My group combines X-ray crystallography with other biochemical and biophysical techniques to understand the detailed molecular mechanisms that underlie cellular processes. Our primary aim is to understand the molecular mechanisms that underlie secretory trafficking. In particular, we have been studying the assembly and regulation of two so-called tethering complexes, the exocyst and TRAPP. These are large multimeric protein assemblies that regulate the last steps of vesicle traffic, just before a transport vesicle fuses with its target compartment. We are also working on protein:RNA interactions that are important for RNA folding and quality control.