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1.
J Cell Sci ; 137(6)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38323935

RESUMO

Robust linkage between adherens junctions and the actomyosin cytoskeleton allows cells to change shape and move during morphogenesis without tearing tissues apart. The Drosophila multidomain protein Canoe and its mammalian homolog afadin are crucial for this, as in their absence many events of morphogenesis fail. To define the mechanism of action for Canoe, we are taking it apart. Canoe has five folded protein domains and a long intrinsically disordered region. The largest is the Dilute domain, which is shared by Canoe and myosin V. To define the roles of this domain in Canoe, we combined biochemical, genetic and cell biological assays. AlphaFold was used to predict its structure, providing similarities and contrasts with Myosin V. Biochemical data suggested one potential shared function - the ability to dimerize. We generated Canoe mutants with the Dilute domain deleted (CnoΔDIL). Surprisingly, they were viable and fertile. CnoΔDIL localized to adherens junctions and was enriched at junctions under tension. However, when its dose was reduced, CnoΔDIL did not provide fully wild-type function. Furthermore, canoeΔDIL mutants had defects in the orchestrated cell rearrangements of eye development. This reveals the robustness of junction-cytoskeletal connections during morphogenesis and highlights the power of natural selection to maintain protein structure.


Assuntos
Proteínas de Drosophila , Miosina Tipo V , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Miosina Tipo V/metabolismo , Citoesqueleto/metabolismo , Junções Intercelulares/metabolismo , Junções Aderentes/metabolismo , Morfogênese , Caderinas/metabolismo , Mamíferos/metabolismo
2.
J Cell Sci ; 136(2)2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36661138

RESUMO

The fate of the two daughter cells is intimately connected to their positioning, which is in turn regulated by cell junction remodelling and orientation of the mitotic spindle. How multiple cues are integrated to dictate the ultimate positioning of daughters is not clear. Here, we identify novel mechanisms of regulation of daughter positioning in single MCF10A cells. The polarity protein, Scribble cooperates with E-cadherin for sequential roles in daughter positioning. First Scribble stabilises E-cadherin at the mitotic cortex as well as the retraction fibres, to mediate spindle orientation. Second, Scribble re-locates to the junction between the two daughters to allow a new E-cadherin-based-interface to form between them, influencing the width of the nascent daughter-daughter junction and subsequent cell positioning. Thus, E-cadherin and Scribble dynamically relocate to different intracellular sites during cell division to orient the mitotic spindle and control placement of the daughter cells after cell division. This article has an associated First Person interview with the first author of the paper.


Assuntos
Caderinas , Fuso Acromático , Humanos , Caderinas/genética , Caderinas/metabolismo , Divisão Celular/genética , Polaridade Celular/fisiologia , Junções Intercelulares/metabolismo , Fuso Acromático/metabolismo
3.
Exp Cell Res ; 435(1): 113927, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38190868

RESUMO

Microtubules constitute pivotal structural elements integral to cellular architecture and physiological functionality. Within the epidermis of the skin, microtubules undergo a noteworthy transition in orientation, shifting from centrosomal to non-centrosomal configurations during the processes of differentiation and stratification. This transition aligns with a discernible increase in the expression of CAMSAP3, a protein that binds to the minus end of microtubules, thereby regulating their orientation. In this study, we identified microtubule-bound CAMSAP3 within HaCaT keratinocytes, revealing an upregulation during the mitotic phase and accumulation at the intercellular bridge during cytokinesis. Building upon this observation, we scrutinized cellular responses upon a tetracycline/doxycycline-inducible CAMSAP3 expression in CAMSAP3-deficient HaCaT cells. Remarkably, CAMSAP3 deficiency induced shifts in microtubule orientation, resulting in cell cycle exit and delayed cytokinesis in a subset of the cells. Furthermore, our inquiry unveiled that CAMSAP3 deficiency adversely impacted the formation and stability of Adherens Junctions and Tight Junctions. In contrast, these perturbations were rectified upon the re-expression of CAMSAP3, underscoring the pivotal role of CAMSAP3 in manifesting differentiation-dependent characteristics in stratified keratinocytes. These observations emphasize the significance of CAMSAP3 in maintaining epidermal homeostasis.


