Genomics and proteomics technologies together with computational methods have led to identification of many signaling protein/enzyme interactions which have been validated as drug target candidates for treating various human diseases such as cancers, inability for the central nerve system (CNS) regeneration and SARS.Biophysical characterization of these protein-protein interactions represents a powerful strategy for discovery and design of drugs in the post-genomics era.My laboratory is devoted to developing this strategy with focus on three categories of signaling pathways by an integrated use of various biochemical and biophysical techniques including isothermal titration calorimetry (ITC), crystallography and NMR spectroscopy etc.In the present talk, I would summarize our published and unpublished results on: 1) Nogo system which is a key pathway for designing drugs to enhance CNS regeneration (1-2);2) Eph-ephrin network critical for treating cancers (3-6) and 3) SARS 3C-like protease validated for design ofanti-SARS drugs (7-8).