G Proteins and Their Associated Receptors

G proteins and their associated receptors constitute a major group of macromolecular devices for the detection and propagation of extracellular signals. Researchers have now cloned and characterized (both structurally and biochemically) many G-protein-coupled receptors and G protein subunits. This publication highlights a number of interesting findings uncovered by this recent proliferation of information. For example, the functions of G proteins are now known to be regulated by lipid modifications. Some of the functions of the more newly discovered G proteins, such as Gz, G12, G13 and G16, are only now beginning to be unraveled. These include their role in, among many others, the control of cell growth and differentiation, regulation of ionic homeostasis, and signal integration. Resolution of the crystal structures of G protein subunits have led to a better understanding on how receptors and G proteins maintain specific linkages. Armed with this knowledge, one can thoroughly study the functional importance of G-protein-signaling machinery in specialized tissues (e.g. vascular smooth muscles) as well as in simple organisms such as protozoa and metazoa. This informative work will be of immense value to researchers and molecular pharmacologists who are interested in signal transduction.