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1.
Cells ; 13(11)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38891112

RESUMO

Matrin-3 (MATR3) was initially discovered as a component of the nuclear matrix about thirty years ago. Since then, accumulating studies have provided evidence that MATR3 not only plays a structural role in the nucleus, but that it is also an active protein involved in regulating gene expression at multiple levels, including chromatin organization, DNA transcription, RNA metabolism, and protein translation in the nucleus and cytoplasm. Furthermore, MATR3 may play a critical role in various cellular processes, including DNA damage response, cell proliferation, differentiation, and survival. In addition to the revelation of its biological role, recent studies have reported MATR3's involvement in the context of various diseases, including neurodegenerative and neurodevelopmental diseases, as well as cancer. Moreover, sequencing studies of patients revealed a handful of disease-associated mutations in MATR3 linked to amyotrophic lateral sclerosis (ALS), which further elevated the gene's importance as a topic of study. In this review, we synthesize the current knowledge regarding the diverse functions of MATR3 in DNA- and RNA-related processes, as well as its involvement in various diseases, with a particular emphasis on ALS.


Assuntos
Esclerose Lateral Amiotrófica , Regulação da Expressão Gênica , Proteínas Associadas à Matriz Nuclear , Matriz Nuclear , Humanos , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Proteínas Associadas à Matriz Nuclear/metabolismo , Proteínas Associadas à Matriz Nuclear/genética , Matriz Nuclear/metabolismo , Animais , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética
2.
Genetics ; 227(3)2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38797871

RESUMO

Nuclear migration through narrow constrictions is important for development, metastasis, and proinflammatory responses. Studies performed in tissue culture cells have implicated linker of nucleoskeleton and cytoskeleton (LINC) complexes, microtubule motors, the actin cytoskeleton, and nuclear envelope repair machinery as important mediators of nuclear movements through constricted spaces. However, little is understood about how these mechanisms operate to move nuclei in vivo. In Caenorhabditis elegans larvae, six pairs of hypodermal P cells migrate from lateral to ventral positions through a constricted space between the body wall muscles and the cuticle. P-cell nuclear migration is mediated in part by LINC complexes using a microtubule-based pathway and by an independent CDC-42/actin-based pathway. However, when both LINC complex and actin-based pathways are knocked out, many nuclei still migrate, suggesting the existence of additional pathways. Here, we show that FLN-2 functions in a third pathway to mediate P-cell nuclear migration. The predicted N-terminal actin-binding domain in FLN-2 that is found in canonical filamins is dispensable for FLN-2 function; this and structural predictions suggest that FLN-2 does not function as a filamin. The immunoglobulin-like repeats 4-8 of FLN-2 were necessary for P-cell nuclear migration. Furthermore, in the absence of the LINC complex component unc-84, fln-2 mutants had an increase in P-cell nuclear rupture. We conclude that FLN-2 functions to maintain the integrity of the nuclear envelope in parallel with the LINC complex and CDC-42/actin-based pathways to move P-cell nuclei through constricted spaces.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Núcleo Celular , Animais , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Núcleo Celular/metabolismo , Actinas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Citoesqueleto de Actina/metabolismo , Membrana Nuclear/metabolismo , Membrana Nuclear/genética , Proteínas dos Microfilamentos/metabolismo , Proteínas dos Microfilamentos/genética , Transdução de Sinais , Matriz Nuclear/metabolismo , Proteínas de Ligação ao GTP
3.
Nat Commun ; 15(1): 1286, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38346986

