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1.
Commun Biol ; 6(1): 4, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36596888

RESUMO

Hypertrophic cardiomyopathy is an inherited disorder due to mutations in contractile proteins that results in a stiff, hypercontractile myocardium. To understand the role of cardiac stiffness in disease progression, here we create an in vitro model of hypertrophic cardiomyopathy utilizing hydrogel technology. Culturing wild-type cardiac myocytes on hydrogels with a Young's Moduli (stiffness) mimicking hypertrophic cardiomyopathy myocardium is sufficient to induce a hypermetabolic mitochondrial state versus myocytes plated on hydrogels simulating healthy myocardium. Significantly, these data mirror that of myocytes isolated from a murine model of human hypertrophic cardiomyopathy (cTnI-G203S). Conversely, cTnI-G203S myocyte mitochondrial function is completely restored when plated on hydrogels mimicking healthy myocardium. We identify a mechanosensing feedback mechanism between the extracellular matrix and cytoskeletal network that regulates mitochondrial function under healthy conditions, but participates in the progression of hypertrophic cardiomyopathy pathophysiology resulting from sarcomeric gene mutations. Importantly, we pinpoint key 'linker' sites in this schema that may represent potential therapeutic targets.


Assuntos
Cardiomiopatia Hipertrófica , Camundongos , Humanos , Animais , Retroalimentação , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/metabolismo , Citoesqueleto/metabolismo , Miócitos Cardíacos/metabolismo , Troponina I/genética , Troponina I/metabolismo , Matriz Extracelular/metabolismo , Hidrogéis
2.
Skelet Muscle ; 13(1): 1, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609344

RESUMO

BACKGROUND: The dystrophin-glycoprotein complex (DGC) is a critical adhesion complex of the muscle cell membrane, providing a mechanical link between the extracellular matrix (ECM) and the cortical cytoskeleton that stabilizes the sarcolemma during repeated muscle contractions. One integral component of the DGC is the transmembrane protein, sarcospan (SSPN). Overexpression of SSPN in the skeletal muscle of mdx mice (murine model of DMD) restores muscle fiber attachment to the ECM in part through an associated increase in utrophin and integrin adhesion complexes at the cell membrane, protecting the muscle from contraction-induced injury. In this study, we utilized transcriptomic and ECM protein-optimized proteomics data sets from wild-type, mdx, and mdx transgenic (mdxTG) skeletal muscle tissues to identify pathways and proteins driving the compensatory action of SSPN overexpression. METHODS: The tibialis anterior and quadriceps muscles were isolated from wild-type, mdx, and mdxTG mice and subjected to bulk RNA-Seq and global proteomics analysis using methods to enhance capture of ECM proteins. Data sets were further analyzed through the ingenuity pathway analysis (QIAGEN) and integrative gene set enrichment to identify candidate networks, signaling pathways, and upstream regulators. RESULTS: Through our multi-omics approach, we identified 3 classes of differentially expressed genes and proteins in mdxTG muscle, including those that were (1) unrestored (significantly different from wild type, but not from mdx), (2) restored (significantly different from mdx, but not from wild type), and (3) compensatory (significantly different from both wild type and mdx). We identified signaling pathways that may contribute to the rescue phenotype, most notably cytoskeleton and ECM organization pathways. ECM-optimized proteomics revealed an increased abundance of collagens II, V, and XI, along with ß-spectrin in mdxTG samples. Using ingenuity pathway analysis, we identified upstream regulators that are computationally predicted to drive compensatory changes, revealing a possible mechanism of SSPN rescue through a rewiring of cell-ECM bidirectional communication. We found that SSPN overexpression results in upregulation of key signaling molecules associated with regulation of cytoskeleton organization and mechanotransduction, including Yap1, Sox9, Rho, RAC, and Wnt. CONCLUSIONS: Our findings indicate that SSPN overexpression rescues dystrophin deficiency partially through mechanotransduction signaling cascades mediated through components of the ECM and the cortical cytoskeleton.