Assuntos
Proteínas Associadas aos Microtúbulos , Microtúbulos , Células Epiteliais/metabolismo , Queratinócitos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Humanos
4.
J Biol Chem ; 299(5): 104571, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36871754

RESUMO

Metastasis-suppressor 1 (MTSS1) is a membrane-interacting scaffolding protein that regulates the integrity of epithelial cell-cell junctions and functions as a tumor suppressor in a wide range of carcinomas. MTSS1 binds phosphoinositide-rich membranes through its I-BAR domain and is capable of sensing and generating negative membrane curvature in vitro. However, the mechanisms by which MTSS1 localizes to intercellular junctions in epithelial cells and contributes to their integrity and maintenance have remained elusive. By carrying out EM and live-cell imaging on cultured Madin-Darby canine kidney cell monolayers, we provide evidence that adherens junctions of epithelial cells harbor lamellipodia-like, dynamic actin-driven membrane folds, which exhibit high negative membrane curvature at their distal edges. BioID proteomics and imaging experiments demonstrated that MTSS1 associates with an Arp2/3 complex activator, the WAVE-2 complex, in dynamic actin-rich protrusions at cell-cell junctions. Inhibition of Arp2/3 or WAVE-2 suppressed actin filament assembly at adherens junctions, decreased the dynamics of junctional membrane protrusions, and led to defects in epithelial integrity. Together, these results support a model in which membrane-associated MTSS1, together with the WAVE-2 and Arp2/3 complexes, promotes the formation of dynamic lamellipodia-like actin protrusions that contribute to the integrity of cell-cell junctions in epithelial monolayers.


Assuntos
Actinas , Proteínas dos Microfilamentos , Pseudópodes , Animais , Cães , Citoesqueleto de Actina/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Actinas/metabolismo , Junções Aderentes/metabolismo , Células Epiteliais/metabolismo , Junções Intercelulares/metabolismo , Células Madin Darby de Rim Canino , Proteínas de Membrana/metabolismo , Pseudópodes/metabolismo , Proteínas dos Microfilamentos/metabolismo
5.
EMBO J ; 39(21): e105479, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32985705

RESUMO

Structural integrity and cellular homeostasis of the embryonic stem cell niche are critical for normal tissue development. In the telencephalic neuroepithelium, this is controlled in part by cell adhesion molecules and regulators of progenitor cell lineage, but the specific orchestration of these processes remains unknown. Here, we studied the role of microRNAs in the embryonic telencephalon as key regulators of gene expression. By using the early recombiner Rx-Cre mouse, we identify novel and critical roles of miRNAs in early brain development, demonstrating they are essential to preserve the cellular homeostasis and structural integrity of the telencephalic neuroepithelium. We show that Rx-Cre;DicerF/F mouse embryos have a severe disruption of the telencephalic apical junction belt, followed by invagination of the ventricular surface and formation of hyperproliferative rosettes. Transcriptome analyses and functional experiments in vivo show that these defects result from upregulation of Irs2 upon loss of let-7 miRNAs in an apoptosis-independent manner. Our results reveal an unprecedented relevance of miRNAs in early forebrain development, with potential mechanistic implications in pediatric brain cancer.


