G protein betagamma subunits induce stress fiber formation and focal adhesion assembly in a Rho-dependent manner in HeLa cells.
In fibroblasts, the G protein alpha subunits Galpha(12) and Galpha(13) stimulate Rho-dependent stress fiber formation and focal adhesion assembly, whereas G protein betagamma subunits instead exert a disruptive influence. We show here that the latter can, however, stimulate the formation of stress fibers and focal adhesions in epithelial-like HeLa cells. Transient expression of beta(1) with gamma(2), gamma(5), gamma(7), and gamma(12) in quiescent HeLa cells induced stress fiber formation and focal adhesion assembly as did expression of the constitutively active Galpha(12). Co-expression of betagamma with Galpha(i2) and the C-terminal fragment of the beta-adrenergic receptor kinase, both of which are known to bind and sequester free betagamma, blocked betagamma-induced stress fiber and focal adhesion formation. Inhibition was also noted with co-expression of a dominant negative mutant of Rho. Botulinum C3 exoenzyme, which ADP-ribosylates and inactivates Rho, and a Rho-associated protein kinase inhibitor, Y-27632, similarly inhibited betagamma-induced stress fiber and focal adhesion assembly. These results indicate that G protein betagamma subunits regulate Rho-dependent actin polymerization in HeLa cells.
Ueda
H
H
Department of Biochemistry, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan.
Itoh
H
H
Yamauchi
J
J
Morishita
R
R
Kaziro
Y
Y
Kato
K
K
Asano
T
T
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005799:Genes, Dominant; D006367:HeLa Cells; D020962:Heterotrimeric GTP-Binding Proteins; D006801:Humans; D051379:Mice; D011493:Protein Kinase C / Q000378:metabolism; D014162:Transfection; D016596:Vinculin / Q000378:metabolism
D000199:Actins; D004791:Enzyme Inhibitors; C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D016596:Vinculin; D011493:Protein Kinase C; D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C031715:rho-ATPase; D020962:Heterotrimeric GTP-Binding Proteins