CONTROL OF T CELL SYNAPSE STABILIZATION AND SIGNALING

PROJECT SUMMARY How do T cells find and their targets? Thanks to studies using high abundance, high affinity agonists and antibodies, many of the signaling pathways downstream from TCR engagement – through lck, ZAP-70, LAT, and further adapters and transcription factors – are described. Decades of structural analyses have also revealed the critical residues for ligand binding. Yet, as we have attempted to make T cells more tuneable and use them as cellular therapies, it is evident that we still cannot create a T cell that has all the features—sensitivity, specificity, effector functions—that we want in order to achieve clinical efficacy. Receptors reside on cell membranes. Cell membranes move and bend and provide 3D surfaces on which receptors can transit, both individually and in patches. We hypothesize that the relationship of T cell receptors to their underlying membrane is critical for determining their function. This proposal will study the effect of the subsurface domain distribution of receptors, achieved through engineering of T cells (Aim 1), engineering of surrogate ligands and cells (Aim 2) and through adoption of cell- cell fusogens that alter the immediate sequellae of membrane-membrane apposition (Aim 3). In all cases, we will be studying the output across a range of measures, starting by studying the 3D distribution of engineered receptors over time, moving to studying the effect of the perturbation on activation measures, and finally assessing these modification in models of human disease. The results of these studies will provide us with critical information about the interacting nature of receptors and membranes as they influence T cell activation.