RESUMO

The nuclear matrix is a nuclear compartment that has diverse functions in chromatin regulation and transcription. However, how this structure influences epigenetic modifications and gene expression in plants is largely unknown. In this study, we show that a nuclear matrix binding protein, AHL22, together with the two transcriptional repressors FRS7 and FRS12, regulates hypocotyl elongation by suppressing the expression of a group of genes known as SMALL AUXIN UP RNAs (SAURs) in Arabidopsis thaliana. The transcriptional repression of SAURs depends on their attachment to the nuclear matrix. The AHL22 complex not only brings these SAURs, which contain matrix attachment regions (MARs), to the nuclear matrix, but it also recruits the histone deacetylase HDA15 to the SAUR loci. This leads to the removal of H3 acetylation at the SAUR loci and the suppression of hypocotyl elongation. Taken together, our results indicate that MAR-binding proteins act as a hub for chromatin and epigenetic regulators. Moreover, we present a mechanism by which nuclear matrix attachment to chromatin regulates histone modifications, transcription, and hypocotyl elongation.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Cromatina/genética , Cromatina/metabolismo , Hipocótilo/genética , Hipocótilo/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Matriz Nuclear/metabolismo , Regulação da Expressão Gênica de Plantas , Histona Desacetilases/genética , Histona Desacetilases/metabolismo
4.
J Biol Chem ; 300(1): 105547, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38072047

RESUMO

As an important posttranslational modification, SUMOylation plays critical roles in almost all biological processes. Although it has been well-documented that SUMOylated proteins are mainly localized in the nucleus and have roles in chromatin-related processes, we showed recently that the SUMOylation machinery is actually enriched in the nuclear matrix rather than chromatin. Here, we provide compelling biochemical, cellular imaging and proteomic evidence that SUMOylated proteins are highly enriched in the nuclear matrix. We demonstrated that inactivation of SUMOylation by inhibiting SUMO-activating E1 enzyme or KO of SUMO-conjugating E2 enzyme UBC9 have only mild effect on nuclear matrix composition, indicating that SUMOylation is neither required for nuclear matrix formation nor for targeting proteins to nuclear matrix. Further characterization of UBC9 KO cells revealed that loss of SUMOylation did not result in significant DNA damage, but led to mitotic arrest and chromosome missegregation. Altogether, our study demonstrates that SUMOylated proteins are selectively enriched in the nuclear matrix and suggests a role of nuclear matrix in mediating SUMOylation and its regulated biological processes.


Assuntos
Segregação de Cromossomos , Matriz Nuclear , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina , Sumoilação , Cromatina/metabolismo , Matriz Nuclear/metabolismo , Proteômica , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/metabolismo , Humanos , Animais , Drosophila melanogaster
5.
Biophys J ; 122(23): 4582-4597, 2023 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-37924205

RESUMO

The linkers of the nucleoskeleton and cytoskeleton (LINC) complex comprises Sad-1 and UNC-84 (SUN) and Klarsicht, ANC-1, SYNE homology (KASH) domain proteins, whose conserved interactions provide a physical coupling between the cytoskeleton and the nucleoskeleton, thereby mediating the transfer of physical forces across the nuclear envelope. The LINC complex can perform distinct cellular functions by pairing various KASH domain proteins with the same SUN domain protein. Recent studies have suggested a higher-order assembly of SUN and KASH instead of a more widely accepted linear trimer model for the LINC complex. In the present study, we use molecular dynamics simulations to investigate the mechanism of force transfer across the two proposed models of LINC complex assembly, namely the 3:3 linear trimer model and the 6:6 higher-order model. Employing steered molecular dynamics simulations with various structures using forces at different rates and directions, we examine the structural stability of the two models under various biologically relevant conditions. Our results suggest that both models can withstand and transfer significant levels of force while retaining their structural integrity. However, the force response of various SUN/KASH assemblies depend on the force direction and pulling rates. Slower pulling rates result in higher mean square fluctuations of the 3:3 assembly compared to the fast pulling. Interestingly, the 6:6 assembly tends to provide an additional range of motion flexibility and might be more advantageous to the structural rigidity and pliability of the nuclear envelope. These findings offer insights into how the SUN and KASH proteins maintain the structural integrity of the nuclear membrane.


Assuntos
Proteínas de Membrana , Proteínas Nucleares , Proteínas Nucleares/metabolismo , Proteínas de Membrana/química , Citoesqueleto/metabolismo , Matriz Nuclear/metabolismo , Membrana Nuclear/metabolismo
6.
Mol Cell Proteomics ; 22(12): 100671, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37863319

RESUMO

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.