Assuntos
Distrofina , Distrofia Muscular de Duchenne , Camundongos , Animais , Distrofina/genética , Distrofina/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Mecanotransdução Celular , Camundongos Endogâmicos mdx , Músculo Esquelético/metabolismo , Citoesqueleto/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo
3.
Biomater Adv ; 145: 213277, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36621197

RESUMO

Cells are not only anchored to the extracellular matrix via the focal adhesion complex, the focal adhesion complex also serves as a sensor for force transduction. How tension influences the structure of focal adhesions is not well understood. Here, we analyse the effect of tension on the location of key focal adhesion proteins, namely vinculin, paxillin and actin. We use micropatterning on gold surfaces to manipulate the cell shape, to create focal adhesions at specific cell areas, and to perform metal-induced energy transfer (MIET) measurements on the patterned cells. MIET resolves the different protein locations with respect to the gold surface with nanometer accuracy. Further, we use drugs influencing the cellular motor protein myosin or mechanosensitive ion channels to get deeper insight into focal adhesions at different tension states. We show here that in particular actin is affected by the rationally tuned force balance. Blocking mechanosensitive ion channels has a particularly high influence on the actin and focal adhesion architecture, resulting in larger focal adhesions with elevated paxillin and vinculin and strongly lowered actin stress fibres. Our results can be explained by a balance of adhesion tension with cellular tension together with ion channel-controlled focal adhesion homeostasis, where high cellular tension leads to an elevation of vinculin and actin, while high adhesion tension lowers these proteins.


Assuntos
Actinas , Adesões Focais , Adesões Focais/metabolismo , Actinas/metabolismo , Paxilina/metabolismo , Citoesqueleto/metabolismo , Vinculina/metabolismo , Forma Celular
4.
Proc Natl Acad Sci U S A ; 120(4): e2208536120, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36656858

RESUMO

Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.


Assuntos
Citoesqueleto de Actina , Citoesqueleto , Citoesqueleto de Actina/metabolismo , Citoesqueleto/metabolismo , Fatores de Despolimerização de Actina/metabolismo , Miosinas/metabolismo , Ligação Proteica , Actinas/metabolismo
5.
Cells ; 12(2)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36672231

RESUMO

Astrocytes' organisation affects the functioning and the fine morphology of the brain, both in physiological and pathological contexts. Although many aspects of their role have been characterised, their complex functions remain, to a certain extent, unclear with respect to their contribution to brain cell communication. Here, we studied the effects of nanotopography and microconfinement on primary hippocampal rat astrocytes. For this purpose, we fabricated nanostructured zirconia surfaces as homogenous substrates and as micrometric patterns, the latter produced by a combination of an additive nanofabrication and micropatterning technique. These engineered substrates reproduce both nanotopographical features and microscale geometries that astrocytes encounter in their natural environment, such as basement membrane topography, as well as blood vessels and axonal fibre topology. The impact of restrictive adhesion manifests in the modulation of several cellular properties of single cells (morphological and actin cytoskeletal changes) and the network organisation and functioning. Calcium wave signalling was observed only in astrocytes grown in confined geometries, with an activity enhancement in cells forming elongated agglomerates with dimensions typical of blood vessels or axon fibres. Our results suggest that calcium oscillation and wave propagation are closely related to astrocytic morphology and actin cytoskeleton organisation.


Assuntos
Astrócitos , Sinalização do Cálcio , Ratos , Animais , Astrócitos/metabolismo , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Hipocampo/metabolismo
6.
Theranostics ; 13(1): 59-76, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36593959

