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European Heart Journal Jan 2023Atherosclerosis preferentially develops in arterial branches and curvatures where vascular endothelium is exposed to disturbed flow. In this study, the effects of...
BACKGROUND AND AIMS
Atherosclerosis preferentially develops in arterial branches and curvatures where vascular endothelium is exposed to disturbed flow. In this study, the effects of disturbed flow on the regulation of vascular endothelial phosphoproteins and their contribution to therapeutic application in atherogenesis were elucidated.
METHODS
Porcine models, large-scale phosphoproteomics, transgenic mice, and clinical specimens were used to discover novel site-specific phosphorylation alterations induced by disturbed flow in endothelial cells (ECs).
RESULTS
A large-scale phosphoproteomics analysis of native endothelium from disturbed (athero-susceptible) vs. pulsatile flow (athero-resistant) regions of porcine aortas led to the identification of a novel atherosclerosis-related phosphoprotein vinculin (VCL) with disturbed flow-induced phosphorylation at serine 721 (VCLS721p). The induction of VCLS721p was mediated by G-protein-coupled receptor kinase 2 (GRK2)S29p and resulted in an inactive form of VCL with a closed conformation, leading to the VE-cadherin/catenin complex disruption to enhance endothelial permeability and atherogenesis. The generation of novel apolipoprotein E-deficient (ApoE-/-) mice overexpressing S721-non-phosphorylatable VCL mutant in ECs confirmed the critical role of VCLS721p in promoting atherosclerosis. The administration of a GRK2 inhibitor to ApoE-/- mice suppressed plaque formation by inhibiting endothelial VCLS721p. Studies on clinical specimens from patients with coronary artery disease (CAD) revealed that endothelial VCLS721p is a critical clinicopathological biomarker for atherosclerosis progression and that serum VCLS721p level is a promising biomarker for CAD diagnosis.
CONCLUSIONS
The findings of this study indicate that endothelial VCLS721p is a valuable hemodynamic-based target for clinical assessment and treatment of vascular disorders resulting from atherosclerosis.
Topics: Animals; Mice; Atherosclerosis; Endothelial Cells; Endothelium, Vascular; Mice, Knockout, ApoE; Phosphorylation; Swine; Vinculin; Humans
PubMed: 36380599
DOI: 10.1093/eurheartj/ehac647 -
Biochemistry Nov 2019Life is an emergent property of transient interactions between biomolecules and other organic and inorganic molecules that somehow leads to harmony and order.... (Review)
Review
Life is an emergent property of transient interactions between biomolecules and other organic and inorganic molecules that somehow leads to harmony and order. Measurement and quantitation of these biological interactions are of value to scientists and are major goals of biochemistry, as affinities provide insight into biological processes. In an organism, these interactions occur in the context of forces and the need for a consideration of binding affinities in the context of a changing mechanical landscape necessitates a new way to consider the biochemistry of protein-protein interactions. In the past few decades, the field of mechanobiology has exploded, as both the appreciation of, and the technical advances required to facilitate the study of, how forces impact biological processes have become evident. The aim of this review is to introduce the concept of force dependence of biomolecular interactions and the requirement to be able to measure force-dependent binding constants. The focus of this discussion will be on the mechanotransduction that occurs at the integrin-mediated adhesions with the extracellular matrix and the major mechanosensors talin and vinculin. However, the approaches that the cell uses to sense and respond to forces can be applied to other systems, and this therefore provides a general discussion of the force dependence of biomolecule interactions.
Topics: Animals; Biophysical Phenomena; Cell Adhesion; Extracellular Matrix; Focal Adhesions; Humans; Integrins; Mechanotransduction, Cellular; Protein Binding; Talin; Vinculin
PubMed: 31315399
DOI: 10.1021/acs.biochem.9b00453 -
Nature Communications Jul 2023The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear....
The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear. By combining single-molecule magnetic tweezers experiments, Molecular Dynamics simulations, actin-bundling assays, and adhesion assembly experiments in live cells, we here describe a two-ways allosteric network within vinculin as a regulator of the talin-vinculin interaction. We directly observe a maturation process of vinculin upon talin binding, which reinforces the binding to talin at a rate of 0.03 s. This allosteric transition can compete with force-induced dissociation of vinculin from talin only at forces up to 10 pN. Mimicking the allosteric activation by mutation yields a vinculin molecule that bundles actin and localizes to focal adhesions in a force-independent manner. Hence, the allosteric switch confines talin-vinculin interactions and focal adhesion build-up to intermediate force levels. The 'allosteric vinculin mutant' is a valuable molecular tool to further dissect the mechanical and biochemical signalling circuits at focal adhesions and elsewhere.
Topics: Actins; Talin; Vinculin; Allosteric Regulation; Focal Adhesions; Protein Binding
PubMed: 37463895
DOI: 10.1038/s41467-023-39646-4 -
The landscape of genetic variation in dilated cardiomyopathy as surveyed by clinical DNA sequencing.Genetics in Medicine : Official Journal... Aug 2014Dilated cardiomyopathy is characterized by substantial locus, allelic, and clinical heterogeneity that necessitates testing of many genes across clinically overlapping...
PURPOSE
Dilated cardiomyopathy is characterized by substantial locus, allelic, and clinical heterogeneity that necessitates testing of many genes across clinically overlapping diseases. Few studies have sequenced sufficient individuals; thus, the contributions of individual genes and the pathogenic variant spectrum are still poorly defined. We analyzed 766 dilated cardiomyopathy patients tested over 5 years in our molecular diagnostics laboratory.
METHODS
Patients were tested using gene panels of increasing size from 5 to 46 genes, including 121 cases tested with a multiple-cardiomyopathy next-generation panel covering 46 genes. All variants were reassessed using our current clinical-grade scoring system to eliminate false-positive disease associations that afflict many older analyses.
RESULTS
Up to 37% of dilated cardiomyopathy cases carry a clinically relevant variant in one of 20 genes, titin (TTN) being the largest contributor (up to 14%). Desmoplakin (DSP), an arrhythmogenic right ventricular cardiomyopathy gene, contributed 2.4%, illustrating the utility of multidisease testing. The clinical sensitivity increased from 10 to 37% as gene panel sizes increased. However, the number of inconclusive cases also increased from 4.6 to 51%.
CONCLUSION
Our data illustrate the utility of broad gene panels for genetically and clinically heterogeneous diseases but also highlight challenges as molecular diagnostics moves toward genome-wide testing.
Topics: Cardiomyopathy, Dilated; Carrier Proteins; Connectin; Desmoplakins; Female; Genetic Predisposition to Disease; Genetic Variation; Humans; Male; Sequence Analysis, DNA; Vinculin
PubMed: 24503780
DOI: 10.1038/gim.2013.204 -
ELife Jul 2023Integrin-mediated cell attachment rapidly induces tyrosine kinase signaling. Despite years of research, the role of this signaling in integrin activation and focal...
Integrin-mediated cell attachment rapidly induces tyrosine kinase signaling. Despite years of research, the role of this signaling in integrin activation and focal adhesion assembly is unclear. We provide evidence that the Src-family kinase (SFK) substrate Cas (Crk-associated substrate, p130Cas, BCAR1) is phosphorylated and associated with its Crk/CrkL effectors in clusters that are precursors of focal adhesions. The initial phospho-Cas clusters contain integrin β1 in its inactive, bent closed, conformation. Later, phospho-Cas and total Cas levels decrease as integrin β1 is activated and core focal adhesion proteins including vinculin, talin, kindlin, and paxillin are recruited. Cas is required for cell spreading and focal adhesion assembly in epithelial and fibroblast cells on collagen and fibronectin. Cas cluster formation requires Cas, Crk/CrkL, SFKs, and Rac1 but not vinculin. Rac1 provides positive feedback onto Cas through reactive oxygen, opposed by negative feedback from the ubiquitin proteasome system. The results suggest a two-step model for focal adhesion assembly in which clusters of phospho-Cas, effectors and inactive integrin β1 grow through positive feedback prior to integrin activation and recruitment of core focal adhesion proteins.
Topics: Phosphorylation; Focal Adhesions; Phosphoproteins; Integrin beta1; Crk-Associated Substrate Protein; Protein-Tyrosine Kinases; Integrins; Focal Adhesion Protein-Tyrosine Kinases; Focal Adhesion Kinase 1
PubMed: 37489578
DOI: 10.7554/eLife.90234 -
Biomolecules Feb 2023The interface between the cellular actin network and diverse forms of integrin-mediated cell adhesions displays a unique capacity to serve as accurate chemical and... (Review)
Review
The interface between the cellular actin network and diverse forms of integrin-mediated cell adhesions displays a unique capacity to serve as accurate chemical and mechanical sensors of the cell's microenvironment. Focal adhesion-like structures of diverse cell types, podosomes in osteoclasts, and invadopodia of invading cancer cells display distinct morphologies and apparent functions. Yet, all three share a similar composition and mode of coupling between a protrusive structure (the lamellipodium, the core actin bundle of the podosome, and the invadopodia protrusion, respectively), and a nearby adhesion site. Cytoskeletal or external forces, applied to the adhesion sites, trigger a cascade of unfolding and activation of key adhesome components (e.g., talin, vinculin, integrin), which in turn, trigger the assembly of adhesion sites and generation of adhesion-mediated signals that affect cell behavior and fate. The structural and molecular mechanisms underlying the dynamic crosstalk between the actin cytoskeleton and the adhesome network are discussed.
