Vinculin, cadherin mechanotransduction and homeostasis of cell-cell junctions

Loss-of-function or gain-of-function variations in VINCULIN (VCL) are risk factors of human neural tube defects

Background

Neural tube defects (NTDs) are severe birth defects resulting from the failure of neural tube closure during embryogenesis. Both genetic and environmental factors contribute to the occurrence of NTDs and the heritability of NTDs is approximately 70%. As a key component of focal adhesions, Vinculin (VCL) plays pivotal roles in cell skeleton remodeling and signal transduction. Vcl deficient mice displayed NTD, but how VCL variants contribute to human NTDs has not been addressed yet.

Methods

We screened VCL variants in a Chinese cohort of 387 NTDs and 244 controls by targeted next‐generation sequencing.

Results

We identified four case‐specific VCL variations (p.M209L, p.D256fs, p.L555V and p.R586Q). VCL p.D256fs and p.L555V are novel variations that have never been reported. Our analysis revealed that p.D256fs is a loss‐of‐function variant, while p.L555V showed a gain of function in planner cell polarity (PCP) pathway regulation and cell migration, probably due to its enhanced protein stability.

Conclusion

Our study reports human NTD specific novel variations in VCL and provides the functional evaluation of VCL variants related to the etiology of human NTDs.

Cell-Cell Adhesion-Driven Contact Guidance and Its Effect on Human Mesenchymal Stem Cell Differentiation

Contact guidance has been extensively explored using patterned adhesion functionalities that predominantly mimic cell-matrix interactions. Whether contact guidance can also be driven by other types of interactions, such as cell-cell adhesion, still remains a question. Herein, this query is addressed by engineering a set of microstrip patterns of (i) cell-cell adhesion ligands and (ii) segregated cell-cell and cell-matrix ligands as a simple yet versatile set of platforms for the guidance of spreading, adhesion, and differentiation of mesenchymal stem cells. It was unprecedently found that micropatterns of cell-cell adhesion ligands can induce contact guidance. Surprisingly, it was found that patterns of alternating cell-matrix and cell-cell strips also induce contact guidance despite providing a spatial continuum for cell adhesion. This guidance is believed to be due to the difference between the potencies of the two adhesions. Furthermore, patterns that combine the two segregated adhesion functionalities were shown to induce more human mesenchymal stem cell osteogenic differentiation than monofunctional patterns. This work provides new insight into the functional crosstalk between cell-cell and cell-matrix adhesions and, overall, further highlights the ubiquitous impact of the biochemical anisotropy of the extracellular environment on cell function.

Mechanical Forces Regulate Cardiomyocyte Myofilament Maturation via the VCL-SSH1-CFL Axis

Mechanical forces regulate cell behavior and tissue morphogenesis. During cardiac development, mechanical stimuli from the heartbeat are required for cardiomyocyte maturation, but the underlying molecular mechanisms remain unclear. Here, we first show that the forces of the contracting heart regulate the localization and activation of the cytoskeletal protein vinculin (VCL), which we find to be essential for myofilament maturation. To further analyze the role of VCL in this process, we examined its interactome in contracting versus non-contracting cardiomyocytes and, in addition to several known interactors, including actin regulators, identified the slingshot protein phosphatase SSH1. We show how VCL recruits SSH1 and its effector, the actin depolymerizing factor cofilin (CFL), to regulate F-actin rearrangement and promote cardiomyocyte myofilament maturation. Overall, our results reveal that mechanical forces generated by cardiac contractility regulate cardiomyocyte maturation through the VCL-SSH1-CFL axis, providing further insight into how mechanical forces are transmitted intracellularly to regulate myofilament maturation.

Soft culture substrates favor stem-like cellular phenotype and facilitate reprogramming of human mesenchymal stem/stromal cells (hMSCs) through mechanotransduction

