Gelation and phase separation in LAT membrane complexes

It has been observed that the membrane-localized molecular assemblies of LAT:Grb2:SOS, a protein complex relevant for T-cell signaling, form condensates across a broad range of conditions. We have developed a particle based reaction diffusion model of LAT that incorporates multivalent bonding and diffusive dynamics to study the kinetics and thermodynamics of condensate formation. We find that LAT undergoes a gel transition, with significant slowing down of monomer diffusion and condensate coarsening with a small change in temperature. The mechanism of condensate formation depends senstively on the relative timescales of protein complexation and membrane diffusion, in some cases resulting in finite domains over long time scales.