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1.
Cells ; 13(9)2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38727316

RESUMO

Epithelial-mesenchymal transition (EMT) is a process during which epithelial cells lose epithelial characteristics and gain mesenchymal features. Here, we used several cell models to study migratory activity and redistribution of cell-cell adhesion proteins in cells in different EMT states: EGF-induced EMT of epithelial IAR-20 cells; IAR-6-1 cells with a hybrid epithelial-mesenchymal phenotype; and their more mesenchymal derivatives, IAR-6-1-DNE cells lacking adherens junctions. In migrating cells, the cell-cell adhesion protein α-catenin accumulated at the leading edges along with ArpC2/p34 and α-actinin. Suppression of α-catenin shifted cell morphology from fibroblast-like to discoid and attenuated cell migration. Expression of exogenous α-catenin in MDA-MB-468 cells devoid of α-catenin drastically increased their migratory capabilities. The Y654 phosphorylated form of ß-catenin was detected at integrin adhesion complexes (IACs). Co-immunoprecipitation studies indicated that α-catenin and pY654-ß-catenin were associated with IAC proteins: vinculin, zyxin, and α-actinin. Taken together, these data suggest that in cells undergoing EMT, catenins not participating in assembly of adherens junctions may affect cell migration.


Assuntos
Citoesqueleto de Actina , Movimento Celular , Transição Epitelial-Mesenquimal , alfa Catenina , Humanos , Citoesqueleto de Actina/metabolismo , alfa Catenina/metabolismo , beta Catenina/metabolismo , Vinculina/metabolismo , Junções Aderentes/metabolismo , Adesão Celular , Actinina/metabolismo , Linhagem Celular Tumoral , Zixina/metabolismo , Fosforilação , Integrinas/metabolismo , Animais , Células Epiteliais/metabolismo
2.
Commun Biol ; 7(1): 286, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454140

RESUMO

Through its involvement in gene transcription and heterochromatin formation, DNA methylation regulates how cells interact with their environment. Nevertheless, the extracellular signaling cues that modulate the distribution of this central chromatin modification are largely unclear. DNA methylation is highly abundant at repetitive elements, but its investigation in live cells has been complicated by methodological challenges. Utilizing a CRISPR/dCas9 biosensor that reads DNA methylation of human α-satellite repeats in live cells, we here uncover a signaling pathway linking the chromatin and transcriptional state of repetitive elements to epithelial adherens junction integrity. Specifically, we find that in confluent breast epithelial cell monolayers, α-satellite repeat methylation is reduced by comparison to low density cultures. This is coupled with increased transcriptional activity at repeats. Through comprehensive perturbation experiments, we identify the junctional protein E-cadherin, which links to the actin cytoskeleton, as a central molecular player for signal relay into the nucleus. Furthermore, we find that this pathway is impaired in cancer cells that lack E-cadherin and are not contact-inhibited. This suggests that the molecular connection between cell density and repetitive element methylation could play a role in the maintenance of epithelial tissue homeostasis.


Assuntos
Junções Aderentes , Metilação de DNA , Humanos , Junções Aderentes/genética , Junções Aderentes/metabolismo , Caderinas/genética , Caderinas/metabolismo , Transdução de Sinais , Cromatina/metabolismo
3.
Mol Biol Cell ; 35(5): ar65, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38507238

RESUMO

α-catenin (α-cat) displays force-dependent unfolding and binding to actin filaments through direct and indirect means, but features of adherens junction structure and function most vulnerable to loss of these allosteric mechanisms have not been directly compared. By reconstituting an α-cat F-actin-binding domain unfolding mutant known to exhibit enhanced binding to actin (α-cat-H0-FABD+) into α-cat knockout Madin Darby Canine Kidney (MDCK) cells, we show that partial loss of the α-cat catch bond mechanism (via an altered H0 α-helix) leads to stronger epithelial sheet integrity with greater colocalization between the α-cat-H0-FABD+ mutant and actin. α-cat-H0-FABD+ -expressing cells are less efficient at closing scratch-wounds, suggesting reduced capacity for more dynamic cell-cell coordination. Evidence that α-cat-H0-FABD+ is equally accessible to the conformationally sensitive α18 antibody epitope as WT α-cat and shows similar vinculin recruitment suggests this mutant engages lower tension cortical actin networks, as its M-domain is not persistently open. Conversely, α-cat-M-domain salt-bridge mutants with persistent recruitment of vinculin and phosphorylated myosin light chain show only intermediate monolayer adhesive strengths, but display less directionally coordinated and thereby slower migration speeds during wound-repair. These data show α-cat M- and FABD-unfolding mutants differentially impact cell-cell cohesion and migration properties, and suggest signals favoring α-cat-cortical actin interaction without persistent M-domain opening may improve epithelial monolayer strength through enhanced coupling to lower tension actin networks.


