Vafabakhsh uses single-molecule FRET to resolve the conformational dynamics of membrane receptors and channels -- including class C GPCRs, adhesion GPCRs, and potassium channels -- as they gate and signal, and applies related single-molecule methods to viral DNA packaging motors and synaptic protein complexes, aiming to build a quantitative, multi-scale picture of synaptic protein organization from the single-molecule to the synapse level.