RESUMO

Rationale: Cells migrating through interstitial matrix enables stiffening of the tumor micro-environment. To overcome the stiff resistance of extracellular matrix, aggressive cells require the extracellular mechanosensory activation and intracellular tension response. Mechanotransduction linker srGAP2 can synergistically control the mechanical-biochemical process of malignant cell migration. Methods: To mimic the tumor micro-environment containing abundant collagen fibers and moving durotaxis of triple-negative breast cancer cells, the stiff-directed matrix was established. The newly designed srGAP2 tension probe was used to real-time supervise srGAP2 tension in living cells. The phosphorylation sites responsible for srGAP2 tension were identified by phosphorylated mutagenesis. Transwell assays and Xenograft mouse model were performed to evaluate TNBC cells invasiveness in vitro and in vivo. Fluorescence staining and membrane protein isolation were used to detect protein localization. Results: The present study shows srGAP2 serves as a linker to transmit the mechanical signals among cytoskeleton and membrane. SrGAP2 exhibits tension gradients among different parts in the stiff-directionally migrating triple-negative breast cancer cells. Cells showing the polarized tension that increased in the leading edge move faster, particularly guided by the stiff interstitial matrix. The srGAP2 tension-directed cell migration results from the upstream events of PKCα-mediated phosphorylation at Ser206 in the F-bar domain of srGAP2. In addition, Syndecan-4 (SDC4), a transmembrane mechanoreceptor protein, drives PKCα regional recruit on the area of membrane trending deformation, which requires the distinct extent of extracellular mechanics. Conclusion: SDC4-PKCα polarized distribution leads to the intracellular tension gradient of srGAP2, presenting the extra- and intracellular physiochemical integration and essential for persistent cell migration in stiff matrix and caner progression. Targeting the srGAP2-related physicochemical signaling could be developed into the therapeutic strategies of inhibiting breast cancer cell invasion and durotaxis.


Assuntos
Proteína Quinase C-alfa , Neoplasias de Mama Triplo Negativas , Camundongos , Humanos , Animais , Neoplasias de Mama Triplo Negativas/metabolismo , Mecanotransdução Celular , Movimento Celular/fisiologia , Citoesqueleto/metabolismo , Linhagem Celular Tumoral , Microambiente Tumoral , Proteínas Ativadoras de GTPase/metabolismo
7.
Int J Mol Sci ; 24(2)2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36674886

RESUMO

Although the phagocytic activity of macrophages has long been studied, the involvement of microtubules in the process is not well understood. In this study, we improved the fixation protocol and revealed a dynamically rearranging microtubule network in macrophages, consisting of a basal meshwork, thick bundles at the cell edge, and astral microtubules. Some astral microtubules extended beneath the cell cortex and continued to form bundles at the cell edge. These microtubule assemblies were mutually exclusive of actin accumulation during membrane ruffling. Although the stabilization of microtubules with paclitaxel did not affect the resting stage of the macrophages, it reduced the phagocytic activity and membrane ruffling of macrophages activated with serum-MAF, which induced rapid phagocytosis. In contrast, the destabilization of microtubules with nocodazole enhanced membrane ruffling and the internalization of phagocytic targets suggesting an inhibitory effect of the microtubule network on the remodeling of the actin network. Meanwhile, the microtubule network was necessary for phagosome maturation. Our detailed analyses of cytoskeletal filaments suggest a phagocytosis control system involving Ca2+ influx, the destabilization of microtubules, and activation of actin network remodeling, followed by the translocation and acidification of phagosomes on the microtubule bundles.


Assuntos
Actinas , Fagocitose , Actinas/metabolismo , Fagocitose/fisiologia , Macrófagos/metabolismo , Microtúbulos/metabolismo , Citoesqueleto/metabolismo
8.
Methods Mol Biol ; 2626: 365-379, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36715916

RESUMO

We describe a tool, Spatio-Temporal Association Mapping of Proteins (STAMP), for identifying protein interactomes via proximity labeling. For a proof-of-principle study, we use cytidine 5'-triphosphate synthase (CTPS) as an example. CTPS, a metabolic enzyme, forms filamentous structures termed cytoophidia in various tissues. We apply STAMP to a variety of developmental stages and tissues in Drosophila including adult ovaries. Using a cell-specific GAL4 driver, we verify that TurboID can biotinylate the bait protein CTPS, making possible the identification of protein-protein interactions (PPIs) in individual cells. Using the wild-type and mutant CTPS as bait proteins, STAMP results in two distinct sets of proximate proteomes. Our results suggest that STAMP is a feasible tool to catch in vivo PPIs in situ at a defined spatiotemporal resolution.


