CeBiTec Colloquium: 2008/09/01 Prof. Hanno Steen, Ph.D, Department of Pathology, Harvard Medical School and Children's Hospital Boston, Boston, MA, USA

2008/09/01, 17:15

CeBiTec Laboratory Building, Room G2-104

Cell Biology Meets Proteomics

Abstract:
To systematically screen for targets of a specific E3 ligase, we integrated quantitative proteomics and informatics. We analyzed the human proteome at four points through the cell cycle and identified approximately 20,000 identified peptides, which were clustered according to their abundance profile across the cell cycle stages. We focused on one particular cluster in which 10% of the peptides were substrates of the Anaphase-Promoting Complex (APC), an E3 ubiquitin ligase that targets mitotic cyclins for proteasomal degradation. We hypothesized that co-clustered proteins might share common regulatory mechanisms. Biochemical studies on a small subset of these proteins identified two novel APC substrates. One of the two novel substrates is involved in spindle assembly and thus cytokinesis. Using quantitative proteomics and phosphoproteomics strategies, we provide a detailed systems biological framework of the proteins and their modifications involved in the final step of the cell cycle.