Proteomics is a new research area of the post-genomic era that aims at the analysis and identification of the entire proteins present in the cell, tissue or organism, and of the functions and the linkages of these proteins. Protein-protein interactions are characteristic of cellular activities and of course an important part of proteomics. One of the effective techniques to detect protein-protein interaction is yeast two-hybrid system. This system was successfully employed to analyze the protein linkage map of the yeast mRNA splicing machinery, which boded well for its application on human proteome research.