Assuntos
Carbono-Nitrogênio Ligases , Animais , Feminino , Carbono-Nitrogênio Ligases/genética , Carbono-Nitrogênio Ligases/metabolismo , Citoesqueleto/metabolismo , Drosophila/metabolismo , Ovário/metabolismo , Proteoma/metabolismo
9.
Nat Commun ; 14(1): 478, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36717589

RESUMO

A variety of intracellular bacteria modulate the host cytoskeleton to establish subcellular niches for replication. However, the role of intermediate filaments, which are crucial for mechanical strength and resilience of the cell, and in bacterial vacuole preservation remains unclear. Here, we show that Salmonella effector SopB reorganizes the vimentin network to form cage-like structures that surround Salmonella-containing vacuoles (SCVs). Genetic removal of vimentin markedly disrupts SCV organization, significantly reduces bacterial replication and cell death. Mechanistically, SopB uses its N-terminal Cdc42-binding domain to interact with and activate Cdc42 GTPase, which in turn recruits vimentin around SCVs. A high-content imaging-based screening identified that MEK1/2 inhibition led to vimentin dispersion. Our work therefore elucidates the signaling axis SopB-Cdc42-MEK1/2 as mobilizing host vimentin to maintain concrete SCVs and identifies a mechanism contributing to Salmonella replication. Importantly, Trametinib, a clinically-approved MEK1/2 inhibitor identified in the screen, displayed significant anti-infection efficacy against Salmonella both in vitro and in vivo, and may provide a therapeutic option for treating drug-tolerant salmonellosis.


Assuntos
Salmonella typhimurium , Vacúolos , Humanos , Salmonella typhimurium/genética , Vacúolos/metabolismo , Filamentos Intermediários/metabolismo , Vimentina/metabolismo , Citoesqueleto/metabolismo , Proteínas de Bactérias/metabolismo , Células HeLa
10.
Methods Mol Biol ; 2623: 201-219, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36602688

RESUMO

Molecular motors generate force and mechanical work to perform some of the most energy-demanding cellular processes, such as whole cell motility and cell division. These motors experience resistance from the viscoelastic environment of the surrounding cytoplasm, and opposing forces that can originate from other motors bound to cytoskeleton. Optical trapping is the most widely used method to measure the force-generating and force-response characteristics of motor proteins. Here we present the methodologies of three different optical trapping assays we use to measure how forces originating from external factors affect the microtubule-detachment rate and velocity of dynein. We also briefly discuss the remaining challenges and future directions of optical trapping studies of dyneins and other microtubule-based motors.


Assuntos
Dineínas , Pinças Ópticas , Dineínas/metabolismo , Citoesqueleto/metabolismo , Cinesinas/metabolismo , Microtúbulos/metabolismo
11.
Exp Neurol ; 359: 114251, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36243059

RESUMO

Looking at the puzzle that depicts the molecular determinants in neurodegeneration, many pieces are lacking and multiple interconnections among key proteins and intracellular pathways still remain unclear. Here we focus on the concerted action of α-synuclein and the microtubule cytoskeleton, whose interplay, indeed, is emerging but remains largely unexplored in both its physiology and pathology. α-Synuclein is a key protein involved in neurodegeneration, underlying those diseases termed synucleinopathies. Its propensity to interact with other proteins and structures renders the identification of neuronal death trigger extremely difficult. Conversely, the unbalance of microtubule cytoskeleton in terms of structure, dynamics and function is emerging as a point of convergence in neurodegeneration. Interestingly, α-synuclein and microtubules have been shown to interact and mediate cross-talks with other intracellular structures. This is supported by an increasing amount of evidence ranging from their direct interaction to the engagement of in-common partners and culminating with their respective impact on microtubule-dependent neuronal functions. Last, but not least, it is becoming even more clear that α-synuclein and tubulin work synergically towards pathological aggregation, ultimately resulting in neurodegeneration. In this respect, we supply a novel perspective towards the understanding of α-synuclein biology and, most importantly, of the link between α-synuclein with microtubule cytoskeleton and its impact for neurodegeneration and future development of novel therapeutic strategies.


