title: Regulatory GTP-binding proteins: emerging concepts on their role in cell function.
abstract: The last few years have evidenced a tremendous expansion in our appreciation of the role of regulatory GTP-binding proteins in cellular activation. The availability of cholera and pertussis toxins to detect G proteins as well as methodological advances in the study of cellular function has afforded the opportunity to examine G protein participation in many cellular events. Regulation of adenylyl cyclase and cyclic GMP phosphodiesterase by G proteins has been demonstrated. Phosphatidylinositol-4,5-biphosphate specific phospholipase C activity appears to be subject to G protein control. G proteins regulate inward K+ and Ca2+ channels through a mechanism which may be independent of effects on the above mentioned enzymes. Certainly, the number of G proteins which have been identified from sequencing of complementary DNA affords the potential for G protein involvement in many cellular events. Only three G proteins have however been isolated and functionally characterized, Gs, Gi and transducin. Whether all the functions of these proteins have been identified remains to be seen.
mesh_terms: D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000502:physiology; D016283:Proto-Oncogene Proteins p21(ras); D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D007473:Ion Channels; D011518:Proto-Oncogene Proteins; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras)