Faculty host: Dr. Medha M. Pathak
Title: Lipid flow coordinates axon growth and branching
Abstract:
Cell membranes experience constant mechanical perturbations. The ensuing change in membrane tension is a fundamental regulator of many membrane signaling and cellular transport processes. In most non-motile cells, local perturbations to membrane tension remain localized, leading to subcellular Ca2+ influx and vesicle fusion events. Membrane-cortex attachments (MCAs) form a dense network that impedes the propagation of membrane tension. Here, we show that un-myelinated axons are an exception to this rule. Changes in membrane tension propagate at 20 µm/s along the axon, resulting in strong mechanical coupling over distances up to hundreds of microns. Lowering tension at the growth cone initiates branches more than 100 µm away in the axon, whereas increasing tension in the axon causes retraction of the growth cone and disappearance of existing branches. Together, these findings suggest that membrane tension plays an important role in long-range coordination of axonal growth and branching.