Assuntos
Citoesqueleto , alfa-Sinucleína , alfa-Sinucleína/metabolismo , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo , Neurônios/metabolismo
12.
Clin Exp Nephrol ; 27(2): 101-109, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36482266

RESUMO

BACKGROUND: Genetic nephrotic syndrome is caused by pathogenic variants in genes encoding proteins necessary for the stability and functionality of the glomerular filtration barrier. To date, more than 70 genes associated with steroid-resistant nephrotic syndrome have been identified. We review the clinical and molecular aspects of genetic nephrotic syndrome with a particular focus on genes associated with slit membrane and podocyte cytoskeleton defects. Sanger sequencing and next-generation sequencing are widely used in the identification of novel gene variants and help us gain a better understanding of the disease. Despite these findings, therapy is mainly supportive and focused on the reduction of proteinuria and management of chronic kidney disease with an unfavorable outcome for a significant proportion of cases. Positive therapeutic effects of immunosuppressive drugs have been reported in some patients; however, their long-time administration cannot be generally recommended. CONCLUSION: Personalized treatment based on understanding the distinct disease pathogenesis is needed. With this, it will be possible to avoid harmful immunosuppressive therapy and improve outcomes and quality of life for pediatric patients suffering from genetic nephrotic syndrome.


Assuntos
Nefropatias , Síndrome Nefrótica , Podócitos , Humanos , Criança , Podócitos/metabolismo , Síndrome Nefrótica/etiologia , Qualidade de Vida , Glomérulos Renais/patologia , Nefropatias/patologia , Citoesqueleto/metabolismo , Citoesqueleto/patologia
13.
J Cell Biol ; 222(3)2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36562751

RESUMO

Septins are cytoskeletal proteins conserved from algae and protists to mammals. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether septins organize as filaments in cells and if septin organization impacts septin function is not known. Customizing a tripartite split-GFP complementation assay, we show that all septins decorating actin stress fibers are octamer-containing filaments. Depleting octamers or preventing septins from polymerizing leads to a loss of stress fibers and reduced cell stiffness. Super-resolution microscopy revealed septin fibers with widths compatible with their organization as paired septin filaments. Nanometer-resolved distance measurements and single-protein tracking further showed that septin filaments are membrane bound and largely immobilized. Finally, reconstitution assays showed that septin filaments mediate actin-membrane anchoring. We propose that septin organization as octamer-based filaments is essential for septin function in anchoring and stabilizing actin filaments at the plasma membrane.


Assuntos
Actinas , Septinas , Humanos , Actinas/metabolismo , Membrana Celular/metabolismo , Citoesqueleto/metabolismo , Microscopia , Septinas/análise
14.
J Mech Behav Biomed Mater ; 138: 105630, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36565693

RESUMO

Osteogenic differentiation has been reportedly regulated by various mechanical stresses, including fluid shear stress and tensile and compressive loading. The promotion of osteoblastic differentiation by these mechanical stresses is accompanied by reorganization of the F-actin cytoskeleton, which is deeply involved in intracellular forces and the mechanical environment. However, there is limited information about the effect on the mechanical environment of the intracellular nucleus, such as the mechanical properties of the nucleus and intracellular forces exerted on the nucleus, which have recently been found to be directly involved in various cellular functions. Here, we investigated the changes in the intracellular force applied to the nucleus and the effect on nuclear morphology and mechanical properties during osteogenic differentiation in human osteoblast-like cells (Saos-2). We carried out cell morphological analyses with confocal fluorescence microscopy, nuclear indentation test with atomic force microscopy (AFM), and fluorescence recovery after photobleaching (FRAP) for intranuclear DNA. The results revealed that a significant reorganization of the F-actin cytoskeleton from the nuclear surfaces to the cell periphery occurred in the osteogenic differentiation processes, simultaneously with the reduction of compressive forces to the nucleus. Such changes also facilitated nuclear shrinkage and stiffening, and further intranuclear chromatin compaction. The results indicate that the reduction of the intracellular compressive force due to reorganization of the F-actin cytoskeleton affects the intra- and extra-mechanical environment of the nucleus, and this change may affect gene expression and DNA replication in the osteogenic differentiation process.


