I propose to use structural methods to establish the interaction interfaces between molecules that are important to nucleocytoplasmic transport and its integration with other nuclear components of the gene expression machinery and use this information to engineer mutants that can be used to define the functional contribution of each interaction. In nuclear transport, the exchange of cargo macromolecules, such as proteins and mRNA, between the nuclear and cytoplasmic compartments through nuclear pores is mediated by specific carrier molecules. My previous work on nuclear pore proteins (FG nucleoporins) will be extended to address precisely how they contribute to translocation through nuclear pores and serve as scaffolds to facilitate the assembly/disassembly of cargo:carrier complexes and recycling of carriers. The nuclear transport components of major nuclear export pathways, especially those involving mRNA, will also be investigated, with emphasis on the molecular mechanism by which export-competent mRNA complexes are generated in the nucleus and disassembled in the cytoplasm. In addition, previous studies on mRNA export and FG-nucleoporins will be extended to encompass the interactions between different components of the gene expression machinery, especially those that are co-ordinated by scaffolds based on nucleoporins or mRNA export components. The role of nuclear pore proteins in gene gating - the tethering of active genes to nuclear pores - will also be explored, especially in the context of complexes involving Sac3 (GANP in humans). The application of the work on nuclear transport to prostate cancer is being explored in collaboration with Prof David Neal, University of Cambridge.