Direct interaction of the Rho GDP dissociation inhibitor with ezrin/radixin/moesin initiates the activation of the Rho small G protein.
The Rho GDP dissociation inhibitor (GDI) forms a complex with the GDP-bound form of the Rho family small G proteins and inhibits their activation. The GDP-bound form complexed with Rho GDI is not activated by the GDP/GTP exchange factor for the Rho family members, suggesting the presence of another factor necessary for this activation. We have reported that the Rho subfamily members regulate the ezrin/radixin/moesin (ERM)-CD44 system, implicated in reorganization of actin filaments. Here we report that Rho GDI directly interacts with ERM, initiating the activation of the Rho subfamily members by reducing the Rho GDI activity. These results suggest that ERM as well as Rho GDI and the Rho GDP/GTP exchange factor are involved in the activation of the Rho subfamily members, which then regulate reorganization of actin filaments through the ERM system.
Takahashi
K
K
Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565, Japan.
Sasaki
T
T
Mammoto
A
A
Takaishi
K
K
Kameyama
T
T
Tsukita
S
S
Takai
Y
Y
D000199:Actins / Q000378:metabolism; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors; D018960:Hyaluronan Receptors / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins; D010446:Peptide Fragments / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D020692:rab3 GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D000099149:Ezrin
D000199:Actins; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D019204:GTP-Binding Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D018960:Hyaluronan Receptors; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D020692:rab3 GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D000099149:Ezrin; C071058:moesin; C071776:radixin