RESUMEN
Confined cell migration hampers genome integrity and activates the ATR and ATM mechano-transduction pathways. We investigated whether the mechanical stress generated by metastatic interstitial migration contributes to the enhanced chromosomal instability observed in metastatic tumor cells. We employed live cell imaging, micro-fluidic approaches, and scRNA-seq to follow the fate of tumor cells experiencing confined migration. We found that, despite functional ATR, ATM, and spindle assembly checkpoint (SAC) pathways, tumor cells dividing across constriction frequently exhibited altered spindle pole organization, chromosome mis-segregations, micronuclei formation, chromosome fragility, high gene copy number variation, and transcriptional de-regulation and up-regulation of c-MYC oncogenic transcriptional signature via c-MYC locus amplifications. In vivo tumor settings showed that malignant cells populating metastatic foci or infiltrating the interstitial stroma gave rise to cells expressing high levels of c-MYC. Altogether, our data suggest that mechanical stress during metastatic migration contributes to override the checkpoint controls and boosts genotoxic and oncogenic events. Our findings may explain why cancer aneuploidy often does not correlate with mutations in SAC genes and why c-MYC amplification is strongly linked to metastatic tumors.
Asunto(s)
Movimiento Celular , Amplificación de Genes , Proteínas Proto-Oncogénicas c-myc , Estrés Mecánico , Humanos , Movimiento Celular/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Animales , Línea Celular Tumoral , Ratones , Mitosis/genética , Inestabilidad Cromosómica , Regulación Neoplásica de la Expresión Génica , Neoplasias/genética , Neoplasias/patología , Neoplasias/metabolismoRESUMEN
The process in which locally confined epithelial malignancies progressively evolve into invasive cancers is often promoted by unjamming, a phase transition from a solid-like to a liquid-like state, which occurs in various tissues. Whether this tissue-level mechanical transition impacts phenotypes during carcinoma progression remains unclear. Here we report that the large fluctuations in cell density that accompany unjamming result in repeated mechanical deformations of cells and nuclei. This triggers a cellular mechano-protective mechanism involving an increase in nuclear size and rigidity, heterochromatin redistribution and remodelling of the perinuclear actin architecture into actin rings. The chronic strains and stresses associated with unjamming together with the reduction of Lamin B1 levels eventually result in DNA damage and nuclear envelope ruptures, with the release of cytosolic DNA that activates a cGAS-STING (cyclic GMP-AMP synthase-signalling adaptor stimulator of interferon genes)-dependent cytosolic DNA response gene program. This mechanically driven transcriptional rewiring ultimately alters the cell state, with the emergence of malignant traits, including epithelial-to-mesenchymal plasticity phenotypes and chemoresistance in invasive breast carcinoma.
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Actinas , Neoplasias , ADN , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Citosol/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: PALMD (palmdelphin) belongs to the family of paralemmin proteins implicated in cytoskeletal regulation. Single nucleotide polymorphisms in the PALMD locus that result in reduced expression are strong risk factors for development of calcific aortic valve stenosis and predict severity of the disease. METHODS: Immunodetection and public database screening showed dominant expression of PALMD in endothelial cells (ECs) in brain and cardiovascular tissues including aortic valves. Mass spectrometry, coimmunoprecipitation, and immunofluorescent staining allowed identification of PALMD partners. The consequence of loss of PALMD expression was assessed in small interferring RNA-treated EC cultures, knockout mice, and human valve samples. RNA sequencing of ECs and transcript arrays on valve samples from an aortic valve study cohort including patients with the single nucleotide polymorphism rs7543130 informed about gene regulatory changes. RESULTS: ECs express the cytosolic PALMD-KKVI splice variant, which associated with RANGAP1 (RAN GTP hydrolyase activating protein 1). RANGAP1 regulates the activity of the GTPase RAN and thereby nucleocytoplasmic shuttling via XPO1 (Exportin1). Reduced PALMD expression resulted in subcellular relocalization of RANGAP1 and XPO1, and nuclear arrest of the XPO1 cargoes p53 and p21. This indicates an important role for PALMD in nucleocytoplasmic transport and consequently in gene regulation because of the effect on localization of transcriptional regulators. Changes in EC responsiveness on loss of PALMD expression included failure to form a perinuclear actin cap when exposed to flow, indicating lack of protection against mechanical stress. Loss of the actin cap correlated with misalignment of the nuclear long axis relative to the cell body, observed in PALMD-deficient ECs, Palmd-/- mouse aorta, and human aortic valve samples derived from patients with calcific aortic valve stenosis. In agreement with these changes in EC behavior, gene ontology analysis showed enrichment of nuclear- and cytoskeleton-related terms in PALMD-silenced ECs. CONCLUSIONS: We identify RANGAP1 as a PALMD partner in ECs. Disrupting the PALMD/RANGAP1 complex alters the subcellular localization of RANGAP1 and XPO1, and leads to nuclear arrest of the XPO1 cargoes p53 and p21, accompanied by gene regulatory changes and loss of actin-dependent nuclear resilience. Combined, these consequences of reduced PALMD expression provide a mechanistic underpinning for PALMD's contribution to calcific aortic valve stenosis pathology.
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Núcleo Celular/genética , Núcleo Celular/metabolismo , Células Endoteliales/metabolismo , Endotelio/metabolismo , Proteínas de la Membrana/genética , Estrés Mecánico , Anciano , Animales , Comunicación Celular/genética , Línea Celular , Movimiento Celular/genética , Células Cultivadas , Biología Computacional/métodos , Bases de Datos Genéticas , Femenino , Expresión Génica , Perfilación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Ontología de Genes , Humanos , Inmunohistoquímica , Masculino , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Persona de Mediana Edad , Transporte de ProteínasRESUMEN
Circulating tumor cell (CTC) clusters are associated with increased metastatic potential and worse patient prognosis, but are rare, difficult to count, and poorly characterized biophysically. The PillarX device described here is a bimodular microfluidic device (Pillar-device and an X-magnetic device) to profile single CTCs and clusters from whole blood based on their size, deformability, and epithelial marker expression. Larger, less deformable clusters and large single cells are captured in the Pillar-device and sorted according to pillar gap sizes. Smaller, deformable clusters and single cells are subsequently captured in the X-device and separated based on epithelial marker expression using functionalized magnetic nanoparticles. Clusters of established and primary breast cancer cells with variable degrees of cohesion driven by different cell-cell adhesion protein expression are profiled in the device. Cohesive clusters exhibit a lower deformability as they travel through the pillar array, relative to less cohesive clusters, and have greater collective invasive behavior. The ability of the PillarX device to capture clusters is validated in mouse models and patients of metastatic breast cancer. Thus, this device effectively enumerates and profiles CTC clusters based on their unique geometrical, physical, and biochemical properties, and could form the basis of a novel prognostic clinical tool.
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Neoplasias de la Mama , Células Neoplásicas Circulantes , Animales , Neoplasias de la Mama/patología , Línea Celular Tumoral , Separación Celular , Femenino , Humanos , Dispositivos Laboratorio en un Chip , Ratones , Células Neoplásicas Circulantes/patología , PronósticoRESUMEN
During wound repair, branching morphogenesis and carcinoma dissemination, cellular rearrangements are fostered by a solid-to-liquid transition, known as unjamming. The biomolecular machinery behind unjamming and its pathophysiological relevance remain, however, unclear. Here, we study unjamming in a variety of normal and tumorigenic epithelial two-dimensional (2D) and 3D collectives. Biologically, the increased level of the small GTPase RAB5A sparks unjamming by promoting non-clathrin-dependent internalization of epidermal growth factor receptor that leads to hyperactivation of the kinase ERK1/2 and phosphorylation of the actin nucleator WAVE2. This cascade triggers collective motility effects with striking biophysical consequences. Specifically, unjamming in tumour spheroids is accompanied by persistent and coordinated rotations that progressively remodel the extracellular matrix, while simultaneously fluidizing cells at the periphery. This concurrent action results in collective invasion, supporting the concept that the endo-ERK1/2 pathway is a physicochemical switch to initiate collective invasion and dissemination of otherwise jammed carcinoma.
