Biological tuning of the membrane phase transition facilitates plasma membrane organization and function.

Isolated cell plasma membranes are biologically tuned to be in a single phase at growth temperature but close to a critical point of the membrane phase transition. This talk will explore several consequences of this biological tuning through experiments in model and intact cell membranes. For example, near-critical membranes have a high compositional susceptibility, meaning that stable membrane domains can assemble in response to membrane proximal forces. This is demonstrated in live B cells through quantitative super-resolution nanoscopy measurements that detect the emergence of functional domains upon B cell receptor clustering. Near-critical tuning of the membrane phase transition can also enhance the stability of proteins condensed at membranes, and this is demonstrated through simulation and experiments in model and cellular systems.