Assuntos
Citoesqueleto de Actina , Actinas , Movimento Celular , Células Epiteliais , alfa Catenina , Cães , Animais , alfa Catenina/metabolismo , alfa Catenina/genética , Células Madin Darby de Rim Canino , Actinas/metabolismo , Células Epiteliais/metabolismo , Citoesqueleto de Actina/metabolismo , Ligação Proteica , Domínios Proteicos , Mutação , Junções Aderentes/metabolismo , Desdobramento de Proteína , Adesão Celular/fisiologia , Vinculina/metabolismo
4.
Proc Natl Acad Sci U S A ; 121(9): e2316722121, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38377188

RESUMO

Cell-cell apical junctions of epithelia consist of multiprotein complexes that organize as belts regulating cell-cell adhesion, permeability, and mechanical tension: the tight junction (zonula occludens), the zonula adherens (ZA), and the macula adherens. The prevailing dogma is that at the ZA, E-cadherin and catenins are lined with F-actin bundles that support and transmit mechanical tension between cells. Using super-resolution microscopy on human intestinal biopsies and Caco-2 cells, we show that two distinct multiprotein belts are basal of the tight junctions as the intestinal epithelia mature. The most apical is populated with nectins/afadin and lined with F-actin; the second is populated with E-cad/catenins. We name this dual-belt architecture the zonula adherens matura. We find that the apical contraction apparatus and the dual-belt organization rely on afadin expression. Our study provides a revised description of epithelial cell-cell junctions and identifies a module regulating the mechanics of epithelia.


Assuntos
Actinas , Junções Aderentes , Humanos , Junções Aderentes/metabolismo , Actinas/metabolismo , Células CACO-2 , Caderinas/genética , Caderinas/metabolismo , Junções Intercelulares/metabolismo , Junções Íntimas/metabolismo , Cateninas/metabolismo , Células Epiteliais/metabolismo
5.
Cell Rep ; 43(3): 113818, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38402586

RESUMO

Intricate cerebral cortex formation is orchestrated by the precise behavior and division dynamics of radial glial cells (RGCs). Endocytosis functions in the recycling and remodeling of adherens junctions (AJs) in response to changes in RGC activity and function. Here, we show that conditional disruption of ubiquitin-associated protein 1 (UBAP1), a component of endosomal sorting complex required for transport (ESCRT), causes severe brain dysplasia and prenatal ventriculomegaly. UBAP1 depletion disrupts the AJs and polarity of RGCs, leading to failure of apically directed interkinetic nuclear migration. Accordingly, UBAP1 knockout or knockdown results in reduced proliferation and precocious differentiation of neural progenitor cells. Mechanistically, UBAP1 regulates the expression and surface localization of cell adhesion molecules, and ß-catenin over-expression significantly rescues the phenotypes of Ubap1 knockdown in vivo. Our study reveals a critical physiological role of the ESCRT machinery in cortical neurogenesis by regulating AJs of RGCs.


Assuntos
Complexos Endossomais de Distribuição Requeridos para Transporte , Células Ependimogliais , Feminino , Gravidez , Humanos , Células Ependimogliais/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Ubiquitina/metabolismo , Junções Aderentes/metabolismo , Córtex Cerebral/metabolismo , Neurogênese , Proteínas de Transporte/metabolismo
6.
Sci Rep ; 14(1): 1218, 2024 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-38216638

