scholarly journals Conformational states during vinculin unlocking differentially regulate focal adhesion properties

2017 ◽  
Author(s):  
Dror S. Chorev ◽  
Tova Volberg ◽  
Ariel Livne ◽  
Miriam Eisenstein ◽  
Bruno Martins ◽  
...  
Keyword(s):  
Conformational Transition ◽  
Protein Complexes ◽  
Focal Adhesions ◽  
Active Conformation ◽  
Integrin Receptors ◽  
Adhesion Properties ◽  
Structure And Dynamics ◽  
Direct Demonstration ◽  
Growth Stability

AbstractFocal adhesions (FAs) are multi-protein complexes that connect the actin cytoskeleton to the extracellular matrix, via integrin receptors. The growth, stability and adhesive functionality of these structures are tightly regulated by mechanical stress, yet, despite the extensive characterization of the integrin adhesome, the mechanisms underlying FA mechanosensitivity are still poorly understood. One of the key candidates for regulating FA-associated mechanosensing is vinculin, a prominent FA component, which was proposed to possess either closed (“auto-inhibited”) or open (active) conformations. However, a direct demonstration of the nature of conformational transition between the two states is still absent. In this study we combined multiple structural and biological approaches to probe the transition from auto-inhibited to active conformation, and determine its effects on FA structure and dynamics. We further show here that the closed to open transition requires two sequential steps that can differentially regulate FA growth and stability.

scholarly journals Characterization of Integrin–Tetraspanin Adhesion Complexes

1999 ◽  
Vol 146 (2) ◽  
pp. 477-492 ◽  
Author(s):  
Fedor Berditchevski ◽  
Elena Odintsova
Keyword(s):  
Actin Cytoskeleton ◽  
Tyrosine Phosphorylation ◽  
Cellular Localization ◽  
Protein Complexes ◽  
Ectopic Expression ◽  
Cell Periphery ◽  
Integrin Receptors ◽  
Cortical Actin ◽  
In Cells

Tetraspanins (or proteins from the transmembrane 4 superfamily, TM4SF) form membrane complexes with integrin receptors and are implicated in integrin-mediated cell migration. Here we characterized cellular localization, structural composition, and signaling properties of α3β1–TM4SF adhesion complexes. Double-immunofluorescence staining showed that various TM4SF proteins, including CD9, CD63, CD81, CD82, and CD151 are colocalized within dot-like structures that are particularly abundant at the cell periphery. Differential extraction in conjunction with chemical cross-linking indicated that the cell surface fraction of α3β1–TM4SF protein complexes may not be directly linked to the cytoskeleton. However, in cells treated with cytochalasin B α3β1–TM4SF protein complexes are relocated into intracellular vesicles suggesting that actin cytoskeleton plays an important role in the distribution of tetraspanins into adhesion structures. Talin and MARCKS are partially codistributed with TM4SF proteins, whereas vinculin is not detected within the tetraspanin-containing adhesion structures. Attachment of serum-starved cells to the immobilized anti-TM4SF mAbs induced dephosphorylation of focal adhesion kinase (FAK). On the other hand, clustering of tetraspanins in cells attached to collagen enhanced tyrosine phosphorylation of FAK. Furthermore, ectopic expression of CD9 in fibrosarcoma cells affected adhesion-induced tyrosine phosphorylation of FAK, that correlated with the reorganization of the cortical actin cytoskeleton. These results show that tetraspanins can modulate integrin signaling, and point to a mechanism by which TM4SF proteins regulate cell motility.

AFM and SEM Characterization of Chemically Modified Electrodes Based on 5-[(azulen-1-yl) methylene]-2-thioxothiazolidin-4-one

2018 ◽  
Vol 68 (12) ◽  
pp. 2799-2803
Author(s):  
Maria Daniela Pop ◽  
Oana Brincoveanu ◽  
Mihaela Cristea ◽  
George Octavian Buica ◽  
Marius Enachescu ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Roughness Parameter ◽  
Modified Electrodes ◽  
Chemically Modified Electrodes ◽  
Adhesion Properties ◽  
Chemically Modified ◽  
Controlled Potential ◽  
Constant Potential ◽  
Metal Ions Detection

Preparation and microscopy characterization of polymer modified glassy carbon electrodes based on (5-[(azulen-1-yl) methylene]-2-thioxothiazolidin-4-one (L) were reported. Atomic Force Microscopy was used to investigate the morphological and mechanical properties of the deposited polyL films onto glassy carbon. The topography images of the analyzed samples exhibited the presence of some columnar shape features onto the layer surfaces. The surface roughness of the layers deposited at constant charge calculated from topography images, increased with the more positive applied potential for controlled potential electrolysis. At different charges, the roughness parameter showed the same behavior for the layers obtained applying a constant potential without having a noticeable influence on the adhesion properties on the substrate. Analysis using scanning electron microscopy shows a relatively uniform surface arrangement of the polymer and the presence of some clusters which are disturbing the planarity. PolyL chemically modified electrodes have been used for heavy metal ions detection with best results for lead.

