Jian Liu (National Institutes of Health), Applied Mathematics Colloquium

Tea at 3:30 in Phillips Hall 330

Title:  Theory of a curvature sensing-mediated traveling wave

Abstract:  Immune cells exhibit stimulation-dependent traveling waves within the cortex, much faster than typical cortical actin waves. These waves reflect rhythmic assembly of both actin machinery and periphery membrane proteins such as F-BAR domain proteins. Combining theory and experiments, we develop a mechanochemical feedback model involving membrane shape changes and F-BAR domain proteins that shapes into an excitable system. We show that this excitability can only manifests itself as phase wave. That is, the spatial gradient in the timing of excitability on the cortex gives the impression of propagation. And the resulting phase speed dictates the observed fast propagation speeds. We further provide evidences that membrane shape undulations accompany such rhythms, excite further cortical activation along the wave propagation path, and potentiate curvature propagation beyond the initial cortical activation site. Therefore, membrane shape change has underappreciated roles in setting high-speed signal transduction rhythms across the entire cortex.