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Diferenciación Celular , Movimiento Celular , Línea Celular Tumoral , Proliferación Celular , Receptores ErbB/metabolismo , Humanos , Cinética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Proteínas de Unión al GTP rab5/metabolismoRESUMEN
Dynamics of epithelial monolayers has recently been interpreted in terms of a jamming or rigidity transition. How cells control such phase transitions is, however, unknown. Here we show that RAB5A, a key endocytic protein, is sufficient to induce large-scale, coordinated motility over tens of cells, and ballistic motion in otherwise kinetically arrested monolayers. This is linked to increased traction forces and to the extension of cell protrusions, which align with local velocity. Molecularly, impairing endocytosis, macropinocytosis or increasing fluid efflux abrogates RAB5A-induced collective motility. A simple model based on mechanical junctional tension and an active cell reorientation mechanism for the velocity of self-propelled cells identifies regimes of monolayer dynamics that explain endocytic reawakening of locomotion in terms of a combination of large-scale directed migration and local unjamming. These changes in multicellular dynamics enable collectives to migrate under physical constraints and may be exploited by tumours for interstitial dissemination.
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Endocitosis , Epitelio/metabolismo , Fenómenos Biomecánicos , Línea Celular Tumoral , Membrana Celular/metabolismo , Humanos , Proteínas de Unión al GTP rab5/metabolismoRESUMEN
Cells constantly sense and respond to mechanical signals by reorganizing their actin cytoskeleton. Although a number of studies have explored the effects of mechanical stimuli on actin dynamics, the immediate response of actin after force application has not been studied. We designed a method to monitor the spatiotemporal reorganization of actin after cell stimulation by local force application. We found that force could induce transient actin accumulation in the perinuclear region within â¼ 2 min. This actin reorganization was triggered by an intracellular Ca(2+) burst induced by force application. Treatment with the calcium ionophore A23187 recapitulated the force-induced perinuclear actin remodeling. Blocking of actin polymerization abolished this process. Overexpression of Klarsicht, ANC-1, Syne Homology (KASH) domain to displace nesprins from the nuclear envelope did not abolish Ca(2+)-dependent perinuclear actin assembly. However, the endoplasmic reticulum- and nuclear membrane-associated inverted formin-2 (INF2), a potent actin polymerization activator (mutations of which are associated with several genetic diseases), was found to be important for perinuclear actin assembly. The perinuclear actin rim structure colocalized with INF2 on stimulation, and INF2 depletion resulted in attenuation of the rim formation. Our study suggests that cells can respond rapidly to external force by remodeling perinuclear actin in a unique Ca(2+)- and INF2-dependent manner.
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Citoesqueleto de Actina/fisiología , Núcleo Celular/fisiología , Mecanotransducción Celular/fisiología , Citoesqueleto de Actina/ultraestructura , Animales , Fenómenos Biomecánicos , Calcio/metabolismo , Técnica del Anticuerpo Fluorescente , Forminas , Immunoblotting , Ratones , Proteínas de Microfilamentos/metabolismo , Microscopía de Fuerza Atómica , Células 3T3 NIH , Estimulación FísicaRESUMEN
Cells sense physical cues at the level of focal adhesions and transduce them to the nucleus by biochemical and mechanical pathways. While the molecular intermediates in the mechanical links have been well studied, their dynamic coupling is poorly understood. In this study, fibroblast cells were adhered to micropillar arrays to probe correlations in the physical coupling between focal adhesions and nucleus. For this, we used novel imaging setup to simultaneously visualize micropillar deflections and EGFP labeled chromatin structure at high spatial and temporal resolution. We observed that micropillar deflections, depending on their relative positions, were positively or negatively correlated to nuclear and heterochromatin movements. Our results measuring the time scales between micropillar deflections and nucleus centroid displacement are suggestive of a strong elastic coupling that mediates differential force transmission to the nucleus.