Biophysical cues influence many aspects of cell behavior. Stiffness of the extracellular matrix is probed by cells and transduced into biochemical signals through mechanotransduction protein networks, strongly influencing stem cell behavior. Cellular stemness is intimately related with mechanical properties of the cell, like intracellular contractility and stiffness, which in turn are influenced by the microenvironment. Pluripotency is associated with soft and low-contractility cells. Hence, we postulated that soft cell culture substrates, presumably inducing low cellular contractility and stiffness, increase the reprogramming efficiency of mesenchymal stem/stromal cells (MSCs) into induced pluripotent stem cells (iPSCs). We demonstrate that soft substrates (1.5 or 15 kPa polydimethylsiloxane – PDMS) caused modulation of several cellular features of MSCs into a phenotype closer to pluripotent stem cells (PSCs). MSCs cultured on soft substrates presented more relaxed nuclei, lower maturation of focal adhesions and F-actin assembling, more euchromatic and less heterochromatic nuclear DNA regions, and increased expression of pluripotency-related genes. These changes correlate with the reprogramming of MSCs, with a positive impact on the kinetics, robustness of colony formation and reprogramming efficiency. Additionally, substrate stiffness influences several phenotypic features of iPS cells and colonies, and data indicates that soft substrates favor full iPSC reprogramming.

Putting VE-cadherin into JAIL for junction remodeling

Junction dynamics of endothelial cells are based on the integration of signal transduction, cytoskeletal remodeling and contraction, which are necessary for the formation and maintenance of monolayer integrity, but also enable repair and regeneration. The VE-cadherin–catenin complex forms the molecular basis of the adherence junctions and cooperates closely with actin filaments. Several groups have recently described small actin-driven protrusions at the cell junctions that are controlled by the Arp2/3 complex, contributing to cell junction regulation. We identified these protrusions as the driving force for VE-cadherin dynamics, as they directly induce new VE-cadherin-mediated adhesion sites, and have accordingly referred to these structures as junction-associated intermittent lamellipodia (JAIL). JAIL extend over only a few microns and thus provide the basis for a subcellular regulation of adhesion. The local (subcellular) VE-cadherin concentration and JAIL formation are directly interdependent, which enables autoregulation. Therefore, this mechanism can contribute a subcellularly regulated adaptation of cell contact dynamics, and is therefore of great importance for monolayer integrity and relative cell migration during wound healing and angiogenesis, as well as for inflammatory responses. In this Review, we discuss the mechanisms and functions underlying these actin-driven protrusions and consider their contribution to the dynamic regulation of endothelial cell junctions.

Histamine causes endothelial barrier disruption via Ca2+-mediated RhoA activation and tension at adherens junctions

During inflammation, the disruption of the endothelial barrier leads to increased microvascular permeability. Whether tension along cell junctions contributes to histamine-induced endothelial barrier disruption remains unknown. Rapid Ca²⁺ influx induced by both histamine and thrombin was accompanied by endothelial barrier breakdown revealed as drop of transendothelial electric resistance in primary human microvascular endothelial cells. Interestingly, GLISA measurements revealed activation of RhoA but not inactivation of Rac1 at the time-point of barrier breakdown. FRET measurements showed activation of RhoA at intercellular junctions after both thrombin and histamine exposure. Breakdown coincided with increased stress fiber formation but not with translocation of vinculin, which was located along junctions in the resting state similar to postcapillary venules ex vivo. Moreover, increased tension at AJs was indicated by immunostaining with a conformation-sensitive antibody targeting the α18-subunit of α-catenin. Ca²⁺ chelation by BAPTA-AM and ROCK1 inhibition by Y27632 abolished both increase of tension along AJs as well as barrier dysfunction. Moreover, BAPTA-AM decreased RhoA activation following histamine stimulation, indicating a key role of Ca²⁺ signaling in barrier breakdown. Taken together, in response to histamine, Ca²⁺ via RhoA/ROCK activation along endothelial adherens junctions (AJs) appears to be critical for barrier disruption and presumably correlated with enhanced tension. However, vinculin appears not to be critical in this process.

The force-sensitive protein Ajuba regulates cell adhesion during epithelial morphogenesis

Mechanical forces are generated during epithelial morphogenesis, but how cells maintain adhesion when exposed to these forces is poorly understood. Razzell et al. show that the LIM domain protein Ajuba localizes to adherens junctions under tension in the Drosophila embryo and is required to maintain cell adhesion during epithelial remodeling.

