Reference : RhoA-GDP regulates RhoB protein stability. Potential involvement of RhoGDIalpha.
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/13662
RhoA-GDP regulates RhoB protein stability. Potential involvement of RhoGDIalpha.
English
Ho, Thi Thanh Giang mailto [Université de Liège - ULG > Département des sciences médicales et précliniques > Laboratoire de Biologie des Tissus Conjonctifs > >]
Merajver, Sofia D [> > > >]
Lapière, Charles [> >]
Nusgens, Betty mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > LBTC > >]
Deroanne, Christophe mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > LBTC > >]
2008
Journal of Biological Chemistry
American Society for Biochemistry and Molecular Biology
283
31
21588-98
Yes (verified by ORBi)
International
0021-9258
1083-351X
Baltimore
MD
[en] Animals ; Gene Silencing ; Genetic Vectors ; Guanine Nucleotide Dissociation Inhibitors/metabolism ; Guanosine Diphosphate/chemistry ; Humans ; Models, Biological ; Protein Transport ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Transfection ; Up-Regulation ; rho GTP-Binding Proteins/metabolism ; rhoA GTP-Binding Protein/metabolism/physiology ; rhoB GTP-Binding Protein/metabolism
[en] RhoA plays a significant role in actin stress fibers formation. However, silencing RhoA alone or RhoA and RhoC did not completely suppress the stress fibers suggesting a residual "Rho-like" activity. RhoB, the third member of the Rho subclass, is a shortlived protein barely detectable in basal conditions. In various cell types, the silencing of RhoA induced a strong up-regulation of both total and active RhoB protein levels that were rescued by re-expressing RhoA and related to an enhanced half-life of the protein. The RhoA-dependent regulation of RhoB does not depend on the activity of RhoA but is mediated by its GDP-bound form. The stabilization of RhoB was not dependent on isoprenoid biosynthesis, Rho kinase, extracellular signal-regulated kinase, p38 mitogen-activated kinase, or phosphatidylinositol 3'-OH kinase pathways but required RhoGDIalpha. The forced expression of RhoGDIalpha increased RhoB half-life, whereas its knock-down antagonized the induction of RhoB following RhoA silencing. Moreover, a RhoA mutant (RhoAR68E) unable to bind RhoGDIalpha was significantly less efficient as compared with wild-type RhoA in reversing RhoB up-regulation upon RhoA silencing. These results suggest that, in basal conditions, RhoGDIalpha is rate-limiting and the suppression of RhoA makes it available to stabilize RhoB. Our results highlight RhoGDIalpha-dependent cross-talks that regulate the stability of RhoGTPases.
Researchers
http://hdl.handle.net/2268/13662
10.1074/jbc.M710033200

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