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Published May 26, 1989 | public
Journal Article

A G protein gamma subunit shares homology with ras proteins


Guanine nucleotide binding proteins (G proteins) that transduce signals from cell surface receptors to effector molecules are made up of three subunits, alpha, beta, and gamma. A complementary DNA clone that encodes a 71-amino acid protein was isolated from bovine brain; this protein contains peptide sequences that were derived from the purified gamma subunit of Gi and Go. The primary sequence of this G protein gamma subunit (G gamma) has 55 percent homology to the gamma subunit of transducin (T gamma) and also has homology to functional domains of mammalian ras proteins. The probe for isolating the clone was generated with the use of the polymerase chain reaction (PCR). The extent of divergence between T gamma and G gamma, the isolation of homologous PCR-generated fragments, and the differences between the predicted amino acid sequence of G gamma and that derived from the gamma subunit of Gi and Go indicate that gamma subunits are encoded by a family of genes.

Additional Information

© 1989 American Association for the Advancement of Science. 27 January 1989; Accepted 29 March 1989. We thank J. K. Northup for the G_i and G_o proteins, R. Miake-Lye for the cDNA library and RNAs, B. W. Birren for the genomic DNA, M. Strathmann for discussions, and T. Amatruda and T. Wilkie for comments on the manuscript.

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October 19, 2023