The reorganization of cells in response to mechanical forces converts simple epithelial sheets into complex tissues of various shapes and dimensions. Epithelial integrity is maintained throughout tissue remodeling, but the mechanisms that regulate dynamic changes in cell adhesion under tension are not well understood. In Drosophila melanogaster, planar polarized actomyosin forces direct spatially organized cell rearrangements that elongate the body axis. We show that the LIM-domain protein Ajuba is recruited to adherens junctions in a tension-dependent fashion during axis elongation. Ajuba localizes to sites of myosin accumulation at adherens junctions within seconds, and the force-sensitive localization of Ajuba requires its N-terminal domain and two of its three LIM domains. We demonstrate that Ajuba stabilizes adherens junctions in regions of high tension during axis elongation, and that Ajuba activity is required to maintain cell adhesion during cell rearrangement and epithelial closure. These results demonstrate that Ajuba plays an essential role in regulating cell adhesion in response to mechanical forces generated by epithelial morphogenesis.

Epidermal growth factor receptor and integrins control force-dependent vinculin recruitment to E-cadherin junctions

This study reports novel findings that link E-cadherin (also known as CDH1)-mediated force-transduction signaling to vinculin targeting to intercellular junctions via epidermal growth factor receptor (EGFR) and integrins. These results build on previous findings that demonstrated that mechanically perturbed E-cadherin receptors activate phosphoinositide 3-kinase and downstream integrins in an EGFR-dependent manner. Results of this study show that this EGFR-mediated kinase cascade controls the force-dependent recruitment of vinculin to stressed E-cadherin complexes - a key early signature of cadherin-based mechanotransduction. Vinculin targeting requires its phosphorylation at tyrosine 822 by Abl family kinases (hereafter Abl), but the origin of force-dependent Abl activation had not been identified. We now present evidence that integrin activation, which is downstream of EGFR signaling, controls Abl activation, thus linking E-cadherin to Abl through a mechanosensitive signaling network. These findings place EGFR and integrins at the center of a positive-feedback loop, through which force-activated E-cadherin signals regulate vinculin recruitment to cadherin complexes in response to increased intercellular tension.This article has an associated First Person interview with the first author of the paper.

Molecular Regulation of Sprouting Angiogenesis

The term angiogenesis arose in the 18th century. Several studies over the next 100 years laid the groundwork for initial studies performed by the Folkman laboratory, which were at first met with some opposition. Once overcome, the angiogenesis field has flourished due to studies on tumor angiogenesis and various developmental models that can be genetically manipulated, including mice and zebrafish. In addition, new discoveries have been aided by the ability to isolate primary endothelial cells, which has allowed dissection of various steps within angiogenesis. This review will summarize the molecular events that control angiogenesis downstream of biochemical factors such as growth factors, cytokines, chemokines, hypoxia-inducible factors (HIFs), and lipids. These and other stimuli have been linked to regulation of junctional molecules and cell surface receptors. In addition, the contribution of cytoskeletal elements and regulatory proteins has revealed an intricate role for mobilization of actin, microtubules, and intermediate filaments in response to cues that activate the endothelium. Activating stimuli also affect various focal adhesion proteins, scaffold proteins, intracellular kinases, and second messengers. Finally, metalloproteinases, which facilitate matrix degradation and the formation of new blood vessels, are discussed, along with our knowledge of crosstalk between the various subclasses of these molecules throughout the text. Compr Physiol 8:153-235, 2018.

Stiff Substrates Increase Inflammation-Induced Endothelial Monolayer Tension and Permeability

Arterial stiffness and inflammation are associated with atherosclerosis, and each have individually been shown to increase endothelial monolayer tension and permeability. The objective of this study was to determine if substrate stiffness enhanced endothelial monolayer tension and permeability in response to inflammatory cytokines. Porcine aortic endothelial cells were cultured at confluence on polyacrylamide gels of varying stiffness and treated with either tumor necrosis factor-α (TNFα) or thrombin. Monolayer tension was measured through vinculin localization at the cell membrane, traction force microscopy, and phosphorylated myosin light chain quantity and actin fiber colocalization. Cell permeability was measured by cell-cell junction confocal microscopy and a dextran permeability assay. When treated with TNFα or thrombin, endothelial monolayers on stiffer substrates showed increased traction forces, vinculin at the cell membrane, and vinculin phosphorylation, suggesting elevated monolayer tension. Interestingly, VE-cadherin shifted toward a smaller molecular weight in endothelial monolayers on softer substrates, which may relate to increased VE-cadherin endocytosis and degradation. Phosphorylated myosin light chain colocalization with actin stress fibers increased in endothelial monolayers treated with TNFα or thrombin on stiffer substrates, indicating elevated cell monolayer contractility. Endothelial monolayers also developed focal adherens intercellular junctions and became more permeable when cultured on stiffer substrates in the presence of the inflammatory cytokines. Whereas each of these effects was likely mitigated by Rho/ROCK, Rho/ROCK pathway inhibition via Y27632 disrupted cell-cell junction morphology, showing that cell contractility is required to maintain adherens junction integrity. These data suggest that stiff substrates change intercellular junction protein localization and degradation, which may counteract the inflammation-induced increase in endothelial monolayer tension and thereby moderate inflammation-induced junction loss and associated endothelial monolayer permeability on stiffer substrates.

Nanonet Force Microscopy for Measuring Cell Forces

The influence of physical forces exerted by or felt by cells on cell shape, migration, and cytoskeleton arrangement is now widely acknowledged and hypothesized to occur due to modulation of cellular inside-out forces in response to changes in the external fibrous environment (outside-in). Our previous work using the non-electrospinning Spinneret-based Tunable Engineered Parameters' suspended fibers has revealed that cells are able to sense and respond to changes in fiber curvature and structural stiffness as evidenced by alterations to focal adhesion cluster lengths. Here, we present the development and application of a suspended nanonet platform for measuring C2C12 mouse myoblast forces attached to fibers of three diameters (250, 400, and 800 nm) representing a wide range of structural stiffness (3-50 nN/μm). The nanonet force microscopy platform measures cell adhesion forces in response to symmetric and asymmetric external perturbation in single and cyclic modes. We find that contractility-based, inside-out forces are evenly distributed at the edges of the cell, and that forces are dependent on fiber structural stiffness. Additionally, external perturbation in symmetric and asymmetric modes biases cell-fiber failure location without affecting the outside-in forces of cell-fiber adhesion. We then extend the platform to measure forces of (1) cell-cell junctions, (2) single cells undergoing cyclic perturbation in the presence of drugs, and (3) cancerous single-cells transitioning from a blebbing to a pseudopodial morphology.

Selective Role of Vinculin in Contractile Mechanisms of Endothelial Permeability

Increased vascular endothelial cell (EC) permeability is a result of intercellular gap formation that may be induced by contraction-dependent and contraction-independent mechanisms. This study investigated a role of the adaptor protein vinculin in EC permeability induced by contractile (thrombin) and noncontractile (IL-6) agonists. Although thrombin and IL-6 caused a similar permeability increase in human pulmonary ECs and disrupted the association between vinculin and vascular endothelial-cadherin, they induced different patterns of focal adhesion (FA) arrangement. Thrombin, but not IL-6, caused formation of large, vinculin-positive FAs, phosphorylation of FA proteins, FA kinase and Crk-associated substrate, and increased vinculin-talin association. Thrombin-induced formation of talin-positive FA and intercellular gaps were suppressed in ECs with small interfering RNA-induced vinculin knockdown. Vinculin knockdown and inhibitors of Rho kinase and myosin-II motor activity also attenuated thrombin-induced EC permeability. Importantly, ectopic expression of the vinculin mutant lacking the F-actin-binding domain decreased thrombin-induced Rho pathway activation and EC permeability. In contrast, IL-6-induced EC permeability did not involve RhoA- or myosin-dependent mechanisms but engaged Janus kinase/signal transducer and activator of transcription-mediated phosphorylation and internalization of vascular endothelial-cadherin. This process was vinculin independent but Janus kinase/tyrosine kinase Src-dependent. These data suggest that vinculin participates in a contractile-dependent mechanism of permeability by integrating FA with stress fibers, leading to maximal RhoA activation and EC permeability response. Vinculin inhibition does not affect contractile-independent mechanisms of EC barrier failure. This study provides, for the first time, a comparative analysis of two alternative mechanisms of vascular endothelial barrier dysfunction and defines a specific role for vinculin in the contractile type of permeability response.

