| First Author | Levine MA | Year | 1990 |
| Journal | Proc Natl Acad Sci U S A | Volume | 87 |
| Issue | 6 | Pages | 2329-33 |
| PubMed ID | 2107550 | Mgi Jnum | J:31002 |
| Mgi Id | MGI:78311 | Doi | 10.1073/pnas.87.6.2329 |
| Citation | Levine MA, et al. (1990) Molecular cloning of beta 3 subunit, a third form of the G protein beta-subunit polypeptide. Proc Natl Acad Sci U S A 87(6):2329-33 |
| abstractText | The signal-transducing guanine nucleotide-binding regulatory (G) proteins are heterotrimers composed of three subunits--alpha, beta, and gamma. Although multiple distinctive forms of the alpha subunit have been described, only two forms of the beta subunits of the G proteins have been identified. To investigate further the structural diversity of the beta subunits, we screened bovine and human retina cDNA libraries and isolated clones encoding three distinct types of G protein beta subunit. One form was identical to previously isolated beta 1-subunit cDNA clones that encode the 36-kDa form of the beta subunit, whereas a second form was identical to previously described beta 2 cDNAs that encode the 35-kDa beta isoform. In addition, we identified another species, designated beta 3 subunit, which encodes a third distinct form of the beta subunit. The beta 3-subunit cDNA corresponds to a 2.0-kilobase mRNA expressed in all tissues and clonal cell lines examined. Nucleotide sequence analysis indicates that the encoded peptide consists of 340-amino acid residues with a Mr of 37,221. The amino acid sequences of the three beta subunits are closely related: 83% identity between beta 1 and beta 3 subunits and 81% identity between beta 2 and beta 3 subunits. By contrast, the 3'-untranslated regions of the three cDNAs show no significant homology. Our data support the hypothesis that a family of beta-subunit polypeptides exists and extend understanding of beta-subunit structure. |
