In Core II, the overall goals and objectives are to examine the effects of xenobiotics on cellular signal transduction.  It is becoming increasingly apparent that a wide range of toxicants and drugs exert their biological actions by interfering with cell-cell and intracellular signaling pathways. These agents either mimic a signaling molecule or alter a signaling pathway in such a way as to lead to toxicity.  The goals of the Signal Transduction Core are to bring together investigators with common interests in understanding how xenobiotics modulate cellular signal transduction pathways. The specific objectives of Core II are to characterize xenobiotic-induced alterations in membrane receptors and proteins. This includes structural as well as functional changes in these proteins. In addition, efforts are currently focused on analyzing mechanisms by which xenobiotics modulate both receptor and non-receptor associated protein kinases. Studies are in progress to determine mechanisms by which oxidants, as well as chemicals that generate oxidants, modulate signaling pathways. In addition, studies focus on identifying specific DNA binding proteins including transcription factors that are targets of xenobiotic action.  This will include elucidating mechanisms by which interaction of xenobiotics with DNA alters its functioning.