RESUMO

Vascular permeability is mediated by Cortactin (Cttn) and regulated by several molecules including cyclic-adenosine-monophosphate, small Rho family GTPases and the actin cytoskeleton. However, it is unclear whether Cttn directly interacts with any of the junctional components or if Cttn intervenes with signaling pathways affecting the intercellular contacts and the cytoskeleton. To address these questions, we employed immortalized microvascular myocardial endothelial cells derived from wild-type and Cttn-knock-out mice. We found that lack of Cttn compromised barrier integrity due to fragmented membrane distribution of different junctional proteins. Moreover, immunoprecipitations revealed that Cttn is within the VE-cadherin-based adherens junction complex. In addition, lack of Cttn slowed-down barrier recovery after Ca2+ repletion. The role of Cttn for cAMP-mediated endothelial barrier regulation was analyzed using Forskolin/Rolipram. In contrast to Cttn-KO, WT cells reacted with increased transendothelial electrical resistance. Absence of Cttn disturbed Rap1 and Rac1 activation in Cttn-depleted cells. Surprisingly, despite the absence of Cttn, direct activation of Rac1/Cdc42/RhoA by CN04 increased barrier resistance and induced well-defined cortical actin and intracellular actin bundles. In summary, our data show that Cttn is required for basal barrier integrity by allowing proper membrane distribution of junctional proteins and for cAMP-mediated activation of the Rap1/Rac1 signaling pathway.


Assuntos
Junções Aderentes , Antígenos CD , Células Endoteliais , Camundongos , Animais , Junções Aderentes/metabolismo , Células Endoteliais/metabolismo , Actinas/metabolismo , Cortactina/genética , Cortactina/metabolismo , Caderinas/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo
7.
Cancer Gene Ther ; 31(2): 322-333, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38057358

RESUMO

Intrahepatic cholangiocarcinoma (iCCA) is a subtype of CCA and has a high mortality rate and a relatively poor prognosis. However, studies focusing on increased cell motility and loss of epithelial integrity during iCCA progression remain relatively scarce. We collected seven fresh tumor samples from four patients to perform RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin using sequencing (ATAC-seq) to determine the transcriptome profile and chromatin accessibility of iCCA. The increased expression of cell cycle regulators, including PLK1 and its substrate MISP, was identified. Ninety-one iCCA patients were used to validate the clinical significance of PLK1 and MISP. The upregulation of PLK1 and MISP was determined in iCCA tissues. Increased expression of PLK1 and MISP was significantly correlated with tumor number, N stage, and lymphatic invasion in an iCCA cohort. Knockdown of PLK1 or MISP reduced trans-lymphatic endothelial migration and wound healing and affected focal adhesions in vitro. In cell‒cell junctions, MISP localized to adherens junctions and suppressed E-cadherin dimerization. PLK1 disrupted adherens junctions in a myosin-dependent manner. Furthermore, PLK1 and MISP promoted cell proliferation in vitro and tumorigenesis in vivo. In iCCA, PLK1 and MISP promote aggressiveness by increasing lymphatic invasion, tumor growth, and motility through the repression of E-cadherin adherens junctions.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Humanos , Junções Aderentes/genética , Junções Aderentes/metabolismo , Junções Aderentes/patologia , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/metabolismo , Ductos Biliares Intra-Hepáticos/metabolismo , Caderinas/genética , Caderinas/metabolismo , Colangiocarcinoma/genética , Colangiocarcinoma/metabolismo
8.
Mol Biol Cell ; 35(1): br3, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37903230

RESUMO

Apical extrusion is a tissue-intrinsic process that allows epithelia to eliminate unfit or surplus cells. This is exemplified by the early extrusion of apoptotic cells, which is critical to maintain the epithelial barrier and prevent inflammation. Apoptotic extrusion is an active mechanical process, which involves mechanotransduction between apoptotic cells and their neighbors, as well as local changes in tissue mechanics. Here we report that the preexisting mechanical tension at adherens junctions (AJs) conditions the efficacy of apoptotic extrusion. Specifically, increasing baseline mechanical tension by overexpression of a phosphomimetic Myosin II regulatory light chain (MRLC) compromises apoptotic extrusion. This occurs when tension is increased in either the apoptotic cell or its surrounding epithelium. Further, we find that the proinflammatory cytokine, TNFα, stimulates Myosin II and increases baseline AJ tension to disrupt apical extrusion, causing apoptotic cells to be retained in monolayers. Importantly, reversal of mechanical tension with an inhibitory MRLC mutant or tropomyosin inhibitors is sufficient to restore apoptotic extrusion in TNFα-treated monolayers. Together, these findings demonstrate that baseline levels of tissue tension are important determinants of apoptotic extrusion, which can potentially be coopted by pathogenetic factors to disrupt the homeostatic response of epithelia to apoptosis.