Dual role of vinculin in barrier-disruptive and barrier-enhancing endothelial cell responses

Endothelial cell (EC) barrier disruption induced by edemagenic agonists such as thrombin is a result of increased actomyosin contraction and enforcement of focal adhesions (FA) anchoring contracting stress fibers, which leads to cell retraction and force-induced disruption of cell junctions. In turn, EC barrier enhancement by oxidized phospholipids (OxPAPC) and other agonists is a result of increased tethering forces due to enforcement of the peripheral actin rim and enhancement of cell-cell adherens junction (AJ) complexes promoting EC barrier integrity. This study tested participation of the mechanosensitive adaptor, vinculin, which couples FA and AJ to actin cytoskeleton, in control of the EC permeability response to barrier disruptive (thrombin) and barrier enhancing (OxPAPC) stimulation. OxPAPC and thrombin induced different patterns of FA remodeling. Knockdown of vinculin attenuated both, OxPAPC-induced decrease and thrombin-induced increase in EC permeability. Thrombin stimulated the vinculin association with FA protein talin and suppressed the interaction with AJ protein, VE-cadherin. In contrast, OxPAPC stimulated the vinculin association with VE-cadherin. Thrombin and OxPAPC induced different levels of myosin light chain (MLC) phosphorylation and caused different patterns of intracellular phospho-MLC distribution. Thrombin-induced talin-vinculin and OxPAPC-induced VE-cadherin-vinculin association were abolished by myosin inhibitor blebbistatin. Expression of the vinculin mutant unable to interact with actin attenuated EC permeability changes and MLC phosphorylation caused by both, thrombin and OxPAPC. These data suggest that the specific vinculin interaction with FA or AJ in different contexts of agonist stimulation is defined by development of regional actyomyosin-based tension and participates in both, the barrier-disruptive and barrier-enhancing endothelial responses.

Vinculin network-mediated cytoskeletal remodeling regulates contractile function in the aging heart

The human heart is capable of functioning for decades despite minimal cell turnover or regeneration, suggesting that molecular alterations help sustain heart function with age. However, identification of compensatory remodeling events in the aging heart remains elusive. We present the cardiac proteomes of young and old rhesus monkeys and rats, from which we show that certain age-associated remodeling events within the cardiomyocyte cytoskeleton are highly conserved and beneficial rather than deleterious. Targeted transcriptomic analysis in Drosophila confirmed conservation and implicated vinculin as a unique molecular regulator of cardiac function during aging. Cardiac-restricted vinculin overexpression reinforced the cortical cytoskeleton and enhanced myofilament organization, leading to improved contractility and hemodynamic stress tolerance in healthy and myosin-deficient fly hearts. Moreover, cardiac-specific vinculin overexpression increased median life span by more than 150% in flies. A broad array of potential therapeutic targets and regulators of age-associated modifications, specifically for vinculin, are presented. These findings suggest that the heart has molecular mechanisms to sustain performance and promote longevity, which may be assisted by therapeutic intervention to ameliorate the decline of function in aging patient hearts.

Force transmission at cell-cell and cell-matrix adhesions

All cells are subjected to mechanical forces throughout their lifetimes. These forces are sensed by cell surface adhesion receptors and trigger robust actin cytoskeletal rearrangements and growth of the associated adhesion complex to counter the applied force. In this review, we discuss how integrins and cadherins sense force and transmit these forces into the cell interior. We focus on the complement of proteins each adhesion complex recruits to bear the force and the signal transduction pathways activated to allow the cell to tune its contractility. A discussion of the similarities, differences, and crosstalk between cadherin- and integrin-mediated force transmission is also presented.

Changes in integrin αv, vinculin and connexin43 in the medial prefrontal cortex in rats under single-prolonged stress

Post‑traumatic stress disorder (PTSD) is a stress‑accociated mental disorder that occurs as a result of exposure to a traumatic event, with characteristic symptoms, including intrusive memories, hyperarousal and avoidance. The medial prefrontal cortex (mPFC) is known to be significantly involved in emotional adjustment, particularly introspection, inhibition of the amygdala and emotional memory. Previous structural neuroimaging studies have revealed that the mPFC of PTSD patients was significantly smaller when compared with that of controls and their emotional adjustment function was weakened. However, the mechanisms that cause such atrophy remain to be elucidated. The aim of the present study was to elucidate the possible mechanisms involved in apoptosis induced by single‑prolonged stress (SPS) in the mPFC of PTSD rats. SPS is an animal model reflective of PTSD. Of the proposed animal models of PTSD, SPS is one that has been shown to be reliably reproducible in patients with PTSD. Wistar rats were sacrificed at 1, 4, 7 and 14 days after exposure to SPS. Apoptotic cells were assessed using electron microscopy and the TUNEL method. Expression of integrin αv, vinculin and connexin43 were detected using immunohistochemistry, western blotting and reverse transcription polymerase chain reaction. The present results demonstrated that apoptotic cells significantly increased in the mPFC of SPS rats, accompanied with changes in expression of integrin αv, vinculin and connexin43. The present results indicated that SPS‑induced apoptosis in the mPFC of PTSD rats and the mitochondrial pathway were involved in the process of SPS‑induced apoptosis.