Topics: Actins; Integrins; Cytoskeleton; Cell Adhesion; Actin Cytoskeleton
PubMed: 36830665
DOI: 10.3390/biom13020294 -
Biology Nov 2021The cytoskeleton provides structure to cells and supports intracellular transport. Actin fibres are crucial to both functions. Focal Adhesions (FAs) are large... (Review)
Review
The cytoskeleton provides structure to cells and supports intracellular transport. Actin fibres are crucial to both functions. Focal Adhesions (FAs) are large macromolecular multiprotein assemblies at the ends of specialised actin fibres linking these to the extracellular matrix. FAs translate forces on actin fibres into forces contributing to cell migration. This review will discuss recent insights into FA protein dynamics and their organisation within FAs, made possible by advances in fluorescence imaging techniques and data analysis methods. Over the last decade, evidence has accumulated that FAs are composed of three layers parallel to the plasma membrane. We focus on some of the most frequently investigated proteins, two from each layer, paxillin and FAK (bottom, integrin signalling layer), vinculin and talin (middle, force transduction layer) and zyxin and VASP (top, actin regulatory layer). Finally, we discuss the potential impact of this layered nature on different aspects of FA behaviour.
PubMed: 34827182
DOI: 10.3390/biology10111189 -
Cellular and Molecular Life Sciences :... Aug 2017Vinculin was identified as a component of focal adhesions and adherens junctions nearly 40 years ago. Since that time, remarkable progress has been made in understanding... (Review)
Review
Vinculin was identified as a component of focal adhesions and adherens junctions nearly 40 years ago. Since that time, remarkable progress has been made in understanding its activation, regulation and function. Here we discuss the current understanding of the roles of vinculin in cell-cell and cell-matrix adhesions. Emphasis is placed on the how vinculin is recruited, activated and regulated. We also highlight the recent understanding of how vinculin responds to and transmits force at integrin- and cadherin-containing adhesion complexes to the cytoskeleton. Furthermore, we discuss roles of vinculin in binding to and rearranging the actin cytoskeleton.
Topics: Actin Cytoskeleton; Adherens Junctions; Animals; Cadherins; Cell Adhesion; Cell Movement; Focal Adhesions; Humans; Integrins; Mechanotransduction, Cellular; Models, Molecular; Protein Interaction Maps; Vinculin
PubMed: 28401269
DOI: 10.1007/s00018-017-2511-3 -
Methods in Cell Biology 2018Productive chromosome movements require that a large multiprotein complex called the kinetochore assemble on sister centromeres. The kinetochore fulfills two critical...
Productive chromosome movements require that a large multiprotein complex called the kinetochore assemble on sister centromeres. The kinetochore fulfills two critical functions as (1) the physical linkage between chromosomes and spindle microtubules and (2) a mechanomolecular sensor that relays a spindle assembly checkpoint signal delaying anaphase onset until chromosomes are attached to spindle microtubules and bioriented. Given its central roles in such a vital process, the kinetochore is one of the most important force-transducing structures in cells; yet it has been technically challenging to measure kinetochore forces. Barriers to measuring cellular forces have begun to be broken by the development of fluorescence-based tension sensors. In this chapter, two methods will be described for measuring kinetochore forces in living cells and strategies for applying these sensors to other force-transducing processes and molecules will be discussed.
Topics: Animals; Biomechanical Phenomena; Biosensing Techniques; Cytological Techniques; Drosophila; Fluorescence Resonance Energy Transfer; Mitosis; Photobleaching; Talin; Vinculin
PubMed: 29804669
DOI: 10.1016/bs.mcb.2018.03.007 -
The FEBS Journal Jun 2022Focal adhesions (FA) are large macromolecular assemblies relevant for various cellular and pathological events such as migration, polarization, and metastatic cancer... (Review)
Review
Focal adhesions (FA) are large macromolecular assemblies relevant for various cellular and pathological events such as migration, polarization, and metastatic cancer formation. At FA sites at the migrating periphery of a cell, hundreds of players gather and form a network to respond to extra cellular stimuli transmitted by the integrin receptor, the most upstream component within a cell, initiating the FA signaling pathway. Numerous cellular experiments have been performed to understand the FA architecture and functions; however, their intricate network formation hampers unraveling the precise molecular actions of individual players. Here, in vitro bottom-up reconstitution presents an advantageous approach for elucidating the FA machinery and the hierarchical crosstalk of involved cellular players.
Topics: Actins; Cell Adhesion; Focal Adhesions; Integrins; Talin; Vinculin
PubMed: 33999507
DOI: 10.1111/febs.16023