Assuntos
Homeostase , Proteínas Substratos do Receptor de Insulina/metabolismo , MicroRNAs/metabolismo , Proteínas Repressoras/metabolismo , Telencéfalo/embriologia , Telencéfalo/metabolismo , Junções Aderentes , Animais , Apoptose , Proliferação de Células , Humanos , Proteínas Substratos do Receptor de Insulina/genética , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Proteínas do Tecido Nervoso/metabolismo , Neurogênese , Fator de Transcrição PAX6/metabolismo , Proteínas Repressoras/genética , Células-Tronco/metabolismo , Telencéfalo/citologia , Fatores de Transcrição/metabolismo
6.
J Cell Sci ; 135(2)2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34918736

RESUMO

Krev-interaction trapped protein 1 (KRIT1) is an endothelial scaffold protein that promotes adherens junction (AJ) stability. The precise mechanism by which KRIT1 promotes barrier stabilization is unclear. We tested the ability of a panel of KRIT1 constructs containing mutations that inhibit Rap1 binding, ICAP1α binding, disrupt KRIT1's phosphotyrosine-binding (PTB) domain, or direct KRIT1 to the plasma membrane, either alone or in combination, to restore barrier function in KRIT1-deficient endothelial cells. We found that ablating the 192NPAY195 motif or disrupting the PTB domain was sufficient to restore AJ protein localization and barrier function to control levels, irrespective of the junctional localization of KRIT1 or Rap1 binding. The ability of our KRIT1 constructs to rescue AJ and barrier function in KRIT1-depleted endothelial cells correlated with decreased ß1 integrin activity and maintenance of cortical actin fibers. Taken together, our findings indicate that Rap1 binding, ICAP1α binding and junctional localization are not required for the ability of KRIT1 to stabilize endothelial contacts, and suggest that the ability of KRIT1 to limit integrin activity could be involved in barrier stabilization.


Assuntos
Células Endoteliais , Proteínas Associadas aos Microtúbulos , Comunicação Celular , Integrina beta1 , Proteína KRIT1/genética , Proteínas Proto-Oncogênicas
7.
Development ; 148(10)2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33999996

RESUMO

Movement of epithelial cells in a tissue occurs through neighbor exchange and drives tissue shape changes. It requires intercellular junction remodeling, a process typically powered by the contractile actomyosin cytoskeleton. This has been investigated mainly in homogeneous epithelia, where intercalation takes minutes. However, in some tissues, intercalation involves different cell types and can take hours. Whether slow and fast intercalation share the same mechanisms remains to be examined. To address this issue, we used the fly eye, where the cone cells exchange neighbors over ∼10 h to shape the lens. We uncovered three pathways regulating this slow mode of cell intercalation. First, we found a limited requirement for MyosinII. In this case, mathematical modeling predicts an adhesion-dominant intercalation mechanism. Genetic experiments support this prediction, revealing a role for adhesion through the Nephrin proteins Roughest and Hibris. Second, we found that cone cell intercalation is regulated by the Notch pathway. Third, we show that endocytosis is required for membrane removal and Notch activation. Taken together, our work indicates that adhesion, endocytosis and Notch can direct slow cell intercalation during tissue morphogenesis.


Assuntos
Adesão Celular/fisiologia , Proteínas de Drosophila/metabolismo , Drosophila/embriologia , Endocitose/fisiologia , Receptores Notch/metabolismo , Retina/embriologia , Células Fotorreceptoras Retinianas Cones/metabolismo , Actomiosina/metabolismo , Junções Aderentes/fisiologia , Animais , Padronização Corporal/fisiologia , Moléculas de Adesão Celular Neuronais/metabolismo , Comunicação Celular , Proteínas de Drosophila/genética , Células Epiteliais/citologia , Proteínas do Olho/metabolismo , Adesões Focais/fisiologia , Proteínas de Membrana/metabolismo , Miosina Tipo II/metabolismo , Receptores Notch/genética , Transdução de Sinais/fisiologia
8.
Biochem Soc Trans ; 52(1): 137-150, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38323651

