Multiple heterotrimeric guanine nucleotide binding protein (G protein) subunits have evolved to couple a large variety of receptors to intracellular effectors. G protein βγ subunits are essential for efficient coupling of α subunits to receptors, and they are also important for modulation of effectors. Several different β and γ subunits exist, but it is not known whether all possible combinations of β and γ can form functional dimers. To answer this question, we have compared the ability of in vitro translated β1, β2, and β3 to form dimers with either γ1 or γ2. Dimerization was monitored by gel filtration, resistance to tryptic digestion, and chemical cross-linking. The results indicate that β1 binds both γ subunits, β2 binds only γ2, and β3 will bind neither γ1 or γ2. Hence, the occurrence of βγ dimers may be partially regulated by the ability of the subunits to associate. Specificity of dimerization might allow cells to co-express multiple β and γ subunits while maintaining efficient and specific signal transduction.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - 1992|
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