BPS2026 – Flow-mediated transport of membrane proteins across living cells

All life takes place in water, so fluid flows are a ubiquitous feature of the environment for living cells. Individual cells sense and respond to flows in order to regulate physiological factors such as blood pressure and bone density. However, important features of the molecular mechanisms for flow sensing remain undefined. For example, endothelial cells respond to shear stress from cardiovascular flow. Yet the force from cardiovascular shear stress is so small that an individual protein “flow sensor” would need to detect forces much smaller than thermal noise. We use microfluidics and confocal microscopy to show that such small forces are sufficient to laterally redistribute lipid-anchored proteins in both simplified model membranes and on the surface of living cells. Measurements of flow-mediated mobility can yield information about membrane protein size, shape, and the surrounding nanoscale membrane environment. Flow-mediated lateral transport provides information about protein-lipid interactions and may form the initial step in flow mechanosensing by cells.