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 γ subunits of G proteins. Recently two cDNA clones encoding β subunits, β1 and β2, were isolated from bovine and human cDNA libraries. We report here that the β2 gene encodes the 35-kilodalton (kDa) component of the β35/β36 subunit of G proteins and that the β1 gene encodes the 36-kilodalton component. The in vitro translation product of the β2 cDNA co-migrates with the 35-kDa β subunit (β35), while the in vitro product of the β1 cDNA co-migrates with the 36-kDa β subunit (β36) on denaturing polyacrylamide gels. In addition, antisera generated against synthetic β2 peptides bind specifically to the β35 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.
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - Jan 1 1988|