Assuntos
Matriz Nuclear , Proteômica , Matriz Nuclear/metabolismo , Proteoma/metabolismo , DNA/metabolismo , RNA/metabolismo , Núcleo Celular
7.
FEBS Lett ; 597(22): 2823-2832, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37846646

RESUMO

The concept of mechanotransduction to the nucleus through a direct force transmission mechanism has fascinated cell biologists for decades. Central to such a mechanism is the linker of nucleoskeleton and cytoskeleton (LINC) complex, which spans the nuclear envelope to couple the cytoplasmic cytoskeleton to the nuclear lamina. In reality, there is not one LINC complex identity, but instead, a family of protein configurations of varied composition that exert both shared and unique functions. Regulated expression of LINC complex components, splice variants, and mechanoresponsive protein turnover mechanisms together shape the complement of LINC complex forms present in a given cell type. Disrupting specific gene(s) encoding LINC complex components therefore gives rise to a range of organismal defects. Moreover, evidence suggests that the mechanical environment remodels LINC complexes, providing a feedback mechanism by which cellular context influences the integration of the nucleus into the cytoskeleton. In particular, evidence for crosstalk between the nuclear and cytoplasmic intermediate filament networks communicated through the LINC complex represents an emerging theme in this active area of ongoing investigation.


Assuntos
Citoesqueleto , Mecanotransdução Celular , Mecanotransdução Celular/fisiologia , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Matriz Nuclear/metabolismo , Membrana Nuclear , Núcleo Celular/metabolismo
8.
Plant Cell ; 35(12): 4284-4303, 2023 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-37738557

RESUMO

The nucleoskeleton forms a filamentous meshwork under the nuclear envelope and contributes to the regulation of nuclear shape and gene expression. To understand how the Arabidopsis (Arabidopsis thaliana) nucleoskeleton physically connects to the nuclear periphery in plants, we investigated the Arabidopsis nucleoskeleton protein KAKU4 and sought for functional regions responsible for its localization at the nuclear periphery. We identified 3 conserved peptide motifs within the N-terminal region of KAKU4, which are required for intermolecular interactions of KAKU4 with itself, interaction with the nucleoskeleton protein CROWDED NUCLEI (CRWN), localization at the nuclear periphery, and nuclear elongation in differentiated tissues. Unexpectedly, we find these motifs to be present also in NUP82 and NUP136, 2 plant-specific nucleoporins from the nuclear pore basket. We further show that NUP82, NUP136, and KAKU4 have a common evolutionary history predating nonvascular land plants with KAKU4 mainly localizing outside the nuclear pore suggesting its divergence from an ancient nucleoporin into a new nucleoskeleton component. Finally, we demonstrate that both NUP82 and NUP136, through their shared N-terminal motifs, interact with CRWN and KAKU4 proteins revealing the existence of a physical continuum between the nuclear pore and the nucleoskeleton in plants.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Poro Nuclear/genética , Poro Nuclear/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Motivos de Aminoácidos , Membrana Nuclear/genética , Membrana Nuclear/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Matriz Nuclear/metabolismo
9.
Nat Plants ; 9(7): 1010-1011, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37400512
10.
Cells ; 12(6)2023 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-36980273

RESUMO

The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex transduces nuclear mechanical inputs suggested to control chromatin organization and gene expression; however, the underlying mechanism is currently unclear. We show here that the LINC complex is needed to minimize chromatin repression in muscle tissue, where the nuclei are exposed to significant mechanical inputs during muscle contraction. To this end, the genomic binding profiles of Polycomb, Heterochromatin Protein1 (HP1a) repressors, and of RNA-Pol II were studied in Drosophila larval muscles lacking functional LINC complex. A significant increase in the binding of Polycomb and parallel reduction of RNA-Pol-II binding to a set of muscle genes was observed. Consistently, enhanced tri-methylated H3K9 and H3K27 repressive modifications and reduced chromatin activation by H3K9 acetylation were found. Furthermore, larger tri-methylated H3K27me3 repressive clusters, and chromatin redistribution from the nuclear periphery towards nuclear center, were detected in live LINC mutant larval muscles. Computer simulation indicated that the observed dissociation of the chromatin from the nuclear envelope promotes growth of tri-methylated H3K27 repressive clusters. Thus, we suggest that by promoting chromatin-nuclear envelope binding, the LINC complex restricts the size of repressive H3K27 tri-methylated clusters, thereby limiting the binding of Polycomb transcription repressor, directing robust transcription in muscle fibers.


