In vivo functions of heterotrimeric G-proteins: studies in G alpha-deficient mice

Heterotrimeric guanine nucleotide binding proteins (G-proteins) mediate the effects of numerous hormones, neurotransmitters or sensory stimuli by coup ling their transmembranous receptors to various effecters like enzymes and ion channels. Changes in the activity of these effector molecules eventuall y lead to the regulation of multiple cellular functions ranging from short term regulatory processes like the control of secretion rates, muscle tonus or metabolic processes to long term effects like regulation of growth and differentiation. Heterotrimeric G-proteins play a pivotal role in this tran smembrane signaling process as they take part in processing and sorting of incoming signals as well as in adjusting the sensitivity of the system, Thi s review describes some of the new insights into the biological role of G-p rotein mediated signaling processes provided by the analysis of mice geneti cally engineered to lack distinct G-protein alpha -subunits.