Assuntos
Junções Aderentes , Células Epiteliais , Junções Aderentes/metabolismo , Células Epiteliais/metabolismo , Mecanotransdução Celular , Fator de Necrose Tumoral alfa , Epitélio/metabolismo , Miosina Tipo II/metabolismo
9.
Mol Biol Cell ; 34(13): ar129, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37819702

RESUMO

Adherens junctions are cadherin-based structures critical for cellular architecture. E-cadherin junctions in mature epithelial cell monolayers tether to an apical actomyosin ring to form the zonula adherens (ZA). We have previously shown that the adherens junction protein PLEKHA7 associates with and regulates the function of the core RNA interference (RNAi) component AGO2 specifically at the ZA. However, the mechanism mediating AGO2 recruitment to the ZA remained unexplored. Here, we reveal that this ZA-specific recruitment of AGO2 depends on both the structural and tensile integrity of the actomyosin cytoskeleton. We found that depletion of not only PLEKHA7, but also either of the three PLEKHA7-interacting, LIM-domain family proteins, namely LMO7, LIMCH1, and PDLIM1, results in disruption of actomyosin organization and tension, as well as disruption of AGO2 junctional localization and of its miRNA-binding ability. We also show that AGO2 binds Myosin IIB and that PLEKHA7, LMO7, LIMCH1, and PDLIM1 all disrupt interaction of AGO2 with Myosin IIB at the ZA. These results demonstrate that recruitment of AGO2 to the ZA is sensitive to actomyosin perturbations, introducing the concept of mechanosensitive RNAi machinery, with potential implications in tissue remodeling and in disease.


Assuntos
Actinas , Junções Aderentes , Actinas/metabolismo , Actomiosina/metabolismo , Junções Aderentes/metabolismo , Caderinas/metabolismo , Citocinese , Células Epiteliais/metabolismo , Miosina não Muscular Tipo IIB/metabolismo , Humanos
10.
STAR Protoc ; 4(4): 102626, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37792537

RESUMO

Adherens junctions (AJs) are multi-protein adhesion structures that couple contractile actomyosin networks of epithelial cells within a tissue. Here, we present an epithelial cell spreading assay on E-cadherin-coated glass or polydimethylsiloxane (PDMS) substrates for detailed microscopy-based analysis of cadherin adhesions. We describe steps for preparation of glass coverslips and PDMS gels, E-cadherin coating, and epithelial cell spreading. Epithelial cells can be seeded on E-cadherin-coated surfaces, thereby mimicking AJ formation in X-Y dimension, making it suitable for microscopy analysis. For complete details on the use and execution of this protocol, please refer to Noordstra et al. (2023).1.


Assuntos
Caderinas , Microscopia , Caderinas/química , Caderinas/metabolismo , Células Epiteliais , Junções Aderentes/metabolismo , Dimetilpolisiloxanos
11.
J Cell Biol ; 222(12)2023 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-37796194

RESUMO

Notch receptors control tissue morphogenic processes that involve coordinated changes in cell architecture and gene expression, but how a single receptor can produce these diverse biological outputs is unclear. Here, we employ a 3D model of a human ductal epithelium to reveal tissue morphogenic defects result from loss of Notch1, but not Notch1 transcriptional signaling. Instead, defects in duct morphogenesis are driven by dysregulated epithelial cell architecture and mitogenic signaling which result from the loss of a transcription-independent, Notch1 cortical signaling mechanism that ultimately functions to stabilize adherens junctions and cortical actin. We identify that Notch1 localization and cortical signaling are tied to apical-basal cell restructuring and discover that a Notch1-FAM83H interaction underlies control of epithelial adherens junctions and cortical actin. Together, these results offer new insights into Notch1 signaling and regulation and advance a paradigm in which transcriptional and cell adhesive programs might be coordinated by a single receptor.