Assuntos
Cromatina , Proteínas de Drosophila , Animais , Cromatina/metabolismo , Simulação por Computador , Citoesqueleto/metabolismo , Fatores de Transcrição/metabolismo , Matriz Nuclear/metabolismo , Proteínas do Grupo Polycomb/genética , Proteínas do Grupo Polycomb/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , RNA/metabolismo
11.
Nat Commun ; 14(1): 1111, 2023 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-36849521

RESUMO

Transcription factors (TFs) are transported from the cytoplasm to the nucleus and disappear from the nucleus after they regulate gene expression. Here, we discover an unconventional nuclear export of the TF, orthodenticle homeobox 2 (OTX2), in nuclear budding vesicles, which transport OTX2 to the lysosome. We further find that torsin1a (Tor1a) is responsible for scission of the inner nuclear vesicle, which captures OTX2 using the LINC complex. Consistent with this, in cells expressing an ATPase-inactive Tor1aΔE mutant and the LINC (linker of nucleoskeleton and cytoskeleton) breaker KASH2, OTX2 accumulated and formed aggregates in the nucleus. Consequently, in the mice expressing Tor1aΔE and KASH2, OTX2 could not be secreted from the choroid plexus for transfer to the visual cortex, leading to failed development of parvalbumin neurons and reduced visual acuity. Together, our results suggest that unconventional nuclear egress and secretion of OTX2 are necessary not only to induce functional changes in recipient cells but also to prevent aggregation in donor cells.


Assuntos
Núcleo Celular , Genes Homeobox , Animais , Camundongos , Lisossomos , Divisão Celular , Matriz Nuclear , Vesícula
12.
Chromosome Res ; 31(1): 8, 2023 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-36725757

RESUMO

The nucleus is a complex organelle that hosts the genome and is essential for vital processes like DNA replication, DNA repair, transcription, and splicing. The genome is non-randomly organized in the three-dimensional space of the nucleus. This functional sub-compartmentalization was thought to be organized on the framework of nuclear matrix (NuMat), a non-chromatin scaffold that functions as a substratum for various molecular processes of the nucleus. More recently, nuclear bodies or membrane-less subcompartments of the nucleus are thought to arise due to phase separation of chromatin, RNA, and proteins. The nuclear architecture is an amalgamation of the relative organization of chromatin, epigenetic landscape, the nuclear bodies, and the nucleoskeleton in the three-dimensional space of the nucleus. During mitosis, the nucleus undergoes drastic changes in morphology to the degree that it ceases to exist as such; various nuclear components, including the envelope that defines the nucleus, disintegrate, and the chromatin acquires mitosis-specific epigenetic marks and condenses to form chromosome. Upon mitotic exit, chromosomes are decondensed, re-establish hierarchical genome organization, and regain epigenetic and transcriptional status similar to that of the mother cell. How this mitotic memory is inherited during cell division remains a puzzle. NuMat components that are a part of the mitotic chromosome in the form of mitotic chromosome scaffold (MiCS) could potentially be the seeds that guide the relative re-establishment of the epigenome, chromosome territories, and the nuclear bodies. Here, we synthesize the advances towards understanding cellular memory of nuclear architecture across mitosis and propose a hypothesis that a subset of NuMat proteome essential for nucleation of various nuclear bodies are retained in MiCS to serve as seeds of mitotic memory, thus ensuring the daughter cells re-establish the complex status of nuclear architecture similar to that of the mother cells, thereby maintaining the pre-mitotic transcriptional status.


