Protein crystallography has become an integral part of modern pharmaceutical research. Recent technological advances have led to a rapid expansion of its role in low molecular weight drug discovery, from the traditional structure-based drug design approaches to fragment-based screening and the triaging, validation and characterization of high-throughput screening hits. Moreover, protein crystallography supports the design, optimization and characterization of novel therapeutic antibodies, a very fast-growing class of biological drugs. Our interest is in applying X-ray analysis, combined with other biophysical approaches (SPR, DSF, DSC, ITC, NMR, etc), to better understand molecular recognition processes such as ligand binding and protein-protein interactions, with the objective of supporting current drug discovery projects. In addition, a more fundamental research endeavor of our laboratory is to augment our structural understanding of cytokine-receptor signaling by determining crystal structures of selected, disease-relevant cytokine-receptor complexes.