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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.

Abstract: Heterotrimeric G proteins dissociate into their component G{alpha} and Gβ{gamma} 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.

*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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