RESUMO

Neuropilin-1 (NRP1) is a transmembrane glycoprotein expressed by several cell types including, neurons, endothelial cells (ECs), smooth muscle cells, cardiomyocytes and immune cells comprising macrophages, dendritic cells and T cell subsets. Since NRP1 discovery in 1987 as an adhesion molecule in the frog nervous system, more than 2300 publications on PubMed investigated the function of NRP1 in physiological and pathological contexts. NRP1 has been characterised as a coreceptor for class 3 semaphorins and several members of the vascular endothelial growth factor (VEGF) family. Because the VEGF family is the main regulator of blood and lymphatic vessel growth in addition to promoting neurogenesis, neuronal patterning, neuroprotection and glial growth, the role of NRP1 in these biological processes has been extensively investigated. It is now established that NRP1 promotes the physiological growth of new vessels from pre-existing ones in the process of angiogenesis. Furthermore, several studies have shown that NRP1 mediates signalling pathways regulating pathological vascular growth in ocular neovascular diseases and tumour development. Less defined are the roles of NRP1 in maintaining the function of the quiescent established vasculature in an adult organism. This review will focus on the opposite roles of NRP1 in regulating transforming growth factor ß signalling pathways in different cell types, and on the emerging role of endothelial NRP1 as an atheroprotective, anti-inflammatory factor involved in the response of ECs to shear stress.


Assuntos
Aterosclerose , Neuropilina-1 , Humanos , Adulto , Neuropilina-1/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Células Endoteliais/metabolismo , Angiogênese , Inflamação
9.
Microvasc Res ; 154: 104682, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38521153

RESUMO

Dysfunctional pericytes and disruption of adherens or tight junctions are related to many microvascular diseases, including diabetic retinopathy. In this context, visualizing retinal vascular architecture becomes essential for understanding retinal vascular disease pathophysiology. Although flat mounts provide a demonstration of the retinal blood vasculature, they often lack a clear view of microaneurysms and capillary architecture. Trypsin and elastase digestion are the two techniques for isolating retinal vasculatures in rats, mice, and other animal models. Our observations in the present study reveal that trypsin digestion impacts the association between pericytes and endothelial cells. In contrast, elastase digestion effectively preserves these features in the blood vessels. Furthermore, trypsin digestion disrupts endothelial adherens and tight junctions that elastase digestion does not. Therefore, elastase digestion emerges as a superior technique for isolating retinal vessels, which can be utilized to collect reliable and consistent data to comprehend the pathophysiology of disorders involving microvascular structures.


Assuntos
Camundongos Endogâmicos C57BL , Elastase Pancreática , Pericitos , Vasos Retinianos , Tripsina , Animais , Elastase Pancreática/metabolismo , Tripsina/metabolismo , Vasos Retinianos/metabolismo , Vasos Retinianos/patologia , Pericitos/metabolismo , Pericitos/patologia , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Células Endoteliais/enzimologia , Junções Íntimas/metabolismo , Camundongos , Masculino
10.
Cell Commun Signal ; 22(1): 290, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38802833

RESUMO

The Crumbs protein (CRB) family plays a crucial role in maintaining the apical-basal polarity and integrity of embryonic epithelia. The family comprises different isoforms in different animals and possesses diverse structural, localization, and functional characteristics. Mutations in the human CRB1 or CRB2 gene may lead to a broad spectrum of retinal dystrophies. Various CRB-associated experimental models have recently provided mechanistic insights into human CRB-associated retinopathies. The knowledge obtained from these models corroborates the importance of CRB in retinal development and maintenance. Therefore, complete elucidation of these models can provide excellent therapeutic prospects for human CRB-associated retinopathies. In this review, we summarize the current animal models and human-derived models of different CRB family members and describe the main characteristics of their retinal phenotypes.


Assuntos
Proteínas de Membrana , Doenças Retinianas , Humanos , Animais , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Doenças Retinianas/genética , Doenças Retinianas/patologia , Doenças Retinianas/metabolismo , Retina/metabolismo , Retina/patologia , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Modelos Animais de Doenças , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Mutação
11.
Proc Natl Acad Sci U S A ; 118(24)2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34099568

