Rapid Mapping of Interactions between Human SNX-BAR Proteins Measured In Vitro by

Protein dimerization and oligomerization is commonly used by nature to increase the structural and functional complexity of proteins. Regulated protein assembly is es-sential to transfer information in signaling, transcriptional, and membrane trafficking events. Here we show that a combination of cell-free protein expression, a proximity based interaction assay (AlphaScreen), and single-mole-cule fluorescence allow rapid mapping of homo- and hetero-oligomerization of proteins. We have applied this approach to the family of BAR domain-containing sorting nexin (SNX-BAR) proteins, which are essential regulators of membrane trafficking and remodeling in all eukaryotes. Dimerization of BAR domains is essential for creating a concave structure capable of sensing and inducing mem-brane curvature. We have systematically mapped 144 pair-