Signal transduction is the process by which signals outside of the cells, such as hormones, sensory inputs, growth factors, and neurotransmitters coordinate and regulate the physiology of individual cells. Coordinated interactions between cells in the body is critical to the development and proper functioning of multicellular organisms. In humans, disregulation of these pathways can contribute to diseases such as cancer, neurological degeneration, and cardiovascular disease. Research in this area spans a spectrum of disciplines including studies on the individual molecules involved in recognition of the signal (receptors), studies on the individual molecules that help to convert the signal into cellular changes, and how these interactions result in changes in the physiology and proper functioning of cells and multicellular organisms. Understanding at all of these levels is required for a complete picture of cellular regulation and disease. Many drugs act on cellular signaling pathways. The molecular basis of cellular signaling and its control by various drugs is a major aspect of modern pharmacology.The majority of signal transduction pathways still awaits discovery or at least a thorough molecular characterization. Members of this Unit employ the whole spectrum of modern biochemical, cell and molecular biological,physiological and pharmacological methods in a strictly basic research-oriented scientific environment to unravel the several unsolved mysteries underlying cellular regulation and signaling. Certain research initiatives have a tanslational component, with the goal of applying basic discoveries to developing new therapeutic modalities.