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Published April 15, 1988 | public
Journal Article

The 35- and 36-kDa β Subunits of GTP-binding Regulatory Proteins Are Products of Separate Genes


The wide range of functions attributed to GTP-binding regulatory proteins (G proteins) is reflected in the structural diversity which exists among the α, β, and y subunits of G proteins. Recently two cDNA clones encoding β subunits, β_1 and β_2, were isolated from bovine and human cDNA libraries. We report here that the β_2 gene encodes the 35-kilodalton (kDa) component of the β_(35)/β_(36) subunit of G proteins and that the β_1 gene encodes the 36-kilodalton component. The in vitro translation product of the β_2 cDNA co-migrates with the 35-kDa β subunit (β_(35)), while the in vitro product of the β_1 cDNA co-migrates with the 36-kDa β subunit (β_(36)) on denaturing polyacrylamide gels. In addition, antisera generated against synthetic β_2 peptides bind specifically to the β_(35) component of isolated G proteins and to a 35-kDa protein in myeloid cell membranes. Our results suggest that the two β subunits could serve distinct functions, as they are derived from separate genes which have been highly conserved in evolution.

Additional Information

© 1988 American Society for Biochemistry and Molecular Biology. Received for publication, December 3, 1987. This work was supported by a Clinical Investigator Award from The National Cancer Institute, National Institutes of Health (to T. T. A.) and by Grant GM34236 from the National Institutes of Health. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. We thank Drs. Bruce Birren, Ryn Miake-Lye, and Stephanie Ruby for helpful discussions and review of the manuscript; and Connie Katz and Cathy Elkins for assistance in manuscript preparation. Note Added in Proof--After this manuscript was submitted for review, a paper containing similar data and conclusions was published by Gao, B., Mumby, S., and Gilman, A. G. ((1987) J. Biol. Chem. 262, 17524-17527).

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