Assuntos
Núcleo Celular , Cromatina , Núcleo Celular/genética , Núcleo Celular/metabolismo , Cromatina/genética , Cromatina/metabolismo , Cromossomos/genética , Matriz Nuclear/metabolismo , Mitose
13.
Methods Mol Biol ; 2604: 203-214, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36773235

RESUMO

The plant nucleus and the actin cytoskeleton are intimately connected. The actin cytoskeleton is pivotal for nuclear positioning, shape, and dynamics. These properties of the nucleus are important for its functions during normal development and in response to external cues such as biotic and abiotic stresses. Moreover, we know that there is a direct physical connection between the actin cytoskeleton and the nucleus which spans the double-membraned nuclear envelope into the nuclear lamina, and this connection is called the linker of nucleoskeleton and cytoskeleton (LINC) complex. Recently a role for actin in regulating inter-nuclear organization via the control of nuclear invaginations has emerged. Therefore, a detailed understanding of nuclear shape, organization, and dynamics and the techniques used to measure and quantify these metrics will allow us to determine and further understand the contribution made by actin to these parameters. The protocols described here will allow researchers to determine the circularity index of a nucleus, quantify nuclear deformations, and determine dynamics of nuclei within plant cells.


Assuntos
Actinas , Proteínas Nucleares , Núcleo Celular , Membrana Nuclear , Citoesqueleto , Matriz Nuclear
14.
Int J Mol Sci ; 24(4)2023 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-36834575

RESUMO

In this report, we describe the kinetics characteristics of the diacylglycerol lipase-α (DGLα) located at the nuclear matrix of nuclei derived from adult cortical neurons. Thus, using high-resolution fluorescence microscopy, classical biochemical subcellular fractionation, and Western blot techniques, we demonstrate that the DGLα enzyme is located in the matrix of neuronal nuclei. Furthermore, by quantifying the 2-arachidonoylglycerol (2-AG) level by liquid chromatography and mass spectrometry when 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) was exogenously added as substrate, we describe the presence of a mechanism for 2-AG production through DGLα dependent biosynthesis with an apparent Km (Kmapp) of 180 µM and a Vmax of 1.3 pmol min-1 µg-1 protein. We also examined the presence of enzymes with hydrolytic and oxygenase activities that are able to use 2-AG as substrate, and described the localization and compartmentalization of the major 2-AG degradation enzymes, namely monoacylglycerol lipase (MGL), fatty acid amide hydrolase (FAAH), α/ß-hydrolase domain 12 protein (ABHD12) and cyclooxygenase-2 (COX2). Of these, only ABHD12 exhibited the same distribution with respect to chromatin, lamin B1, SC-35 and NeuN as that described for DGLα. When 2-AG was exogenously added, we observed the production of arachidonic acid (AA), which was prevented by inhibitors (but not specific MGL or ABHD6 inhibitors) of the ABHD family. Overall, our results expand knowledge about the subcellular distribution of neuronal DGLα, and provide biochemical and morphological evidence to ensure that 2-AG is produced in the neuronal nuclear matrix. Thus, this work paves the way for proposing a working hypothesis about the role of 2-AG produced in neuronal nuclei.


Assuntos
Endocanabinoides , Neurônios , Ratos , Animais , Endocanabinoides/metabolismo , Neurônios/metabolismo , Monoacilglicerol Lipases/metabolismo , Matriz Nuclear , Encéfalo/metabolismo
15.
J Radiat Res ; 64(2): 358-368, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36694940

RESUMO

The linker of nucleoskeleton and cytoskeleton (LINC) complex has been implicated in various functions of the nuclear envelope, including nuclear migration, mechanotransduction and DNA repair. We previously revealed that the LINC complex component Sad1 and UNC84 domain containing 1 (SUN1) is required for sublethal-dose X-ray-enhanced cell migration and invasion. This study focused on epithelial-mesenchymal transition (EMT), which contributes to cell migration. Hence, the present study aimed to examine whether sublethal-dose X-irradiation induces EMT and whether LINC complex component SUN1 is involved in low-dose X-ray-induced EMT. This study showed that low-dose (0.5 Gy or 2 Gy) X-irradiation induced EMT in human breast cancer MDA-MB-231 cells. Additionally, X-irradiation increased the expression of SUN1. Therefore, SUN1 was depleted using siRNA. In SUN1-depleted cells, low-dose X-irradiation did not induce EMT. In addition, although the SUN1 splicing variant SUN1_916-depleted cells (containing 916 amino acids [AA] of SUN1) were induced EMT by low-dose X-irradiation like as non-transfected control cells, SUN1_888-depleted cells (which encodes 888 AA) were not induced EMT by low-dose X-irradiation. Moreover, since the Wnt/ß-catenin signaling pathway regulates E-cadherin expression via the expression of the E-cadherin repressor Snail, the expression of ß-catenin after X-irradiation was examined. After 24 hours of irradiation, ß-catenin expression increased in non-transfected cells or SUN1_916-depleted cells, whereas ß-catenin expression remained unchanged and did not increase in SUN1- or SUN1_888-depleted cells. Therefore, in this study, we found that low-dose X-irradiation induces EMT, and LINC complex component SUN1, especially SUN1_888, is required for X-ray-induced EMT via activation of the Wnt/ß-catenin signaling pathway.


