G12 requirement for thrombin-stimulated gene expression and DNA synthesis in 1321N1 astrocytoma cells.
J Biol Chem
; 270(34): 20073-7, 1995 Aug 25.
Article
en En
| MEDLINE
| ID: mdl-7650024
Thrombin stimulation of 1321N1 astrocytoma cells leads to Ras-dependent AP-1-mediated transcriptional activation and to DNA replication. In contrast to what has been observed in most cell systems, in 1321N1 cells these responses are pertussis toxin-insensitive. The pertussis toxin-insensitive G-protein G12 has been implicated in cell growth and transformation in different cell systems. We have examined the potential role of this protein in AP-1-mediated transcriptional activation and DNA synthesis in 1321N1 cells. Transient expression of an activated (GTPase-deficient) mutant of G alpha 12 increased AP-1-dependent gene expression. This response was inhibited by co-expression of a dominant negative Ala-15 Ras protein. To determine whether the pertussis toxin-insensitive G12 protein is involved in the thrombin-stimulated DNA synthesis, an inhibitory antibody against the C-terminal sequence of G alpha 12 subunit was microinjected into 1321N1 cells. Microinjection of the anti-G alpha 12 resulted in a concentration-dependent inhibition of thrombin-stimulated DNA synthesis. In contrast, microinjection of nonimmune IgG or an antibody directed against the C terminus of G alpha o did not reduce the mitogenic response to thrombin. Furthermore, microinjection of the anti-G alpha 12 antibody had no effect on fibroblast growth factor-stimulated DNA synthesis. These results demonstrate a specific role for G alpha 12 in the mitogenic response to thrombin in human astroglial cells.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ADN
/
Trombina
/
Proteínas de Unión al GTP
Límite:
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
1995
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos