The GTP-binding regulatory proteins, or G proteins, are a family of signal transduction proteins that couple hormone and neurotransmitter receptors to effector proteins involved in the generation of intracellular and transmembrane signals. G proteins have been implicated in such diverse functions as regulation of cell growth, exocytosis, fertilization, and oncogenesis. Both the number and functions of G proteins have grown dramatically and the Society of General Physiologists dedicated their 43rd annual symposium to the topic of G proteins and signal transduction. This book contains the abstracts and proceedings of that symposium.