Elucidating distinct ion channel populations on the surface of hippocampal neurons via single-particle tracking recurrence analysis

摘要

Protein and lipid nanodomains are prevalent on the surface of mammalian cells. In particular, it has been recentlyrecognized that ion channels assemble into surface nanoclusters in the soma of cultured neurons. However, theinteractions of these molecules with surface nanodomains display a considerable degree of heterogeneity. Here,we investigate this heterogeneity and develop statistical tools based on the recurrence of individual trajectories toidentify subpopulations within ion channels in the neuronal surface.We specifically study the dynamics of the K+channelKv1.4 and the Na+ channelNav1.6 on the surface of cultured hippocampal neurons at the single-moleculelevel. We find that both these molecules are expressed in two different forms with distinct kinetics with regardsto surface interactions, emphasizing the complex proteomic landscape of the neuronal surface. Further, the toolspresented in this work provide new methods for the analysis of membrane nanodomains, transient confinement,and identification of populations within single-particle trajectories.