Two main foci characterize my research. First, we aim to understand cellular signaling and communication across cell membranes at the molecular level. The second focus is on understanding how macromolecular structure encodes specificity and affinity, at protein – protein and at protein – ligand interfaces, and how this can be used for drug design. To these ends we have determined the high resolution three dimensional structures of numerous proteins of different classes, and used these structures to define biological, biochemical, and cellular function, and as templates for drug design. We seek to determine the structures of membrane receptors, channels and transporters. We address the cellular partners of HIV proteins in attempts to elucidate novel drug targets for anti-HIV therapy.