Assuntos
Transição Epitelial-Mesenquimal , beta Catenina , Humanos , beta Catenina/metabolismo , Raios X , Mecanotransdução Celular , Citoesqueleto/metabolismo , Matriz Nuclear/metabolismo , Movimento Celular , Linhagem Celular Tumoral , Caderinas/metabolismo
16.
Hum Mol Genet ; 32(2): 177-191, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-35925868

RESUMO

Mutations in LMNA, the gene encoding A-type lamins, cause laminopathies-diseases of striated muscle and other tissues. The aetiology of laminopathies has been attributed to perturbation of chromatin organization or structural weakening of the nuclear envelope (NE) such that the nucleus becomes more prone to mechanical damage. The latter model requires a conduit for force transmission to the nucleus. NE-associated Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes are one such pathway. Using clustered regularly interspaced short palindromic repeats to disrupt the Nesprin-1 KASH (Klarsicht, ANC-1, Syne Homology) domain, we identified this LINC complex protein as the predominant NE anchor for microtubule cytoskeleton components, including nucleation activities and motor complexes, in mouse cardiomyocytes. Loss of Nesprin-1 LINC complexes resulted in loss of microtubule cytoskeleton proteins at the nucleus and changes in nuclear morphology and positioning in striated muscle cells, but with no overt physiological defects. Disrupting the KASH domain of Nesprin-1 suppresses Lmna-linked cardiac pathology, likely by reducing microtubule cytoskeleton activities at the nucleus. Nesprin-1 LINC complexes thus represent a potential therapeutic target for striated muscle laminopathies.


Assuntos
Laminopatias , Músculo Estriado , Animais , Camundongos , Proteínas dos Microtúbulos/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Membrana/genética , Citoesqueleto/genética , Citoesqueleto/metabolismo , Matriz Nuclear/genética , Microtúbulos/metabolismo , Membrana Nuclear/genética , Membrana Nuclear/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Músculo Estriado/metabolismo , Laminopatias/metabolismo
17.
Cells ; 11(24)2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36552829

RESUMO

Mutations in genes encoding proteins associated with the linker of nucleoskeleton and cytoskeleton (LINC) complex within the nuclear envelope cause different diseases with varying phenotypes including skeletal muscle, cardiac, metabolic, or nervous system pathologies. There is some understanding of the structure of LINC complex-associated proteins and how they interact, but it is unclear how mutations in genes encoding them can cause the same disease, and different diseases with different phenotypes. Here, published mutations in LINC complex-associated proteins were systematically reviewed and analyzed to ascertain whether patterns exist between the genetic sequence variants and clinical phenotypes. This revealed LMNA is the only LINC complex-associated gene in which mutations commonly cause distinct conditions, and there are no clear genotype-phenotype correlations. Clusters of LMNA variants causing striated muscle disease are located in exons 1 and 6, and metabolic disease-associated LMNA variants are frequently found in the tail of lamin A/C. Additionally, exon 6 of the emerin gene, EMD, may be a mutation "hot-spot", and diseases related to SYNE1, encoding nesprin-1, are most often caused by nonsense type mutations. These results provide insight into the diverse roles of LINC-complex proteins in human disease and provide direction for future gene-targeted therapy development.