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Núcleo Celular/metabolismo , Fibroblastos/citología , Adhesiones Focales/metabolismo , Mecanotransducción Celular , Animales , Adhesión Celular , Núcleo Celular/ultraestructura , Elasticidad , Diseño de Equipo , Adhesiones Focales/ultraestructura , Ratones , Microscopía Confocal/instrumentación , Células 3T3 NIH , Imagen Óptica/instrumentaciónRESUMEN
Ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) DNA damage response (DDR) kinases contain elastic domains. ATM also responds to reactive oxygen species (ROS) and ATR to nuclear mechanical stress. Mre11 mediates ATM activation following DNA damage; ATM mutations cause ataxia telangiectasia (A-T). Here, using in vivo imaging, electron microscopy, proteomic, and mechano-biology approaches, we study how ATM responds to mechanical stress. We report that cytoskeleton and ROS, but not Mre11, mediate ATM activation following cell deformation. ATM deficiency causes hyper-stiffness, stress fiber accumulation, Yes-associated protein (YAP) nuclear enrichment, plasma and nuclear membrane alterations during interstitial migration, and H3 hyper-methylation. ATM locates to the actin cytoskeleton and, following cytoskeleton stress, promotes phosphorylation of key cytoskeleton and chromatin regulators. Our data contribute to explain some clinical features of patients with A-T and pinpoint the existence of an integrated mechano-response in which ATM and ATR have distinct roles unrelated to their canonical DDR functions.
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Ataxia Telangiectasia , Proteínas Serina-Treonina Quinasas , Humanos , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Cromatina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteómica , Proteínas de Unión al ADN/metabolismo , Fosforilación , Daño del ADN , Citoesqueleto/metabolismoRESUMEN
Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome characterized by impaired left ventricular (LV) diastolic function, with normal LV ejection fraction. Aortic valve stenosis can cause an HFpEF-like syndrome by inducing sustained pressure overload (PO) and cardiac remodeling, as cardiomyocyte (CM) hypertrophy and fibrotic matrix deposition. Recently, in vivo studies linked PO maladaptive myocardial changes and DNA damage response (DDR) activation: DDR-persistent activation contributes to mouse CM hypertrophy and inflammation, promoting tissue remodeling, and HF. Despite the wide acknowledgment of the pivotal role of the stromal compartment in the fibrotic response to PO, the possible effects of DDR-persistent activation in cardiac stromal cell (C-MSC) are still unknown. Finally, this novel mechanism was not verified in human samples. This study aims to unravel the effects of PO-induced DDR on human C-MSC phenotypes. Human LV septum samples collected from severe aortic stenosis with HFpEF-like syndrome patients undergoing aortic valve surgery and healthy controls (HCs) were used both for histological tissue analyses and C-MSC isolation. PO-induced mechanical stimuli were simulated in vitro by cyclic unidirectional stretch. Interestingly, HFpEF tissue samples revealed DNA damage both in CM and C-MSC. DDR-activation markers γH2AX, pCHK1, and pCHK2 were expressed at higher levels in HFpEF total tissue than in HC. Primary C-MSC isolated from HFpEF and HC subjects and expanded in vitro confirmed the increased γH2AX and phosphorylated checkpoint protein expression, suggesting a persistent DDR response, in parallel with a higher expression of pro-fibrotic and pro-inflammatory factors respect to HC cells, hinting to a DDR-driven remodeling of HFpEF C-MSC. Pressure overload was simulated in vitro, and persistent activation of the CHK1 axis was induced in response to in vitro mechanical stretching, which also increased C-MSC secreted pro-inflammatory and pro-fibrotic molecules. Finally, fibrosis markers were reverted by the treatment with a CHK1/ATR pathway inhibitor, confirming a cause-effect relationship. In conclusion we demonstrated that, in severe aortic stenosis with HFpEF-like syndrome patients, PO induces DDR-persistent activation not only in CM but also in C-MSC. In C-MSC, DDR activation leads to inflammation and fibrosis, which can be prevented by specific DDR targeting.
RESUMEN
Mechanosignaling, initiated by extracellular forces and propagated through the intracellular cytoskeletal network, triggers signaling cascades employed in processes as embryogenesis, tissue maintenance and disease development. While signal transduction by transcription factors occurs downstream of cellular mechanosensing, little is known about the cell intrinsic mechanisms that can regulate mechanosignaling. Here we show that transcription factor PREP1 (PKNOX1) regulates the stiffness of the nucleus, the expression of LINC complex proteins and mechanotransduction of YAP-TAZ. PREP1 depletion upsets the nuclear membrane protein stoichiometry and renders nuclei soft. Intriguingly, these cells display fortified actomyosin network with bigger focal adhesion complexes resulting in greater traction forces at the substratum. Despite the high traction, YAP-TAZ translocation is impaired indicating disrupted mechanotransduction. Our data demonstrate mechanosignaling upstream of YAP-TAZ and suggest the existence of a transcriptional mechanism actively regulating nuclear membrane homeostasis and signal transduction through the active engagement/disengagement of the cell from the extracellular matrix.
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Proteínas Adaptadoras Transductoras de Señales , Factores de Transcripción , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Mecanotransducción Celular/fisiología , Membrana Nuclear/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ , Proteínas Señalizadoras YAPRESUMEN
REF52 fibroblasts have a well-developed contractile machinery, the most prominent elements of which are actomyosin stress fibers with highly ordered organization of actin and myosin IIA filaments. The relationship between contractile activity and turnover dynamics of stress fibers is not sufficiently understood. Here, we simultaneously measured the forces exerted by stress fibers (using traction force microscopy or micropillar array sensors) and the dynamics of actin and myosin (using photoconversion-based monitoring of actin incorporation and high-resolution fluorescence microscopy of myosin II light chain). Our data revealed new features of the crosstalk between myosin II-driven contractility and stress fiber dynamics. During normal stress fiber turnover, actin incorporated all along the stress fibers and not only at focal adhesions. Incorporation of actin into stress fibers/focal adhesions, as well as actin and myosin II filaments flow along stress fibers, strongly depends on myosin II activity. Myosin II-dependent generation of traction forces does not depend on incorporation of actin into stress fibers per se, but still requires formin activity. This previously overlooked function of formins in maintenance of the actin cytoskeleton connectivity could be the main mechanism of formin involvement in traction force generation.
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Actomiosina , Fibras de Estrés , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Actomiosina/metabolismo , Proteínas del Citoesqueleto/metabolismo , Forminas , Cadenas Ligeras de Miosina/metabolismo , Miosina Tipo II/metabolismo , Fibras de Estrés/metabolismoRESUMEN
Glioblastoma are heterogeneous tumors composed of highly invasive and highly proliferative clones. Heterogeneity in invasiveness could emerge from discrete biophysical properties linked to specific molecular expression. We identified clones of patient-derived glioma propagating cells that were either highly proliferative or highly invasive and compared their cellular architecture, migratory, and biophysical properties. We discovered that invasiveness was linked to cellular fitness. The most invasive cells were stiffer, developed higher mechanical forces on the substrate, and moved stochastically. The mechano-chemical-induced expression of the formin FMN1 conferred invasive strength that was confirmed in patient samples. Moreover, FMN1 expression was also linked to motility in other cancer and normal cell lines, and its ectopic expression increased fitness parameters. Mechanistically, FMN1 acts from the microtubule lattice and promotes a robust mechanical cohesion, leading to highly invasive motility.
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Movimiento Celular/fisiología , Forminas/metabolismo , Glioblastoma/metabolismo , Invasividad Neoplásica/patología , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Proteínas Fetales/metabolismo , Glioblastoma/patología , Humanos , Proteínas de Microfilamentos/metabolismoRESUMEN
The spectrin-based membrane skeleton is a major component of the cell cortex. While expressed by all metazoans, its dynamic interactions with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, are poorly understood. Here, we investigate how spectrin re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We find spectrin and acto-myosin to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence that organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.
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Actomiosina/metabolismo , Membrana Celular/metabolismo , Espectrina/metabolismo , Actinas/metabolismo , Animales , Invaginaciones Cubiertas de la Membrana Celular/metabolismo , Endocitosis/fisiología , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Compuestos Heterocíclicos de 4 o más Anillos/farmacología , Membrana Dobles de Lípidos/química , Membrana Dobles de Lípidos/metabolismo , Ratones , Microscopía Confocal , Células 3T3 NIH , Espectrina/genética , Estrés MecánicoRESUMEN
ATR responds to mechanical stress at the nuclear envelope and mediates envelope-associated repair of aberrant topological DNA states. By combining microscopy, electron microscopic analysis, biophysical and in vivo models, we report that ATR-defective cells exhibit altered nuclear plasticity and YAP delocalization. When subjected to mechanical stress or undergoing interstitial migration, ATR-defective nuclei collapse accumulating nuclear envelope ruptures and perinuclear cGAS, which indicate loss of nuclear envelope integrity, and aberrant perinuclear chromatin status. ATR-defective cells also are defective in neuronal migration during development and in metastatic dissemination from circulating tumor cells. Our findings indicate that ATR ensures mechanical coupling of the cytoskeleton to the nuclear envelope and accompanying regulation of envelope-chromosome association. Thus the repertoire of ATR-regulated biological processes extends well beyond its canonical role in triggering biochemical implementation of the DNA damage response.
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Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Núcleo Celular/metabolismo , Estrés Mecánico , Citoesqueleto de Actina , Animales , Proteínas de la Ataxia Telangiectasia Mutada/genética , Encéfalo , Cromatina , Citoplasma , Citoesqueleto/metabolismo , Daño del ADN , Ratones Noqueados , Metástasis de la Neoplasia , Neurogénesis , Membrana Nuclear/metabolismoRESUMEN
Phagocytosis of invading pathogens or cellular debris requires a dramatic change in cell shape driven by actin polymerization. For antibody-covered targets, phagocytosis is thought to proceed through the sequential engagement of Fc-receptors on the phagocyte with antibodies on the target surface, leading to the extension and closure of the phagocytic cup around the target. We find that two actin-dependent molecular motors, class 1 myosins myosin 1e and myosin 1f, are specifically localized to Fc-receptor adhesions and required for efficient phagocytosis of antibody-opsonized targets. Using primary macrophages lacking both myosin 1e and myosin 1f, we find that without the actin-membrane linkage mediated by these myosins, the organization of individual adhesions is compromised, leading to excessive actin polymerization, slower adhesion turnover, and deficient phagocytic internalization. This work identifies a role for class 1 myosins in coordinated adhesion turnover during phagocytosis and supports a mechanism involving membrane-cytoskeletal crosstalk for phagocytic cup closure.
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Actinas/metabolismo , Adhesión Celular/fisiología , Miosina Tipo I/metabolismo , Miosinas/metabolismo , Fagocitosis/fisiología , Actinas/ultraestructura , Animales , Células de la Médula Ósea , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Citoesqueleto/metabolismo , Citoesqueleto/ultraestructura , Femenino , Microscopía Intravital , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Electrónica , Microscopía Fluorescente , Miosina Tipo I/genética , Miosinas/genética , Cultivo Primario de Células , Células RAW 264.7 , Receptores Fc/metabolismo , Receptores Fc/ultraestructura , Imagen de Lapso de TiempoRESUMEN
Extracellular microenvironmental signals modulate the coupling between cytoskeleton to nuclear links to regulate gene expression profiles. However the influence of actomyosin assembly on the morphology of the nucleus is not well understood. In this paper, we quantitatively demonstrate the role of cell geometry and specific actomyosin molecular components in their control of nuclear morphology.