FRET biosensor allows spatio-temporal observation of shear stress-induced polar RhoGDIα activation.

Rho GDP-dissociation inhibitor α (RhoGDIα) is a known negative regulator of the Rho family that shuts off GDP/GTP cycling and cytoplasm/membrane translocation to regulate cell migration. However, to our knowledge, no reports are available that focus on how the RhoGDIα-Rho GTPases complex is activated by laminar flow through exploring the activation of RhoGDIα itself. Here, we constructed a new biosensor using fluorescence resonance energy transfer (FRET) technology to measure the spatio-temporal activation of RhoGDIα in its binding with Rho GTPases in living HeLa cells. Using this biosensor, we find that the dissociation of the RhoGDIα-Rho GTPases complex is increased by shear stress, and its dissociation rate varies with subcellular location. Moreover, this process is mediated by membrane fluidity, cytoskeleton and Src activity, which indicates that the regulation of RhoGDIα activation under shear stress application represents a relatively separate pathway from the shear stress-induced Rho pathway.