| Type: | Domain | Name: | Rho GDP-dissociation inhibitor domain |
| Description: | The GDP dissociation inhibitor for rho proteins, rho GDI, regulates GDP/GTP exchange by inhibiting the dissociation of GDP from them. The protein contains 204 amino acids, with a calculated Mr valueof 23,421. Hydropathy analysis shows it to be largely hydrophilic, with a single hydrophobic region. Results of database searches suggest rho GDI isa novel protein, currently with no known homologue. The protein plays an important role in the activation of the superoxide(O2-)-generating NADPH oxidase of phagocytes. This process requires the interaction of membrane-associated cytochrome b559 with 3 cytosoliccomponents: p47-phox, p67-phox and a heterodimer of the small G-protein p21rac1 and rho GDI []. The association of p21rac and GDI inhibitsdissociation of GDP from p21rac, thereby maintaining it in an inactive form. The proteins are attached via a lipid tail on p21rac that binds to thehydrophobic region of GDI []. Dissociation of these proteins might bemediated by the release of lipids (e.g., arachidonate and phosphatidate) from membranes through the action of phospholipases []. The lipids may thencompete with the lipid tail on p21rac for the hydrophobic pocket on GDI. The rhoGDI structural domain contains both a structured, immunoglobulin-like fold, and a highly flexible N terminus of 50-60 residues []. The N-terminal region becomes ordered upon complex formation and contributes more than 60% to the interface area []. | Short Name: | RhoGDI_domain |
