Membrane proteins reside on the cell surface and transduce extracellular signals to the interior of the cell. We seek to understand the molecular mechanism of cell signaling through structural biology at the cell membrane. By learning what membrane proteins are involved, what their atomic structures look like, how these structures give rise to their function, and how these membrane proteins interact with each other, we aspire to construct a spatial and temporal representation of the signaling events at the cell membrane. To ensure faithful reconstruction, we place particular emphasis on investigating the structures of membrane proteins within environments that closely resemble the native cell membrane.