The purpose of this proposal is to obtain funding for the purchase of a capillary column HPLC-electrospray ionization-quadrupole-time-of- flight (Q-TOF) tandem mass spectrometry system that will be used for automated, high-throughput sequencing and identification of proteins separated by gel electrophoresis. The instrument will be located in an established protein sequencing laboratory in the Lerner Research Institute at the Cleveland Clinic Foundation and used to support the research programs of a group of NIH-funded Major Users at both the Cleveland Clinic and Case Western Reserve University. The research programs of the Major Users are broad, encompassing projects in the areas of cancer biology, vascular biology and atherosclerosis, cardiology, neuroscience, translational control, cell-to-cell communication, and intracellular signaling. All of the Major User's projects need mass spectrometry to sequence and identify relatively large numbers of proteins at trace levels. The protein sequencing laboratory in which the requested instrument will be located already contains other important equipment to support these analyses, including a matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry system and an electrospray ionization-ion trap tandem mass spectrometry system. However, the laboratory is severely limited by the time available on the ion trap instrument that has no provision for automation. The requested Q-TOF instrument system will provide new sample capacity that is essential to accommodate the Major Users and carry out the sequencing experiments they require in a timely and rigorous manner. The requested instrument also complements and expands the established capabilities of an experienced and successful laboratory that is serving a large number of additional NIH-funded users. Therefore, the requested instrument will have a secondary benefit to these programs as well. The Cleveland Clinic Foundation has provided and continues to provide substantial resources for the availability of mass spectrometry in the Cleveland area. These resources include renovated laboratory space, equipment, experienced personnel, financial support, and a financial plan that will enable the long-term success of the facility. The requested instrument will add significantly to these resources, facilitating and advancing research programs throughout the Cleveland area including programs at the Cleveland Clinic Foundation, Case Western Reserve University, University Hospitals, MetroHealth Hospital, and Cleveland State University.