Assuntos
Núcleo Celular , Osteogênese , Humanos , Núcleo Celular/metabolismo , Citoesqueleto/metabolismo , Citoesqueleto de Actina/metabolismo , Diferenciação Celular , Actinas/metabolismo , Estresse Mecânico , Mecanotransdução Celular
15.
J Neurochem ; 160(2): 185-202, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34478582

RESUMO

Co-ordinating the dynamic behaviour of actin filaments (F-actin) and microtubules in filopodia is an important underlying process in neuritogenesis, but the molecular pathways involved are ill-defined. The drebrin/end-binding protein 3 (EB3) pathway is a candidate pathway for linking F-actin to microtubules in filopodia. Drebrin binds F-actin and, simultaneously, the microtubule-binding protein EB3 when bound to microtubule plus-ends. We assessed the effect on neuritogenesis of gain- or loss-of-function of proteins in the drebrin/EB3 pathway in rat embryonic cortical neurons in culture. Loss-of-function of drebrin by gene editing or pharmacological inhibition of drebrin binding to F-actin reduced the number of dynamic microtubules in the cell periphery and simultaneously delayed the initiation of neuritogenesis, whereas over-expression of drebrin induced supernumerary neurites. Similarly, loss of EB3 inhibited neuritogenesis, whereas loss of end-binding protein 1 (EB1), a related protein that does not bind to drebrin, did not affect neuritogenesis. Over-expression of EB3, but not EB1, induced supernumerary neurites. We discovered that EB3 is more proximally located at dynamic microtubule plus-ends than EB1 in growth cone filopodia allowing for continuous microtubule elongation as the drebrin/EB3 pathway zippers microtubules to F-actin in filopodia. Finally, we showed that preventing the entry of dynamic microtubules into filopodia using a pharmacological inhibitor of microtubule dynamics is associated with a loss of EB3, but not EB1, from microtubule plus-ends and a concurrent attenuation of neuritogenesis. Collectively, these findings support the idea that neuritogenesis depends on microtubule/F-actin zippering in filopodia orchestrated by the drebrin/EB3 pathway.


Assuntos
Córtex Cerebral/embriologia , Citoesqueleto/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Animais , Córtex Cerebral/metabolismo , Embrião de Mamíferos , Ratos , Transdução de Sinais/fisiologia
16.
Mediators Inflamm ; 2022: 6255012, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36530558

RESUMO

Ezrin is an actin binding protein connecting the cell membrane and the cytoskeleton, which is crucial to maintaining cell morphology, intercellular adhesion, and cytoskeleton remodeling. Asthma involves dysfunction of inflammatory cells, cytokines, and airway structural cells. Recent studies have shown that ezrin, whose function is affected by extensive phosphorylation and protein interactions, is closely associated with asthma, may be a therapeutic target for asthma treatment. In this review, we summarize studies on ezrin and discuss its role in asthma-related airway inflammation and remodeling.


Assuntos
Asma , Proteínas do Citoesqueleto , Humanos , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Inflamação , Remodelação das Vias Aéreas
17.
Biomolecules ; 12(12)2022 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-36551290

RESUMO

Cytoskeleton proteins have been long recognized as structural proteins that provide the necessary mechanical architecture for cell development and tissue homeostasis. With the completion of the cancer genome project, scientists were surprised to learn that huge numbers of mutated genes are annotated as cytoskeletal or associated proteins. Although most of these mutations are considered as passenger mutations during cancer development and evolution, some genes show high mutation rates that can even determine clinical outcomes. In addition, (phospho)proteomics study confirms that many cytoskeleton-associated proteins, e.g., ß-catenin, PIK3CA, and MB21D2, are important signaling mediators, further suggesting their biofunctional roles in cancer development. With emerging evidence to indicate the involvement of mechanotransduction in stemness formation and cell differentiation, mutations in these key cytoskeleton components may change the physical/mechanical properties of the cells and determine the cell fate during cancer development. In particular, tumor microenvironment remodeling triggered by such alterations has been known to play important roles in autophagy, metabolism, cancer dormancy, and immune evasion. In this review paper, we will highlight the current understanding of how aberrant cytoskeleton networks affect cancer behaviors and cellular functions through mechanotransduction.


