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Sci. Signal., 24 June 2008
Vol. 1, Issue 25, p. re5
[DOI: 10.1126/scisignal.125re5]


Dissociation of Heterotrimeric G Proteins in Cells

Nevin A. Lambert*

Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912–2300, USA.

Gloss: Heterotrimeric G proteins are among the most important and widely studied classes of signaling proteins. The long-standing model of G protein function includes physical dissociation of G{alpha} subunits and Gβ{gamma} dimers as an essential prerequisite for signaling, even though physical dissociation had, until recently, only been observed by using isolated proteins in solution. Some recent studies have concluded that G protein dissociation does not occur in intact cells, whereas others have reported that dissociation does occur. This mini-review reconciles these points of view by emphasizing a model that includes an equilibrium between active heterotrimers and dissociated subunits. This model is consistent with all of the available experimental evidence. Attention then turns to a related question: Is heterotrimer dissociation necessary for signaling? The answer to this question is less clear and may be different for different signaling pathways.

*Corresponding author. E-mail: nlambert{at}

Citation: N. A. Lambert, Dissociation of Heterotrimeric G Proteins in Cells. Sci. Signal. 1, re5 (2008).

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