Membrane trafficking of heterotrimeric G proteins via the endoplasmic reticulum and Golgi.
Mol Biol Cell
; 13(9): 3294-302, 2002 Sep.
Article
em En
| MEDLINE
| ID: mdl-12221133
ABSTRACT
Membrane targeting of G-protein alphabetagamma heterotrimers was investigated in live cells by use of Galpha and Ggamma subunits tagged with spectral mutants of green fluorescent protein. Unlike Ras proteins, Gbetagamma contains a single targeting signal, the CAAX motif, which directed the dimer to the endoplasmic reticulum. Endomembrane localization of farnesylated Ggamma(1), but not geranylgeranylated Ggamma(2), required carboxyl methylation. Targeting of the heterotrimer to the plasma membrane (PM) required coexpression of all three subunits, combining the CAAX motif of Ggamma with the fatty acyl modifications of Galpha. Galpha associated with Gbetagamma on the Golgi and palmitoylation of Galpha was required for translocation of the heterotrimer to the PM. Thus, two separate signals, analogous to the dual-signal targeting mechanism of Ras proteins, cooperate to target heterotrimeric G proteins to the PM via the endomembrane.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Ligação ao GTP
/
Retículo Endoplasmático
/
Complexo de Golgi
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Mol Biol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos