C-terminal Opening Mimics 'Inside-Out' Activation of Integrin alpha5beta1

摘要: Integrins are adhesion molecules that convey signals both to and from the cytoplasm across plasma membrane. In resting cells, integrins in a low affinity state can be activated by 'inside-out signaling', which affecting integrin heterodimer cytoplasmic domains cause conformational change ligand-binding headpiece connected membrane two long, approximately 16 nm stalks. Here we demonstrate mechanism for conveying over long distance headpiece. We prepared soluble, alpha5beta1 extracellular fragments interactions between alpha- beta-subunit were replaced with an artificial clasp. Release of this C-terminal clasp specific protease cleavage resulted 14 separation stalks coupled increased binding fibronectin. This activation did not require any associated or clustering was observed physiological concentrations divalent cations. These findings suggest overall inside-out involves spatial and/or transmembrane domains.