Research in our laboratory is focused on investigating the architecture, dynamics, and function of the actin cytoskeleton. The context for our studies is the brush border: an array of actin-based protrusions known as microvilli, which extend from the surface of polarized epithelial cells. In the gut, the brush border serves as the sole site of nutrient absorption and a barrier to micro-organisms that reside in the lumenal space. Using an approach that combines biophysics, biochemistry, and cell biology, we are currently studying mechanisms that control microvillar dynamics, morphology, and function. We have also begun to dissect the mechanism of microvillar assembly, which was jumpstarted by our recent elucidation of the entire brush border proteome. A broad long-term goal is to develop our understanding of molecules and pathways that may be perturbed in GI diseases characterized by loss of the brush border (e.g. enteropathogenic E. coli infection, celiac disease, and microvillus inclusion disease).