RESUMO

Cadherins harness the actin cytoskeleton to build cohesive sheets of cells using paradoxically weak bonds, but the molecular mechanisms are poorly understood. In one popular model, actin organizes cadherins into large, micrometer-sized clusters known as puncta. Myosin is thought to pull on these puncta to generate strong adhesion. Here, however, we show that cadherin puncta are actually interdigitated actin microspikes generated by actin polymerization mediated by three factors (Arp2/3, EVL, and CRMP-1). The convoluted membranes in these regions give the impression of cadherin clustering by fluorescence microscopy, but the ratio of cadherin to membrane is constant. Nevertheless, these interlocking fingers of membrane are important for adhesion because perturbing their formation disrupts cell adhesion. In contrast, blocking myosin-dependent contractility does not disrupt either the interdigitated microspikes or lateral membrane adhesion. "Puncta" are zones of strong cell-cell adhesion not due to cadherin clustering but that occur because the interdigitated microspikes expand the surface area available for adhesive bond formation and increase the asperity of the cell surface to promote friction between cells.


Assuntos
Actinas/metabolismo , Caderinas/metabolismo , Extensões da Superfície Celular/metabolismo , Animais , Adesão Celular , Extensões da Superfície Celular/ultraestrutura , Cães , Recuperação de Fluorescência Após Fotodegradação , Proteínas de Fluorescência Verde/metabolismo , Imageamento Tridimensional , Células Madin Darby de Rim Canino , Miosinas/metabolismo , Polimerização
12.
Int J Mol Sci ; 25(14)2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39063127

RESUMO

The production of nanoparticles has recently surged due to their varied applications in the biomedical, pharmaceutical, textile, and electronic sectors. However, this rapid increase in nanoparticle manufacturing has raised concerns about environmental pollution, particularly its potential adverse effects on human health. Among the various concerns, inhalation exposure to nanoparticles poses significant risks, especially affecting the respiratory system. Airway epithelial cells play a crucial role as the primary defense against inhaled particulate matter and pathogens. Studies have shown that nanoparticles can disrupt the airway epithelial barrier, triggering inflammatory responses, generating reactive oxygen species, and compromising cell viability. However, our understanding of how different types of nanoparticles specifically impact the airway epithelial barrier remains limited. Both in vitro cell culture and in vivo murine models are commonly utilized to investigate nanoparticle-induced cellular responses and barrier dysfunction. This review discusses the methodologies frequently employed to assess nanoparticle toxicity and barrier disruption. Furthermore, we analyze and compare the distinct effects of various nanoparticle types on the airway epithelial barrier. By elucidating the diverse responses elicited by different nanoparticles, we aim to provide insights that can guide future research endeavors in assessing and mitigating the potential risks associated with nanoparticle exposure.


Assuntos
Células Epiteliais , Nanopartículas , Humanos , Animais , Nanopartículas/toxicidade , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Testes de Toxicidade/métodos , Espécies Reativas de Oxigênio/metabolismo
13.
Int J Environ Health Res ; 34(2): 1034-1043, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36970877

RESUMO

Teucrium persicum Boiss. an Iranian endemic plant is used in Iranian traditional medicine. E-cadherin transmembrane protein participates in adherens junctions and is the main partner for ß-catenin protein. The GC-MS analysis was used to detect the chemical constituents of the methanolic extract. Its effects on the transcription of the E-cadherin encoding gene, cellular levels, and localization of E-cadherin protein in PC-3 cells were investigated. About 70 chemical constituents were identified. Indirect immunofluorescence microscopy and western blotting results revealed the restoration of E-cadherin protein at cell adhesion contact sites in cells treated with T. persicum extract. Gene expression studies revealed that the extract increased the transcription of the E-cadherin encoding gene in PC-3 cells. These results suggest that T. persicum extract may contain potent compounds that provide further support for the anticancer properties of T. persicum. Surely, detailed molecular investigations are needed to find the mechanism(s) behind these effects.


