This volume in the Advances in Protein Chemistry series features cutting-edge articles on topics in protein chemistry. This volume includes chapters on the structural basis of effector regulation and signal termination in heterotrimeric GfÑfnfnproteins; How do receptors activate G proteins; Some mechanistic insights into GPCR activation from detergent solubilized ternary complexes on beads; Activation of G protein coupled receptors; Kinetic analysis of g-protein-coupled receptor signaling using fluorescence resonance energy transfer in living cells; Regulation of Rho Guanine Nucleotide Exchange Factors (RhoGEFs) by G proteins.