scholarly journals Induction of ligand promiscuity of αVβ3 integrin by mechanical force

2020 ◽  
Vol 133 (9) ◽  
pp. jcs242404 ◽  
Author(s):  
Michael Bachmann ◽  
Markus Schäfer ◽  
Vasyl V. Mykuliak ◽  
Marta Ripamonti ◽  
Lia Heiser ◽  
...  
Keyword(s):  
Mechanical Force ◽  
Αvβ3 Integrin ◽  
Ligand Promiscuity

scholarly journals Single-molecule measurements of the effect of force on Thy-1/αvβ3-integrin interaction using nonpurified proteins

2018 ◽  
Vol 29 (3) ◽  
pp. 326-338 ◽  
Author(s):  
Francesca Burgos-Bravo ◽  
Nataniel L. Figueroa ◽  
Nathalie Casanova-Morales ◽  
Andrew F. G. Quest ◽  
Christian A. M. Wilson ◽  
...  
Keyword(s):  
Protein Purification ◽  
Single Molecule ◽  
Mechanical Force ◽  
Αvβ3 Integrin ◽  
Bimolecular Interactions

Single-molecule measurements combined with a novel mathematical strategy were applied to accurately characterize how bimolecular interactions respond to mechanical force, especially when protein purification is not possible. Specifically, we studied the effect of force on Thy-1/αvβ3 integrin interaction, a mediator of neuron-astrocyte communication.

scholarly journals Ligand binding promiscuity of αVβ3 integrin is enlarged in response to mechanical force

2017 ◽  
Author(s):  
Michael Bachmann ◽  
Markus Schäfer ◽  
Vasyl V. Mykuliak ◽  
Marta Ripamonti ◽  
Lia Heiser ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Mechanical Load ◽  
Matrix Proteins ◽  
Αvβ3 Integrin ◽  
Superresolution Imaging ◽  
Hybrid Domain ◽  
Open Conformation ◽  
Dynamics Simulations ◽  
Integrin Ligand ◽  
Ligand Promiscuity

AbstractαVβ3 integrin recognizes multiple extracellular matrix proteins, including vitronectin (Vn) and fibronectin (Fn). However, cell experiments are frequently performed on homogenously coated substrates with only one integrin ligand present. Here, we employed binary-choice substrates of Fn and Vn to dissect αVβ3 integrin-mediated binding to both ligands on the subcellular scale. Superresolution imaging revealed that αVβ3 integrin preferred binding to Vn under various conditions. In contrast, binding to Fn required mechanical load on αVβ3 integrin. Integrin mutations, structural analysis, and molecular dynamics simulations established a model where the extended-closed conformation of αVβ3 integrin binds Vn but not Fn. Force-mediated hybrid domain swing-out characterizes the extended-open conformation needed for efficient Fn binding. Thus, force-dependent conformational changes in αVβ3 integrin increase the number of available ligands and therefore the ligand promiscuity of this integrin. These findings for αVβ3 integrin were shown to regulate cell migration and mechanotransduction differentially on Fn compared to Vn and therefore to regulate cell behavior.

Synthesis and Characterization of ROSA Dye - A Rhodamine B-type Fluorophore, Suitable for Bioconjugation and Fluorescence Studies in Live Cells

2019 ◽  
Vol 26 (10) ◽  
pp. 758-767
Author(s):  
Vicente Rubio ◽  
Vijaya Iragavarapu ◽  
Maciej J. Stawikowski
Keyword(s):  
Quantum Yield ◽  
Cancer Cells ◽  
Fluorescent Probe ◽  
Extinction Coefficient ◽  
Rhodamine B ◽  
Solid Phase ◽  
Total Yield ◽  
Molar Extinction Coefficient ◽  
Αvβ3 Integrin ◽  
Αvβ3 Integrins

Background: Herein we report the multigram-scale synthesis, characterization and application of a rhodamine B-based fluorophore (ROSA) suitable for fluorescent studies in biological applications. This fluorophore is devoid of rhodamine spirolactone formation and furthermore characterized by a high molar extinction coefficient (ϵ=87250 ± 1630 M-1cm-1) and quantum yield (φ) of 0.589 ± 0.070 in water. Reported here is also the application of ROSA towards synthesis of a ROSA-PEG-GRGDS-NH2 fluorescent probe suitable for live cell imaging of αvβ3 integrins for in vitro assays. Objective: The main objective of this study is to efficiently prepare rhodamine B derivative, devoid of spirolactone formation that would be suitable for bioconjugation and subsequent bioimaging. Methods: Rhodamine B was transformed into rhodamine B succinimide ester (RhoB-OSu) using N-hydroxysuccinimide. RhoB-OSu was further coupled to sarcosine to obtain rhodamine Bsarcosine dye (ROSA) in good yield. The ROSA dye was then coupled to a αvβ3 integrin binding sequence using standard solid-phase conditions. Resulting ROSA-PEG-GRGDS-NH2 probe was used to image integrins on cancer cells. Results: The rhodamine B-sarcosine dye (ROSA) was obtained in multigram scale in good total yield of 47%. Unlike rhodamine B, the ROSA dye does not undergo pH-dependent spirolactone/spirolactam formation as compared with rhodamine B-glycine. It is also characterized by excellent quantum yield (φ) of 0.589 ± 0.070 in water and high molar extinction coefficient of 87250 ± 1630 M-1cm-1. ROSA coupling to the RGD-like peptide was proved to be efficient and straightforward. Imaging using standard filters on multimode plate reader and confocal microscope was performed. The αvβ3 integrins present on the surface of live WM-266-4 (melanoma) and MCF- 7 (breast cancer) cells were successfully imaged. Conclusion: We successfully derivatized rhodamine B to create an inexpensive, stable and convenient to use fluorescent probe. The obtained derivative has excellent photochemical properties and it is suitable for bioconjugation and many imaging applications.

Recent developments of colorimetric mechanical sensors based on polymer composites

2020 ◽  
Vol 8 (35) ◽  
pp. 12036-12053
Author(s):  
Ezgi Inci ◽  
Gokhan Topcu ◽  
Tugrul Guner ◽  
Merve Demirkurt ◽  
Mustafa M. Demir
Keyword(s):  
Polymer Composites ◽  
Mechanical Action ◽  
Mechanical Force ◽  
Naked Eye ◽  
Recent Developments ◽  
Structural Deformations ◽  
Mechanical Sensors ◽  
Force Pressure

Colorimetric mechanical (force, pressure, strain, and impact) sensors allow naked-eye visualization of existing structural deformations of a system occurring upon application of a mechanical action.

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