Coupled membrane fluctuations and protein mobility in supported intermembrane junctions

Junctions between lipid membranes make possible cell-free explorations of physical mechanisms that can contribute to protein and lipid organization at a variety of biophysical interfaces. Recent studies of mobile antibodies sandwiched between lipid bilayer membranes have shown that strong intermembrane adhesion and protein mobility alone are sufficient to drive inert proteins into micron-scale patterns of dense and sparse zones. Though the length scale of these patterns was suspected to be related to membrane rigidity, a quantitative understanding has so far been unavailable. We introduce data showing radially structured protein patterns that also demonstrate micron-scale organization. We then provide a simple model that relates the spectrum of membrane fluctuations to the observed protein distributions; in brief, only membrane modes that are slow enough to couple to the protein mobility drive intermembrane protein patterns.