Phase separation of signaling molecules promotes T cell receptor signal transduction

Phase separation organizes signaling In T cell receptors, signaling molecules reorganize into tiny phase-separated droplets—like oil in water. Su et al. used an in vitro system with artificial membranes and 12 components of the T cell receptor signaling system to closely monitor the role of these molecular clusters (see the Perspective by Dustin and Muller). The clusters formed through phosphorylation-dependent association of the linker protein LAT (linker for activation of T cells) with other proteins. These clusters also managed to exclude an inactivating phosphatase and increased the specific activity of enzymes controlling actin polymerization. Science , this issue p. 595 ; see also p. 516