Protein Assembly on Membrane Surface alters the Dynamical Spectrum of Downstream Signaling Reactions

Protein-protein interactions have been well documented to give rise to an elaborated spatial pattern of signaling molecules during signal transduction. In the case of T-cell receptor (TCR) signaling, multivalent interactions at the linker for activation of T-cell (LAT) promote an assembly structure with downstream molecules on the membrane surface upon TCR activation. However, the perturbation of an assembly structure on the downstream dynamics remains largely unknown. We reconstituted the signaling geometry of LAT assembly with minimum components in TCR signaling on supported membranes. With single-molecule analysis, we directly observe the dynamic alteration of downstream signaling reactions by the assembly structure. The signaling consequence of altered kinetics is further analyzed with analytical calculations. Together, we propose an assembly-dependent mechanism for signal triggering, which can be a general statement for other receptors with multivalent interactions.