Assuntos
Mecanotransdução Celular , Neoplasias , Humanos , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Proteínas do Citoesqueleto/metabolismo , Neoplasias/metabolismo , Diferenciação Celular , Microambiente Tumoral
18.
Cells ; 11(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36497166

RESUMO

Desmin is the major intermediate filament protein of all three muscle cell types, and connects different cell organelles and multi-protein complexes such as the cardiac desmosomes. Several pathogenic mutations in the DES gene cause different skeletal and cardiac myopathies. However, the significance of the majority of DES missense variants is currently unknown, since functional data are lacking. To determine whether desmin missense mutations within the highly conserved 1A coil domain cause a filament assembly defect, we generated a set of variants with unknown significance and systematically analyzed the filament assembly using confocal microscopy in transfected SW-13, H9c2 cells and cardiomyocytes derived from induced pluripotent stem cells. We found that mutations in the N-terminal part of the 1A coil domain affect filament assembly, leading to cytoplasmic desmin aggregation. In contrast, mutant desmin in the C-terminal part of the 1A coil domain forms filamentous structures comparable to wild-type desmin. Our findings suggest that the N-terminal part of the 1A coil domain is a hot spot for pathogenic desmin mutations, which affect desmin filament assembly. This study may have relevance for the genetic counselling of patients carrying variants in the 1A coil domain of the DES gene.


Assuntos
Desmina , Filamentos Intermediários , Doenças Musculares , Humanos , Sequência de Bases , Citoesqueleto/metabolismo , Desmina/genética , Filamentos Intermediários/genética , Filamentos Intermediários/metabolismo , Doenças Musculares/patologia , Animais , Camundongos , Linhagem Celular
19.
Cells ; 11(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36496968

RESUMO

Small GTPases act as molecular switches in regulating a myriad of cellular signaling, cytoskeletal dynamics, vesicular trafficking, and membrane/organelle transport processes. Here, I provide an editorial overview of papers collected in this Special Issue on the "Regulation and Function of Small GTPases 2.0".


Assuntos
Proteínas Monoméricas de Ligação ao GTP , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Transdução de Sinais , Citoesqueleto/metabolismo
20.
Cells ; 11(23)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36497035

RESUMO

Formation and maintenance of tissue barriers require the coordination of cell mechanics and cell-cell junction assembly. Here, we combined methods to modulate ECM stiffness and to measure mechanical forces on adhesion complexes to investigate how tight junctions regulate cell mechanics and epithelial morphogenesis. We found that depletion of the tight junction adaptor ZO-1 disrupted junction assembly and morphogenesis in an ECM stiffness-dependent manner and led to a stiffness-dependant reorganisation of active myosin. Both junction formation and morphogenesis were rescued by inhibition of actomyosin contractility. ZO-1 depletion also impacted mechanical tension at cell-matrix and E-cadherin-based cell-cell adhesions. The effect on E-cadherin also depended on ECM stiffness and correlated with effects of ECM stiffness on actin cytoskeleton organisation. However, ZO-1 knockout also revealed tension-independent functions of ZO-1. ZO-1-deficient cells could assemble functional barriers at low tension, but their tight junctions remained corrupted with strongly reduced and discontinuous recruitment of junctional components. Our results thus reveal that reciprocal regulation between ZO-1 and cell mechanics controls tight junction assembly and epithelial morphogenesis, and that, in a second, tension-independent step, ZO-1 is required to assemble morphologically and structurally fully assembled and functionally normal tight junctions.


Assuntos
Fosfoproteínas , Junções Íntimas , Junções Íntimas/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo , Fosfoproteínas/metabolismo , Caderinas/metabolismo , Citoesqueleto/metabolismo
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