Bovine brain GO isoforms have distinct gamma subunit compositions.
J Biol Chem
; 270(9): 4189-92, 1995 Mar 03.
Article
em En
| MEDLINE
| ID: mdl-7876173
ABSTRACT
The gamma subunit composition of the major bovine brain Go and Gi proteins (GOA, GOB, GOC, Gi1, and Gi2) was characterized using antibodies against specific gamma isoforms. Each of the purified G protein heterotrimers contained a heterogeneous population of gamma subunits, and the profiles of the gamma subunits found with Gi1, Gi2, and GOA were similar. In contrast, each GO isoform had a distinct pattern of associated gamma subunits. These differences were surprising given that all three alpha O isoforms are thought to share a common amino-terminal sequence important for the binding of beta gamma dimers and that the alpha OA and alpha OC proteins may come from the same alpha O1 mRNA. The free alpha OA and alpha OC subunits had unique elution behaviors during MonoQ chromatography, compatible with differences in their post-translational processing. These results indicate that both the alpha and gamma subunit compositions of heterotrimers define the structure of an intact G protein. Furthermore, the exact subunit composition of G protein heterotrimers may depend upon regulated expression of different subunit isoforms or upon cellular processing of alpha subunits.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Química Encefálica
/
Proteínas de Ligação ao GTP
Limite:
Animals
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article