Induction of ligand promiscuity of αVβ3 integrin by mechanical force.

Journal of cell science (2020-03-21)
Michael Bachmann, Markus Schäfer, Vasyl V Mykuliak, Marta Ripamonti, Lia Heiser, Kai Weißenbruch, Sarah Krübel, Clemens M Franz, Vesa P Hytönen, Bernhard Wehrle-Haller, Martin Bastmeyer
ABSTRACT

αVβ3 integrin can bind to multiple extracellular matrix proteins, including vitronectin (Vn) and fibronectin (Fn), which are often presented to cells in culture as homogenous substrates. However, in tissues, cells experience highly complex and changing environments. To better understand integrin ligand selection in such complex environments, we employed binary-choice substrates of Fn and Vn to dissect αVβ3 integrin-mediated binding to different ligands on the subcellular scale. Super-resolution imaging revealed that αVβ3 integrin preferred binding to Vn under various conditions. In contrast, binding to Fn required higher mechanical load on αVβ3 integrin. Integrin mutations, structural analysis and chemical inhibition experiments indicated that the degree of hybrid domain swing-out is relevant for the selection between Fn and Vn; only a force-mediated, full hybrid domain swing-out facilitated αVβ3-Fn binding. Thus, force-dependent conformational changes in αVβ3 integrin increased the diversity of available ligands for binding and therefore enhanced the ligand promiscuity of this integrin.This article has an associated First Person interview with the first author of the paper.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-Fibronectin antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution
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Acrylic acid N-hydroxysuccinimide ester, ≥90%
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Vitronectin human, recombinant, expressed in HEK 293 cells, ≥95% (SDS-PAGE), ≥95% (HPLC), suitable for cell culture
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Monoclonal Anti-Talin antibody produced in mouse, clone 8d4, ascites fluid
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Vitronectin from human plasma, lyophilized powder, BioReagent, suitable for cell culture
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HEPBS, ≥99% (titration)
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Osteopontin from bovine milk, lyophilized powder
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Monoclonal Anti-Vitronectin antibody produced in mouse, clone VIT-2, ascites fluid

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