Extracellular Redox Regulation of α7β Integrin-Mediated Cell Migration Is Signaled via a Dominant Thiol-Switch

• Published in: Antioxidants 2020-03, Vol.9 (3), p.227
• Main Authors: Bergerhausen, Lukas, Grosche, Julius, Meißner, Juliane, Hecker, Christina, Caliandro, Michele F, Westerhausen, Christoph, Kamenac, Andrej, Rezaei, Maryam, Mörgelin, Matthias, Poschmann, Gereon, Vestweber, Dietmar, Hanschmann, Eva-Maria, Eble, Johannes A
• Format: Article
• Language: English
• Subjects: Amino acids; Atomic force microscopy; Cell adhesion; Cell adhesion & migration; Cell migration; Chemical bonds; Cloning; Conformation; Cysteine; Extracellular matrix; extracellular thioredoxin-1; Flow cytometry; Hydrogen peroxide; integrin α7β1; Laboratories; Laminin; laminin binding; Ligands; Mutagenesis; Mutants; Peptides; redox regulation; redox signaling; Regulation; thiol-switch; Thioredoxin
• ISSN: 2076-3921; 2076-3921
• DOI: 10.3390/antiox9030227

While adhering to extracellular matrix (ECM) proteins, such as laminin-111, cells temporarily produce hydrogen peroxide at adhesion sites. To study the redox regulation of α7β1 integrin-mediated cell adhesion to laminin-111, a conserved cysteine pair within the α-subunit hinge region was replaced for alanines. The molecular and cellular effects were analyzed by electron and atomic force microscopy, impedance-based migration assays, flow cytometry and live cell imaging. This cysteine pair constitutes a thiol-switch, which redox-dependently governs the equilibrium between an extended and a bent integrin conformation with high and low ligand binding activity, respectively. Hydrogen peroxide oxidizes the cysteines to a disulfide bond, increases ligand binding and promotes cell migration toward laminin-111. Inversely, extracellular thioredoxin-1 reduces the disulfide, thereby decreasing laminin binding. Mutation of this cysteine pair into the non-oxidizable hinge-mutant shows molecular and cellular effects similar to the reduced wild-type integrin, but lacks redox regulation. This proves the existence of a dominant thiol-switch within the α subunit hinge of α7β1 integrin, which is sufficient to implement activity regulation by extracellular redox agents in a redox-regulatory circuit. Our data reveal a novel and physiologically relevant thiol-based regulatory mechanism of integrin-mediated cell-ECM interactions, which employs short-lived hydrogen peroxide and extracellular thioredoxin-1 as signaling mediators.