Project Summary Since its inception, the Yeast Resource Center has focused on understanding how genome sequence relates to protein function. The Center began just as budding yeast became the first eukaryote to have its genome sequence completed, and we proposed to use an array of technologies to interpret this sequence. In this application, we undertake novel challenges, centered on understanding how variation in proteins affects their levels, modification, function and structure. We will develop new technologies in three areas: 1) Perturbing and sensing changes to complex pathways; 2) Protein detection and quantitation by mass spectrometry; and 3) Higher order protein structure. These technologies will be driven by ten closely integrated Driving Biomedical Projects. Yeast remains an unparalleled experimental system to develop, test and refine these technologies. As the technologies mature, we will extend their application to higher eukaryotes through internal projects and external collaborations. Furthermore, we make our technologies available as they become robust, through broad collaboration and a well-established track record of dissemination and training.