Molecular characterization of the centrosome/nucleus-connector

• Applicant: Professor Dr. Ralph Gräf
• Subject Area: Cell Biology
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 54227160

The attachment of the centrosome to the nucleus is crucial for proper mitosis, nuclear positioning and directional cell migration. It is mediated by a protein complex involving nuclear envelope proteins of the ubiquitous SUNfamily and several unknown direct and indirect binding partners of these proteins, which together make up the centrosome-nucleus connector (CNC). Here we will use Dictyostelium amoebae to isolate CNC protein complexes and will identify and functionally characterize novel proteins involved in centrosome/nucleus attachment. These cells are well suited for analyses of CNC mutations, since disruption of their CNC is not lethal. Furthermore, their centrosome is well characterized and SUN1 is an approved marker for their CNC. Our goals will be achieved through mass spectrometrical analysis of isolated CNC components, raising of CNCspecific monoclonal antibodies for functional analyses, generation of knockout or gene silencing mutants, live cell imaging of CNC protein dynamics and subcellular localization of novel CNC components up to the ultrastructural level. Database searches will reveal mammalian orthologues of the discovered Dictyostelium CNC components. Their potential role in centrosome nucleus attachment will be investigated by localization and RNAi studies in mammalian cells. In addition to an improved understanding of the fundamental process of centroso me/nucleus attachment, our work will help to explain the pathogenesis of developmental neuronal diseases such as lissencephaly or DYT1 dystonia.

• DFG Programme: Research Grants