This is a request to the Division of Research Resources Biomedical Research Support Program for a shared instrumentation grant to support the purchase of a PDQUEST System. This system will permit the scanning, analysis and quantitation of 2 dimensional (2D)-gel electrophoresis and will permit the development of and communication with other established protein databases. Twelve established investigators who have PHS funded grants and represent 8 departments, 3 organized research units and one interdisciplinary division on our UCSF School of Medicine campus will be major users of the system. In the research proposed by the 12 major users, a wide variety of cell types derived from several organisms will examined for changes in protein patterns in response to processes as diverse as development, stress, radiation, genetic variation and mutation, DNA repair and drug resistance and to agents as diverse as the biological response modifiers and several types of hormones. The UCSF designated Principal Investigator and her internal advisory committee has proposed a plan for the daily and long term management of the shared system and for the training of major users in its use. The commitment of the university for this endeavor is documented and the numerous benefits to the major users and the UCSF campus have been detailed. The PDQUEST system, developed in the laboratory of Dr. James Garrels, represents state of the art technology, already proven in several other institutions. This would represent the introduction for the first time of this technology to the UCSF campus.