Characterization of Protein Complexes using Targeted Proteomics

2014 ◽  
Vol 14 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Yassel Gomez ◽  
Sebastien Gallien ◽  
Vivian Huerta ◽  
Jan Oostrum ◽  
Bruno Domon ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Targeted Proteomics

scholarly journals Protein complex formation in methionine chain-elongation and leucine biosynthesis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Qun Chen ◽  
Shweta Chhajed ◽  
Tong Zhang ◽  
Joseph M. Collins ◽  
Qiuying Pang ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Complete Characterization ◽  
Bimolecular Fluorescence Complementation ◽  
Chain Elongation ◽  
Substrate Channeling ◽  
Leucine Biosynthesis ◽  
Protein Complex Formation ◽  
Genes Encoding ◽  
Isopropylmalate Dehydrogenase

AbstractDuring the past two decades, glucosinolate (GLS) metabolic pathways have been under extensive studies because of the importance of the specialized metabolites in plant defense against herbivores and pathogens. The studies have led to a nearly complete characterization of biosynthetic genes in the reference plant Arabidopsis thaliana. Before methionine incorporation into the core structure of aliphatic GLS, it undergoes chain-elongation through an iterative three-step process recruited from leucine biosynthesis. Although enzymes catalyzing each step of the reaction have been characterized, the regulatory mode is largely unknown. In this study, using three independent approaches, yeast two-hybrid (Y2H), coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC), we uncovered the presence of protein complexes consisting of isopropylmalate isomerase (IPMI) and isopropylmalate dehydrogenase (IPMDH). In addition, simultaneous decreases in both IPMI and IPMDH activities in a leuc:ipmdh1 double mutants resulted in aggregated changes of GLS profiles compared to either leuc or ipmdh1 single mutants. Although the biological importance of the formation of IPMI and IPMDH protein complexes has not been documented in any organisms, these complexes may represent a new regulatory mechanism of substrate channeling in GLS and/or leucine biosynthesis. Since genes encoding the two enzymes are widely distributed in eukaryotic and prokaryotic genomes, such complexes may have universal significance in the regulation of leucine biosynthesis.

scholarly journals Characterization of Locus Specific Chromatin Structure and Dynamics using Correlative Conventional Super Resolution Crispr dCas9/Ms2 Imaging

2021 ◽  
Vol 120 (3) ◽  
pp. 9a
Author(s):  
Dushyant Mehra ◽  
Chiranjib Banerjee ◽  
Santosh Adhikari ◽  
Jacob M. Ritz ◽  
Angel Mancebo ◽  
...  
Keyword(s):  
Chromatin Structure ◽  
Super Resolution ◽  
Structure And Dynamics ◽  
Chromatin Structure And Dynamics

scholarly journals Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches

2012 ◽  
Vol 13 (8) ◽  
pp. 10537-10552 ◽  
Author(s):  
Vincent J. B. Ruigrok ◽  
Mark Levisson ◽  
Johan Hekelaar ◽  
Hauke Smidt ◽  
Bauke W. Dijkstra ◽  
...  
Keyword(s):  
Protein Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alternative Approaches

Characterization of Adhesion Properties by Delamination of Ceramic-Metal Interfaces in Four Point Bending

2018 ◽  
Vol 774 ◽  
pp. 66-71 ◽  
Author(s):  
Martin Lederer ◽  
Agnieszka Betzwar Kotas ◽  
Golta Khatibi ◽  
Herbert Danninger
Keyword(s):  
Plastic Deformation ◽  
Energy Consumption ◽  
Stress Intensity ◽  
Theoretical Interpretation ◽  
Adhesion Properties ◽  
Fem Simulations ◽  
Four Point Bending ◽  
Metal Interfaces ◽  
Stress Invariant

The adhesive strength of ceramic - copper interfaces was measured in four point bending using a central notch for crack initiation. According to our method, plastic deformation may occur during the delamination process. FEM simulations were employed in order to separate elastic and plastic contributions to the energy consumption of the experiment. In conclusion, a novel delamination criterion based on the stress intensity at the crack tip was established. Here, the stress invariant J3is used as indicator for delamination of the interface. Agreement between experiments and theoretical interpretation is demonstrated for copper layers directly bonded to aluminum oxide.

Identification and characterization of the small nuclear ribonucleoprotein particle D' core protein

1990 ◽  
Vol 10 (9) ◽  
pp. 4480-4485
Author(s):  
J Andersen ◽  
R J Feeney ◽  
G W Zieve
Keyword(s):  
Electrophoretic Mobility ◽  
Protein Complexes ◽  
Ribonucleoprotein Particle ◽  
Small Nuclear Ribonucleoprotein ◽  
Core Proteins ◽  
Nuclear Ribonucleoprotein ◽  
Identification And Characterization ◽  
Snrnp Core ◽  
Small Nuclear Ribonucleoprotein Particle

The addition of urea to sodium dodecyl sulfate (SDS)-polyacrylamide gels has allowed the identification and characterization of the small nuclear ribonucleoprotein particle (snRNP) D' protein and has also improved resolution of the E, F, and G snRNP core proteins. In standard SDS-polyacrylamide gels, the D' and D snRNP core proteins comigrate at approximately 16 kilodaltons. The addition of urea to the separating gel caused the D' protein to shift to a slower electrophoretic mobility that is distinct from that of the D protein. The shift to a slower electrophoretic mobility in the presence of urea suggests that the D' protein has extensive secondary structure that is not totally disrupted by SDS alone. Both N-terminal sequencing and partial peptide maps indicate that the D and D' proteins are distinct gene products, and the sequence data have identified the faster moving of the two proteins as the previously cloned D protein (L. A. Rokeach, J. A. Haselby, and S. O. Hoch, Proc. Natl. Acad. Sci. USA 85:4832-4836, 1988). In the cytoplasm, the D protein is found primarily in the small-nuclear-RNA-free 6S protein complexes, while the D' protein is found primarily in the 20S protein complexes. Like the D protein, the D' protein is an autoantigen in patients with systemic lupus erythematosus and is recognized by some of the Sm class of autoimmune antisera.

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