We are applying for a Shared Instrumentation Grant to purchase a BIACORE T100 surface plasmon resonance instrument, which will be used to measure molecular interactions in vitro. Four major users have projects studying: molecular intractions in RNA trafficking, ankyrin repeat protein interactions, protein-protein interactions in secretory granule formation and molecular interactions in herpes virus replication. Three minor users have projects studying: protein-protein interactions in bacterial cell division, molecular interactions in DMA mismatch repair and molecular interactions in bacterial pilus formation. Each of the major and minor investigators have experience analzying molecular interactions by conventional techniques. However, their individual projects will benefit by the capability of the BIACORE T100 instrument to directly measure kinetic binding constants. The quantitative data provided by the BIACORE T100 will be used as input parameters for computational models of specific cell biological systems. Thus, the BIACORE T100 represents an enabling technology for computational modeling of cell biological processes. [unreadable] This work will further human health as most, if not all, cell biological processes are mediated by networks of reversible molecular interactions. Diseases such as cancer, multiple sclerosis and Alzheimer's disease are caused by disruption of specific interaction networks. In order to understand how a particualr interaction network functions it is necessary to know how rapidly each molecule in the network binds to its partners and how rapidly they dissociate. The instrument we are requesting, the BIACORE T100, will enable us to directly measure how rapidly individual molecules associate and dissociate. This quantitative information will enable us to understand how molecular interaction networks mediate specific cell biological processes and how such networks are disrupted in disease [unreadable] [unreadable]