In:
Journal of Cell Science, The Company of Biologists, Vol. 110, No. 13 ( 1997-07-01), p. 1503-1511
Abstract:
Recent studies have suggested an association between heterotrimeric G proteins, which play a major role in transmembrane signal transduction, and intracellular components. We therefore examined the subcellular localization of isoforms of G protein γ subunits in Swiss 3T3 and C6 glioma cells, mainly containing the γ5 and γ12 subunits. Immunocytochemical double staining with phalloidin showed co-localization of the γ12 subunit with actin filaments (F-actin), while the γ5 co-localized with vinculin, suggesting an association with focal adhesion. Pretreatment of cells with Triton X-100 eliminated the γ5 but not the γ12 staining. Co-localization of γ12 and F-actin was preserved when F-actin was disorganized with cytochalasin D or reorganized using fetal calf serum. Large amounts of γ12 were recovered in the vimentinand tubulin-free F-actin-rich fraction prepared from crude cytoskeleton preparations by double depolymerization-repolymerization. Co-localization of Gi2α, β and γ12 in the F-actin-rich fraction suggested the existence of γ12 as a βγ or heterotrimeric complex. Furthermore, purified βγ12 was found to associate with F-actin in vitro more tightly than βγ5. These results strongly suggest that the γ12 subunit associates with F-actin in cells. The observed differential distribution of γ12 and γ5 implies functional differences for the two γ subunits.
Type of Medium:
Online Resource
ISSN:
0021-9533
,
1477-9137
DOI:
10.1242/jcs.110.13.1503
Language:
English
Publisher:
The Company of Biologists
Publication Date:
1997
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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