Yale University, Department of Molecular, Cellular, Developmental Biology, 266 Whitney Ave., New Haven, CT 06511
| | - Lauren Penfield
- Current address: Department of Molecular, Cellular, and Developmental Biology at University of California, Santa Barbara, CA
| | - Shirin Bahmanyar
- Yale University, Department of Molecular, Cellular, Developmental Biology, 266 Whitney Ave., New Haven, CT 06511
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14
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Zhang B, Powers JD, McCulloch AD, Chi NC. Nuclear mechanosignaling in striated muscle diseases. Front Physiol 2023; 14:1126111. [PMID: 36960155 PMCID: PMC10027932 DOI: 10.3389/fphys.2023.1126111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/22/2023] [Indexed: 03/09/2023] Open
Abstract
Mechanosignaling describes processes by which biomechanical stimuli are transduced into cellular responses. External biophysical forces can be transmitted via structural protein networks that span from the cellular membrane to the cytoskeleton and the nucleus, where they can regulate gene expression through a series of biomechanical and/or biochemical mechanosensitive mechanisms, including chromatin remodeling, translocation of transcriptional regulators, and epigenetic factors. Striated muscle cells, including cardiac and skeletal muscle myocytes, utilize these nuclear mechanosignaling mechanisms to respond to changes in their intracellular and extracellular mechanical environment and mediate gene expression and cell remodeling. In this brief review, we highlight and discuss recent experimental work focused on the pathway of biomechanical stimulus propagation at the nucleus-cytoskeleton interface of striated muscles, and the mechanisms by which these pathways regulate gene regulation, muscle structure, and function. Furthermore, we discuss nuclear protein mutations that affect mechanosignaling function in human and animal models of cardiomyopathy. Furthermore, current open questions and future challenges in investigating striated muscle nuclear mechanosignaling are further discussed.
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Affiliation(s)
- Bo Zhang
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - Joseph D. Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - Andrew D. McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA, United States
| | - Neil C. Chi
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA, United States
- Department of Medicine, Division of Cardiovascular Medicine, University of California San Diego, La Jolla, CA, United States
- Institute of Genomic Medicine, University of California San Diego, La Jolla, CA, United States
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15
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Duan T, Thyagarajan S, Amoiroglou A, Rogers GC, Geyer PK. Analysis of a rare progeria variant of Barrier-to-autointegration factor in Drosophila connects centromere function to tissue homeostasis. Cell Mol Life Sci 2023; 80:73. [PMID: 36842139 PMCID: PMC9968693 DOI: 10.1007/s00018-023-04721-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/27/2023]
Abstract
Barrier-to-autointegration factor (BAF/BANF) is a nuclear lamina protein essential for nuclear integrity, chromatin structure, and genome stability. Whereas complete loss of BAF causes lethality in multiple organisms, the A12T missense mutation of the BANF1 gene in humans causes a premature aging syndrome, called Néstor-Guillermo Progeria Syndrome (NGPS). Here, we report the first in vivo animal investigation of progeroid BAF, using CRISPR editing to introduce the NGPS mutation into the endogenous Drosophila baf gene. Progeroid BAF adults are born at expected frequencies, demonstrating that this BAF variant retains some function. However, tissue homeostasis is affected, supported by studies of the ovary, a tissue that depends upon BAF for stem cell survival and continuous oocyte production. We find that progeroid BAF causes defects in germline stem cell mitosis that delay anaphase progression and compromise chromosome segregation. We link these defects to decreased recruitment of centromeric proteins of the kinetochore, indicating dysfunction of cenBAF, a localized pool of dephosphorylated BAF produced by Protein Phosphatase PP4. We show that DNA damage increases in progenitor germ cells, which causes germ cell death due to activation of the DNA damage transducer kinase Chk2. Mitotic defects appear widespread, as aberrant chromosome segregation and increased apoptosis occur in another tissue. Together, these data highlight the importance of BAF in establishing centromeric structures critical for mitosis. Further, these studies link defects in cenBAF function to activation of a checkpoint that depletes progenitor reserves critical for tissue homeostasis, aligning with phenotypes of NGPS patients.
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Affiliation(s)
- Tingting Duan
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, 15232, USA
| | - Srikantha Thyagarajan
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA
| | - Anastasia Amoiroglou
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85724, USA
| | - Gregory C Rogers
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85724, USA
| | - Pamela K Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA.
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16
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Borah S, Dhanasekaran K, Kumar S. The LEM-ESCRT toolkit: Repair and maintenance of the nucleus. Front Cell Dev Biol 2022; 10:989217. [PMID: 36172278 PMCID: PMC9512039 DOI: 10.3389/fcell.2022.989217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/24/2022] [Indexed: 12/04/2022] Open
Abstract
The eukaryotic genome is enclosed in a nuclear envelope that protects it from potentially damaging cellular activities and physically segregates transcription and translation.Transport across the NE is highly regulated and occurs primarily via the macromolecular nuclear pore complexes.Loss of nuclear compartmentalization due to defects in NPC function and NE integrity are tied to neurological and ageing disorders like Alzheimer’s, viral pathogenesis, immune disorders, and cancer progression.Recent work implicates inner-nuclear membrane proteins of the conserved LEM domain family and the ESCRT machinery in NE reformation during cell division and NE repair upon rupture in migrating cancer cells, and generating seals over defective NPCs. In this review, we discuss the recent in-roads made into defining the molecular mechanisms and biochemical networks engaged by LEM and many other integral inner nuclear membrane proteins to preserve the nuclear barrier.
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Affiliation(s)
- Sapan Borah
- National Institute of Immunohaematology, Mumbai, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Karthigeyan Dhanasekaran
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Santosh Kumar
- National Centre for Cell Science, Pune, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
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17
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Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
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Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
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18
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Abstract
The nuclear envelope is composed of the nuclear membranes, nuclear lamina, and nuclear pore complexes. Laminopathies are diseases caused by mutations in genes encoding protein components of the lamina and these other nuclear envelope substructures. Mutations in the single gene encoding lamin A and C, which are expressed in most differentiated somatic cells, cause diseases affecting striated muscle, adipose tissue, peripheral nerve, and multiple systems with features of accelerated aging. Mutations in genes encoding other nuclear envelope proteins also cause an array of diseases that selectively affect different tissues or organs. In some instances, the molecular and cellular consequences of laminopathy-causing mutations are known. However, even when these are understood, mechanisms explaining specific tissue or organ pathology remain enigmatic. Current mechanistic hypotheses focus on how alterations in the nuclear envelope may affect gene expression, including via the regulation of signaling pathways, or cellular mechanics, including responses to mechanical stress.
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Affiliation(s)
- Ji-Yeon Shin
- Department of Medicine and Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Howard J. Worman
- Department of Medicine and Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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19
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Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
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Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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20
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Expression of the Ebola Virus VP24 Protein Compromises the Integrity of the Nuclear Envelope and Induces a Laminopathy-Like Cellular Phenotype. mBio 2021; 12:e0097221. [PMID: 34225493 PMCID: PMC8406168 DOI: 10.1128/mbio.00972-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ebola virus (EBOV) VP24 protein is a nucleocapsid-associated protein that inhibits interferon (IFN) gene expression and counteracts the IFN-mediated antiviral response, preventing nuclear import of signal transducer and activator of transcription 1 (STAT1). Proteomic studies to identify additional EBOV VP24 partners have pointed to the nuclear membrane component emerin as a potential element of the VP24 cellular interactome. Here, we have further studied this interaction and its impact on cell biology. We demonstrate that VP24 interacts with emerin but also with other components of the inner nuclear membrane, such as lamin A/C and lamin B. We also show that VP24 diminishes the interaction between emerin and lamin A/C and compromises the integrity of the nuclear membrane. This disruption is associated with nuclear morphological abnormalities, activation of a DNA damage response, the phosphorylation of extracellular signal-regulated kinase (ERK), and the induction of interferon-stimulated gene 15 (ISG15). Interestingly, expression of VP24 also promoted the cytoplasmic translocation and downmodulation of barrier-to-autointegration factor (BAF), a common interactor of lamin A/C and emerin, leading to repression of the BAF-regulated CSF1 gene. Importantly, we found that EBOV infection results in the activation of pathways associated with nuclear envelope damage, consistent with our observations in cells expressing VP24. In summary, here we demonstrate that VP24 acts at the nuclear membrane, causing morphological and functional changes in cells that recapitulate several of the hallmarks of laminopathy diseases.
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21
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Deolal P, Mishra K. Regulation of diverse nuclear shapes: pathways working independently, together. Commun Integr Biol 2021; 14:158-175. [PMID: 34262635 PMCID: PMC8259725 DOI: 10.1080/19420889.2021.1939942] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
Membrane-bound organelles provide physical and functional compartmentalization of biological processes in eukaryotic cells. The characteristic shape and internal organization of these organelles is determined by a combination of multiple internal and external factors. The maintenance of the shape of nucleus, which houses the genetic material within a double membrane bilayer, is crucial for a seamless spatio-temporal control over nuclear and cellular functions. Dynamic morphological changes in the shape of nucleus facilitate various biological processes. Chromatin packaging, nuclear and cytosolic protein organization, and nuclear membrane lipid homeostasis are critical determinants of overall nuclear morphology. As such, a multitude of molecular players and pathways act together to regulate the nuclear shape. Here, we review the known mechanisms governing nuclear shape in various unicellular and multicellular organisms, including the non-spherical nuclei and non-lamin-related structural determinants. The review also touches upon cellular consequences of aberrant nuclear morphologies.
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Affiliation(s)
- Pallavi Deolal
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Krishnaveni Mishra
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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22
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Drosophila female germline stem cells undergo mitosis without nuclear breakdown. Curr Biol 2021; 31:1450-1462.e3. [PMID: 33548191 DOI: 10.1016/j.cub.2021.01.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/18/2020] [Accepted: 01/11/2021] [Indexed: 02/02/2023]
Abstract
Stem cell homeostasis requires nuclear lamina (NL) integrity. In Drosophila germ cells, compromised NL integrity activates the ataxia telangiectasia and Rad3-related (ATR) and checkpoint kinase 2 (Chk2) checkpoint kinases, blocking germ cell differentiation and causing germline stem cell (GSC) loss. Checkpoint activation occurs upon loss of either the NL protein emerin or its partner barrier-to-autointegration factor, two proteins required for nuclear reassembly at the end of mitosis. Here, we examined how mitosis contributes to NL structural defects linked to checkpoint activation. These analyses led to the unexpected discovery that wild-type female GSCs utilize a non-canonical mode of mitosis, one that retains a permeable but intact nuclear envelope and NL. We show that the interphase NL is remodeled during mitosis for insertion of centrosomes that nucleate the mitotic spindle within the confines of the nucleus. We show that depletion or loss of NL components causes mitotic defects, including compromised chromosome segregation associated with altered centrosome positioning and structure. Further, in emerin mutant GSCs, centrosomes remain embedded in the interphase NL. Notably, these embedded centrosomes carry large amounts of pericentriolar material and nucleate astral microtubules, revealing a role for emerin in the regulation of centrosome structure. Epistasis studies demonstrate that defects in centrosome structure are upstream of checkpoint activation, suggesting that these centrosome defects might trigger checkpoint activation and GSC loss. Connections between NL proteins and centrosome function have implications for mechanisms associated with NL dysfunction in other stem cell populations, including NL-associated diseases, such as laminopathies.
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23
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Shet AS, Lizarralde-Iragorri MA, Naik RP. The molecular basis for the prothrombotic state in sickle cell disease. Haematologica 2020; 105:2368-2379. [PMID: 33054077 PMCID: PMC7556662 DOI: 10.3324/haematol.2019.239350] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/22/2020] [Indexed: 12/15/2022] Open
Abstract
The genetic and molecular basis of sickle cell disease (SCD) has long since been characterized but the pathophysiological basis is not entirely defined. How a red cell hemolytic disorder initiates inflammation, endothelial dysfunction, coagulation activation and eventually leads to vascular thrombosis, is yet to be elucidated. Recent evidence has demonstrated a high frequency of unprovoked/recurrent venous thromboembolism (VTE) in SCD, with an increased risk of mortality among patients with a history of VTE. Here, we thoroughly review the molecular basis for the prothrombotic state in SCD, specifically highlighting emerging evidence for activation of overlapping inflammation and coagulation pathways, that predispose to venous thromboembolism. We share perspectives in managing venous thrombosis in SCD, highlighting innovative therapies with the potential to influence the clinical course of disease and reduce thrombotic risk, while maintaining an acceptable safety profile.
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Affiliation(s)
- Arun S. Shet
- Laboratory of Sickle Thrombosis and Vascular Biology, National Heart, Lung, and Blood Institute, NIH, Bethesda
| | | | - Rakhi P. Naik
- Division of Hematology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
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24
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Richardson A, Zentz ZA, Chambers AE, Sandwith SN, Reisinger MA, Saunders DW, Tompkins JD, Riggs AD, Routh ED, Rubenstein EM, Smaldino MA, Vaughn JP, Haney RA, Smaldino PJ. G-Quadruplex Helicase DHX36/G4R1 Engages Nuclear Lamina Proteins in Quiescent Breast Cancer Cells. ACS OMEGA 2020; 5:24916-24926. [PMID: 33015511 PMCID: PMC7528498 DOI: 10.1021/acsomega.0c03723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
G-quadruplexes (G4s) are nucleic acid structures found enriched within gene regulatory sequences. G4s control fundamental cellular processes, including replication, transcription, and translation. Proto-oncogenes are enriched with G4 sequences, while tumor-suppressor genes are depleted, suggesting roles for G4s in cell survival and proliferation. Specialized helicases participate in G4-mediated gene regulation via enzymatic unwinding activity. One such enzyme, DHX36/G4R1, is the major G4-helicase and is a master regulator of G4-DNAs and mRNAs. G4-resolution promotes the expression of proproliferative genes; as such, DHX36/G4R1 promotes cell proliferation. Little is known about how DHX36/G4R1 itself is regulated in nondividing cells. We hypothesized that DHX36/G4R1 protein binding partners are altered when a cell transitions from a dividing to a quiescent state. We found that DHX36/G4R1 co-purifies with a distinct set of proteins under quiescent conditions, which may represent a novel complex that regulates DHX36/G4R1 during cell cycle transitions and have implications for development and cancer.
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Affiliation(s)
- Adam.
E. Richardson
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Zachary. A. Zentz
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Antonio E. Chambers
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Siara N. Sandwith
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Michael A. Reisinger
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Destinee W. Saunders
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Joshua D. Tompkins
- Department
of Diabetes Complications and Metabolism, City of Hope, Duarte, California 91010, United States
| | - Arthur D. Riggs
- Department
of Diabetes Complications and Metabolism, City of Hope, Duarte, California 91010, United States
| | - Eric D. Routh
- Lineberger
Comprehensive Cancer Center, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Eric M. Rubenstein
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Melissa A. Smaldino
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - James P. Vaughn
- NanoMedica
LLC, Winston-Salem, North Carolina 27101, United States
| | - Robert A. Haney
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Philip J. Smaldino
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
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25
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Nuclear mechanosensing: mechanism and consequences of a nuclear rupture. Mutat Res 2020; 821:111717. [PMID: 32810711 DOI: 10.1016/j.mrfmmm.2020.111717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/25/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022]
Abstract
The physical connections between the cytoskeletal system and the nucleus provide a route for the nucleus to sense the mechanical stress both inside and outside of the cell. Failure to withstand such stress leads to nuclear rupture, which is observed in human diseases. In this review, we will go through the recent findings and our current understandings of nuclear rupture. Starting with the triggers of nuclear rupture, including the aberrant nuclear lamina composition and the elevated actomyosin contractility. We will also discuss the role of ESCRT-III in nuclear rupture repair and the biological consequences of nuclear rupture, including the negative impacts on cellular compartmentalization, DNA damage, and cellular differentiation. Recent studies on nuclear rupture provide further insights into the direct mechanistic link between nuclear rupture and several pathological conditions. Such knowledge can guide us in developing potential therapeutic solutions for the patients.
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26
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Duan T, Kitzman SC, Geyer PK. Survival of Drosophila germline stem cells requires the chromatin-binding protein Barrier-to-autointegration factor. Development 2020; 147:dev.186171. [PMID: 32345742 DOI: 10.1242/dev.186171] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/31/2020] [Indexed: 11/20/2022]
Abstract
The nuclear lamina (NL) is an extensive protein network that underlies the inner nuclear envelope. This network includes LAP2-emerin-MAN1 domain (LEM-D) proteins that associate with the chromatin and DNA-binding protein Barrier-to-autointegration factor (BAF). Here, we investigate the partnership between three NL Drosophila LEM-D proteins and BAF. In most tissues, only Emerin/Otefin is required for NL enrichment of BAF, revealing an unexpected dependence on a single LEM-D protein. Prompted by these observations, we studied BAF contributions in the ovary, a tissue where Emerin/Otefin function is essential. We show that germ cell-specific BAF knockdown causes phenotypes that mirror emerin/otefin mutants. Loss of BAF disrupts NL structure, blocks differentiation and promotes germ cell loss, phenotypes that are partially rescued by inactivation of the ATR and Chk2 kinases. These data suggest that, similar to emerin/otefin mutants, BAF depletion activates the NL checkpoint that causes germ cell loss. Taken together, our findings provide evidence for a prominent NL partnership between the LEM-D protein Emerin/Otefin and BAF, revealing that BAF functions with this partner in the maintenance of an adult stem cell population.
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Affiliation(s)
- Tingting Duan
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - S Cole Kitzman
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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27
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Probing the Environment of Emerin by Enhanced Ascorbate Peroxidase 2 (APEX2)-Mediated Proximity Labeling. Cells 2020; 9:cells9030605. [PMID: 32138363 PMCID: PMC7140434 DOI: 10.3390/cells9030605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022] Open
Abstract
Emerin is one of the best characterized proteins of the inner nuclear membrane, but can also occur at the level of the endoplasmic reticulum. We now use enhanced ascorbate peroxidase 2 (APEX2) to probe the environment of emerin. APEX2 can be used as a genetic tag that produces short-lived yet highly reactive biotin species, allowing the modification of proteins that interact with or are in very close proximity to the tagged protein. Biotinylated proteins can be isolated using immobilized streptavidin and analyzed by mass spectrometry. As an alternative to the standard approach with a genetic fusion of APEX2 to emerin, we also used RAPIDS (rapamycin- and APEX-dependent identification of proteins by SILAC), a method with improved specificity, where the peroxidase interacts with the protein of interest (i.e., emerin) only upon addition of rapamycin to the cells. We compare these different approaches, which, together, identify well-known interaction partners of emerin like lamin A and the lamina associated polypeptide 1 (LAP1), as well as novel proximity partners.
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28
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Moser B, Basílio J, Gotzmann J, Brachner A, Foisner R. Comparative Interactome Analysis of Emerin, MAN1 and LEM2 Reveals a Unique Role for LEM2 in Nucleotide Excision Repair. Cells 2020; 9:cells9020463. [PMID: 32085595 PMCID: PMC7072835 DOI: 10.3390/cells9020463] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/06/2020] [Accepted: 02/11/2020] [Indexed: 12/19/2022] Open
Abstract
LAP2-Emerin-MAN1 (LEM) domain-containing proteins represent an abundant group of inner nuclear membrane proteins involved in diverse nuclear functions, but their functional redundancies remain unclear. Here, using the biotinylation-dependent proximity approach, we report proteome-wide comparative interactome analysis of the two structurally related LEM proteins MAN1 (LEMD3) and LEM2 (LEMD2), and the more distantly related emerin (EMD). While over 60% of the relatively small group of MAN1 and emerin interactors were also found in the LEM2 interactome, the latter included a large number of candidates (>85%) unique for LEM2. The interacting partners unique for emerin support and provide further insight into the previously reported role of emerin in centrosome positioning, and the MAN1-specific interactors suggest a role of MAN1 in ribonucleoprotein complex assembly. Interestingly, the LEM2-specific interactome contained several proteins of the nucleotide excision repair pathway. Accordingly, LEM2-depleted cells, but not MAN1- and emerin-depleted cells, showed impaired proliferation following ultraviolet-C (UV-C) irradiation and prolonged accumulation of γH2AX, similar to cells deficient in the nucleotide excision repair protein DNA damage-binding protein 1 (DDB1). These findings indicate impaired DNA damage repair in LEM2-depleted cells. Overall, this interactome study identifies new potential interaction partners of emerin, MAN1 and particularly LEM2, and describes a novel potential involvement of LEM2 in nucleotide excision repair at the nuclear periphery.
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Affiliation(s)
- Bernhard Moser
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - José Basílio
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Josef Gotzmann
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
| | - Andreas Brachner
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Correspondence: (A.B.); (R.F.)
| | - Roland Foisner
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Correspondence: (A.B.); (R.F.)
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29
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Link N, Chung H, Jolly A, Withers M, Tepe B, Arenkiel BR, Shah PS, Krogan NJ, Aydin H, Geckinli BB, Tos T, Isikay S, Tuysuz B, Mochida GH, Thomas AX, Clark RD, Mirzaa GM, Lupski JR, Bellen HJ. Mutations in ANKLE2, a ZIKA Virus Target, Disrupt an Asymmetric Cell Division Pathway in Drosophila Neuroblasts to Cause Microcephaly. Dev Cell 2019; 51:713-729.e6. [PMID: 31735666 DOI: 10.1016/j.devcel.2019.10.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/19/2019] [Accepted: 10/14/2019] [Indexed: 12/12/2022]
Abstract
The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division.
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Affiliation(s)
- Nichole Link
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hyunglok Chung
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Angad Jolly
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA
| | - Marjorie Withers
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Burak Tepe
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Priya S Shah
- Department of Chemical Engineering and Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biosciences, QB3, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hatip Aydin
- Center of Genetics Diagnosis, Zeynep Kamil Maternity and Children's Training and Research Hospital, Istanbul, Turkey
| | - Bilgen B Geckinli
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Tulay Tos
- Department of Medical Genetics, Dr. Sami Ulus Research and Training Hospital of Women's and Children's Health and Diseases, Ankara, Turkey
| | - Sedat Isikay
- Department of Physiotherapy and Rehabilitation, Hasan Kalyoncu University, School of Health Sciences, Gaziantep, Turkey
| | - Beyhan Tuysuz
- Department of Pediatrics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Ganesh H Mochida
- Division of Genetics and Genomics, Department of Pediatrics and Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ajay X Thomas
- Department of Pediatrics, Section of Neurology and Developmental Neuroscience, BCM, Houston, TX 77030, USA; Section of Child Neurology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Robin D Clark
- Division of Medical Genetics, Department of Pediatrics, Loma Linda University Medical Center, Loma Linda, CA 92354, USA
| | - Ghayda M Mirzaa
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98105, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Department of Pediatrics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA.
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30
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Abstract
Emery-Dreifuss muscular dystrophy (EDMD), clinically characterized by scapulo-humero-peroneal muscle atrophy and weakness, multi-joint contractures with spine rigidity and cardiomyopathy with conduction defects, is associated with structural/functional defect of genes that encode the proteins of nuclear envelope, including lamin A and several lamin-interacting proteins. This paper presents clinical aspects of EDMD in context to causative genes, genotype-phenotype correlation and its emplacement within phenotypic spectrum of skeletal muscle diseases associated with envelopathies.
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Affiliation(s)
- Agnieszka Madej-Pilarczyk
- a Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences , Warsaw , Poland
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31
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Constitutional abnormality of nuclear membrane proteins in small cell lung carcinoma. Virchows Arch 2019; 475:407-414. [PMID: 31201505 DOI: 10.1007/s00428-019-02597-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/06/2019] [Accepted: 06/03/2019] [Indexed: 10/26/2022]
Abstract
Nuclear membrane proteins reportedly play important roles in maintaining nuclear structures and coordinating cell activities. Studying profiles of nuclear membrane proteins may help us evaluate the biological and/or clinical nature of malignant tumors. Using immunohistochemistry with antibodies for emerin, lamin A/C, lamin B, and LAP2, we examined 105 lung cancer tissues from 33 small cell lung carcinomas (SCLCs) and 72 non-SCLCs (34 adenocarcinomas, 30 squamous cell carcinomas, and 8 large cell carcinomas). Emerin had negative or local/weak positivity in 79% of SCLCs and 1% of non-SCLCs, and lamin A/C had similar positivity in 91% of SCLCs and 3% of non-SCLCs. LAP2's expression was similar between SCLCs and non-SCLCs. RT-PCR analyses for these four nuclear membrane proteins over 7 cell lines showed that mRNA of emerin and lamin A/C were distinctly downregulated in the SCLC cell lines, supporting the immunohistochemical results. In conclusion, we suggest that downregulation of the nuclear membrane proteins emerin and lamin A/C is characteristic of SCLC cells, and this constitutional abnormality of the nuclear membrane may be related to the biological and/or clinical nature of SCLC. In addition, knowing the nuclear protein profile in SCLC cells may contribute to our understanding of nuclear fragility known as the crush artifact in pulmonary biopsy specimens.
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32
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Liu C, Yu H, Shen X, Qiao J, Wu X, Chang J, Zhu X, Wang J, Shen X. Prognostic significance and biological function of Lamina-associated polypeptide 2 in non-small-cell lung cancer. Onco Targets Ther 2019; 12:3817-3827. [PMID: 31190881 PMCID: PMC6529027 DOI: 10.2147/ott.s179870] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 04/26/2019] [Indexed: 01/24/2023] Open
Abstract
Purpose: Lamina-associated polypeptide 2 (LAP2; encoded by TMPO), is a nuclear protein that may affect chromatin regulation and gene expression through dynamically binding to nuclear lamin. TMPO (LAP2) plays dual roles of either suppressing or promoting proliferation of cells, depending on the status of the cell. It has been reported that TMPO is up-regulated in various cancer types. However, its function in lung cancer has not been studied yet. Materials and methods: A series of clinical microarray datasets for lung cancer were investigated to demonstrate the expression of TMPO. The transcription of TMPO gene in human lung cancer was analyzed using Oncomine platform (www.oncomine.org) according to the standardized procedures described previously. Four separate datasets (Hou Lung, Okayama Lung, Beer Lung, and Garber Lung) were analyzed. Results: Here, we show that TMPO is over-expressed in lung cancer tissues, and that a high level of TMPO indicates a poor prognosis in lung cancer patients. Knockdown of TMPO in lung cancer cells inhibits cell proliferation and induces apoptosis. Also, down-regulation of TMPO leads to an impaired metastatic ability of tumor cells. A nude mice tumor model show that knockdown of TMPO suppresses tumor formation in vivo. Conclusion: Collectively, this study suggests TMPO as an oncogene and a novel prognostic gene in lung cancer.
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Affiliation(s)
- Chang Liu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Hui Yu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xuxia Shen
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China.,Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China
| | - Jie Qiao
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xianghua Wu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Jianhua Chang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xunxia Zhu
- Department of Thoracic Surgery, The Affiliated Huadong Hospital of Fudan University, Shanghai 200040, People's Republic of China
| | - Jialei Wang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xiaoyong Shen
- Department of Thoracic Surgery, The Affiliated Huadong Hospital of Fudan University, Shanghai 200040, People's Republic of China
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33
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Kinugasa Y, Hirano Y, Sawai M, Ohno Y, Shindo T, Asakawa H, Chikashige Y, Shibata S, Kihara A, Haraguchi T, Hiraoka Y. The very-long-chain fatty acid elongase Elo2 rescues lethal defects associated with loss of the nuclear barrier function in fission yeast cells. J Cell Sci 2019; 132:jcs.229021. [PMID: 30975915 DOI: 10.1242/jcs.229021] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/03/2019] [Indexed: 12/21/2022] Open
Abstract
In eukaryotic cells, chromosomes are confined to the nucleus, which is compartmentalized by the nuclear membranes; these are continuous with the endoplasmic reticulum membranes. Maintaining the homeostasis of these membranes is an important cellular activity performed by lipid metabolic enzymes. However, how lipid metabolic enzymes affect nuclear membrane functions remains to be elucidated. We found that the very-long-chain fatty acid elongase Elo2 is located in the nuclear membrane and prevents lethal defects associated with nuclear membrane ruptures in mutants of the nuclear membrane proteins Lem2 and Bqt4 in the fission yeast Schizosaccharomyces pombe. Lipid composition analysis shows that t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe The quantity of this ceramide is reduced in the absence of Lem2, and restored by increased expression of Elo2. Furthermore, loss of S. pombe Elo2 can be rescued by its human orthologs. These results suggest that the conserved very-long-chain fatty acid elongase producing the ceramide component is essential for nuclear membrane integrity and cell viability in eukaryotes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Yasuha Kinugasa
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Megumi Sawai
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Yusuke Ohno
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tomoko Shindo
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Akio Kihara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan .,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
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34
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Dubińska-Magiera M, Kozioł K, Machowska M, Piekarowicz K, Filipczak D, Rzepecki R. Emerin Is Required for Proper Nucleus Reassembly after Mitosis: Implications for New Pathogenetic Mechanisms for Laminopathies Detected in EDMD1 Patients. Cells 2019; 8:E240. [PMID: 30871242 PMCID: PMC6468536 DOI: 10.3390/cells8030240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/26/2019] [Accepted: 03/05/2019] [Indexed: 12/29/2022] Open
Abstract
Emerin is an essential LEM (LAP2, Emerin, MAN1) domain protein in metazoans and an integral membrane protein associated with inner and outer nuclear membranes. Mutations in the human EMD gene coding for emerin result in the rare genetic disorder: Emery⁻Dreifuss muscular dystrophy type 1 (EDMD1). This disease belongs to a broader group called laminopathies-a heterogeneous group of rare genetic disorders affecting tissues of mesodermal origin. EDMD1 phenotype is characterized by progressive muscle wasting, contractures of the elbow and Achilles tendons, and cardiac conduction defects. Emerin is involved in many cellular and intranuclear processes through interactions with several partners: lamins; barrier-to-autointegration factor (BAF), β-catenin, actin, and tubulin. Our study demonstrates the presence of the emerin fraction which associates with mitotic spindle microtubules and centrosomes during mitosis and colocalizes during early mitosis with lamin A/C, BAF, and membranes at the mitotic spindle. Transfection studies with cells expressing EGFP-emerin protein demonstrate that the emerin fusion protein fraction also localizes to centrosomes and mitotic spindle microtubules during mitosis. Transient expression of emerin deletion mutants revealed that the resulting phenotypes vary and are mutant dependent. The most frequent phenotypes include aberrant nuclear shape, tubulin network mislocalization, aberrant mitosis, and mislocalization of centrosomes. Emerin deletion mutants demonstrated different chromatin binding capacities in an in vitro nuclear assembly assay and chromatin-binding properties correlated with the strength of phenotypic alteration in transfected cells. Aberrant tubulin staining and microtubule network phenotype appearance depended on the presence of the tubulin binding region in the expressed deletion mutants. We believe that the association with tubulin might help to "deliver" emerin and associated membranes to decondensing chromatin. Preliminary analyses of cells from Polish patients with EDMD1 revealed that for several mutations thought to be null for emerin protein, a truncated emerin protein was present. We infer that the EDMD1 phenotype may be strengthened by the toxicity of truncated emerin expressed in patients with certain nonsense mutations in EMD.
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Affiliation(s)
- Magda Dubińska-Magiera
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wroclaw, Sienkiewicza 21, 50-335 Wroclaw, Poland.
| | - Katarzyna Kozioł
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Magdalena Machowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Katarzyna Piekarowicz
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Daria Filipczak
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Ryszard Rzepecki
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
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35
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Ma Z, Shi H, Shen Y, Li H, Yang Y, Yang J, Zhao H, Wang G, Wang J. Emerin anchors Msx1 and its protein partners at the nuclear periphery to inhibit myogenesis. Cell Biosci 2019; 9:34. [PMID: 31044068 PMCID: PMC6460851 DOI: 10.1186/s13578-019-0296-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Previous studies have shown that in myogenic precursors, the homeoprotein Msx1 and its protein partners, histone methyltransferases and repressive histone marks, tend to be enriched on target myogenic regulatory genes at the nuclear periphery. The nuclear periphery localization of Msx1 and its protein partners is required for Msx1's function of preventing myogenic precursors from pre-maturation through repressing target myogenic regulatory genes. However, the mechanisms underlying the maintenance of Msx1 and its protein partners' nuclear periphery localization are unknown. RESULTS We show that an inner nuclear membrane protein, Emerin, performs as an anchor settled at the inner nuclear membrane to keep Msx1 and its protein partners Ezh2, H3K27me3 enriching at the nuclear periphery, and participates in inhibition of myogenesis mediated by Msx1. Msx1 interacts with Emerin both in C2C12 myoblasts and mouse developing limbs, which is the prerequisite for Emerin mediating the precise location of Msx1, Ezh2, and H3K27me3. The deficiency of Emerin in C2C12 myoblasts disturbs the nuclear periphery localization of Msx1, Ezh2, and H3K27me3, directly indicating Emerin functioning as an anchor. Furthermore, Emerin cooperates with Msx1 to repress target myogenic regulatory genes, and assists Msx1 with inhibition of myogenesis. CONCLUSIONS Emerin cooperates with Msx1 to inhibit myogenesis through maintaining the nuclear periphery localization of Msx1 and Msx1's protein partners.
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Affiliation(s)
- Zhangjing Ma
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Huiyuan Shi
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Yi Shen
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Huixia Li
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Yu Yang
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Jiange Yang
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
| | - Hui Zhao
- Zhengzhou Revogene Inc, Zhengzhou, 450000 People's Republic of China
| | - Gang Wang
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China.,3State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031 People's Republic of China
| | - Jingqiang Wang
- 1State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438 People's Republic of China
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36
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Gao A, Sun T, Ma G, Cao J, Hu Q, Chen L, Wang Y, Wang Q, Sun J, Wu R, Wu Q, Zhou J, Liu L, Hu J, Dong JT, Zhu Z. LEM4 confers tamoxifen resistance to breast cancer cells by activating cyclin D-CDK4/6-Rb and ERα pathway. Nat Commun 2018; 9:4180. [PMID: 30301939 PMCID: PMC6177406 DOI: 10.1038/s41467-018-06309-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 07/02/2018] [Indexed: 02/07/2023] Open
Abstract
The elucidation of molecular events that confer tamoxifen resistance to estrogen receptor α (ER) positive breast cancer is of major scientific and therapeutic importance. Here, we report that LEM4 overexpression renders ER+ breast cancer cells resistant to tamoxifen by activating the cyclin D-CDK4/6 axis and the ERα signaling. We show that LEM4 overexpression accelerates tumor growth. Interaction with LEM4 stabilizes CDK4 and Rb, promotes Rb phosphorylation and the G1/S phase transition. LEM4 depletion or combined tamoxifen and PD0332991 treatment significantly reverses tamoxifen resistance. Furthermore, LEM4 interacts with and stabilizes both Aurora-A and ERα, promotes Aurora-A mediated phosphorylation of ERα-Ser167, leading to increase in ERα DNA-binding and transactivation activity. Elevated levels of LEM4 correlates with poorer relapse-free survival in patients with ER+ breast cancer undergoing endocrine therapy. Thus, LEM4 represents a prognostic marker and an attractive target for breast cancer therapeutics. Functional antagonism of LEM4 could overcome tamoxifen resistance.
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Affiliation(s)
- Ang Gao
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Tonghua Sun
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Gui Ma
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jiangran Cao
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Qingxia Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Ling Chen
- Department of Pathology, Tianjin Central Hospital of Gynecology and Obstetrics, Tianjin, 300100, China
| | - Yanxin Wang
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qianying Wang
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jiafu Sun
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Rui Wu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Qiao Wu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jiaxi Zhou
- State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, 288 Nanjing Road, Tianjin, 300020, China
| | - Lin Liu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Junjie Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Jin-Tang Dong
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
- Department of Hematology and Medical Oncology, School of Medicine, Winship Cancer Institute, Emory University, Atlanta, Georgia.
| | - Zhengmao Zhu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
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37
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Chambers DM, Moretti L, Zhang JJ, Cooper SW, Chambers DM, Santangelo PJ, Barker TH. LEM domain-containing protein 3 antagonizes TGFβ-SMAD2/3 signaling in a stiffness-dependent manner in both the nucleus and cytosol. J Biol Chem 2018; 293:15867-15886. [PMID: 30108174 DOI: 10.1074/jbc.ra118.003658] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/31/2018] [Indexed: 12/28/2022] Open
Abstract
Transforming growth factor-β (TGFβ) signaling through SMAD2/3 is an important driver of pathological fibrosis in multiple organ systems. TGFβ signaling and extracellular matrix (ECM) stiffness form an unvirtuous pathological circuit in which matrix stiffness drives activation of latent TGFβ, and TGFβ signaling then drives cellular stress and ECM synthesis. Moreover, ECM stiffness also appears to sensitize cells to exogenously activated TGFβ through unknown mechanisms. Here, using human fibroblasts, we explored the effect of ECM stiffness on a putative inner nuclear membrane protein, LEM domain-containing protein 3 (LEMD3), which is physically connected to the cell's actin cytoskeleton and inhibits TGFβ signaling. We showed that LEMD3-SMAD2/3 interactions are inversely correlated with ECM stiffness and TGFβ-driven luciferase activity and that LEMD3 expression is correlated with the mechanical response of the TGFβ-driven luciferase reporter. We found that actin polymerization but not cellular stress or LEMD3-nuclear-cytoplasmic couplings were necessary for LEMD3-SMAD2/3 interactions. Intriguingly, LEMD3 and SMAD2/3 frequently interacted in the cytosol, and we discovered LEMD3 was proteolytically cleaved into protein fragments. We confirmed that a consensus C-terminal LEMD3 fragment binds SMAD2/3 in a stiffness-dependent manner throughout the cell and is sufficient for antagonizing SMAD2/3 signaling. Using human lung biopsies, we observed that these nuclear and cytosolic interactions are also present in tissue and found that fibrotic tissues exhibit locally diminished and cytoplasmically shifted LEMD3-SMAD2/3 interactions, as noted in vitro Our work reveals novel LEMD3 biology and stiffness-dependent regulation of TGFβ by LEMD3, providing a novel target to antagonize pathological TGFβ signaling.
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Affiliation(s)
- Dwight M Chambers
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Leandro Moretti
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, and
| | - Jennifer J Zhang
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Spencer W Cooper
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Davis M Chambers
- the College of Arts and Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Philip J Santangelo
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Thomas H Barker
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, and
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38
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Linker of nucleoskeleton and cytoskeleton complex proteins in cardiomyopathy. Biophys Rev 2018; 10:1033-1051. [PMID: 29869195 PMCID: PMC6082319 DOI: 10.1007/s12551-018-0431-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/24/2018] [Indexed: 12/21/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex couples the nuclear lamina to the cytoskeleton. The LINC complex and its associated proteins play diverse roles in cells, ranging from genome organization, nuclear morphology, gene expression, to mechanical stability. The importance of a functional LINC complex is highlighted by the large number of mutations in genes encoding LINC complex proteins that lead to skeletal and cardiac myopathies. In this review, the structure, function, and interactions between components of the LINC complex will be described. Mutations that are known to cause cardiomyopathy in patients will be discussed alongside their respective mouse models. Furthermore, future challenges for the field and emerging technologies to investigate LINC complex function will be discussed.
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39
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Brady GF, Kwan R, Cunha JB, Elenbaas JS, Omary MB. Lamins and Lamin-Associated Proteins in Gastrointestinal Health and Disease. Gastroenterology 2018; 154:1602-1619.e1. [PMID: 29549040 PMCID: PMC6038707 DOI: 10.1053/j.gastro.2018.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 02/07/2023]
Abstract
The nuclear lamina is a multi-protein lattice composed of A- and B-type lamins and their associated proteins. This protein lattice associates with heterochromatin and integral inner nuclear membrane proteins, providing links among the genome, nucleoskeleton, and cytoskeleton. In the 1990s, mutations in EMD and LMNA were linked to Emery-Dreifuss muscular dystrophy. Since then, the number of diseases attributed to nuclear lamina defects, including laminopathies and other disorders, has increased to include more than 20 distinct genetic syndromes. Studies of patients and mouse genetic models have pointed to important roles for lamins and their associated proteins in the function of gastrointestinal organs, including liver and pancreas. We review the interactions and functions of the lamina in relation to the nuclear envelope and genome, the ways in which its dysfunction is thought to contribute to human disease, and possible avenues for targeted therapies.
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S. Elenbaas
- Medical Scientist Training Program, Washington University, St Louis, Missouri
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,Ǻbo Akademi University, Turku, Finland
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40
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Hirano Y, Kinugasa Y, Asakawa H, Chikashige Y, Obuse C, Haraguchi T, Hiraoka Y. Lem2 is retained at the nuclear envelope through its interaction with Bqt4 in fission yeast. Genes Cells 2018; 23:122-135. [PMID: 29292846 DOI: 10.1111/gtc.12557] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/04/2017] [Indexed: 12/31/2022]
Abstract
Inner nuclear membrane (INM) proteins are thought to play important roles in modulating nuclear organization and function through their interactions with chromatin. However, these INM proteins share redundant functions in metazoans that pose difficulties for functional studies. The fission yeast Schizosaccharomyces pombe exhibits a relatively small number of INM proteins, and molecular genetic tools are available to separate their redundant functions. In S. pombe, it has been reported that among potentially redundant INM proteins, Lem2 displays a unique genetic interaction with another INM protein, Bqt4, which is involved in anchoring telomeres to the nuclear envelope. Double mutations in the lem2 and bqt4 genes confer synthetic lethality during vegetative growth. Here, we show that Lem2 is retained at the nuclear envelope through its interaction with Bqt4, as the loss of Bqt4 results in the exclusive accumulation of Lem2 to the spindle pole body (SPB). An N-terminal nucleoplasmic region of Lem2 bears affinity to both Bqt4 and the SPB in a competitive manner. In contrast, the synthetic lethality of the lem2 bqt4 double mutant is suppressed by the C-terminal region of Lem2. These results indicate that the N-terminal and C-terminal domains of Lem2 show independent functions with respect to Bqt4.
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Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yasuha Kinugasa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.,Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 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, Kobe, Japan
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41
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Yang HJ, Iwamoto M, Hiraoka Y, Haraguchi T. Function of nuclear membrane proteins in shaping the nuclear envelope integrity during closed mitosis. J Biochem 2017; 161:471-477. [PMID: 28398483 DOI: 10.1093/jb/mvx020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 02/28/2017] [Indexed: 11/13/2022] Open
Abstract
The nuclear envelope (NE) not only protects the genome from being directly accessed by detrimental agents but also regulates genome organization. Breaches in NE integrity threaten genome stability and impede cellular function. Nonetheless, the NE constantly remodels, and NE integrity is endangered in dividing or differentiating cells. Specifically, in unicellular eukaryotes undergoing closed mitosis, the NE expands instead of breaking down during chromosome segregation. The newly assembling nuclear pore complexes (NPCs) penetrate the existing NE in interphase. A peculiar example of NE remodelling during nuclear differentiation in Tetrahymena involves formation of the redundant NE and clustered NPCs. Even under these conditions, the NE remains intact. Many recent studies on unicellular organisms have revealed that nuclear membrane proteins, such as LEM-domain proteins, play a role in maintaining NE integrity. This review summarizes and discusses how nuclear membrane proteins participate in NE integrity.
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Affiliation(s)
- Hui-Ju Yang
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Masaaki Iwamoto
- Advance ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advance ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advance ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
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42
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Abstract
Nuclear lamins are components of the peripheral lamina that define the mechanical properties of nuclei and tether heterochromatin to the periphery. A-type lamins localize also to the nuclear interior, but the regulation and specific functions of this nucleoplasmic lamin pool are poorly understood. In this Commentary, we summarize known pathways that are potentially involved in the localization and dynamic behavior of intranuclear lamins, including their post-translational modifications and interactions with nucleoplasmic proteins, such as lamina-associated polypeptide 2α (LAP2α; encoded by TMPO). In addition, new data suggest that lamins in the nuclear interior have an important role in chromatin regulation and gene expression through dynamic binding to both hetero- and euchromatic genomic regions and promoter subdomains, thereby affecting epigenetic pathways and chromatin accessibility. Nucleoplasmic lamins also have a role in spatial chromatin organization and may be involved in mechanosignaling. In view of this newly emerging concept, we propose that the previously reported cellular phenotypes in lamin-linked diseases are, at least in part, rooted in an impaired regulation and/or function of the nucleoplasmic lamin A/C pool.
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Affiliation(s)
- Nana Naetar
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Simona Ferraioli
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Roland Foisner
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
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43
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Heit JA, Armasu SM, McCauley BM, Kullo IJ, Sicotte H, Pathak J, Chute CG, Gottesman O, Bottinger EP, Denny JC, Roden DM, Li R, Ritchie MD, de Andrade M. Identification of unique venous thromboembolism-susceptibility variants in African-Americans. Thromb Haemost 2017; 117:758-768. [PMID: 28203683 DOI: 10.1160/th16-08-0652] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/12/2017] [Indexed: 12/30/2022]
Abstract
To identify novel single nucleotide polymorphisms (SNPs) associated with venous thromboembolism (VTE) in African-Americans (AAs), we performed a genome-wide association study (GWAS) of VTE in AAs using the Electronic Medical Records and Genomics (eMERGE) Network, comprised of seven sites each with DNA biobanks (total ~39,200 unique DNA samples) with genome-wide SNP data (imputed to 1000 Genomes Project cosmopolitan reference panel) and linked to electronic health records (EHRs). Using a validated EHR-driven phenotype extraction algorithm, we identified VTE cases and controls and tested for an association between each SNP and VTE using unconditional logistic regression, adjusted for age, sex, stroke, site-platform combination and sickle cell risk genotype. Among 393 AA VTE cases and 4,941 AA controls, three intragenic SNPs reached genome-wide significance: LEMD3 rs138916004 (OR=3.2; p=1.3E-08), LY86 rs3804476 (OR=1.8; p=2E-08) and LOC100130298 rs142143628 (OR=4.5; p=4.4E-08); all three SNPs validated using internal cross-validation, parametric bootstrap and meta-analysis methods. LEMD3 rs138916004 and LOC100130298 rs142143628 are only present in Africans (1000G data). LEMD3 showed a significant differential expression in both NCBI Gene Expression Omnibus (GEO) and the Mayo Clinic gene expression data, LOC100130298 showed a significant differential expression only in the GEO expression data, and LY86 showed a significant differential expression only in the Mayo expression data. LEMD3 encodes for an antagonist of TGF-β-induced cell proliferation arrest. LY86 encodes for MD-1 which down-regulates the pro-inflammatory response to lipopolysaccharide; LY86 variation was previously associated with VTE in white women; LOC100130298 is a non-coding RNA gene with unknown regulatory activity in gene expression and epigenetics.
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Affiliation(s)
- John A Heit
- John A. Heit, MD, Stabile 6-Hematology Research, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA, Tel.: +1 507 284 4634, Fax: +1 507 266 9302, E-mail:
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44
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Flora P, McCarthy A, Upadhyay M, Rangan P. Role of Chromatin Modifications in Drosophila Germline Stem Cell Differentiation. Results Probl Cell Differ 2017; 59:1-30. [PMID: 28247044 DOI: 10.1007/978-3-319-44820-6_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During Drosophila oogenesis, germline stem cells (GSCs) self-renew and differentiate to give rise to a mature egg. Self-renewal and differentiation of GSCs are regulated by both intrinsic mechanisms such as regulation of gene expression in the germ line and extrinsic signaling pathways from the surrounding somatic niche. Epigenetic mechanisms, including histone-modifying proteins, nucleosome remodeling complexes, and histone variants, play a critical role in regulating intrinsic gene expression and extrinsic signaling cues from the somatic niche. In the GSCs, intrinsic epigenetic modifiers are required to maintain a stem cell fate by promoting expression of self-renewal factors and repressing the differentiation program. Subsequently, in the GSC daughters, epigenetic regulators activate the differentiation program to promote GSC differentiation. During differentiation, the GSC daughter undergoes meiosis to give rise to the developing egg, containing a compacted chromatin architecture called the karyosome. Epigenetic modifiers control the attachment of chromosomes to the nuclear lamina to aid in meiotic recombination and the release from the lamina for karyosome formation. The germ line is in close contact with the soma for the entirety of this developmental process. This proximity facilitates signaling from the somatic niche to the developing germ line. Epigenetic modifiers play a critical role in the somatic niche, modulating signaling pathways in order to coordinate the transition of GSC to an egg. Together, intrinsic and extrinsic epigenetic mechanisms modulate this exquisitely balanced program.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Alicia McCarthy
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Maitreyi Upadhyay
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA.
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
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Abstract
The nucleus is separated from the cytosol by the nuclear envelope, which is a double lipid bilayer composed of the outer nuclear membrane and the inner nuclear membrane. The intermediate filament proteins lamin A, lamin B, and lamin C form a network underlying the inner nuclear membrane. This proteinaceous network provides the nucleus with its strength, rigidity, and elasticity. Positioned within the inner nuclear membrane are more than 150 inner nuclear membrane proteins, many of which interact directly with lamins and require lamins for their inner nuclear membrane localization. Inner nuclear membrane proteins and the nuclear lamins define the nuclear lamina. These inner nuclear membrane proteins have tissue-specific expression and diverse functions including regulating cytoskeletal organization, nuclear architecture, cell cycle dynamics, and genomic organization. Loss or mutations in lamins and inner nuclear membrane proteins cause a wide spectrum of diseases. Here, I will review the functions of the well-studied nuclear lamina proteins and the diseases associated with loss or mutations in these proteins. © 2016 American Physiological Society. Compr Physiol 6:1655-1674, 2016.
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Affiliation(s)
- James M. Holaska
- Department of Pharmaceutical Sciences, University of the Sciences, Philadelphia, Pennsylvania, USA
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46
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Mutation in LEMD3 (Man1) Associated with Osteopoikilosis and Late-Onset Generalized Morphea: A New Buschke-Ollendorf Syndrome Variant. Case Rep Dermatol Med 2016; 2016:2483041. [PMID: 27382493 PMCID: PMC4921644 DOI: 10.1155/2016/2483041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/26/2016] [Indexed: 11/18/2022] Open
Abstract
Introduction. Buschke-Ollendorf syndrome (BOS) is an uncommon syndrome characterized by osteopoikilosis and other bone abnormalities, accompanied by skin lesions, most frequently connective tissue nevi. BOS is caused by mutations in the LEMD3 gene, which encodes the inner nuclear membrane protein Man1. We describe a unique case of osteopoikilosis associated with late-onset localized scleroderma and familial LEMD3 mutations. Case Report. A 72-year-old woman presented with adult-onset diffuse morphea and bullous skin lesions. Evaluation revealed multiple hyperostotic lesions (osteopoikilosis) suggestive of BOS. DNA sequencing identified a previously undescribed nonsense mutation (Trp621X) in the LEMD3 gene encoding Man1. Two additional family members were found to have osteopoikilosis and carry the same LEMD3 mutation. Conclusions and Relevance. We report a unique familial LEMD3 mutation in an individual with osteopoikilosis and late-onset morphea. We propose that this constellation represents a novel syndromic variant of BOS.
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Tange Y, Chikashige Y, Takahata S, Kawakami K, Higashi M, Mori C, Kojidani T, Hirano Y, Asakawa H, Murakami Y, Haraguchi T, Hiraoka Y. Inner nuclear membrane protein Lem2 augments heterochromatin formation in response to nutritional conditions. Genes Cells 2016; 21:812-32. [PMID: 27334362 DOI: 10.1111/gtc.12385] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/08/2016] [Indexed: 12/29/2022]
Abstract
Inner nuclear membrane proteins interact with chromosomes in the nucleus and are important for chromosome activity. Lem2 and Man1 are conserved members of the LEM-domain nuclear membrane protein family. Mutations of LEM-domain proteins are associated with laminopathy, but their cellular functions remain unclear. Here, we report that Lem2 maintains genome stability in the fission yeast Schizosaccharomyces pombe. S. pombe cells disrupted for the lem2(+) gene (lem2∆) showed slow growth and increased rate of the minichromosome loss. These phenotypes were prominent in the rich culture medium, but not in the minimum medium. Centromeric heterochromatin formation was augmented upon transfer to the rich medium in wild-type cells. This augmentation of heterochromatin formation was impaired in lem2∆ cells. Notably, lem2∆ cells occasionally exhibited spontaneous duplication of genome sequences flanked by the long-terminal repeats of retrotransposons. The resulting duplication of the lnp1(+) gene, which encodes an endoplasmic reticulum membrane protein, suppressed lem2∆ phenotypes, whereas the lem2∆ lnp1∆ double mutant showed a severe growth defect. A combination of mutations in Lem2 and Bqt4, which encodes a nuclear membrane protein that anchors telomeres to the nuclear membrane, caused synthetic lethality. These genetic interactions imply that Lem2 cooperates with the nuclear membrane protein network to regulate genome stability.
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Affiliation(s)
- Yoshie Tange
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Shinya Takahata
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kei Kawakami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Masato Higashi
- Graduate school of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-0810, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Tomoko Kojidani
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan.,Laboratory of Electron Microscopy, Faculty of Science, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo, 112-8681, Japan
| | - Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Yota Murakami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
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48
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Zhang Q, Mo ZH, Dong CS, Yang F, Xie YH, Jin P. Identification of a novel LEMD3 Y871X mutation in a three-generation family with osteopoikilosis and review of the literature. J Endocrinol Invest 2016; 39:679-85. [PMID: 26694706 DOI: 10.1007/s40618-015-0419-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/02/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Osteopoikilosis is a rare and benign autosomal dominant genetic disorder, characterized by a symmetric but unequal distribution of multiple hyperostotic areas in different parts of the skeleton. Recent studies have reported loss-of-function mutations in the LEM domain containing 3 (LEMD3) gene, encoding an inner nuclear membrane protein, as a cause of osteopoikilosis. METHODS We investigated LEMD3 gene in a three-generation family from China, with six patients affected with osteopoikilosis. Peripheral blood samples were collected from family members and 100 healthy controls. All exons of the LEMD3 gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. RESULTS A novel heterozygous c.2612_2613insA (p.Y871X) mutation in exon 13 of LEMD3 was identified, which resulted in a frame shift predicted to generate a premature stop codon at amino acid position 871. The mutation co-segregates with the osteopoikilosis phenotype and was not found in 100 ethnically matched controls. CONCLUSION We identified a new mutation in LEMD3 gene, accounting for the familial case of osteopoikilosis. In addition we also review the clinical manifestation, diagnosis and treatment of osteopoikilosis.
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Affiliation(s)
- Q Zhang
- Department of Endocrinology, 3nd Xiangya Hospital, Central South University, Tongzipo Road, Changsha, 410007, Hunan Province, People's Republic of China
| | - Z H Mo
- Department of Endocrinology, 3nd Xiangya Hospital, Central South University, Tongzipo Road, Changsha, 410007, Hunan Province, People's Republic of China
| | - C S Dong
- Department of Anesthesia, The Affiliated Tumor Hospital of Xiangya Medical School of Central South University, Changsha, 410007, Hunan Province, People's Republic of China
| | - F Yang
- Department of Endocrinology, 3nd Xiangya Hospital, Central South University, Tongzipo Road, Changsha, 410007, Hunan Province, People's Republic of China
| | - Y H Xie
- Department of Endocrinology, 3nd Xiangya Hospital, Central South University, Tongzipo Road, Changsha, 410007, Hunan Province, People's Republic of China
| | - P Jin
- Department of Endocrinology, 3nd Xiangya Hospital, Central South University, Tongzipo Road, Changsha, 410007, Hunan Province, People's Republic of China.
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49
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Zlopasa L, Brachner A, Foisner R. Nucleo-cytoplasmic shuttling of the endonuclease ankyrin repeats and LEM domain-containing protein 1 (Ankle1) is mediated by canonical nuclear export- and nuclear import signals. BMC Cell Biol 2016; 17:23. [PMID: 27245214 PMCID: PMC4888674 DOI: 10.1186/s12860-016-0102-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/19/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ankyrin repeats and LEM domain containing protein 1 (Ankle1) belongs to the LEM protein family, whose members share a chromatin-interacting LEM motif. Unlike most other LEM proteins, Ankle1 is not an integral protein of the inner nuclear membrane but shuttles between the nucleus and the cytoplasm. It contains a GIY-YIG-type nuclease domain, but its function is unknown. The mammalian genome encodes only one other GIY-YIG domain protein, termed Slx1. Slx1 has been described as a resolvase that processes Holliday junctions during homologous recombination-mediated DNA double strand break repair. Resolvase activity is regulated in a spatial and temporal manner during the cell cycle. We hypothesized that Ankle1 may have a similar function and its nucleo-cytoplasmic shuttling may contribute to the regulation of Ankle1 activity. Hence, we aimed at identifying the domains mediating Ankle1 shuttling and investigating whether cellular localization is affected during DNA damage response. RESULTS Sequence analysis predicts the presence of two canonical nuclear import and export signals in Ankle1. Immunofluorescence microscopy of cells expressing wild-type and various mutated Ankle1-fusion proteins revealed a C-terminally located classical monopartite nuclear localization signal and a centrally located CRM1-dependent nuclear export signal that mediate nucleo-cytoplasmic shuttling of Ankle1. These sequences are also functional in heterologous proteins. The predominant localization of Ankle1 in the cytoplasm, however, does not change upon induction of several DNA damage response pathways throughout the cell cycle. CONCLUSIONS We identified the domains mediating nuclear import and export of Ankle1. Ankle1's cellular localization was not affected following DNA damage.
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Affiliation(s)
- Livija Zlopasa
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Andreas Brachner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Roland Foisner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
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Barton LJ, Lovander KE, Pinto BS, Geyer PK. Drosophila male and female germline stem cell niches require the nuclear lamina protein Otefin. Dev Biol 2016; 415:75-86. [PMID: 27174470 DOI: 10.1016/j.ydbio.2016.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
The nuclear lamina is an extensive protein network that underlies the inner nuclear envelope. This network includes the LAP2-emerin-MAN1-domain (LEM-D) protein family, proteins that share an association with the chromatin binding protein Barrier-to-autointegration factor (BAF). Loss of individual LEM-D proteins causes progressive, tissue-restricted diseases, known as laminopathies. Mechanisms associated with laminopathies are not yet understood. Here we present our studies of one of the Drosophila nuclear lamina LEM-D proteins, Otefin (Ote), a homologue of emerin. Previous studies have shown that Ote is autonomously required for the survival of female germline stem cells (GSCs). We demonstrate that Ote is also required for survival of somatic cells in the ovarian niche, with loss of Ote causing a decrease in cap cell number and altered signal transduction. We show germ cell-restricted expression of Ote rescues these defects, revealing a non-autonomous function for Ote in niche maintenance and emphasizing that GSCs contribute to the maintenance of their own niches. Further, we investigate the requirement of Ote in the male fertility. We show that ote mutant males become prematurely sterile as they age. Parallel to observations in females, this sterility is associated with GSC loss and changes in somatic cells of the niche, phenotypes that are largely rescued by germ cell-restricted Ote expression. Taken together, our studies demonstrate that Ote is required autonomously for survival of two stem cell populations, as well as non-autonomously for maintenance of two somatic niches. Finally, our data add to growing evidence that LEM-D proteins have critical roles in stem cell survival and tissue homeostasis.
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Affiliation(s)
- Lacy J Barton
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Kaylee E Lovander
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Belinda S Pinto
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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