Interaction of radixin with Rho small G protein GDP/GTP exchange protein Dbl.
The Rho small G protein family, consisting of the Rho, Rac, and Cdc42 subfamilies, regulates various actin cytoskeleton-dependent cell functions. The Rho subfamily members regulate ERM (ezrin, radixin and moesin)-dependent association of the actin cytoskeleton with the plasma membrane. Moreover, the N-terminal regions of ERM interact with Rho GDI, an inhibitory regulator of all the Rho family members, and reduce its inhibitory action, finally initiating the activation of the Rho family members. We show here that the N-terminal region of radixin furthermore interacts with Dbl, a stimulatory GDP/GTP exchange protein of the Rho family members. This interaction does not affect the Dbl activity to stimulate the GDP/GTP exchange reaction of RhoA, a member of the Rho subfamily. Dbl does not interact with radixin which is precomplexed with Rho GDI, and Rho GDI displaces Dbl from radixin. Thus, radixin plays an important role in activation of the Rho family members by recruiting their positive and negative regulators.
Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita, Japan.
K
K
Takahashi
T
T
Sasaki
A
A
Mammoto
I
I
Hotta
K
K
Takaishi
H
H
Imamura
K
K
Nakano
A
A
Kodama
Y
Y
Takai
D001665:Binding Sites; D001798:Blood Proteins / Q000737:chemistry* / Q000378:metabolism; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D005982:Glutathione Transferase / Q000737:chemistry / Q000378:metabolism; D020730:Guanine Nucleotide Dissociation Inhibitors; D006153:Guanosine Diphosphate / Q000737:chemistry / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D015682:Retroviridae Proteins, Oncogenic / Q000737:chemistry* / Q000378:metabolism; D012234:Rho Factor / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D008565:Membrane Proteins; D010446:Peptide Fragments; D015682:Retroviridae Proteins, Oncogenic; D012234:Rho Factor; D014157:Transcription Factors; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; C071776:radixin; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D005982:Glutathione Transferase; D019204:GTP-Binding Proteins