Assuntos
Teucrium , Humanos , Teucrium/química , Teucrium/metabolismo , Células PC-3 , Irã (Geográfico) , Caderinas/genética , Caderinas/metabolismo , Extratos Vegetais/farmacologia
14.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 55(1): 74-80, 2024 Jan 20.
Artigo em Chinês | MEDLINE | ID: mdl-38322523

RESUMO

Objective: To explore the mechanobiological mechanism of fluid shear force (FSF) on the protection, injury, and destruction of the structure and function of the blood-brain barrier (BBB) under normal physiological conditions, ischemic hypoperfusion, and postoperative hyperperfusion conditions. BBB is mainly composed of brain microvascular endothelial cells. Rat brain microvascular endothelial cells (rBMECs) were used as model cells to conduct the investigation. Methods: rBMECs were seeded at a density of 1×105 cells/cm2 and incubated for 48 h. FSF was applied to the rBMECs at 0.5, 2, and 20 dyn/cm2, respectively, simulating the stress BBB incurs under low perfusion, normal physiological conditions, and high FSF after bypass grafting when there is cerebral vascular stenosis. In addition, a rBMECs static culture group was set up as the control (no force was applied). Light microscope, scanning electron microscope (SEM), and laser confocal microscope (LSCM) were used to observe the changes in cell morphology and cytoskeleton. Transmission electron microscope (TEM) was used to observe the tight junctions. Immunofluorescence assay was performed to determine changes in the distribution of tight junction-associated proteins claudin-5, occludin, and ZO-1 and adherens junction-associated proteins VE-cadherin and PECAM-1. Western blot was performed to determine the expression levels of tight junction-associated proteins claudin-5, ZO-1, and JAM4, adherens junction-associated protein VE-cadherin, and key proteins in Rho GTPases signaling (Rac1, Cdc42, and RhoA) under FSF at different intensities. Results: Microscopic observation showed that the cytoskeleton exhibited disorderly arrangement and irregular orientation under static culture and low shear force (0.5 dyn/cm2). Under normal physiological shear force (2 dyn/cm2), the cytoskeleton was rearranged in the orientation of the FSF and an effective tight junction structure was observed between cells. Under high shear force (20 dyn/cm2), the intercellular space was enlarged and no effective tight junction structure was observed. Immunofluorescence results showed that, under low shear force, the gap between the cells decreased, but there was also decreased distribution of tight junction-associated proteins and adherens junction-associated proteins at the intercellular junctions. Under normal physiological conditions, the cells were tightly connected and most of the tight junction-associated proteins were concentrated at the intercellular junctions. Under high shear force, the gap between the cells increased significantly and the tight junction and adherens junction structures were disrupted. According to the Western blot results, under low shear force, the expression levels of claudin-5, ZO-1, and VE-cadherin were significantly up-regulated compared with those of the control group (P<0.05). Under normal physiological shear force, claudin-5, ZO-1, JAM4, and VE-cadherin were highly expressed compared with those of the control group (P<0.05). Under high shear force, the expressions of claudin-5, ZO-1, JAM4, and VE-cadherin were significantly down-regulated compared with those of the normal physiological shear force group (P<0.05). Under normal physiological shear force, intercellular expressions of Rho GTPases proteins (Rac1, Cdc42, and RhoA) were up-regulated and were higher than those of the other experimental groups (P<0.05). The expressions of Rho GTPases under low and high shear forces were down-regulated compared with that of the normal physiological shear force group (P<0.05). Conclusion: Under normal physiological conditions, FSF helps maintain the integrity of the BBB structure, while low or high shear force can damage or destroy the BBB structure. The regulation of BBB by FSF is closely related to the expression and distribution of tight junction-associated proteins and adherens junction-associated proteins.


Assuntos
Barreira Hematoencefálica , Células Endoteliais , Ratos , Animais , Claudina-5/metabolismo , Encéfalo/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo
15.
Biophys J ; 122(12): 2456-2474, 2023 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-37147801

RESUMO

The cell-cell adhesion cadherin-catenin complexes recruit vinculin to the adherens junction (AJ) to modulate the mechanical couplings between neighboring cells. However, it is unclear how vinculin influences the AJ structure and function. Here, we identified two patches of salt bridges that lock vinculin in the head-tail autoinhibited conformation and reconstituted the full-length vinculin activation mimetics bound to the cadherin-catenin complex. The cadherin-catenin-vinculin complex contains multiple disordered linkers and is highly dynamic, which poses a challenge for structural studies. We determined the ensemble conformation of this complex using small-angle x-ray and selective deuteration/contrast variation small-angle neutron scattering. In the complex, both α-catenin and vinculin adopt an ensemble of flexible conformations, but vinculin has fully open conformations with the vinculin head and actin-binding tail domains well separated from each other. F-actin binding experiments show that the cadherin-catenin-vinculin complex binds and bundles F-actin. However, when the vinculin actin-binding domain is removed from the complex, only a minor fraction of the complex binds to F-actin. The results show that the dynamic cadherin-catenin-vinculin complex employs vinculin as the primary F-actin binding mode to strengthen AJ-cytoskeleton interactions.


Assuntos
Actinas , Caderinas , Caderinas/metabolismo , Actinas/metabolismo , Vinculina/metabolismo , alfa Catenina/química , Ligação Proteica , Citoesqueleto de Actina/metabolismo , Adesão Celular
16.
Curr Issues Mol Biol ; 45(10): 7813-7826, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37886936

RESUMO

Evidence showing the functional significance of the choroid plexus is accumulating. Epithelial cells with tight and adherens junctions of the choroid plexus play important roles in cerebrospinal fluid production and circadian rhythm formation. Although specific types of cadherin expressed in adherens junctions of choroid plexus epithelium (CPE) have been examined, they remained uncertain. Recent mass spectrometry and immunolocalization analysis revealed that non-epithelial cadherins, P- and N-cadherins, are expressed in the lateral membrane of CPE, whereas E-cadherin expression has not been confirmed in CPE of humans or mice. In this study, we examined E-cadherin expression in CPE of mice and humans by RT-PCR, immunohistochemical-, and Western blotting analyses. We confirmed, by using RT-PCR analysis, the mRNA expression of E-cadherin in the choroid plexus of mice. The immunohistochemical expression of E-cadherin was noted in the lateral membrane of CPE of mice and humans. We further confirmed, in Western blotting, the specific immunoreactivity for E-cadherin. Immunohistochemically, the expression of E- and N-cadherins or vimentin was unevenly distributed in some CPE, whereas that of E- and P-cadherins or ß-catenin frequently co-existed in other CPE. These findings indicate that E-cadherin is expressed in the lateral membrane of CPE, possibly correlated with the expression of other cadherins and cytoplasmic proteins.

17.
Angiogenesis ; 26(3): 349-362, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36867287

RESUMO

Angiogenesis, barriergenesis, and immune cell migration are all key physiological events that are dependent on the functional characteristics of the vascular endothelium. The protein family of Nectins and Nectin-like molecules (Necls) is a group of cell adhesion molecules that are widely expressed by different endothelial cell types. The family includes four Nectins (Nectin-1 to -4) and five Necls (Necl-1 to -5) that either interact with each other by forming homo- and heterotypical interactions or bind to ligands expressed within the immune system. Nectin and Necl proteins are mainly described to play a role in cancer immunology and in the development of the nervous system. However, Nectins and Necls are underestimated players in the formation of blood vessels, their barrier properties, and in guiding transendothelial migration of leukocytes. This review summarizes their role in supporting the endothelial barrier through their function in angiogenesis, cell-cell junction formation, and immune cell migration. In addition, this review provides a detailed overview of the expression patterns of Nectins and Necls in the vascular endothelium.


Assuntos
Moléculas de Adesão Celular , Migração Transendotelial e Transepitelial , Nectinas , Movimento Celular/fisiologia , Adesão Celular
18.
J Cell Sci ; 134(17)2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34368835

RESUMO

Epithelia migrate as physically coherent populations of cells. Previous studies have revealed that mechanical stress accumulates in these cellular layers as they move. These stresses are characteristically tensile in nature and have often been inferred to arise when moving cells pull upon the cell-cell adhesions that hold them together. We now report that epithelial tension at adherens junctions between migrating cells also increases due to an increase in RhoA-mediated junctional contractility. We found that active RhoA levels were stimulated by p114 RhoGEF (also known as ARHGEF18) at the junctions between migrating MCF-7 monolayers, and this was accompanied by increased levels of actomyosin and mechanical tension. Applying a strategy to restore active RhoA specifically at adherens junctions by manipulating its scaffold, anillin, we found that this junctional RhoA signal was necessary to stabilize junctional E-cadherin (CDH1) during epithelial migration and promoted orderly collective movement. We suggest that stabilization of E-cadherin by RhoA serves to increase cell-cell adhesion to protect against the mechanical stresses of migration. This article has an associated First Person interview with the first author of the paper.


Assuntos
Junções Aderentes , Proteína rhoA de Ligação ao GTP , Citoesqueleto de Actina/metabolismo , Actomiosina/metabolismo , Junções Aderentes/metabolismo , Caderinas/genética , Caderinas/metabolismo , Células Epiteliais/metabolismo , Humanos , Fatores de Troca de Nucleotídeo Guanina Rho/genética , Transdução de Sinais , Proteína rhoA de Ligação ao GTP/metabolismo
19.
J Anat ; 243(4): 684-689, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37294692

RESUMO

Recent studies in mouse models have demonstrated that the multi-cellular rosette structure of the adrenal zona glomerulosa (ZG) is crucial for aldosterone production by ZG cells. However, the rosette structure of human ZG has remained unclear. The human adrenal cortex undergoes remodeling during aging, and one surprising change is the occurrence of aldosterone-producing cell clusters (APCCs). It is intriguing to know whether APCCs form a rosette structure like normal ZG cells. In this study, we investigated the rosette structure of ZG in human adrenal with and without APCCs, as well as the structure of APCCs. We found that glomeruli in human adrenal are enclosed by a laminin subunit ß1 (lamb1)-rich basement membrane. In slices without APCCs, each glomerulus contains an average of 11 ± 1 cells. In slices with APCCs, each glomerulus in normal ZG contains around 10 ± 1 cells, while each glomerulus in APCCs has significantly more cells (average of 22 ± 1). Similar to what was observed in mice, cells in normal ZG or in APCCs of human adrenal formed rosettes through ß-catenin- and F-actin-rich adherens junctions. The cells in APCCs form larger rosettes through enhanced adherens junctions. This study provides, for the first time, a detailed characterization of the rosette structure of human adrenal ZG and shows that APCCs are not an unstructured cluster of ZG cells. This suggests that the multi-cellular rosette structure may also be necessary for aldosterone production in APCCs.


Assuntos
Córtex Suprarrenal , Zona Glomerulosa , Humanos , Camundongos , Animais , Zona Glomerulosa/metabolismo , Aldosterona/metabolismo , Córtex Suprarrenal/metabolismo
20.
Nano Lett ; 22(1): 302-310, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-34939414

RESUMO

The binding strength between epithelial cells is crucial for tissue integrity, signal transduction and collective cell dynamics. However, there is no experimental approach to precisely modulate cell-cell adhesion strength at the cellular and molecular level. Here, we establish DNA nanotechnology as a tool to control cell-cell adhesion of epithelial cells. We designed a DNA-E-cadherin hybrid system consisting of complementary DNA strands covalently bound to a truncated E-cadherin with a modified extracellular domain. DNA sequence design allows to tune the DNA-E-cadherin hybrid molecular binding strength, while retaining its cytosolic interactions and downstream signaling capabilities. The DNA-E-cadherin hybrid facilitates strong and reversible cell-cell adhesion in E-cadherin deficient cells by forming mechanotransducive adherens junctions. We assess the direct influence of cell-cell adhesion strength on intracellular signaling and collective cell dynamics. This highlights the scope of DNA nanotechnology as a precision technology to study and engineer cell collectives.


Assuntos
Junções Aderentes , Caderinas , Caderinas/genética , Adesão Celular , DNA/metabolismo , Células Epiteliais/metabolismo
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