Close association of the alpha subunits of Gq and G11 G proteins with actin filaments in WRK1 cells: relation to G protein-mediated phospholipase C activation.
AUTOR(ES)
Ibarrondo, J
RESUMO
A selective polyclonal antibody directed toward the C-terminal decapeptide common to the alpha subunits of Gq and G11 G proteins (G alpha q/G alpha 11) was prepared and used to investigate the subcellular distribution fo these proteins in WRK1 cells, a rat mammary tumor cell line. In immunoblots, the antibody recognized purified G alpha q and G alpha 11 proteins and labeled only two bands corresponding to these alpha subunits. Functional studies indicated that this antibody inhibited vasopressin- and guanosine 5'-[alpha-thio]triphosphate-sensitive phospholipase C activities. Immunofluorescence experiments done with this antibody revealed a filamentous labeling corresponding to intracytoplasmic and perimembranous actin-like filament structures. Colocalization of G alpha q/G alpha 11 and F-actin filaments (F-actin) was demonstrated by double-labeling experiments with anti-G alpha q/G alpha 11 and anti-actin antibodies. Immunoblot analysis of membrane, cytoskeletal, and F-actin-rich fractions confirmed the close association of G alpha q/G alpha 11 with actin. Large amounts of G alpha q/G alpha 11 were recovered in the desmin- and tubulin-free F-actin-rich fraction obtained by a double depolymerization-repolymerization cycle. Disorganization of F-actin filaments with cytochalasin D preserved G alpha q/G alpha 11 and F-actin colocalization but partially inhibited vasopressin- and fluoroaluminate-sensitive phospholipase C activity, suggesting that actin-associated G alpha q/G alpha 11 proteins play a role in signal transduction.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=41167Documentos Relacionados
- Purification and characterization of recombinant G16 alpha from Sf9 cells: activation of purified phospholipase C isozymes by G-protein alpha subunits.
- RGS3 Inhibits G Protein-Mediated Signaling via Translocation to the Membrane and Binding to Gα11
- Tobacco mosaic virus movement protein-mediated protein transport between trichome cells.
- Protein-mediated surface structuring in biomembranes
- Rhizobium nod factor signaling. Evidence for a g protein-mediated transduction mechanism