From stem cells to cardiomyocytes: the role of forces in cardiac maturation, aging, and disease

Stem cell differentiation into a variety of lineages is known to involve signaling from the extracellular niche, including from the physical properties of that environment. What regulates stem cell responses to these cues is there ability to activate different mechanotransductive pathways. Here, we will review the structures and pathways that regulate stem cell commitment to a cardiomyocyte lineage, specifically examining proteins within muscle sarcomeres, costameres, and intercalated discs. Proteins within these structures stretch, inducing a change in their phosphorylated state or in their localization to initiate different signals. We will also put these changes in the context of stem cell differentiation into cardiomyocytes, their subsequent formation of the chambered heart, and explore negative signaling that occurs during disease.

Contact inhibition of locomotion probabilities drive solitary versus collective cell migration

Contact inhibition of locomotion (CIL) is the process whereby cells collide, cease migrating in the direction of the collision, and repolarize their migration machinery away from the collision. Quantitative analysis of CIL has remained elusive because cell-to-cell collisions are infrequent in traditional cell culture. Moreover, whereas CIL predicts mutual cell repulsion and 'scattering' of cells, the same cells in vivo are observed to undergo CIL at some developmental times and collective cell migration at others. It remains unclear whether CIL is simply absent during collective cell migration, or if the two processes coexist and are perhaps even related. Here, we used micropatterned stripes of extracellular matrix to restrict cell migration to linear paths such that cells polarized in one of two directions and collisions between cells occurred frequently and consistently, permitting quantitative and unbiased analysis of CIL. Observing repolarization events in different contexts, including head-to-head collision, head-to-tail collision, collision with an inert barrier, or no collision, and describing polarization as a two-state transition indicated that CIL occurs probabilistically, and most strongly upon head-to-head collisions. In addition to strong CIL, we also observed 'trains' of cells moving collectively with high persistence that appeared to emerge from single cells. To reconcile these seemingly conflicting observations of CIL and collective cell migration, we constructed an agent-based model to simulate our experiments. Our model quantitatively predicted the emergence of collective migration, and demonstrated the sensitivity of such emergence to the probability of CIL. Thus CIL and collective migration can coexist, and in fact a shift in CIL probabilities may underlie transitions between solitary cell migration and collective cell migration. Taken together, our data demonstrate the emergence of persistently polarized, collective cell movement arising from CIL between colliding cells.

A mechanobiological perspective on cadherins and the actin-myosin cytoskeleton

Classical cadherin receptors mediate morphogenetic cell-cell interactions within many tissues of the body. Their biological impact often entails cooperation between cadherin adhesion and the actin cytoskeleton, but how this may occur and – even more urgently – how this leads to morphogenetic outcomes are questions that remain poorly understood. Here, we suggest that the emerging field of cadherin mechanobiology provides a useful new perspective from which to revisit these issues. We propose that the actin cytoskeleton can be considered as an active agent that mediates how cadherin junctions resist, sense and transduce forces between cells.

α-catenin, vinculin, and F-actin in strengthening E-cadherin cell-cell adhesions and mechanosensing

Classical cadherins play a crucial role in establishing intercellular adhesion, regulating cortical tension, and maintaining mechanical coupling between cells. The mechanosensitive regulation of intercellular adhesion strengthening depends on the recruitment of adhesion complexes at adhesion sites and their anchoring to the actin cytoskeleton. Thus, the molecular mechanisms coupling cadherin-associated complexes to the actin cytoskeleton are actively being studied, with a particular focus on α-catenin and vinculin. We have recently addressed the role of these proteins by analyzing the consequences of their depletion and the expression of α-catenin mutants in the formation and strengthening of cadherin-mediated adhesions. We have used the dual pipette assay to measure the forces required to separate cell doublets formed in suspension. In this commentary, we briefly summarize the current knowledge on the role of α-catenin and vinculin in cadherin-actin cytoskeletal interactions. These data shed light on the tension-dependent contribution of α-catenin and vinculin in a mechanoresponsive complex that promotes the connection between cadherin and the actin cytoskeleton and their requirement in the development of adhesion strengthening.