This Shared Instrument Grant application is for a state-of-the-art High Throughput Microscope that will facilitate the studies by 15 defined investigators at the University of California San Francisco. Resources from two established Core Facilities will provide substantial support for the operation and maintenance of this Instrument. This plan will permit access to this equipment by an even larger number of NIH-supported research projects at UCSF (833 Research Grants in 2004). The manufacturer has agreed to lower the price of maintenance contracts by 20%. This will reduce operating costs to facilitate high throughput studies of the complexities and cross-talk in biochemical pathways that affect biologic response and drug action. The NIH has identified high throughput studies and capabilities as a key element of its Roadmap. Uncovering, analyzing and understanding biologic complexities depend upon the ability to conduct highly multiplexed studies with large numbers of variables. End-stage markers of signaling and even the direct interactions, conformation and subcellular partitioning of components of the signaling cascade itself, are readily measured using fluorescent microscopic techniques. For example, the applicant investigators routinely use antibody staining to track the amounts and locations of multiple fluorescent-tagged factors in cell, stem cell or organ cultures treated with hormones, growth factors and molecular or pharmacologic agents. For some studies, the amounts and locations of fluorophore-marked proteins or cells are tracked with time in live cell or organ cultures. We also routinely characterize the interactions and conformations of proteins flagged with different fluorescent proteins through measurements of the amounts of energy transferred between the fluorescent proteins. Our studies now demand that we follow the cellular effects of multiple (and even large libraries of) growth factors, hormones, pharmacologic agents and molecular over- expressions/knock-downs. However, conventional microscopy severely constrains the amount of time required to manually collect and analyze images, thereby limiting important studies. The High Throughput Microscopy system selected, the Cellomics ArrayScan VTI with integrated plate handling, robotic compound delivery, data analysis and database managing capabilities, will allow our investigators to accomplish in hours what previously had required months of effort. An incubation chamber will permit live cell imaging, and an Apotome attachment will permit the optional collection of specific optical sections, in three dimensional organ or cell multi-well cultures. In short, the installation of the proposed equipment would dramatically increase the ability of our investigators to make rapid and deep inroads into the understanding of pathways and interventions for a wide variety of human diseases. ? ? ?