A C-terminal mutant of the G protein beta subunit deficient in the activation of phospholipase C-beta.
J Biol Chem
; 271(33): 20208-12, 1996 Aug 16.
Article
en En
| MEDLINE
| ID: mdl-8702747
The molecular mechanism by which the G protein betagamma complex modulates multiple mammalian effector pathways is unknown. Homolog-scanning mutagenesis of the G protein beta subunit was employed to identify residues critical for the activation of phospholipase C-beta2 (PLC-beta2). A series of chimeras was made by introducing small segments of the Dictyostelium beta subunit into a background of mammalian beta1 and tested in COS cell cotransfection assays for their ability to activate PLC-beta2 and assemble with mammalian gamma2. A chimera that contained four Dictyostelium beta substitutions within the C-terminal 14 residues was unable to activate PLC-beta2 when cotransfected with gamma, despite its demonstrable expression in a gamma-dependent manner. Cotransfection of the mutant blocked m2 muscarinic receptor activation of PLC by a pertussis toxin-sensitive pathway. This C-terminal mutant retained the ability, however, to stimulate the mitogen-activated protein kinase pathway. These results imply that activation of different betagamma-responsive effectors is mediated by distinct domains.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosfolipasas de Tipo C
/
Proteínas de Unión al GTP
/
Isoenzimas
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
1996
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos