Heterotrimeric G-proteins and development.

Heterotrimeric G-proteins are well-known transducers of signaling from a populous class of heptihelical, membrane receptors to a smaller group of effector molecules that includes adenylylcyclases, cyclic GMP phosphodiesterases, phospholipases (type C beta), and various ion channels. Dramatic changes in specific G-protein subunits that coincide with commitment to highly-specialized cell types suggest a key role for these extrinsic membrane proteins in cell differentiation and development. Through analysis of the effects of gain-of-function and loss-of-function mutants, it has been possible to explore this new dimension in G-protein biology, intimately linking specific G-proteins to development. G-protein subunits are shown to be important molecular switches in the complex biological processes controlling both cellular differentiation and early development.