title: Dissociation of heterotrimeric g proteins in cells.
abstract: Heterotrimeric G proteins dissociate into their component Galpha and Gbetagamma subunits when these proteins are activated in solution. Until recently, it has not been known if subunit dissociation also occurs in cells. The development of optical methods to study G protein activation in live cells has made it possible to demonstrate heterotrimer dissociation at the plasma membrane. However, subunit dissociation is far from complete, and many active [guanosine triphosphate (GTP)-bound] heterotrimers are intact in a steady state. This unexpectedly reluctant dissociation calls for inclusion of a GTP-bound heterotrimeric state in models of the G protein cycle and places renewed emphasis on the relation between subunit dissociation and effector activation.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912-2300, USA. nlambert@mcg.edu
authors.forename: Nevin A
authors.initials: NA
authors.lastname: Lambert
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D002468:Cell Physiological Phenomena; D031541:Fluorescence Resonance Energy Transfer; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000145:classification / Q000378:metabolism*; D006801:Humans; D021122:Protein Subunits / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D000263:Adenylate Kinase; D010738:Type C Phospholipases; D020962:Heterotrimeric GTP-Binding Proteins