Assuntos
Actinas , Junções Aderentes , Adesão Celular , Receptor Notch1 , Humanos , Junções Aderentes/genética , Proliferação de Células , Células Epiteliais , Proteínas , Receptor Notch1/genética , Transdução de Sinais
12.
Int J Mol Sci ; 24(14)2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37511485

RESUMO

The intercalated disk is a cardiac specific structure composed of three main protein complexes-adherens junctions, desmosomes, and gap junctions-that work in concert to provide mechanical stability and electrical synchronization to the heart. Each substructure is regulated through a variety of mechanisms including proteolysis. Calpain proteases, a class of cysteine proteases dependent on calcium for activation, have recently emerged as important regulators of individual intercalated disk components. In this review, we will examine how calcium homeostasis regulates normal calpain function. We will also explore how calpains modulate gap junctions, desmosomes, and adherens junctions activity by targeting specific proteins, and describe the molecular mechanisms of how calpain dysregulation leads to structural and signaling defects within the heart. We will then examine how changes in calpain activity affects cardiomyocytes, and how such changes underlie various heart diseases.


Assuntos
Cálcio , Calpaína , Calpaína/metabolismo , Cálcio/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Junções Aderentes/metabolismo
13.
Environ Pollut ; 331(Pt 2): 121952, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37270048

RESUMO

Recent findings found that TiO2 nanoparticles (TiO2-NPs) have male reproductive toxicity. However, few reports have studied the toxicity of TiO2-NPs in crustaceans. In this study, we first chose the freshwater crustacean Eriocheir sinensis (E. sinensis) to explore the male toxicity of TiO2-NP exposure and the underlying mechanisms. Three nm and 25 nm TiO2-NPs at a dose of 30 mg/kg bw induced apoptosis and damaged the integrity of the haemolymph-testis-barrier (HTB, a structure similar to the blood-testis-barrier) and the structure of the seminiferous tubule. The 3-nm TiO2-NPs caused more severe spermatogenesis dysfunction than the 25-nm TiO2-NPs. We initially confirmed that TiO2-NP exposure affected the expression patterns of adherens junctions (α-catenin and ß-catenin) and induced tubulin disorganization in the testis of E. sinensis. TiO2-NP exposure caused reactive oxygen species (ROS) generation and an imbalance of mTORC1-mTORC2 (mTORC1/rps6/Akt levels were increased, while mTORC2 activity was not changed). After using the ROS scavenger NAC to inhibit ROS generation, both the mTORC1-mTORC2 imbalance and alterations in AJs were rescued. More importantly, the mTORC1 inhibitor rapamycin abolished mTORC1/rps6/Akt hyperactivation and partially restored the alterations in AJs and tubulin. Collectively, the mTORC1-mTORC2 imbalance induced by TiO2-NPs was involved in the mechanism of AJ and HTB disruption, resulting in spermatogenesis in E. sinensis.


Assuntos
Nanopartículas , Testículo , Masculino , Humanos , Testículo/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tubulina (Proteína)/metabolismo , Junções Aderentes/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espermatogênese/fisiologia , Titânio/toxicidade , Titânio/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Nanopartículas/toxicidade , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo
14.
J Cell Sci ; 136(10)2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-37132654

RESUMO

Collective cell migration is the coordinated movement of multiple cells connected by cadherin-based adherens junctions and is essential for physiological and pathological processes. Cadherins undergo dynamic intracellular trafficking, and their surface level is determined by a balance between endocytosis, recycling and degradation. However, the regulatory mechanism of cadherin turnover in collective cell migration remains elusive. In this study, we show that the Bin/amphiphysin/Rvs (BAR) domain protein pacsin 2 (protein kinase C and casein kinase substrate in neurons protein 2) plays an essential role in collective cell migration by regulating N-cadherin (also known as CDH2) endocytosis in human cancer cells. Pacsin 2-depleted cells formed cell-cell contacts enriched with N-cadherin and migrated in a directed manner. Furthermore, pacsin 2-depleted cells showed attenuated internalization of N-cadherin from the cell surface. Interestingly, GST pull-down assays demonstrated that the pacsin 2 SH3 domain binds to the cytoplasmic region of N-cadherin, and expression of an N-cadherin mutant defective in binding to pacsin 2 phenocopied pacsin 2 RNAi cells both in cell contact formation and N-cadherin endocytosis. These data support new insights into a novel endocytic route of N-cadherin in collective cell migration, highlighting pacsin 2 as a possible therapeutic target for cancer metastasis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Caderinas , Neoplasias , Humanos , Junções Aderentes/metabolismo , Caderinas/genética , Caderinas/metabolismo , Membrana Celular/metabolismo , Movimento Celular , Endocitose/fisiologia , Neoplasias/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo
15.
Curr Biol ; 33(13): 2587-2601.e5, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37244252

RESUMO

Collective cell movements contribute to tissue development and repair and spread metastatic disease. In epithelia, cohesive cell movements require reorganization of adherens junctions and the actomyosin cytoskeleton. However, the mechanisms that coordinate cell-cell adhesion and cytoskeletal remodeling during collective cell migration in vivo are unclear. We investigated the mechanisms of collective cell migration during epidermal wound healing in Drosophila embryos. Upon wounding, the cells adjacent to the wound internalize cell-cell adhesion molecules and polarize actin and the motor protein non-muscle myosin II to form a supracellular cable around the wound that coordinates cell movements. The cable anchors at former tricellular junctions (TCJs) along the wound edge, and TCJs are reinforced during wound closure. We found that the small GTPase Rap1 was necessary and sufficient for rapid wound repair. Rap1 promoted myosin polarization to the wound edge and E-cadherin accumulation at TCJs. Using embryos expressing a mutant form of the Rap1 effector Canoe/Afadin that cannot bind Rap1, we found that Rap1 signals through Canoe for adherens junction remodeling, but not for actomyosin cable assembly. Instead, Rap1 was necessary and sufficient for RhoA/Rho1 activation at the wound edge. The RhoGEF Ephexin localized to the wound edge in a Rap1-dependent manner, and Ephexin was necessary for myosin polarization and rapid wound repair, but not for E-cadherin redistribution. Together, our data show that Rap1 coordinates the molecular rearrangements that drive embryonic wound healing, promoting actomyosin cable assembly through Ephexin-Rho1, and E-cadherin redistribution through Canoe, thus enabling rapid collective cell migration in vivo.


Assuntos
Actomiosina , Proteínas de Drosophila , Animais , Actomiosina/metabolismo , Adesão Celular , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Movimento Celular/fisiologia , Miosinas/metabolismo , Junções Aderentes/metabolismo , Caderinas/genética , Caderinas/metabolismo
16.
J Cell Biol ; 222(7)2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37204781

RESUMO

The mechanisms that regulate the spatial sorting of nonmuscle myosins-2 (NM2) isoforms and couple them mechanically to the plasma membrane are unclear. Here we show that the cytoplasmic junctional proteins cingulin (CGN) and paracingulin (CGNL1) interact directly with NM2s through their C-terminal coiled-coil sequences. CGN binds strongly to NM2B, and CGNL1 to NM2A and NM2B. Knockout (KO), exogenous expression, and rescue experiments with WT and mutant proteins show that the NM2-binding region of CGN is required for the junctional accumulation of NM2B, ZO-1, ZO-3, and phalloidin-labeled actin filaments, and for the maintenance of tight junction membrane tortuosity and apical membrane stiffness. CGNL1 expression promotes the junctional accumulation of both NM2A and NM2B and its KO results in myosin-dependent fragmentation of adherens junction complexes. These results reveal a mechanism for the junctional localization of NM2A and NM2B and indicate that, by binding to NM2s, CGN and CGNL1 mechanically couple the actomyosin cytoskeleton to junctional protein complexes to mechanoregulate the plasma membrane.


Assuntos
Membrana Celular , Proteínas do Citoesqueleto , Citoesqueleto , Miosinas , Junções Aderentes/metabolismo , Membrana Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Miosinas/metabolismo , Junções Íntimas/metabolismo
17.
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
18.
Mol Biol Cell ; 34(5): ar46, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36989029

RESUMO

Given the role of E-cadherin (E-cad) in holding epithelial cells together, an inverse relationship between E-cad levels and cell invasion during the epithelial-mesenchymal transition and cancer metastasis has been well recognized. Here we report that E-cad is necessary for the invasiveness of RasV12-transformed intestinal epithelial cells in Drosophila. E-cad/ß-catenin disassembles at adherens junctions and assembles at invasive protrusions--the actin- and cortactin-rich invadopodium-like protrusions associated with the breach of the extracellular matrix (ECM)--during dissemination of RasV12-transformed intestinal epithelial cells. Loss of E-cad impairs the elongation of invasive protrusions and attenuates the ability of RasV12-transformed cells to compromise the ECM. Notably, E-cad and cortactin affect each other's localization to invasive protrusions. Given the essential roles of cortactin in cell invasion, our observations indicate that E-cad plays a role in the invasiveness of RasV12-transformed intestinal epithelial cells by controlling cortactin localization to invasive protrusions. Thus our study demonstrates that E-cad is a component of invasive protrusions and provides molecular insights into the unconventional role of E-cad in cell dissemination in vivo.


Assuntos
Caderinas , Cortactina , Animais , Cortactina/metabolismo , Caderinas/metabolismo , Células Epiteliais/metabolismo , Actinas/metabolismo , Junções Aderentes/metabolismo , Drosophila/metabolismo
19.
Elife ; 122023 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-36892272

RESUMO

Cancers, such as squamous cell carcinoma, frequently invade as multicellular units. However, these invading units can be organised in a variety of ways, ranging from thin discontinuous strands to thick 'pushing' collectives. Here we employ an integrated experimental and computational approach to identify the factors that determine the mode of collective cancer cell invasion. We find that matrix proteolysis is linked to the formation of wide strands but has little effect on the maximum extent of invasion. Cell-cell junctions also favour wide strands, but our analysis also reveals a requirement for cell-cell junctions for efficient invasion in response to uniform directional cues. Unexpectedly, the ability to generate wide invasive strands is coupled to the ability to grow effectively when surrounded by extracellular matrix in three-dimensional assays. Combinatorial perturbation of both matrix proteolysis and cell-cell adhesion demonstrates that the most aggressive cancer behaviour, both in terms of invasion and growth, is achieved at high levels of cell-cell adhesion and high levels of proteolysis. Contrary to expectation, cells with canonical mesenchymal traits - no cell-cell junctions and high proteolysis - exhibit reduced growth and lymph node metastasis. Thus, we conclude that the ability of squamous cell carcinoma cells to invade effectively is also linked to their ability to generate space for proliferation in confined contexts. These data provide an explanation for the apparent advantage of retaining cell-cell junctions in squamous cell carcinomas.


Assuntos
Junções Aderentes , Carcinoma de Células Escamosas , Humanos , Proteólise , Invasividade Neoplásica/patologia , Linhagem Celular Tumoral , Carcinoma de Células Escamosas/patologia
20.
FASEB J ; 37(3): e22786, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36786724

RESUMO

Adherens junctions (AJs) are a defining feature of all epithelial cells. They regulate epithelial tissue architecture and integrity, and their dysregulation is a key step in tumor metastasis. AJ remodeling is crucial for cancer progression, and it plays a key role in tumor cell survival, growth, and dissemination. Few studies have examined AJ remodeling in cancer cells consequently, it remains poorly understood and unleveraged in the treatment of metastatic carcinomas. Fascin1 is an actin-bundling protein that is absent from the normal epithelium but its expression in colon cancer is linked to metastasis and increased mortality. Here, we provide the molecular mechanism of AJ remodeling in colon cancer cells and identify for the first time, fascin1's function in AJ remodeling. We show that in colon cancer cells fascin1 remodels junctional actin and actomyosin contractility which makes AJs less stable but more dynamic. By remodeling AJs fascin1 drives mechanoactivation of WNT/ß-catenin signaling and generates "collective plasticity" which influences the behavior of cells during cell migration. The impact of mechanical inputs on WNT/ß-catenin activation in cancer cells remains poorly understood. Our findings highlight the role of AJ remodeling and mechanosensitive WNT/ß-catenin signaling in the growth and dissemination of colorectal carcinomas.


Assuntos
Junções Aderentes , Neoplasias do Colo , Humanos , Junções Aderentes/metabolismo , Actinas/metabolismo , beta Catenina/metabolismo , Proteínas dos Microfilamentos/metabolismo , Neoplasias do Colo/metabolismo , Caderinas/metabolismo
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