Homologous Superfamily

Rho GDP-dissociation inhibitor domain superfamily (IPR024792)

Short name: RhoGDI_dom_sf

Overlapping entries


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 value of 23,421. Hydropathy analysis shows it to be largely hydrophilic, with a single hydrophobic region. Results of database searches suggest rho GDI is a 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 cytosolic components: p47-phox, p67-phox and a heterodimer of the small G-protein p21rac1 and rho GDI [PMID: 8223583]. The association of p21rac and GDI inhibits dissociation of GDP from p21rac, thereby maintaining it in an inactive form. The proteins are attached via a lipid tail on p21rac that binds to the hydrophobic region of GDI [PMID: 8796870]. Dissociation of these proteins might be mediated by the release of lipids (e.g., arachidonate and phosphatidate) from membranes through the action of phospholipases [PMID: 8796870]. The lipids may then compete 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 [PMID: 9195882]. The N-terminal region becomes ordered upon complex formation and contributes more than 60% to the interface area [PMID: 10655614].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.