Redox control of integrin adhesion receptors

Abstract

Integrins are transmembrane adhesion receptors that play an essential role in normal tissue development and homeostasis. Many integrins bind to their ligands through the Arg-Gly-Asp tripeptide sequence, which is displayed by a number of extracellular matrix proteins, plasma proteins, and even viruses. Unlike many other classes of receptors, the integrins participate in bidirectional signaling across the membrane. “Inside-out” signals activate, and deactivate, the integrin ligand-binding function. “Outside-in” signals are generated when integrin binds to its ligands and regulate a host of cellular processes including cell proliferation and cell death. This chapter identifies a redox site within the extracellular domain of the integrin. This redox site is composed of between two and five unpaired cysteines, which appear to reshuffle during conformational transitions in integrin. Therefore, it has been suggested that this redox site has the properties that might be expected of a conformational switch involved in bidirectional signaling.