Assuntos
Citoesqueleto , Microtúbulos , Humanos , Citoesqueleto/genética , Citoesqueleto/metabolismo , Membrana Nuclear/metabolismo , Matriz Nuclear , Mutação/genética
18.
Proc Natl Acad Sci U S A ; 119(45): e2116167119, 2022 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-36322767

RESUMO

How cells adjust their growth to the spatial and mechanical constraints of their surrounding environment is central to many aspects of biology. Here, we examined how extracellular matrix (ECM) rigidity affects cell division. We found that cells divide more rapidly when cultured on rigid substrates. While we observed no effect of ECM rigidity on rounding or postmitotic spreading duration, we found that changes in matrix stiffness impact mitosis progression. We noticed that ECM elasticity up-regulates the expression of the linker of nucleoskeleton and cytoskeleton (LINC) complex component SUN2, which in turn promotes metaphase-to-anaphase transition by acting on mitotic spindle formation, whereas when cells adhere to soft ECM, low levels of SUN2 expression perturb astral microtubule organization and delay the onset of anaphase.


Assuntos
Citoesqueleto , Matriz Nuclear , Matriz Nuclear/metabolismo , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Mitose , Matriz Extracelular , Fuso Acromático , Anáfase
19.
Results Probl Cell Differ ; 70: 315-337, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36348113

RESUMO

Mechanical forces play pivotal roles in directing cell functions and fate. To elicit gene expression, either intrinsic or extrinsic mechanical information are transmitted into the nucleus beyond the nuclear envelope via at least two distinct pathways, possibly more. The first and well-known pathway utilizes the canonical nuclear transport of mechanoresponsive transcriptional regulators through the nuclear pore complex, which is an exclusive route for macromolecular trafficking between the cytoplasm and nucleoplasm. The second pathway depends on the linker of the nucleoskeleton and cytoskeleton (LINC) complex, which is a molecular bridge traversing the nuclear envelope between the cytoskeleton and nucleoskeleton. This protein complex is a central component in mechanotransduction at the nuclear envelope that transmits mechanical information from the cytoskeleton into the nucleus to influence the nuclear structure, nuclear stiffness, chromatin organization, and gene expression. Besides the mechanical force transducing function, recent increasing evidence shows that the LINC complex plays a role in controlling nucleocytoplasmic transport of mechanoresponsive transcriptional regulators. Here we discuss recent findings regarding the contribution of the LINC complex to the regulation of intracellular localization of the most-notable mechanosensitive transcriptional regulators, ß-catenin, YAP, and TAZ.


Assuntos
Mecanotransdução Celular , Proteínas Nucleares , Transporte Ativo do Núcleo Celular , Proteínas Nucleares/metabolismo , Matriz Nuclear/metabolismo , Citoesqueleto/metabolismo
20.
Redox Biol ; 58: 102545, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36427398

RESUMO

The cellular response to hypoxia, in addition to HIF-dependent transcriptional reprogramming, also involves less characterized transcription-independent processes, such as alternative splicing of the VEGFA transcript leading to the production of the proangiogenic VEGF form. We now show that this event depends on reorganization of the splicing machinery, triggered after short-term hypoxia by ROS production and intranuclear redistribution of the nucleoskeletal proteins SAFB1/2. Exposure to low oxygen causes fast dissociation of SAFB1/2 from the nuclear matrix, which is reversible, inhibited by antioxidant treatment, and also observed under normoxia when the mitochondrial electron transport chain is blocked. This is accompanied by altered interactions between SAFB1/2 and the splicing machinery, translocation of kinase SRPK1 to the cytoplasm, and dephosphorylation of RS-splicing factors. Depletion of SAFB1/2 under normoxia phenocopies the hypoxic and ROS-mediated switch in VEGF mRNA splicing. These data suggest that ROS-dependent remodeling of the nuclear architecture can promote production of splicing variants that facilitate adaptation to hypoxia.


Assuntos
Proteínas de Ligação à Região de Interação com a Matriz , Proteínas Associadas à Matriz Nuclear , Humanos , Proteínas Associadas à Matriz Nuclear/genética , Proteínas Associadas à Matriz Nuclear/metabolismo , Proteínas de Ligação à Região de Interação com a Matriz/genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Matriz Nuclear/metabolismo , Hipóxia/genética , Hipóxia/metabolismo , RNA Mensageiro/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia Celular/genética , Proteínas Serina-Treonina Quinases
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